title: Adult Female Hip Bone Density Reflects Teenage Sports–Exercise Patterns But Not Teenage Calcium Intake Prevention of bone demineralization by calcium supplementation in precocious puberty during gonadotropin-releasing hormone agonist treatment. Soft Drink and Milk Consumption, Physical Activity, Bone Mass, and Upper Limb Fractures in Children: A Population-Based Case-Control Study The clinical and radiological assessment of cyclic intravenous pamidronate administration in children with osteogenesis imperfecta. Effect of habitual dietary calcium intake on calcium supplementation in 12-14-y-old girls. Effect of a calcium and exercise intervention on the bone mineral status of 16-18-y-old adolescent girls. Effect of calcium supplementation on bone mineral accretion in gambian children accustomed to a low-calcium diet. Double-blind, controlled calcium supplementation and bone mineral accretion in children accustomed to a low-calcium diet. The ratio of animal protein intake to potassium intake is a predictor of bone resorption in space flight analogues and in ambulatory subjects. Calcium supplementation provides an extended window of opportunity for bone mass accretion after menarche. Bone mineral contents and plasma osteocalcin concentrations of Gambian children 12 and 24 mo after the withdrawal of a calcium supplement. Calcium supplementation and bone mineral density in females from childhood to young adulthood: a randomized controlled trial. Nutrition influences skeletal development from childhood to adulthood: a study of hip, spine, and forearm in adolescent females. Calcium retention in relation to calcium intake and postmenarcheal age in adolescent females. Gain in bone mineral mass in prepubertal girls 3–5 years after discontinuation of calcium supplementation: a follow-up study [Effects of calcium supplementation on bone mineral accretion in adolescents]. Bone mineralization in children and adolescents with a milk allergy. Eating attitudes and habitual calcium intake in peripubertal girls are associated with initial bone mineral content and its change over 2 years. The effect of calcium supplementation on bone density during lactation and after weaning. Effect of parenteral calcium and phosphorus therapy on mineral retention and bone mineral content in very low birth weight infants. Treatment with intermittent calcitriol and calcium reduces bone loss after renal transplantation. [Optimization of calcium intake for the prevention of osteoporosis and osteoporotic fractures: a review of the evidence]. A school-based exercise intervention elicits substantial bone health benefits: a 2-year randomized controlled trial in girls. [Calcium supplementation and bone absorptiometry in girls]. Social support, knowledge, and self-efficacy as correlates of osteoporosis preventive behaviors among preadolescent females. Milk, dietary calcium, and bone fractures in women: a 12-year prospective study. High-Impact Exercise and Bones of Growing Girls: A 9-Month Controlled Trial
   The effects of a high calcium dairy food on bone health in pre-pubertal children in New Zealand. Jumping improves hip and lumbar spine bone mass in prepubescent children: a randomized controlled trial. Calcium-enriched foods and bone mass growth in prepubertal girls: a randomized, double-blind, placebo-controlled trial. Reduced rates of skeletal remodeling are associated with increased bone mineral density during the development of peak skeletal mass. Girls on a high-calcium diet gain weight at the same rate as girls on a normal diet: a pilot study. Test of an Educational Intervention for Osteoporosis Prevention With U.S. Adolescents No important influence of limited steroid exposure on bone mass during the first year after renal transplantation: a prospective, randomized, multicenter study. Bone Size and Bone Mass in 10-Year-Old Danish Children: Effect of Current Diet
   [Effects of calcium supplementation using AAACa or milk on nocturnal bone resorption in young women]. Supplementation with oral vitamin D3 and calcium during winter prevents seasonal bone loss: a randomized controlled open-label prospective trial. Benefits of milk powder supplementation on bone accretion in Chinese children Longitudinal study of calcium intake, physical activity, and bone mineral content in infants 6-18 months of age. A Population-Based Study of Fracture Incidence in Southern Tasmania: Lifetime Fracture Risk and Evidence for Geographic Variations within the Same Country
   Cumulative effects of calcium supplementation and physical activity on bone accretion in premenarchal children: a double-blind randomised placebo-controlled trial. A co-twin study of the effect of calcium supplementation on bone density during adolescence One year of oral calcium supplementation maintains cortical bone density in young adult female distance runners. Treatment of osteopenia and osteoporosis in renal transplant children and adolescents. The effect of calcium supplementation and tanner stage on bone density, content and area in teenage women A randomized double-blind controlled calcium supplementation trial, and bone and height acquisition in children. Bone mineral acquisition in low calcium intake children following the withdrawal of calcium supplement Skeletal effects and functional outcome with olpadronate in children with osteogenesis imperfecta: a 2-year randomised placebo-controlled study Modifiable determinants of bone status in young women. A Comparison of Oral and Intravenous Bisphosphonate Therapy for Children with Osteogenesis Imperfecta Randomized trial of varying mineral intake on total body bone mineral accretion during the first year of life. School-milk intervention trial enhances growth and bone mineral accretion in Chinese girls aged 10-12 years in Beijing. Regional specificity of exercise and calcium during skeletal growth in girls: a randomized controlled trial. CAUSAL ANALYSIS OF EXERCISE AND CALCIUM INTAKE BEHAVIORS FOR OSTEOPOROSIS PREVENTION AMONG YOUNG WOMEN IN THAILAND Calcium supplementation and bone mineral density in adolescent girls. Skeletal site selectivity in the effects of calcium supplementation on areal bone mineral density gain: a randomized, double-blind, placebo-controlled trial in prepubertal boys. Milk consumption and bone mineral content in Chinese adolescent girls. YOUTH: decisions and challenges in designing an osteoporosis prevention intervention for teen girls. Increasing fluid milk favorably affects bone mineral density responses to resistance training in adolescent boys. The effect of calcium supplementation on bone density in premenarcheal females: a co-twin approach. Randomized trial of physical activity and calcium supplementation on bone mineral content in 3- to 5-year-old children. Bone mass and density response to a 12-month trial of calcium and vitamin D supplement in preadolescent girls. Calcium supplementation increases stature and bone mineral mass of 16- to 18-year-old boys. The effects of dairy products on body composition, bone mineralization, and weight in adolescent girls. Bone mass at final height in precocious puberty after gonadotropin-releasing hormone agonist with and without calcium supplementation. Milk intake and bone mineral acquisition in adolescent girls: randomised, controlled intervention trial Effects of dairy products on bone and body composition in pubertal girls. Effects of dairy food supplements on bone mineral density in teenage girls Interaction between calcium intake and menarcheal age on bone mass gain: an eight-year follow-up study from prepuberty to postmenarche. Dietary calcium intake by a group of 13 18-year-old Costa Rican teenagers. Calcium supplementation and increases in bone mineral density in children. American Association of Clinical Endocrinologists medical guidelines for clinical practice for the prevention and treatment of postmenopausal osteoporosis: 2001 edition, with selected updates for 2003. The Effects of an Educational Intervention on Calcium Intake and Bone Mineral Content in Young Women with Low Calcium Intake
abstract: Objective . To examine how cumulative teenage sports histories and time-averaged  teenage calcium intake are related to total body bone mineral gain  between ages 12 and 18 years and to proximal femur bone mineral density ( BMD ) at age 18 years . Design . Longitudinal . Setting . University Hospital and local suburban community in Central Pennsylvania . Study Participants . Eighty-one white females in the ongoing Penn State Young Women 's Health Study . Outcome Measures . Total body and proximal femur ( hip ) bone measurements by dual energy radiograph absorptiometry ; nutrient intakes  , including  calcium  , from 33 days of prospect i ve food records collected at regular intervals between ages 12 and 18 years ; and self-reported sports – exercise scores  between ages 12 and 18 years . Results . Cumulative sports – exercise scores between ages 12 and 18 years were associated with hip BMD at age 18 years ( r = .42 ) but were not related to total body bone mineral gain . Time-averaged daily  calcium  intake , which ranged from 500 to 1500 mg/day in this cohort was not associated with hip BMD at age 18 years , or with total body bone mineral gain at age 12 through 18 years . Conclusions . The amount of physical activity that distinguishes a primarily sedentary teenager from one who engages in some form of exercise on a nearly daily basis is related to a significant increase in peak hip BMD We have previously demonstrated a negative impact on peak bone mass in girls with precocious puberty treated with GnRH agonist ( GnRHa ) .  Several studies have shown that a high calcium intake positively influences bone mass in prepubertal girls and leads to a higher peak bone mass . The aim of this study was to evaluate the effect of calcium supplementation in girls with precocious puberty during GnRHa treatment .  Forty girls affected by true central precocious puberty and treated with the GnRHa triptorelin were studied for 2 yr . After diagnosis , the patients were r and omly assigned to three groups : group A , treated only with GnRHa ; group B , treated for 12 months solely with GnRHa and then supplemented with calcium gluconolactate/carbonate ( 1 g calcium/day in two doses ) for 12 months ; and group C , treated from the beginning with combined GnRHa and calcium .  Bone mineral density ( BMD ) at the lumbar spine was measured by dual energy x-ray absorptiometry at the beginning of the study and after 12 and 24 months and was expressed as the calculated true volumetric density ( BMDv ) in milligrams per cm3 . Group A showed a decrease in absolute BMDv levels , in SD score for chronological age ( CA ) , and even more in SD score for bone age ( BA ) . Group B showed the same behavior during the first year , but this trend was reversed in the second year , when calcium supplementation was added to GnRHa treatment . Group C showed an increase in absolute BMDv levels and in SD score for CA and BA . BMDv variations ( expressed as absolute values , SD score for CA , and SD score for BA ) became statistically significant at 24 months between groups C and A ( P = 0.036 , P = 0.032 , and P = 0.025 , respectively ) . The behavior of the lumbar spine BMDv in the three groups is consistent with a positive effect of calcium supplementation during GnRHa treatment . In calcium-supplemented patients , the normal process of bone mass accretion at puberty is preserved despite GnRHa treatment . Therefore , the reduction in BMD during GnRHa treatment in girls with precocious puberty is at least completely reversible and preventable if calcium supplementation is associated from the beginning Carbonated beverages have been reported to increase fracture risk in children but the mechanism is unclear . The aim of this population -based case-control study was to investigate the association between soft drink and milk consumption , physical activity , bone mass , and upper limb fractures in children aged 9–16 years . A total of 206 fracture cases and 206 r and omly selected individually matched controls were studied . There were 47 h and fractures ; 128 wrist and forearm fractures , and 31 upper arm fractures . An interviewer-administered question naire was utilized to retrospectively assess last-year physical activity ( including television , computer , and video watching ) and to recall the average weekly consumption of milk , colas , and total carbonated drinks .  Bone mass at the spine , hip , and total body was assessed by dual-energy X-ray absorptiometry ( DXA ) and metacarpal morphometry . For total fractures , none of the above drink types was significantly different between cases and controls . For wrist and forearm fractures , there was a positive association between cola drink consumption and fracture risk ( OR 1.39/unit , 95 % CI : 1.01 , 1.91 ) . Cola consumption was significantly correlated with television , computer , and video watching ( r = 0.20 , P = 0.001 ) but not bone mineral density or milk drinks . After adjustment for television , computer , and video watching and bone mineral density , the association between cola drinks and fracture risk became nonsignificant ( OR 1.31/unit , 95 % CI : 0.94 , 1.83 ) . No association with other fracture sites was observed . In conclusion , cola , but not total carbonated beverage consumption , is associated with  increased wrist and forearm fracture risk in children . However , this association is not independent of other factors and appears to be mediated by television watching and bone mineral density but not by decreased milk intake Over the past 20 years , orally administered biphosphonates have been used extensively in the management of a number of common skeletal disorders of different etiology . Recently , in clinical practice , in a number of cases in whom oral therapy is insufficient or contraindicated , intravenous administration of pamidronate presents an alternative therapeutic option . In order to investigate the clinical and radiological effects of cyclic intravenous pamidronate administration in children with osteogenesis imperfecta , a prospect i ve open study of pamidronate treatment was undertaken in a cohort of eight bed-bounded ( 3.6 - 13.8 years ) patients with severe osteoporosis and vertebral deformities .  Pamidronate was administered at a dose of 0.5 mg/kg/ day for three days . Tri-monthly cyclic intravenous infusions were performed over-one year . Bone density , verebral corpus heights , estimated volumetric bone density and biochemical measurements were analyzed . Side effects of the therapy were determined via question naire . Significant reductions in the number of bone fractures and pain were observed in all patients . Ambulation scores were significantly altered and seven of eight patients became independent . Serum alkaline phosphatase levels decreased significantly . Lumbar X-ray and densitometry showed a striking improvement by the end of the treatment period . Even spaced dense lines corresponding to infusion periods were observed on roentgenograms of the radio-ulnar region . Pubertal progression and growth velocity were not affected inversely during therapy . Although we did not observe any severe side effect , one patient 's blood urea nitrogen level was altered slightly . In conclusion , one year cyclical pamidronate treatment seems to be effective and safe in improving bone mineralization and in reducing fracture incidence in severe osteoporosis BACKGROUND There is no agreement on how much calcium young girls need for optimal bone mineralization . OBJECTIVE We evaluated whether the effect of calcium supplementation on whole-body bone mineral accretion depends on habitual calcium intake . DESIGN This was a r and omized , double-blind , placebo-controlled , 1-y calcium intervention study of girls aged 12 - 14 y selected from a larger group according to habitual calcium intake : subgroup A ( n = 60 ) habitually consumed 1000 - 1307 mg/d ( 40th-60th percentile ) , and subgroup B ( n = 53 ) habitually consumed < 713 mg/d ( < 20th percentile ) . The girls from each subgroup were r and omly assigned to receive either 500 mg Ca/d or placebo .  Whole-body bone mineral content ( BMC ) , bone area ( BA ) , bone mineral density ( BMD ) , and BMC adjusted for BA , height , and weight ( size-adjusted BMC ) were measured at baseline and after 1 y. RESULTS There was no significant effect modification of baseline habitual calcium intake on the relation between calcium supplementation and height , weight , BMC , size-adjusted BMC , BA , BMD , or alkaline phosphatase .  Calcium supplementation had an effect on BMD ( 0.8 % ; P = 0.049 ) and tended to show signs of an effect on size-adjusted BMC ( 0.5 % ; P = 0.08 ) . CONCLUSION A modest effect of calcium supplementation on BMD was shown . However , the effect was independent of habitual calcium intake BACKGROUND Osteoporosis may be prevented or delayed by maximizing peak bone mass through diet modification and physical activity during adolescence . OBJECTIVE We studied whether increases in calcium intake and physical activity effectively increase the bone mineral status of adolescent girls aged 16 - 18 y. DESIGN We conducted a 15.5-mo study of calcium supplementation ( 1000 mg Ca/d as carbonate ) in 144 adolescent girls aged 17.3 + /- 0.3 y ( + /- SD ) . The subjects were r and omly allocated to an exercise ( three 45-min exercise-to-music classes/wk during term time ) or nonexercise group . Dual-energy X-ray absorptiometry of the whole body , spine , forearm , and hip was performed before and after intervention . RESULTS The mean ( + /- SD ) percentage of subjects compliant with supplement taking was 70 + /- 27 % and with exercise class attendance was 36 + /- 25 % . Baseline calcium intake was 938 + /- 411 mg/d . Calcium supplementation significantly increased size-adjusted bone mineral content . The effect was stronger in subjects with good compliance ( percentage difference + /- SE ) : whole body , 0.8 + /- 0.3 % ( P < or = 0.01 ) ; lumbar spine , 1.9 + /- 0.5 % ( P < or = 0.001 ) ; ultradistal radius , 1.3 + /- 0.6 % ( P < or = 0.05 ) ; total hip , 2.7 + /- 0.6 % ( P < or = 0.001 ) ; femoral neck , 2.2 + /- 0.7 % ( P < or = 0.001 ) ; trochanter , 4.8 + /- 0.9 % ( P < or = 0.001 ) . Attendance at > 50 % of the exercise sessions was significant at the total hip ( 1.4 + /- 0.7 % ; P < or = 0.05 ) and trochanter ( 2.6 + /- 1.2 % ; P < or = 0.05 ) . CONCLUSIONS Calcium supplementation and exercise enhanced bone mineral status in adolescent girls . Whether this is a lasting benefit , leading to the optimization of peak bone mass and a reduction in fracture risk , needs to be determined BACKGROUND Rural Gambian children have poor growth , delayed puberty , a low bone mineral content , and a low calcium intake . OBJECTIVE We investigated the effect of a calcium supplement on bone mineral accretion in rural Gambian children . DESIGN A r and omized , double-blind , placebo-controlled study was conducted in 160 children ( 80 boys , 80 girls ) aged 8.3 - 11.9 y.  Bone mineral content ( BMC ) , bone mineral density ( BMD ) , and BMC adjusted for bone width , body weight , and height ( size-adjusted BMC ) were measured at the midshaft and distal radius . Each child received either 1000 mg Ca/d ( as calcium carbonate ) or a placebo 5 d/wk for 12 mo . Supplementation increased calcium intake from 342 to 1056 mg/d ( 8.6 to 26.4 mmol/d ) . RESULTS Calcium supplementation result ed in a higher BMC , BMD , and size-adjusted BMC ( & xmacr ; difference + /- SE ) : midshaft radius- BMC ( 3.0 + /- 1.4 % ; P = 0.034 ) , BMD ( 4.5 + /- 0.9 % ; P < /= 0.0001 ) , and size-adjusted BMC ( 4.6 + /- 0.9 % ; P < /= 0.0001 ) ; distal radius- BMC ( 8 . 4 + /- 3.2 % ; P = 0.009 ) , BMD ( 7.0 + /- 2.7 % ; P = 0.011 ) , and size-adjusted BMC ( 5.5 + /- 2.7 % ; P = 0.042 ) . Supplementation had no significant effect on height , weight , or bone width at the midshaft radius or distal radius . At the end of the study , the calcium group had a significantly lower mean plasma osteocalcin concentration than the placebo group after adjustment for baseline concentration , sex , and pubertal status ( -21.9 + /- 6.5 % ; P = 0.001 ) . CONCLUSIONS Increased calcium intake result ed in increased bone mineral status , possibly in association with a decreased bone remodeling space . Further studies are needed to determine whether an increased calcium intake has long-term benefits in Gambian children A r and omized , double-blind , controlled calcium supplementation trial was conducted for 18 mo to determine its effects on bone acquisition and height increment in 162 7-y-old Chinese children ( 87 boys and 75 girls ) with habitually low calcium intakes ( 280 mg/d ) . Distal one-third radial bone mineral content ( BMC ) , area bone density ( BMC /bone width ) , and height were evaluated every 6 mo . Baseline dietary intakes , serum 25-hydroxycholecalciferol , and physical activity  were determined . The study group received 300 mg Ca/d as calcium carbonate ; control subjects received placebo tablets . After 18 mo the study group had significantly greater gains in BMC ( 16.5 % vs 13.97 % ; P = 0.02 ) and BMC /bone width ( 9.45 % vs 6.31 % ; P = 0.0008 ) than the control subjects . The findings confirm a positive effect of calcium intake on bone acquisition but no effect on height increment . Whether a higher bone mass attained at age 8 - 9 y would be maintained and beneficial to future peak bone mass requires longitudinal investigation . Further study is warranted to determine calcium requirements for Chinese children BACKGROUND Bone loss is a critical concern for space travelers , and a dietary countermeasure would be of great benefit . Dietary protein and potassium-associated bicarbonate precursors may have opposing effects on the acid-base balance in the body and therefore on bone loss . OBJECTIVE In 2 studies , we examined the ability of dietary protein and potassium to predict markers of bone metabolism . DESIGN In the first study , 8 pairs of male identical twins were assigned to 1 of 2 groups : bed rest ( sedentary , or SED , group ) or bed rest with supine treadmill exercise in a lower-body negative pressure chamber ( EX group ) . In a second study , groups of 4 subjects lived in a closed chamber for 60 or 91 d , and dietary data were collected for two or three 5-d sessions . Urinary calcium , N-telopeptide , and pyridinium cross-links were measured before bed rest ; on bed rest days 5 - 6 , 12 - 13 , 19 - 20 , and 26 - 27 ; and daily during the chamber studies . Data were analyzed by Pearson 's correlation ( P < 0.05 ) . RESULTS The ratio of animal protein intake to potassium intake was significantly correlated with N-telopeptide in the SED group during bed rest weeks 3 and 4 ( r = 0.77 and 0.80 ) and during the 91-d chamber study ( r = 0.75 ) . The ratio of animal protein intake to potassium intake was positively correlated with pyridinium cross-links before bed rest in the EX group ( r = 0.83 ) , in the EX group during bed rest week 1 ( r = 0.84 ) , and in the SED group during bed rest week 2 ( r = 0.72 ) but not during either chamber study . In both studies , these relations were not significant with the ratio of vegetable protein intake to potassium intake . CONCLUSIONS The ratio of animal protein intake to potassium intake may affect bone in ambulatory and bed-rest subjects . Changing this ratio may help to prevent bone loss on Earth and during space flight BACKGROUND High calcium intakes during adolescence may increase bone acquisition . The magnitude of the effect of dietary calcium supplementation and the timing of its administration to achieve significant effects on bone health are still incompletely defined . OBJECTIVE The objective of this study was to assess the effect of calcium supplementation on bone mass accretion in postmenarcheal adolescent girls with low calcium intakes . DESIGN A double-blind , placebo-controlled calcium supplementation study was implemented . One hundred girls with a mean ( + /- SD ) age of 14 + /- 0.5 y with habitual calcium intakes < 800 mg/d completed a 12-mo protocol . The treatment group received a daily supplement containing 1000 mg elemental calcium .  Bone mineral density ( BMD ) and bone mineral content ( BMC ) of the total body , lumbar spine , and femoral neck were determined at inclusion , 6 mo , and 12 mo . Also measured were serum concentrations of biochemical markers of bone turnover ( osteocalcin and deoxypyridinoline ) , parathyroid hormone , and vitamin D. RESULTS The calcium-supplemented group had greater accretion of total-body BMD and lumbar spine BMD but not BMC than did the control group . Calcium supplementation appeared selectively beneficial for girls who were 2 y postmenarcheal . Calcium supplementation significantly decreased bone turnover and decreased serum parathyroid hormone concentrations . CONCLUSION Calcium supplementation of postmenarcheal girls with low calcium intakes enhances bone mineral acquisition , especially in girls > 2 y past the onset of menarche BACKGROUND Our r and omized , placebo-controlled supplementation study of 160 rural Gambian children aged 8.3 - 11.9 y showed that an increase in calcium intake of 714 mg/d for 12 mo result ed in a 5 % increase in forearm bone mineral acquisition and a 22 % decrease in plasma osteocalcin concentration , a bone formation marker , but had no effect on height or bone dimensions . OBJECTIVE We investigated whether these results were sustained after supplement withdrawal . DESIGN All participants were followed up 12 ( FU1 ) and 24 ( FU2 ) mo after supplementation ended . Bone mineral content ( BMC ) , bone mineral density ( BMD ) , and BMC adjusted for bone width , body weight , and height ( size-adjusted BMC ) were measured at the midshaft and distal radius . Plasma osteocalcin concentration was measured at FU1 . RESULTS At follow-up , the calcium group had greater bone mineral status than did the placebo group at the midshaft radius ( mean difference + /- SE ) , FU1 : BMC ( 4.7 + /- 1.6 % ; P = 0.004 ) , BMD ( 5.1 + /- 1.1 % ; P < /= 0.0001 ) , size-adjusted BMC ( 5.0 + /- 1.1 % ; P < /= 0.0001 ) ; FU2 : BMC ( 3.8 + /- 1.6 % ; P = 0.02 ) , BMD ( 2.7 + /- 1.3 % ; P = 0.04 ) , size-adjusted BMC ( 2.5 + /- 1.3 % ; P = 0.06 ) . Similar differentials were observed at the distal radius but were not significant . No significant differences in plasma osteocalcin concentrations ( FU1 : -0.5 + /- 6.5 % ; P = 0.9 ) were observed between groups . CONCLUSION Although some of the effects of calcium supplementation were still evident at follow-up , further studies are required to determine whether short-term increases in calcium intake have lasting benefits for Gambian children BACKGROUND Short-term studies established that calcium influences bone accretion during growth . Whether long-term supplementation influences bone accretion in young adults is not known . OBJECTIVE This study evaluated the long-term effects of calcium supplementation on bone accretion among females from childhood to young adulthood . DESIGN A 4-y r and omized clinical trial recruited 354 females in pubertal stage 2 and optionally was extended for an additional 3 y. The mean dietary calcium intake of the participants over 7 y was approximately 830 mg/d ;  calcium-supplemented persons received an additional approximately 670 mg/d . Primary outcome variables were distal and proximal radius bone mineral density ( BMD ) , total-body BMD ( TBBMD ) , and metacarpal cortical indexes . RESULTS Multivariate analyses of the primary outcomes indicated that  calcium-supplementation  effects vary over time . Follow-up univariate analyses indicated that all primary outcomes were significantly larger in the supplemented group than in the placebo group at the year 4 endpoint . However , at the year 7 endpoint , this effect vanished for TBBMD and distal radius BMD . Longitudinal models for TBBMD and proximal radius BMD , according to the time since menarche , showed a highly significant effect of supplementation during the pubertal growth spurt and a diminishing effect thereafter . Post hoc stratifications by compliance-adjusted total calcium intake and by final stature or metacarpal total cross-sectional area showed that calcium effects depend on compliance and body frame . CONCLUSIONS Calcium supplementation significantly influenced bone accretion  in young females during the pubertal growth spurt . By young adulthood , significant effects remained at metacarpals and at the forearm of tall persons , which indicated that the calcium requirement for growth is associated with skeletal size . These results may be important for both primary prevention of osteoporosis and prevention of bone fragility fractures during growth This study evaluated the long-term efficacy of supplemental calcium and dairy products on bone mineral areal density of the hip and spine and on the bone geometry and volumetric bone mineral density of the forearm in young females during late adolescence . The study was conducted among participants of a r and omized double-blinded , placebo-controlled clinical trial with calcium supplements and among participants of an observational study with higher consumption of dairy products .  Hip and spine measurements by dual-energy X-ray absorptiometry were done every 6 mo ( dairy group every 12 mo ) during last 3 y of the follow-up while peripheral quantitative computerized tomography of the forearm was done at the last visit . The results of the study show a positive influence of calcium supplementation and dairy products on bone mineral density of the hip and the forearm . Dairy products were also associated with a higher bone mineral density of the spine while calcium supplementation did not have an effect . Calcium exerts its action on bone accretion during growth primarily by influencing volumetric bone mineral density while milk may have an additional impact on bone growth and periosteal bone expansion Achievement of maximal calcium retention  during adolescence may influence the magnitude of peak bone mass and subsequently lower the risk of osteoporosis . Calcium retention is generally considered to reach a plateau at a certain calcium intake . To test this hypothesis , calcium balance was measured in 35 females with a mean ( + /-SD ) age of 12.7 + /- 1.2 y ( range : 12 - 15 y ) who consumed from 841 + /- 153 to 2173 + /- 149 mg Ca/d . Subjects ate a basal diet that included a fortified beverage containing different amounts of calcium citrate malate .  Twenty-one subjects were studied at two dietary calcium intakes with use of a crossover design . Results from a previous study in 14 subjects who were studied at only one calcium intake were included in the data analysis . Calcium retention was modeled as a nonlinear function of calcium intake that included a parameter representing mean maximal retention . Mean maximal calcium retention was 473 mg/d ( 95 % CI : 245 , 701 mg Ca/d ) . At higher postmenarcheal ages , maximal calcium retention was lower but the intake required to achieve this was not affected . Calcium intake explained 79 % and 6 % , respectively , of the variation in fecal and urinary calcium excretion . Intake of 1200 mg Ca/d , the recommended dietary allowance for calcium published in 1989 , result ed in a mean calcium retention that was 57 % of the maximal value ( 95 % CI : 25 % , 89 % ) . Intake of 1300 mg Ca/d was the smallest intake that allowed some adolescent females to achieve 100 % of maximal calcium retention ( 95 % CI : 26 % , 100 % ) . These data support the idea that calcium retention plateaus at a certain calcium intake although it continues to increase at intakes > 2 g/d BACKGROUND Calcium supplementation  during childhood and adolescence increases bone-mass accrual . Whether or not this benefit persists after discontinuation of supplementation is not known . We previously showed a favourable effect of milk-extracted calcium phosphate incorporated in various foods on accumulation of bone mineral mass in 8-year-old girls . We now report the results of a follow-up study undertaken more than 3 years after the end of calcium supplementation . METHODS Anthropometric and bone variables were measured in 116 of the 144 girls whose data had been studied at the end of the supplementation period . The mean time elapsed between the end of the intervention period and this follow-up measurement was 3.5 years . Areal bone mineral density was measured by dual-energy X-ray absorptiometry at the same six skeletal sites as those studied during the intervention phase . FINDINGS We were able to remeasure 62 and 54 girls of the calcium-supplemented and placebo groups , respectively . The increase from baseline in the overall mean bone mineral density of the six skeletal sites was still highly significant ( calcium-supplemented group 179 mg/cm(2 ) [ SE 8 ] vs placebo group 151 mg/cm(2 ) [ 7 ] , p=0.012 ) . A significant difference in favour of the supplemented group was also seen with respect to mean bone mineral content ( p=0.031 ) and mean bone area ( p=0.04 ) . Difference in pubertal maturation did not seem to account for the recorded differences . INTERPRETATION Our results suggest that this form of milk-extracted calcium phosphate taken during the prepubertal period can modify the trajectory of bone mass growth and cause a long-st and ing increase in bone mass accrual , which lasts beyond the end of supplementation The trial is conducted to evaluate the effects of calcium on bone mineral accretion in adolescents . 161 healthy adolescents aged of 9 to 20 year-old are recruited and are r and omly divided into experimental groups in which 300 mg Ca is supplemented per day for each participant and control group . The  dietary calcium , physical activity , SMR , distal one-third radial bone mineral content ( BMC ) , bone width ( BW ) , height , weight and serum total ALP are measured at both the beginning and the end of the trial . It is found that the average calcium intake from dietary sources is 500 mg/d in both groups . Increasing daily calcium intake via calcium supplementation in adolescents results in a moderate increases of BMC , and there is a significant increase of BMC in the females during the late adolescence . No significant differences in anthropometry are observed between the two groups at the end of the study while the increase of serum ALP level in the females in experiment group is significantly lower than that in the control group during the late adolescence . It is concluded that during the pubertal years when the BMC accretion is evident , there are no significant differences in bone mass accrual between the two groups . While in the females , calcium supplementation may help enhance the bone mineral accrual during late adolescence when the BMC accretion is remarkably reduced To evaluate the correlation between dietary calcium intake and mineralization of the immature skeleton 55 children and adolescents aged 5 - 14 years ( mean , 9.5 years ) with a positive radioallergosorbent test ( RAST ) for serum antibodies to cow 's milk protein were evaluated .  Bone mineral density ( BMD ) in the lumbar spine and proximal femurs were measured by dual energy X-ray absorptiometry . BMD at each site for each subject was converted to an age-adjusted Z score based on our own series of 95 normal pediatric controls .  Calcium intake was determined using a detailed food frequency question naire administered by a nutritionist during a 30 - 40-min interview . Dietary adjustments to the condition varied and result ed in a wide range of calcium intakes . Calcium supplements were taken by 22 % of the subjects and were included in the determination of daily calcium intake . The group of 55 subjects was divided into quartiles based on calcium intake ( mean + /- S.E mg calcium/day ) : Group 1 , 409 + /- 21 , Group 2 , 663 + /- 16 , Group 3 , 950 + /- 32 , Group 4 , 1437 + /- 124 . Bone density Z scores in the proximal femur serially increased across the calcium intake groups ( mean + /- S.E. ) : Group 1 , -0.16 + /- 0.31 ; Group 2 , 0.05 + /- 0.33 ; Group 3 , 0.44 + /- 0.24 ; Group 4 , 0.79 + /- 0.41 ( P = 0.03 ) . A similar pattern was found with lumbar spine BMD Z scores : Group 1 , -0.16 + /- 0.27 ; Group 2 , 0.10 + /- 0.21 ; Group 3 , 0.18 + /- 0.20 ; Group 4 , 0.30 + /- 0.25 ( P = 0.05 ) . These data add further to the evidence that dietary calcium intake is important for optimal mineralization of the growing skeleton This 2-year prospect i ve study examined associations among bone mineral acquisition and physical , maturational , and lifestyle variables during the pubertal transition in healthy girls . Forty-five girls , initially 10.5+/-0.6 years , participated .  Body composition and bone mineral content ( BMC ) at the spine and total body ( TB ) were assessed at baseline and annually thereafter using dual-energy X-ray absorptiometry ( DXA ) .  Nutrient intakes were assessed using 3-day diet records and a calcium food frequency question naire ( FFQ ) ,  physical activity by question naire , sexual maturation using Tanner 's stages of breast and pubic hair maturation , growth by height and weight , and eating attitudes using the children 's Eating Attitudes Test ( Children 's EAT ) . Mean children 's EAT subscale scores ( dieting , oral control [ OC ] , and bulimia ) were stable over time . Median split of OC subscale scores was used to form high and low OC groups . Groups had similar body composition , dietary intake , activity , and Tanner stage at baseline and 2 years . Using height , weight , and Tanner breast stage as covariates , girls with low OC scores had greater TB BMC at baseline ( 1452+/-221 g vs. 1387+/-197 g ; p = 0.030 ) and 2 years ( 2003+/-323 g vs. 1909+/-299 g ; p = 0.049 ) and greater lumbar spine ( LS ) BMC at 2 years ( 45.2+/-8.8 g vs. 41.2+/-9.6 g ; p = 0.042 ) . In multiple regression analysis , OC score predicted baseline , 2 years , and 2-year change in TB and spinal BMC , contributing 0.9 - 7.6 % to explained variance .  Calcium  intake predicted baseline , 2 years , and 2-year change in TB BMC , explaining 1.6 - 5.3 % of variance . We conclude that both OC and habitual calcium intake may influence bone mineral acquisition BACKGROUND Women may lose bone during lactation because of calcium lost in breast milk . We studied whether calcium supplementation prevents bone loss during lactation or augments bone gain after weaning . METHODS We conducted two r and omized , placebo-controlled trials of calcium supplementation ( 1 g per day ) in postpartum women . In one trial ( the study of lactation ) , 97 lactating and 99 nonlactating women were enrolled a mean ( + /-SD ) of 16+/-2 days post partum . In the second trial ( the study of weaning ) , 95 lactating women who weaned their infants in the 2 months after enrollment and 92 nonlactating women were enrolled 5.6+/-0.8 months post partum . The bone density of the total body , lumbar spine , and forearm was measured at enrollment and after three and six months . RESULTS The bone density of the lumbar spine decreased by 4.2 percent in the lactating women receiving calcium and by 4.9 percent in those receiving placebo and increased by 2.2 and 0.4 percent , respectively , in the nonlactating women ( P<0.001 for the effect of lactation ; P= 0.01 for the effect of calcium ) . After weaning , the bone density of the lumbar spine increased by 5.9 percent in the lactating women receiving calcium and by 4.4 percent in those receiving placebo ; it increased by 2.5 and 1.6 percent , respectively , in the nonlactating women ( P<0.001 for the effects of lactation and calcium ) . There was no effect of either lactation or calcium supplementation on bone density in the forearm , and there was no effect of calcium supplementation on the calcium concentration in breast milk . CONCLUSIONS Calcium supplementation does not prevent bone loss during lactation and only slightly enhances the gain in bone density after weaning HYPOTHESIS If calcium and phosphorus are administered to very low birth weight infants in amounts larger than those currently used in st and ard parenteral nutrition solutions , apparent retention of calcium and phosphorus ( intake minus urinary excretion ) will increase and bone mineralization will improve . DESIGN R and omized , controlled , double-blind trial . SETTING Neonatal intensive care unit . PATIENTS Twenty-four very low birth weight infants ( < 1.2 kg ) expected to receive parenteral nutrition exclusively for approximately 3 weeks beginning 3 days after birth . INTERVENTIONS Infants received parenteral nutrition solutions , either the st and ard mixture containing 1.25 mmol calcium and 1.5 mmol phosphorus per deciliter ( group ST AND : n = 12 , birth weight 921 + /- 171 gm , gestational age 27 + /- 2 weeks ( mean + /- SD ) ) or 1.7 mmol calcium and 2.0 mmol phosphorus per deciliter ( group HIGH : n = 12 , 857 + /- 180 gm , 27 + /- 2 weeks ) . MAIN OUTCOME MEASURES Intake , urinary excretion , and apparent retention of calcium , phosphorus , and magnesium every 3 days during parenteral nutrition therapy .  Serum indexes of mineral status twice during therapy . Bone mineral content of the distal segment of the left radius at 1 , 4 , 8 , and 26 weeks . RESULTS Apparent calcium retention ( 1.2 + /- 0.2 vs 1.6 + /- 0.2 mmol.kg-1.d-1 ) and phosphorus retention ( 1.4 + /- 0.2 vs 1.8 + /- 0.4 mmol.kg-1.d-1 ) differed significantly ( p < 0.01 ) between groups ST AND and HIGH , respectively ; neither changed with the duration of parenteral nutrition therapy . Serum calcium , magnesium , parathyroid hormone , 25-hydroxyvitamin D , and osteocalcin concentrations were similar in both groups . Serum phosphorus concentration was significantly higher in group HIGH than in group ST AND ( p = 0.025 ) . The absolute bone mineral content and the rate of increase in bone mineral content between 1 and 4 , 1 and 8 , and 1 and 26 weeks were significantly greater in group HIGH than in group ST AND . CONCLUSIONS Increased parenteral intakes of calcium and phosphorus result ed in greater retention of these minerals during parenteral nutrition therapy and in greater bone mineral content after therapy BACKGROUND Bone loss occurs during the first 6 months after renal transplantation ( RT ) , and corticosteroid therapy plays an important role . Although calcium plus vitamin D administration prevents corticosteroid-induced osteoporosis , its use in RT recipients is limited by the risk of hypercalcemia . METHODS This double-blind , r and omized , and controlled prospect i ve intervention trial examined the effect of intermittent calcitriol ( 0.5 microg/48 h ) during the first 3 months after RT , plus oral calcium supplementation ( 0.5 g/day ) during 1 year with calcium supplementation alone . The primary outcome measure was the change in bone mineral density ( BMD ) at 3 and 12 months after RT ; we also explored whether the effect of calcitriol on BMD was different among vitamin D receptor ( VDR ) genotypes ( BsmI ) . Forty-five recipients were r and omized to calcitriol therapy ( CT ) and 41 were r and omized to placebo ( PL ) . RESULTS Both groups had a similar degree of pre-existing hyperparathyroidism ( 197 + /- 229 vs. 191 + /- 183 pg/mL ) , but a more pronounced decrease of parathyroid hormone ( PTH ) levels after RT was observed in CT patients ( at 3 months : 61.4 + /- 42.2 vs. 85.7 + /- 53.1 pg/mL , P= 0.02 ; at 12 months : 67.3 + /- 33.7 vs. 82.6 + /- 37 pg/mL ; P= 0.08 ) . CT patients preserved their BMD at the total hip significantly better than those on PL ( 3 months : 0.04 + /- 3.3 vs. -1.93 + /- 3.2 % , P= 0.01 ; 12 months : 0.32 + /- 4.8 vs. -2.17 + /- 4.4 % , P= 0.03 ) ; significant differences were noted at the intertrochanter , trochanter , and Ward 's triangle . Differences did not reach significance at the femoral neck . Two CT patients ( 4.4 % ) and 4 PL patients ( 9.8 % ) developed a hypercalcemic episode during the first 3 months after RT . The effect of  CT  on BMD at 3 months was more prominent in recipients with the at-risk allele of the VDR gene ( P= 0.03 ) . CONCLUSION Therapy with low-dose calcium supplements during 1 year , plus intermittent calcitriol for 3 months after RT , is safe , decreases PTH levels more rapidly , and prevents bone loss at the proximal femur ; a more pronounced effect is seen in recipients with at least one at-risk allele of the VDR genotype One of the main focuses of lifestyle modification for the prevention of osteoporosis and osteoporotic fractures  in Japan is improvement in dietary calcium intake . However , virtually no r and omized controlled trial to assess the preventive effects of administration of calcium on the risk of fractures has been conducted in Japan . In this study , we review ed all the scientific papers currently available from medical literature data bases to propose evidence -based recommendations on the preventive procedures for osteoporosis . The result of the present systematic review gives the evidence showing that calcium supplementation or optimal dietary calcium intake increases bone density in childhood and adolescence and reduces the risk of fracture due to osteoporosis in the elderly people regardless of the gender . The evidence also supports the current health policy guiding the elderly to increase their dietary calcium intake in daily life OBJECTIVE Childhood weight-bearing physical activity is recognized as an important determinant of peak bone mass , and physical activity intervention may represent a feasible strategy for primary prevention of osteoporosis . Previous school-based exercise interventions have all been of < 10 months in duration . We implemented a high-impact , circuit-based , jumping intervention ( 10 minutes , 3 times a week ) over 2 school years and compared changes in bone mineral content ( BMC ) over 20 months ( 2 school years ) in 9.9 + /- 0.6-year-old intervention girls ( N = 32 ) and controls ( 10.3 + /- 0.4 years , N = 43 ) . METHODS We measured BMC for the total body , lumbar spine , proximal femur ( and femoral neck and trochanteric subregions ) , and lean and fat mass by dual-energy radiograph absorptiometry ( Hologic QDR 4500 ) , and height , sitting height , leg length , and weight at baseline and 20 months . We assessed Tanner stage , general physical activity , and calcium intake by question naire . RESULTS Girls were Tanner breast stage 1 to 3 at baseline . There were no significant differences in baseline or 20-month change in body size or composition , average physical activity , or calcium intake between groups . There were substantially greater gains in lumbar spine ( 41.7 % vs 38.0 % ) and femoral neck ( 24.8 % vs 20.2 % ) BMC in intervention than in control girls ( P < .05 , analysis of covariance ; covariates were baseline BMC and height , change in height , physical activity , and final Tanner stage ) . CONCLUSION Three brief sessions of high-impact exercise per week implemented over 2 consecutive years within the elementary school curriculum elicited a substantial bone mineral accrual advantage in pubertal girls BACKGROUND The achievement of a peak bone mass is an important factor in the prevention of osteoporotic fractures . In normal children , the amount of calcium intake could affect bone mineral increment . AIM To assess the effect of a daily 500 mg calcium supplement on bone mineral density , in a group of healthy Chilean girls . PATIENTS AND METHODS Fifty healthy girls were studied and 25 were r and omly assigned to receive a 500 mg calcium supplement during 10 months . Bone mineral density of the distal and ultradistal region of the forearm was measured in all girls by single X ray absorptiometry ( Osteometer DTX-100 ) at the beginning and end of the study . Bone mineral density was expressed as Z values . RESULTS Significant increments in bone mineral density at the distal radioulnar region were obtained in the supplemented girls . No significant changes in bone density were observed in control girls . CONCLUSIONS A daily 500 mg calcium supplement for 10 months increased bone mineral density in healthy girls OBJECTIVE To develop and test a model based on B and ura 's social cognitive theory to predict healthy lifestyle behaviors for the prevention of osteoporosis . METHODS Participants were 354 girls , ages 8 - 11 years , recruited from area Girl Scout troops . Baseline data from a r and omized trial of behavioral interventions are presented . Measures of social support , knowledge , self-efficacy , dietary calcium intake , and weight-bearing physical activity ( WBPA ) were obtained via interviews and self-administered question naires . RESULTS A structural equation model was tested and fit the data well . Family social support , perceived self-efficacy for eating a calcium-rich diet , and knowledge of WBPA significantly predicted calcium intake . Friend and family support for exercise predicted WBPA . Self-efficacy partially mediated the relationship between family support and calcium intake , as confirmed by Holmbeck 's post-hoc probing strategy ( 2002 ) . CONCLUSIONS Suggestions are made for primary prevention interventions such as parent and peer involvement , health education , and problem-solving training OBJECTIVES This study examined whether higher intakes of milk and other calcium-rich foods during adult years can reduce the risk of  osteoporotic fractures .  METHODS This was a 12-year prospect i ve study among 77761 women , aged 34 through 59 years in 1980 , who had never used calcium supplements .  Dietary intake was assessed with a food-frequency question naire in 1980 , 1984 , and 1986 . Fractures of the proximal femur ( n = 133 ) and distal radius ( n = 1046 ) from low or moderate trauma were self-reported on biennial question naires . RESULTS We found no evidence that higher intakes of milk or calcium from food sources reduce fracture incidence . Women who drank two or more glasses of milk per day had relative risks of 1.45 for hip fracture ( 95 % confidence interval [ CI ] = 0.87 , 2.43 ) and 1.05 for forearm fracture ( 95 % CI = 0.88 , 1.25 ) when compared with women consuming one glass or less per week . Likewise , higher intakes of total  dietary calcium or calcium from dairy foods were not associated with decreased risk of hip or forearm fracture . CONCLUSIONS These data do not support the hypothesis that higher consumption of milk or other food sources of calcium  by adult women protects against hip or forearm fractures Abstract : The maximum amount of bone a person can obtain during the first two decades of life is an important determinant of bone mass in later life , and an increase in peak bone mass has been associated with decreased risk for osteoporotic fractures . It is known that growth of bone and thus development of peak bone mass are strongly controlled by genetic factors , but information on the role of environmental factors , such as exercise and nutrition , ( e.g. , exercise ) on growing bone is limited . We tested a hypothesis that in growing girls the benefit of mechanical loading on bone mineral mass and bone strength is better before rather than after the menarche . Sixty-four girls ( 25 premenarcheal , 39 postmenarcheal ) carried out a supervised 9-month step-aerobic program ( two sessions per week ) , each session complemented with additional jumps .  Sixty-two girls ( 33 premenarcheal , 29 postmenarcheal ) served as controls . Bone mineral content ( BMC ) at the lumbar spine and proximal femur was measured by dual-energy X-ray absorptiometry ( DXA ) . In addition , the cortical density ( CoD , mg/cm3 ) and cortical cross-sectional area ( CoA , mm2 ) and the density-weighted polar section modulus ( BSI , mm3 ) of the tibial midshaft were determined by peripheral quantitative tomography ( pQCT ) . In the premenarcheal girls , BMC increased statistically significantly more in the trainees than controls at the lumbar spine ( p= 0.012 ) ( 8.6 % vs 5.3 % ) and femoral neck ( p= 0.014 ) ( 9.3 % vs 5.3 % ) . In the tibial midshaft , the intergroup differences ( CoD , CoA and BSI ) were not significant . The postmenarcheal girls showed no significant post-training intergroup differences in any of the bone parameters ( BMC increased in the lumbar spine 6.0 % vs 4.9 % ; femoral neck 3.4 % vs 3.2 % ; and trochanter 2.6 % vs 3.5 % ) . Although a large proportion of bone mineral increase in the growing girls of this study was attributable to growth itself , this 9-month exercise intervention showed that a clear and large additional bone gain could be obtained in exercising premenarcheal girls , but not in exercising postmenarcheal girls . In other words , exercise seemed more beneficial for additional bone mineral acquisition before menarche ( i.e. , during the growth spurt ) rather than after it Childhood and adolescence is the period of most rapid skeletal growth in an individual 's lifetime . A greater peak bone mass achieved in the first 2 - 3 decades of life , may protect against the risk of osteoporotic fracture in later life . The aim of this r and omized , controlled study was to assess in pre-pubertal boys and girls ( aged 8 - 10 years ) the effect of 18 months of a calcium enriched , cocoa flavoured product on bone density , bone growth and bone size in New Zeal and children . One hundred and fifty four pre-pubertal boys and girls ( aged 8 - 10 years ) were r and omized to receive a high calcium dairy drink or a control drink reconstituted with water for 18 months . They were assessed at baseline and then every 6 months for the first 18 months , while they were having the supplement ; they were then followed up 12 months after supplementation had finished . Bone mineral density and bone mineral content were assessed at the total body , hip and spine . Indicators of bone size ( vertebral width and height ) were also measured at the spine . Anthropometric data was collected , medical history question naires were administered ( including the Tanner or pubertal stage question naire ) , dietary calcium intake was assessed with a calcium food frequency question naire and calcium supplement compliance was determined . There was no significant difference between the 2 groups for bone mineral density or bone mineral content at any time point . There was no difference in vertebral height or width at any stage of the study , indicating no additional influence on bone size at the lumbar vertebrae . There were no significant differences between height , weight , lean mass or fat mass at any time point . Both groups had higher habitual calcium intakes than recommended for this age group going into the study and throughout the study . In this 2(1/2 ) year study ( 18 months supplementation , 1 year follow-up ) we did not observe a difference in bone mineral density in pre-pubertal children . This was probably due to their high habitual dietary calcium intake whereby minimal addition of calcium to the diet reached the threshold level where no further benefit was seen . There were no significant differences between the two groups in body composition . Growth and the mean height and weight remained between the 50th and 75th percentile for their age . We have shown calcium supplementation in children with high habitual dietary calcium intake appears not to have additional effects on bone mass . Calcium supplementation needs to be targeted in those children with low habitual dietary calcium intake Physical activity during childhood is advocated as one strategy for enhancing peak bone mass ( bone mineral content [ BMC ] ) as a means to reduce osteoporosis-related fractures . Thus , we investigated the effects of high-intensity jumping on hip and lumbar spine bone mass in children . Eighty-nine prepubescent children between the ages of 5.9 and 9.8 years were r and omized into a  jumping  ( n = 25 boys and n = 20 girls ) or  control group  ( n = 26 boys and n = 18 girls ) . Both groups participated in the 7-month exercise intervention during the school day three times per week . The jumping group performed 100 , two-footed jumps off 61-cm boxes each session , while the control group performed nonimpact stretching exercises .  BMC ( g ) , bone area ( BA ; cm2 ) , and bone mineral density ( BMD ; g/cm2 ) of the left proximal femoral neck and lumbar spine ( L1-L4 ) were assessed by dual-energy X-ray absorptiometry ( DXA ; Hologic QDR/4500-A ) . Peak ground reaction forces were calculated across 100 , two-footed jumps from a 61-cm box . In addition , anthropometric characteristics ( height , weight , and body fat ) , physical activity , and dietary calcium intake were assessed . At baseline there were no differences between groups for anthropometric characteristics , dietary calcium intake , or bone variables . After 7 months , jumpers and controls had similar increases in height , weight , and body fat . Using repeated measures analysis of covariance ( ANCOVA ; covariates , initial age and bone values , and changes in height and weight ) for BMC , the primary outcome variable , jumpers had significantly greater 7-month changes at the femoral neck and lumbar spine than controls ( 4.5 % and 3.1 % , respectively ) . In repeated measures ANCOVA of secondary outcomes ( BMD and BA ) , BMD at the lumbar spine was significantly greater in jumpers than in controls ( 2.0 % ) and approached statistical significance at the femoral neck ( 1.4 % ; p = 0.085 ) . For BA , jumpers had significantly greater increases at the femoral neck area than controls ( 2.9 % ) but were not different at the spine . Our data indicate that jumping at ground reaction forces of eight times body weight is a safe , effective , and simple method of improving bone mass at the hip and spine in children . This program could be easily incorporated into physical education classes High calcium intake during childhood has been suggested to increase bone mass accrual , potentially result ing in a greater peak bone mass . Whether the effects of calcium supplementation on bone mass accrual vary from one skeletal region to another , and to what extent the level of spontaneous calcium intake may affect the magnitude of the response has , however , not yet been clearly established . In a double-blind , placebo-controlled study , 149 healthy prepubertal girls aged 7.9+/-0.1 yr ( mean+/-SEM ) were either allocated two food products containing 850 mg of calcium ( Ca-suppl . ) or not ( placebo ) on a daily basis for 1 yr . Areal bone mineral density ( BMD ) , bone mineral content ( BMC ) , and bone size were determined at six sites by dual-energy x-ray absorptiometry . The difference in BMD gain between calcium-supplemented ( Ca-suppl . ) and placebo was greater at radial ( metaphysis and diaphysis ) and femoral ( neck , trochanter , and diaphyses ) sites ( 7 - 12 mg/cm2 per yr ) than in the lumbar spine ( 2 mg/cm2 per yr ) . The difference in BMD gains between Ca-suppl . and placebo was greatest in girls with a spontaneous calcium intake below the median of 880 mg/d . The increase in mean BMD of the 6 sites in the low-calcium consumers was accompanied by increased gains in mean BMC , bone size , and statural height . These results suggest a possible positive effect of calcium supplementation on skeletal growth at that age . In conclusion , calcium-enriched foods significantly increased bone mass accrual in prepubertal girls , with a preferential effect in the appendicular skeleton , and greater benefit at lower spontaneous calcium intake Two related studies were conducted to assess the associations between markers of skeletal modeling and remodeling in healthy children . Members of monozygotic twin pairs , aged 6 - 14 , enrolled in a clinical trial of calcium supplementation  , were studied at the end of the period of supplementation and for 3 years thereafter . Supplemented children had significantly higher rates of gain in bone mineral density ( BMD ) ( + 3 % on average ) during the period of supplementation accompanied by significantly lower concentrations of serum osteocalcin ( OC , -15 % ) . During postsupplement follow-up , both differences in BMD and OC disappeared . Black females , age matched to the baseline ages of the white children , had significantly lower serum concentrations of both OC and tartrate-resistant acid phosphatase ( TRAP ) at all ages and higher BMDs . When stratified on serum TRAP concentrations , regardless of race , children with lower concentrations had significantly higher BMDs , and no racial differences were apparent . In regression models accounting for 70 - 80 % of the variability in BMD in children , body size and TRAP , but not race , remained significantly associated with BMD . The skeletal advantages seen with calcium supplementation and black race appear to be associated with reduced rates of skeletal turnover . Given that markers of turnover during growth reflect both skeletal modeling and remodeling , and there is no apparent advantage to reduced skeletal modeling , it seems probable that reduced remodeling is the factor that accounts for the increases in bone mass OBJECTIVE To determine whether pubertal girls assigned to calcium-rich diets or their usual calcium intakes differ significantly in weight gain . DESIGN This is a pilot study conducted on data from an experimental research project . SUBJECTS/ SETTING The sample included 59 girls , 9 years of age , from Omaha metropolitan communities . INTERVENTION Participants were r and omly assigned to a calcium-rich diet supplying at least 1,500 mg of calcium per day or their usual diet . MAIN OUTCOME MEASURE The outcome measure was change in weight during 2 years of study . STATISTICAL ANALYSES Data were analyzed using descriptive statistics , Mann-Whitney U , t tests of paired and independent sample s , and analysis of covariance . RESULTS The girls in the calcium-rich diet group had a mean ( + /-st and ard deviation ) calcium intake of 1,656+/-191 mg/day , whereas the girls on their usual diets averaged 961+/-268 mg/day . Although the participants in the treatment group consumed nearly twice as much dietary calcium -- primarily from dairy foods -- they did not have greater increases in body weight , body mass index , or fat or lean mass than the control group . These findings held when the data were grouped by tertile of calcium intake . Compared with girls on their usual diets , the girls who consumed the calcium-rich diet also significantly increased their intake of essential nutrients . CONCLUSION We conclude that calcium-rich diets do not cause excessive weight gain in pubertal girls but do contribute positively to overall nutrition . These findings provide support for programs to promote calcium-rich diets , which are critical for attaining peak bone mass PURPOSE : To test the effects of an osteoporosis prevention program given to high school students DESIGN : R and omized , multisite field study . SAMPLE : The final sample for analysis was composed of 693 teens from 18 schools . FINDINGS : The average knowledge difference score of the OPTIONS group was 8.4 percentage points higher than that of the control group . Some of the analysis suggested that girls gained more from the intervention than did boys . Students from all types of schools , responded equivalently to the intervention . Health beliefs about barriers to preventive action were not influenced by the intervention . DISCUSSION : This intervention increased students ' knowledge about how to build healthy bones ; however , the real challenge lies in building on that knowledge gain to influence behaviors . The modest gain in knowledge also suggests that educational interventions of this type should be tested with younger children , who might be more receptive BACKGROUND Steroid-related bone loss is a recognized complication after renal transplantation . In a prospect i ve , r and omized , multicenter study we compared the influence of a steroid-free immunosuppressive regimen with a regimen with limited steroid exposure on the changes in bone mass after renal transplantation . METHODS A total of 364 recipients of a renal transplant were r and omized to receive either daclizumab ( 1 mg/kg on days 0 and 10 after transplantation ; steroid-free group n=186 ) or prednisone ( 0.3 mg/kg per day tapered to 0 mg at week 16 after transplantation ; steroids group n=178 ) . All patients received tacrolimus , mycophenolate mofetil , and , during the first 3 days , 100 mg prednisolone intravenously . Changes in bone mineral density ( BMD ) were evaluated in 135 and 126 patients in the steroid-free and steroids group , respectively . RESULTS The mean ( + /- SD ) BMD of the lumbar spine decreased slightly in both groups during the first 3 months after transplantation ( steroid-free -1.3 + /- 4.0 % [ P<0.01 ] ; steroids -2.3 + /-4.2 % [ P<0.01 ] ) . In the following months , lumbar BMD recovered in both groups ( P<0.01 ) , result ing in a lumbar BMD at 12 months after transplantation comparable with the baseline value . No difference between the groups was found at 3 months ( steroid-free versus steroids + 1.0 % ; 95 % confidence interval -0.0%-+2.0 % , P=0.060 ) and at 12 months after transplantation ( steroid-free versus steroids + 0.9 % ; 95 % confidence interval -0.8%-+2.6 % , NS ) . CONCLUSION The use of a moderate dose of steroids during 4 months after transplantation has no important influence on bone mass during the first year after renal transplantation . On average , both regimens prevented accelerated bone loss Abstract : Lifestyle factors , such as diet , are believed to be involved in modifying bone health , although the results remain controversial , particularly in children and adolescents . The objective of the study was to identify associations between dietary factors and whole body bone measurements in 10-year-old children . The study was a cross-sectional analysis of a r and om sample of 105 healthy Danish children , aged 10 years ( 9.97 ± 0.09 ) . Whole body bone mineral content ( BMC ) and bone area ( BA ) were determined by dual-energy X-ray absorptiometry . The influence of diet ( 7 day food records ) on BMC and BA were examined in bi- and multivariate analyses . The mean intakes of calcium , protein , phosphorus and sodium were 1226 mg , 78 g , 1523 mg and 3.3 g , respectively . In bivariate analyses , BMC and BA were strongly positively correlated with height ( p<0.001 ) and weight ( p<0.001 ) , and with intakes of energy ( p<0.005 ) and several nutrients . BMC was adjusted for size by including BA , height and weight in the multiple linear regression , and BA was adjusted for size by including height and weight in the multiple linear regression . In multivariate analyses , size-adjusted BMC was positively associated with calcium intake ( p = 0.02 ) . Size-adjusted BA was positively associated with dietary protein ( p = 0.003 ) , and negatively associated with intakes of sodium ( p = 0.048 ) and phosphorus ( p = 0.01 ) . In conclusion , calcium intake was positively associated with bone mineralization . There was a positive association between protein and BA , while for phosphorus and sodium the association was negative . The findings suggest that in addition to calcium , the intake of other nutrients influences bone development in prepubertal children In order to study the effect of calcium supplementation on bone resorption , a r and omized controlled crossover study was carried out on eight healthy 18 - 19 year old female volunteers using either AAACa heated oyster shell with vacuum-heated seaweed or milk .  Regimen A consisted of an oral dose of 200 mg calcium in the form of AAACa . B 200 ml milk after breakfast and supper and at bedtime , and C control with no calcium supplement .  Early morning fasting blood and urine sampling was carried out after 7 days of calcium supplementation .  Serum calcium was higher in groups A and B than in C , and serum intact parathyroid hormone ( PTH ) was significantly lower in group A than in groups B and C , according to a paired t-test . Urinary excretion of crosslinked collagen degradation product , pyridinoline and deoxypyridinoline showed a similar decrease in groups A and B but not in C. The more effective suppression of PTH by AAACa than by milk may be due to its higher bioavailability and the absence of phosphate stimulating PTH secretion UNLABELLED Bone metabolism follows a seasonal pattern with high bone turnover and bone loss during the winter . In a r and omized , open-label 2-year sequential follow-up study of 55 healthy adults , we found that supplementation with oral vitamin D3 and calcium during winter abolished seasonal changes in calciotropic hormones and markers of bone turnover and led to an increase in BMD . Supplementation with oral vitamin D3 and calcium during the winter months seems to counteract the effects of seasonal changes in vitamin D and thus may be beneficial as a primary prevention strategy for age-related bone loss . INTRODUCTION Bone metabolism follows a seasonal pattern characterized by high bone turnover and bone loss during winter . We investigated whether wintertime supplementation with oral vitamin D3 and calcium had beneficial effects on the circannual changes in bone turnover and bone mass . MATERIAL S AND METHODS This prospect i ve study comprised an initial observation period of 12 months ( " year 1 " ) , followed by an intervention during parts of year 2 . Fifty-five healthy subjects living in southwestern Germany ( latitude , 49.5 degrees N ) were r and omized into two groups : 30 subjects were assigned to the treatment group and received oral cholecalciferol ( 500 IU/day ) and calcium ( 500 mg/day ) during the winter months of year 2 ( October-April ) , while 25 subjects assigned to the control group obtained no supplements . Primary endpoints were changes in calciotropic hormones [ serum 25(OH)D , 1,25(OH)2D , and parathyroid hormone ] , markers of bone formation ( serum bone-specific alkaline phosphatase ) and of bone resorption ( urinary pyridinoline and deoxypyridinoline ) , and changes in lumbar spine and femoral neck BMD . RESULTS Forty-three subjects completed the study . During year 1 , calciotropic hormones , markers of bone turnover , and BMD varied by season in both groups . During the winter months of year 1 , bone turnover was significantly accelerated , and lumbar spine and femoral BMD declined by 0.3 - 0.9 % . In year 2 , seasonal changes in calciotropic hormones and markers of bone turnover were either reversed or abolished in the intervention group while unchanged in the control cohort . In the subjects receiving oral vitamin D3 and calcium , lumbar and femoral BMD increased significantly ( lumbar spine : + 0.8 % , p = 0.04 versus year 1 ; femoral neck : + 0.1 % , p = 0.05 versus year 1 ) , whereas controls continued to lose bone ( intervention group versus control group : lumbar spine , p = 0.03 ; femoral neck , p = 0.05 ) . CONCLUSIONS Supplementation with oral vitamin D3 and calcium during winter prevents seasonal changes in bone turnover and bone loss in healthy adults . It seems conceivable that annually recurring cycles of low vitamin D and mild secondary hyperparathyroidism during the winter months contributes , at least in part and over many years , to age-related bone loss . Supplementation with low-dose oral vitamin D3 and calcium during winter may be an efficient and inexpensive strategy for the primary prevention of bone loss in northern latitudes Low dietary calcium intake has been demonstrated to be a risk factor for hip and vertebral fractures in studies conducted among Hong Kong Chinese . Few studies have demonstrated the effect of milk supplementation in bone accretion in Chinese children . The aim was to examine the effects of milk powder supplementation in enhancing bone accretion in Chinese children . Three hundred and forty-four children , aged 9–10 years old , were r and omized to receive milk powder equivalent to 1300 mg and 650 mg calcium , and to a control group , respectively . Bone mineral density ( BMD ) at the proximal femur , lumbar spine and total body were measured at 6 months , 12 months and 18 months . The treatment effects were modeled using linear mixed effect models and compared using linear contrast F-tests , by intention-to-treat . Subjects r and omized to milk powder equivalent to 1300 mg calcium had significantly higher increase in BMD at both the total hip ( 7.4±0.4 % in treatment group versus 6.3±0.4 % in the control ) and the spine ( 8.4±0.5 % in the treatment group versus 7.0±0.5 % in the control group ) . Subjects r and omized to milk powder equivalent to 650 mg calcium had smaller increases in BMD at the total hip and spine , although the increase in BMD at the total body was significantly higher ( 3.1±0.3 % in treatment group versus 2.4±0.2 % in controls ) . It is concluded that supplementing the diet of Chinese children with milk powder was effective in enhancing bone accretion Although increased physical activity early in life is recommended for optimizing bone health , no controlled trials on the effect of activity on bone mass accretion during periods of rapid growth have been reported . The purpose of this study was to determine whether infants r and omized to a 1 year gross motor activity program  had a greater bone mass accretion than infants r and omized to a fine motor activity program .  The gross motor program included activities that focused on loading the skeleton and were performed for 15 - 20 minutes/day , 5 days/week by study personnel . Infants ( n = 72 ) were enrolled at 6 months of age , and total body bone mineral content ( BMC ) , 3-day diet records , and activity levels were obtained at 6 , 9 , 12 , 15 , and 18 months . BMC was associated with weight , length , and bone area at all ages and correlated with earlier calcium intakes . Calcium intake appeared to modify the effect of  gross motor activity  on bone mass accretion ; infants in both groups had similar bone accretion at moderately high calcium intakes , but at low calcium intakes infants in the gross motor program had less bone accretion than infants in the fine motor program . Compliant infants in the gross motor group had lower BMC at 18 months compared with noncompliant infants . These results indicate that BMC in infants is related to calcium intake , and we speculate that participation in a gross motor program during rapid bone growth may lead to reduced bone accretion in the presence of a moderate to moderately low calcium intake Abstract : Symptomatic fractures are a significant problem in terms of both morbidity and financial cost . Marked variation in both total and site-specific fracture incidence has been documented internationally but there is limited within-country data . This prospect i ve population -based study documented the incidence of all symptomatic fractures occurring from July 1 , 1997 to June 30 , 1999 in adults ≥50 years of age resident in Southern Tasmania ( total population ≥50 years : 64 688 ) . Fractures were ascertained by review ing reports from all the radiology providers within the area . There were 701 fractures in men and 1309 fractures in women . The corresponding fracture incidence in men and women was 1248 and 1916 per 100 000 person-years , respectively . Residual lifetime fracture risk in a person aged 50 years was 27 % for men and 44 % for women with fractures other than hip fractures constituting the majority of symptomatic fracture events . These fracture risk estimates remained remarkably constant with increasing age . In comparison to Geelong , there were significantly lower hip fracture rates ( males : RR 0.59 , 95 % CI 0.45–0.76 ; females : RR 0.61 , 95 % CI 0.53–0.71 ) but significantly higher distal forearm fractures ( males : RR 1.87 , 95 % CI 1.10–3.78 ; females : RR 1.31 , 95 % CI 1.11–1.55 ) and total fractures in men ( RR 1.31 , 95 % CI 1.17–1.46 ) but not women ( RR 1.05 , 95 % CI 0.98–1.13 ) . In contrast , Southern Tasmania had lower age-st and ardized rates of all fractures compared with Dubbo ( RR 0.28–0.79 ) . In conclusion , this study provides compelling evidence that fracture incidence varies between different geographic sites within the same country , which has important implication s for health planning . In addition , the combination of high residual fracture risk and short life expectancy in elderly subjects suggests fracture prevention will be most cost-effective in later life High calcium intake combined with physical activity during childhood have been shown to improve bone mass accrual and bone mineral density . Our aim was to study the combined effect of calcium and exercise on  bone gain in children . Two milk-powder products containing either 800 mg of calcium phosphate ( calcium ) or not ( placebo ) were r and omly allocated to 113 healthy premenarchal girls on a daily basis for 1 year . The group was composed of 63 exercise ( 7.2 + /- 4 hours of exercise/week ) and 50 sedentary ( 1.2 + /- 0.8 hours of exercise/week ) children . The final experiment had 4 groups : exercise/calcium ( n = 12 ) , exercise/placebo ( n = 42 ) , sedentary/calcium ( n = 10 ) , and sedentary/placebo ( n = 21 ) . Bone mineral density ( BMD ) at 6 skeletal sites and body composition were determined by DXA . Bone age was calculated and the daily spontaneous calcium intake was assessed by a frequency question naire . All the tests were performed at baseline and 1 year by the same observer . BMD gains were significantly greater in the exercise/calcium group than in other groups at the total body ( increase of 6.3 % , p < 0.05 ) , lumbar spine ( 11 % , p < 0.05 ) , femoral neck ( 8.2 % , p < 0.02 ) , and Ward 's triangle ( 9.3 % , p < 0.01 ) . There was no difference between the other groups . These data suggest that calcium supplementation increases the effect of physical exercise on bone mineral acquisition in the period preceding puberty , and that calcium supplementation without physical activity does not improve the BMD acquisition during this period . Physical exercise that stimulates bone accretion needs a high calcium intake to be completely effective The effect of calcium supplementation on bone mineral density ( BMD ) was evaluated in female twin pairs aged 10–17 years with a mean age of 14 years . Forty-two twin pairs ( 22 monozygotic , 20 dizygotic ; ( including one monozygotic pair from a set of triplets ) completed at least 6 months of the intervention : 37 pairs to 12 months and 28 pairs to 18 months . BMD was measured by dual-energy X-ray absorptiometry ( DXA ) . In a double-blind manner , one twin in each pair was r and omly assigned to receive daily a 1000 mg effervescent calcium tablet ( S and ocal 1000 ) , and the other a placebo tablet similar in taste and appearance to the calcium supplement but containing no calcium .  Compliance ( at least 80 % tablets consumed ) , as measured by tablet count , was 85 % in the placebo group and 83 % in the calcium group over the 18 months of the study , on average increasing dietary calcium to over 1600 mg/day . There was no within-pair difference in the change in height or weight . When the effect of calcium supplementation  on BMD was compared with placebo at approximately 6 , 12 and 18 months , it was found that there was a 0.015±0.007 g/ cm2 greater increase in BMD ( 1.62±0.84 % ) at the spine in those on calcium after 18 months . At the end of the first 6 months there was a significant within-pair difference of 1.53±0.56 % at the spine and 1.27±0.50 % at the hip . However , there were no significant differences in the changes in BMD after the initial effect over the first 6 months . Therefore , we found an increase in BMD at the spine  with calcium supplementation in females with a mean age of 14 years . The greatest effect was seen in the first 6 months ; thereafter the difference was maintained , but there was no accelerated increase in BMD  associated with calcium supplementation . The continuance of the intervention until the attainment of peak bone mass and follow-up after cessation of calcium supplementation will be important in clarifying the optimal timing for increased dietary calcium and the sustained , long-term effects of this intervention We conducted a double-blind , placebo-controlled , r and omized trial to determine whether 1 year of supplemental calcium intake would augment hip [ greater trochanter , GT , femoral neck ( FN ) , total hip ( TH ) ] , spine ( LS ) , and femoral mid-shaft ( Fmr ) BMD in female distance runners . Twenty-three women ( age : 23.7 + /- 4.7 yrs , height : 165.6 + /- 6.3 cm , weight : 55.7 + /- 6.1 kg ) were r and omly assigned to receive either 1000 mg/d of supplemental calcium ( N = 13 ) or placebo tablets ( N = 10 ) for 1 year . BMD was determined by DXA ( Hologic 1000-W ) and tablet compliance by self-report logs . Compliance averaged 79 % and 71 % for supplement and placebo groups , respectively . Calcium supplementation did not affect hip or spine BMD , but did prevent loss at the femoral mid-shaft ( GT : -0.5 % vs. 0.2 % , FN : 0.9 % vs. 1.1 % , TH : -0.3 % vs. 0.2 % , LS : 0.3 % vs. 1.2 % , Fmr : 0.1 % vs. -1.8 % , for calcium vs. placebo , respectively ) . We conclude that the addition of 800 mg/d of supplemental calcium to the diet of young adult female distance runners with habitual calcium intakes of approximately 1000 mg/d , prevents cortical but not trabecular bone loss Successful renal transplantation corrects many of the metabolic abnormalities associated with the development of renal osteodystrophy , but despite a well-functioning graft osteopenia , growth failure , spontaneous fractures , and avascular necrosis remain prevalent in adult and pediatric kidney recipients . A paucity of information exists regarding the effects of different therapies to prevent and treat bone loss in the renal transplant recipients . We constructed a design to study the effect of different modalities of treatment on bone mass in our renal transplant children . Among 93 patients who underwent renal transplantation at the age of 17 yr or less and were subjected to dual-energy X-ray absorptiometry ( DEXA ) , we blindly r and omized 60 patients who had osteopenia or osteoporosis ( T-score = -1 by DEXA ) in a prospect i ve study . Their mean age at time of transplantation was 13.4 + /- 4.3 yr . The mean duration after transplantation was 48 + /- 34 months . The patients were classified r and omly into four groups . Each group consisted of 15 patients : group 1 was the control group , group 2 received oral alfacalcidol 0.25 microg daily , group 3 received oral alendronate 5 mg daily , and group 4 received 200 IU/day nasal spray calcitonin .  Parameters of bone turnover , calcium metabolism , and DEXA were measured before and after 12 months of treatment duration . The characteristics of all groups were comparable at the beginning of the study . At the lumber spine , bone mass density decreased from -2.4 to -2.8 in group 1 , increased from -2.3 to -0.5 in group 2 , from -2.3 to -1.9 in group 3 , and from -2.3 to -1.0 in group 4 . The four groups had similar patient profiles , serum creatinine , intact parathyroid hormone , osteocalcin , and deoxypyridinoline . This study confirmed the value of alfacalcidol and antiresorptive agents in the treatment of osteopenia and osteoporosis in young renal transplant recipients . These therapies were safe , tolerable , simple to administer and potentially applicable to other renal transplant patients One hundred and twelve Caucasian girls , 11.9±0.5 years of age at entry , were r and omized into a 24-month , double-masked , placebo-controlled trial to determine the effect of calcium supplementation on bone mineral content , bone area and bone density . Supplementation was 500 mg calcium as calcium citrate malate ( CCM ) per day . Controls received placebo pills , and compliance of both groups averaged 72 % . Bone mineral content , bone mineral area and bone mineral density of the lumbar spine and total body were measured by dual energy X-ray absorptiometry ( DXA ) . Calcium intake from dietary sources averaged 983 mg/day for the entire study group . The supplemented group received , on average , an additional 360 mg calcium/day from CCM . At baseline and after 24 months , the two groups did not differ with respect to anthropometric measurements , urinary reproductive hormone levels or any measurement of pubertal progression . The supplemented group had greater increases of total body bone measures : content 39.9 % versus 35.7 % ( p=0.01 ) , area 24.2 % versus 22.5 % ( p=0.15 ) and density 12.2 % versus 10.1 % ( p=0.005 ) . Region-of-interest analyses showed that the supplemented group had greater gains compared with the control group for bone mineral density , content and area . In particular , in the lumbar spine and pelvis , the gains made by the supplemented group were 12%–24 % greater than the increases made by the control group . Bone acquisition rates in the two study groups were further compared by subdividing the groups into those with below- or above-median values for Tanner score and dietary calcium intake . In subjects with below-median Tanner scores , bone acquisition was not affected by calcium supplementation or dietary calicum level . However , the calcium supplemented subjects with above-median Tanner had higher bone acqusition rates than the placebo group with above-median Tanner scores . Relative to the placebo group , the supplemented group had increased yearly gains of bone content , area and density which represented about 1.5 % of adult female values . Such increases , if held to adult skeletal maturity , could provide protection against future risk of osteoporotic fractures There is limited information relating Ca intake to bone and height acquisition among Oriental children who consume little or even no milk . The present controlled study investigated the acquisition of bone mass and height of Chinese children with an initial Ca intake of approximately 567 mg/d who were supplemented to about 800 mg/d . Eighty-four 7-year-old Hong Kong Chinese children underwent an 18-month r and omized , double-blind , controlled Ca-supplementation trial . The children were r and omized to receive either 300 mg elemental Ca or a placebo tablet daily . Bone mass of the distal one-third radius was measured by single-photon absorptiometry , lumbar spine and femoral neck were determined using dual-energy X-ray absorptiometry . Measurements were repeated 6-monthly . Baseline serum 25-hydroxycholecalciferol concentration and physical activity were also assessed . Baseline Ca intakes of the study group and controls were respectively 571 ( SD 326 ) and 563 ( SD 337 ) mg/d . There were no significant differences in baseline serum 25-hydroxycholecalciferol concentration ( P = 0.71 ) and physical activity ( P = 0.36 ) between the study and control groups . After 18 months the study group had significantly greater increases in lumbar-spinal bone mineral content ( 20.9 v. 16.34 % ; P = 0.035 ) , lumbar-spinal area ( 11.16 v. 8.71 % ; P = 0.049 ) , and a moderately greater increment in areal bone mineral density of the radius ( 7.74 v. 6.00 % ; P = 0.081 ) when compared with the controls . The results confirm a positive effect of Ca on bone mass of the spine and radius but no effects on femoral-neck and height increase . A longer trial is warranted to confirm a positive Ca effect during childhood that may modify future peak bone mass Our recent 18‐month calcium supplementation trial demonstrated a significant increase in radial bone mineral mass in 7‐year‐old children with calcium intake ∼ 300 mg/day ( Am J Clin Nutr 1994 ; 60 : 744‐50 ) . The persistence of higher bone mass after cessation of calcium supplementation is unknown . This is a follow‐up study to investigate the lasting effect of calcium supplementation on bone acquisition . Subjects were 159 Chinese children aged 8.7 years . Distal one‐third radial bone mineral content ( BMC ) and bone width ( BW ) were measured by single‐photon absorptiometry . After 12 months , the significant difference in mean ± SD percentage radial BMC disappeared between the study and control groups ( 7.34 ± 6.77 % vs 8.67 ± 6.46 % . p > 0.05 )  . Dietary calcium intakes were similar between the groups . During the supplementation phase , the study group had 17.9 % greater BMC gain than that of controls . In the follow‐up phase , however , the study group had 16.1 % less BMC gain than that of controls . It appears that an increased acquisition rate during the supplementation phase was almost balanced by a reduced acquisition rate during follow‐up phase . Moreover , throughout the entire 30‐month period , the overall BMC acquisition rates of the study and control groups were 25 % and 23.8 % , respectively . Hence , the overall acquisition rate of the study group was only 5 % higher than that of controls . Therefore , the effect of calcium supplementation on bone mineral gain appears to reflect a transient reduction in bone turnover rate . Longer‐term calcium trials are necessary to confirm whether a sustainable higher calcium intake throughout childhood will enhance peak bone mass BACKGROUND Non-r and omised studies have suggested beneficial effects of bisphosphonates in osteogenesis imperfecta . We assessed the effects of oral olpadronate in children with this disorder in a r and omised double-blind placebo-controlled trial . METHODS 34 children recruited from the Dutch national centre for osteogenesis imperfecta were r and omly assigned olpadronate ( 10 mg/m2 daily ; n=16 ) or placebo ( n=18 ) for 2 years . All children also received calcium and vitamin D supplements . Primary endpoints were incident fractures of long bones and changes in bone mineral content ( BMC ) , bone mineral density ( BMD ) , and functional outcome . Anthropometry , vertebral height , and urinary markers of bone resorption were also studied . Analyses were by intention to treat . FINDINGS Fracture follow-up was complete for all the children , including two who withdrew from the study ( one from each group ) . Olpadronate treatment was associated with a 31 % reduction in relative risk of fracture of long bones ( hazard ratio 0.69 [ 95 % CI 0.52 - 0.91 ] , p=0.01 ) . The olpadronate group showed significantly greater increases than the placebo group in spinal BMC ( difference between groups 2.24 g/year [ 0.20 - 4.29 ] , p=0.03 ) and spinal BMD ( difference between groups 0.054 g/cm2 per year [ 0.012 - 0.096 ] , p=0.01 ) . There were no detectable effects on functional outcome , anthropometrics , or vertebral height and no differences between the groups in changes in urinary markers of bone resorption . INTERPRETATION Oral treatment with olpadronate at a daily dose of 10 mg/m2 results in a reduction of fracture risk of long bones in children with osteogenesis imperfecta . However , the issue of whether bisphosphonates will alter the natural course of osteogenesis imperfecta remains unresolved , and further studies are needed The purpose of this study was to evaluate the contributions of exercise , fitness , body composition , and calcium intake during adolescence to peak bone mineral density and bone structural measurements in young women . University Hospital and 75 healthy , white females in the longitudinal Penn State Young Women 's Health Study were included .  Body composition , total body , and hip bone mineral density ( BMD ) were measured by dual-energy X-ray absorptiometry ( DXA ) , exercise scores by sports-exercise question naire during ages 12 - 18 years , and estimated aerobic capacity by bike ergometry .  Section modulus values ( a measurement of bending strength ) cross-sectional area ( CSA ) , subperiosteal width , and cortical thickness were calculated from DXA scan data for the femoral neck and femoral shaft .  Calcium intakes were calculated from 39 days of prospect i ve food records collected at 13 timepoints between ages 12 and 20 years ; supplemental calcium intakes were included . Section moduli at the femoral neck and shaft were correlated significantly with lean body mass , sports-exercise scores ( R(2 ) = 0.07 - 0.19 , p < 0.05 ) , and aerobic capacity ( R(2 ) = 0.06 - 0.57 , p < 0.05 ) . Sports-exercise scores correlated with BMD at the femoral neck and shaft . Average total daily calcium intake at age 12 - 20 years ranged from 486 to 1958 mg/day and was not significantly associated with total or regional peak BMD or bone structure measures at 20 years of age . It was shown that achievable levels of exercise and fitness have a favorable effect on BMD and section modulus of the femoral neck and femoral shaft in young adult women , whereas daily calcium intake of > 500 mg in female adolescents appears to have little , if any effect Bone mineral density and fracture rates in children with osteogenesis imperfecta improve with intravenous bisphosphonates . The efficacy of oral bisphosphonates has not been established . This report is an analysis of an open-label , prospect i ve , r and omized clinical trial of oral compared to intravenous bisphosphonate medications in children with osteogenesis imperfecta . Children were stratified according to bone age , pubertal stage , and type of osteogenesis imperfecta and then r and omized to receive intravenous pamidronate , 3 mg/kg over 3 days every 4 months , or oral alendronate 1 mg/kg , from a minimum of 10 mg to a maximum of 20 mg daily . The primary efficacy outcome was change in bone mineral density . Secondary outcomes included change in biomarkers of bone turnover , fracture incidence , and growth rate .  Ten children were r and omized ( 6 oral and 4 intravenous ) . Two other children were assigned to intravenous treatment due to chronic abdominal pain . In each group , three patients had type III/IV osteogenesis imperfecta , while three had type I. All 12 children completed 8 months of therapy ; nine completed 12 months . Bone mineral density increased in both oral and intravenous groups equally and beyond that expected with normal growth . All children had a decrease in biochemical markers of bone turnover . Linear growth showed a moderate increase above that for age . There was a non-significant decrease in fracture incidence in both groups OBJECTIVE The effect of varying mineral intakes on total body bone mass accretion during the first year of life in healthy full-term infants is unknown . The purpose of this study was to determine whether total body bone mass accretion during the first year of life was influenced by the calcium and phosphorus intake of an infant and whether early differences in bone accretion persist through 1 year of age . DESIGN This prospect i ve , r and omized trial was conducted in two phases . In phase I , 67 infants were r and omized within the first 2 weeks of life into either a low ( 439 mg of calcium per liter and 240 mg of phosphorus per liter ) or moderate ( 510 mg of calcium per liter and 390 mg of phosphorus per liter ) mineral-containing formula feeding group . An additional group of 34 human milk-fed ( low mineral ) infants also was enrolled . Phase II involved an additional r and omization of all infants at 6 months of age into moderate-mineral formula ( see above ) , high-mineral formula ( 1350 mg of calcium per liter and 900 mg of phosphorus per liter ) , or cow milk ( 1230 mg of calcium per liter and 960 mg of phosphorus per liter ) feeding group . Anthropometric measurements , nutrient intake , and total body bone mineral content ( BMC ) by dual-energy x-ray absorptiometry were measured at 1 , 3 , 6 , 9 , and 12 months . RESULTS During the first 6 months , the moderate-mineral group had a greater increase in weight ( 3.42 + /- 0.62 kg ) compared with the human milk group ( 2.93 + /- 0.56 kg ) ; the low-mineral group ( 3.19 + /- 0.62 kg ) was intermediate . Bone mass accretion differed in a similar direction , with the moderate-mineral feeding group having a greater increase than the human milk group and the low-mineral group being intermediate of the two . Including weight , length , and bone area as covariates , both the low-mineral formula- and human milk-fed groups had similar BMC , which was lower than that of the moderate-mineral group at 3 and 6 months of age . Adjusted mean BMC values for the moderate-mineral formula-fed group compared with the low-mineral formula- and human milk-fed groups were 127.8 + /- 1.5 ( SEM ) g vs 119 . 2 + /- 1.5 and 122.1 + /- 1.4 g , respectively , at 3 months of age and 168.7 + /- 2.5 g vs 157.6 + /- 2.5 and 158.7 + /- 2.4 g , respectively , at 6 months of age . The BMC at 6 months of age among the formula-fed infants was correlated with both average dietary phosphorus intake ( r = .592 ) and average daily calcium intake ( r = .620 ) during the first 6 months . The relationships between BMC and these minerals remained significant even after controlling for caloric intake . It was not possible to determine the independent effects of dietary calcium and phosphorus on BMC because of the strong correlation of these minerals with each other . Despite significant differences in both calcium and phosphorus intakes during the second 6 months of life , there were no differences in growth parameters or bone mass accretion . Means for BMC , adjusted for body weight , length , and bone area , were not significantly different among feeding groups at either 9 or 12 months of age . Adjusted means were 199 + /- 2 ( SEM ) and 237 + /- 3 g at 9 and 12 months of age for infants receiving moderate-mineral formula ; 198 + /- 2 and 236 + /- 3 g at 9 and 12 months of age for infants receiving the high-mineral formulas and 202 + /- 5 and 233 + /- 5 g at 9 and 12 months of age for infants receiving  cow milk . The gain in bone mass during the second 6 months differed by the first 6-month feeding group ; mean changes in BMC between 6 and 12 months , adjusted for changes in weight , length , and bone area , were greater in human milk-fed infants than in either the low- or moderate-mineral-containing formula groups : 81 + /- 16 g in human milk-fed infants and 73 + /- 15 and 71 + /- 15 g in the low- and moderate-mineral formula groups , respectively . Infants fed whole cow milk during the second 6 months were excluded from this analysis because of the small number of infants completing the study . By 12 months of age A 2-year milk intervention trial was carried out with 757 girls , aged 10 years , from nine primary schools in Beijing ( April 1999 - March 2001 ) . Schools were r and omised into three groups : group 1 , 238 girls consumed a carton of 330 ml milk fortified with Ca on school days over the study period ; group 2 , 260 girls received the same quantity of milk additionally fortified with 5 or 8 microg cholecalciferol ;  group 3 , 259 control girls .  Anthropometric and bone mineralisation measurements , as well as dietary , health and physical-activity data , were collected at baseline and after 12 and 24 months of the trial . Over the 2-year period the consumption of this milk , with or without added cholecalciferol , led to significant increases in the changes in height ( > or = 0.6 % ) , sitting height ( > or = 0.8 % ) , body weight ( > or 2.9 % ) , and ( size-adjusted ) total-body bone mineral content ( > or = 1.2 % ) and bone mineral density ( > or = 3.2 % ) . Those subjects receiving additional cholecalciferol compared with those receiving the milk without added 25-hydoxycholecalciferol had significantly greater increases in the change in ( size-adjusted ) total-body bone mineral content ( 2.4 v. 1.2 % ) and bone mineral density ( 5.5 v. 3.2 % ) . The milk fortified with cholecalciferol significantly improved vitamin D status at the end of the trial compared with the milk alone or control groups . It is concluded that an increase in milk consumption , e.g. by means of school milk programmes , would improve bone growth during adolescence , particularly when Ca intake and vitamin D status are low Combining exercise with calcium supplementation may produce additive or multiplicative effects at loaded sites ; thus , we conducted a single blind , prospect i ve , r and omized controlled study in pre- and early-pubertal girls to test the following hypotheses . ( 1 ) At the loaded sites , exercise and calcium will produce greater benefits than exercise or calcium alone . ( 2 ) At non-loaded sites , exercise will have no benefit , whereas calcium with or without exercise will increase bone mass over that in exercise alone or no intervention . Sixty-six girls aged 8.8 + /- 0.1 years were r and omly assigned to one of four study groups : moderate-impact exercise with or without calcium or low-impact exercise with or without calcium . All participants exercised for 20 minutes , three times a week and received Ca-fortified ( 434 + /- 19 mg/day ) or non-fortified foods for 8.5 months . Analysis of covariance ( ANCOVA ) was used to determine interaction and main effects for  exercise and calcium  on bone mass after adjusting for baseline bone mineral content and growth in limb lengths . An exercise-calcium interaction was detected at the femur ( 7.1 % , p < 0.05 ) . In contrast , there was no  exercise-calcium interaction detected at the tibia-fibula ; however , there was a main effect of exercise : bone mineral content increased 3 % more in the exercise than non-exercise groups ( p < 0.05 ) . Bone mineral content increased 2 - 4 % more in the calcium-supplemented groups than the non-supplemented groups at the humerus ( 12.0 % vs. 9.8 % , respectively , p < 0.09 ) and radius-ulna ( 12.6 % vs. 8.6 % , respectively , p < 0.01 ) . In conclusion , greater gains in bone mass at loaded sites may be achieved when short bouts of moderate exercise are combined with increased dietary calcium , the former conferring region-specific effects and the latter producing generalized effects The goal of health education is to provide information to affect attitudes , beliefs , and intentions for behavior change . However , little is known about the effects of changes in knowledge on behaviors for osteoporosis prevention . Our objective is to develop and test theoretical models of the effects of knowledge , attitude , and self-efficacy on exercise and calcium intake among young women before and after an intervention program .  First , we hypothesized that knowledge would positively predict attitude , self-efficacy , calcium intake , and exercise .  Second , attitude would positively predict self-efficacy , calcium intake , and exercise .  Third , self-efficacy would positively predict calcium intake and exercise  . Fourth , attitude and self-efficacy would mediate the effect of knowledge on calcium intake and exercise . At the beginning and end of the study , participants in the control group and intervention group completed the  osteoporosis knowledge test , the osteoporosis health belief scale , the osteoporosis self-efficacy scale , a self-report for food records , and exercise .  The causal model was examined as a result of our study . After the intervention program ,  calcium intake and exercise  were predicted by knowledge when mediated by attitudes and self-efficacy . The final model accounted for 30 % and 45 % of the variance in calcium intake and exercise , respectively . We conclude that interventions to enhance young women 's  knowledge and self-efficacy may result in increased calcium intake and exercise OBJECTIVE To evaluate the effect of calcium supplementation on bone acquisition in adolescent white girls . DESIGN A r and omized , double-blind , placebo-controlled trial of the effect of 18 months of calcium supplementation on bone density and bone mass . SUBJECTS Ninety-four girls with a mean age of 11.9 + 0.5 years at study entry . SETTING University hospital in a small town . INTERVENTIONS Calcium supplementation , 500 mg/d calcium as calcium citrate malate ; controls received placebo pills . MAIN OUTCOME MEASURES Bone mineral density and bone mineral content of the lumbar spine and total body were measured by dual-energy x-ray absorptiometry and calcium excretion from 24-hour urine specimens . RESULTS Calcium intake from dietary sources averaged 960 mg/d for the entire study group . The supplemented group received , on average , an additional 354 mg/d of calcium . The supplemented group compared with the placebo group had greater increases of lumbar spine bone density ( 18.7 % vs 15.8 % ; P = .03 ) , lumbar spine bone mineral content ( 39.4 % vs 34.7 % ; P = .06 ) , total body bone mineral density ( 9.6 % vs 8.3 % ; P = .05 ) , and 24-hour urinary calcium excretion ( 90.4 vs 72.9 mg/d ; P = .02 ) , respectively . CONCLUSIONS Increasing daily calcium intake from 80 % of the recommended daily allowance to 110 % via supplementation with calcium citrate malate result ed in significant increases in total body and spinal bone density in adolescent girls . The increase of 24 g of bone gain per year among the supplemented group translates to an additional 1.3 % skeletal mass per year during adolescent growth , which may provide protection against future osteoporotic fracture BACKGROUND Calcium supplementation during childhood and adolescence is considered an early means of preventing osteoporosis in adults . Prepuberty is an opportune time for detecting the benefits of calcium in girls . OBJECTIVE The objective was to assess whether calcium supplementation increases bone mass gain in prepubertal boys in a skeletal site-specific manner . METHODS In a 12-month double-blind , placebo-controlled trial with 1-yr follow-up , 235 healthy prepubertal boys aged 7.4 + /- 0.4 yr ( mean + /- sd ) were r and omized to receive two food products providing 850 mg/d calcium ( calcium supplement group , n = 116 ) or an isocaloric placebo ( n = 119 ) . Areal bone mineral density ( aBMD ) was determined by dual-energy x-ray absorptiometry at radius ( two sites ) , hip ( two sites ) , femoral diaphysis ( FDia ) , and L2-L4 vertebrae . RESULTS At 12 months , aBMD gain was greater at the FDia and at the mean of the five appendicular skeletal sites in the calcium supplement group in both intention-to-treat analysis [ 76 + /- 32 vs. 64 + /- 33 mg/cm(2).yr ; difference , 12.0 ( 95 % confidence interval , CI , 3.6 - 20.3 ) , P = 0.006 ; and 33 + /- 16 vs. 28 + /- 16 mg/cm(2).yr ; difference , 5.1 ( 95 % CI , 0.9 - 9.2 ) ; P = 0.018 , respectively ] and active treatment analysis [ 81 + /- 32 vs. 64 + /- 31 mg/cm(2).yr ; difference , 17.2 ( 95 % CI , 7.9 - 26.5 ) ; n = 174 , P < 0.001 ; and 35 + /- 16 vs. 28 + /- 14 mg/cm(2).yr ; difference , 7.5 ( 95 % CI , 2.9 - 12.2 ) ; P = 0.002 ] . There was no beneficial effect of calcium on lumbar spine . The calcium effect was still detectable by ANOVA repeated measures analysis at the FDia ( P = 0.004 ) and at the mean of the five appendicular skeletal sites ( P = 0.002 ) 1 yr after the end of intervention ( active treatment analysis ) . There was no change in bone size . CONCLUSION In prepubertal boys , calcium-enriched foods increased aBMD at several appendicular skeleton sites , but not at the lumbar spine , and this without any bone size change . This effect was maintained 1 yr after treatment discontinuation A cross-sectional study of a r and om sample of 649 girls , aged 12 - 14 years ( mean + /- SD : 12.9 + /- 0.6 years ) , in the Beijing area examined the relationship between diet and bone mineral status . Food and nutrient intakes over the past year were estimated by means of a semiquantitative food frequency question naire . Bone mineral content ( BMC ) and bone width ( BW ) at the distal one-third and one-tenth radius and ulna were measured by single-photon absorptiometry . Results showed Beijing pubertal girls had a low mean milk consumption  ( fresh and powdered milk , vitamin D-fortified milk , and yogurt ) at 50 g/day ( 95 % confidence interval [ CI ] 44 - 55 g/day whereas one-third consumed no milk at all . Mean calcium intake was 356 + /- 97 mg/day of which only 21 % was provided by milk and milk products .  Milk intake varied by region ( rural , suburban , and urban : 9 , 36 , and 83 g/day , respectively , p < 0.0005 ) as did the proportion of milk consumers in the three areas ( 30 % , 64 % , and 91 % , p < 0.0005 ) . Bone mineral density ( BMD ) at the distal one-third and one-tenth radius and one-tenth ulna was positively associated with milk consumption ( p < 0.05 ) . Multiple regression analysis of BMC on foods and nutrients as well as confounding factors , including weight , bone age , Tanner stage , and School Physical Activity Score ( SPAS ) , showed that milk intake was the only dietary factor included in the models for BMC at the four bone sites measured . The model explained 54%-65 % of the variation in BMC , and milk alone accounted for up to 3.2 % of the variation . Milk was the only food group with significant partial correlation with BMC . SPAS , weight , bone age , and Tanner stage each accounted for a smaller variation in BMC ( < 1.8 % ) . The results indicate that milk ( presumably as an integrated source of nutrients ) had a beneficial effect on bone mass of Beijing pubertal girls and was a better nutritional determinant of BMC than intake of any milk nutrient alone . Promotion of milk consumption should be considered for achieving optimal bone mass in this population group BACKGROUND This paper describes decisions about the experimental design for the Youth , Osteoporosis , and Underst and ing Total Health Project ( YOUTH ) , a trial design ed to test the efficacy of a health plan-based lifestyle intervention for increasing bone mineral density among adolescent women 14 to 16 years of age . METHODS This r and omized controlled trial recruited adolescent women who were at higher risk for developing osteoporosis ( body mass index 16 - 23 ) from a large HMO in the Pacific Northwest . The intervention focused on improving diet ( high calcium foods , fruits , and vegetables ) and increasing physical activity ( high impact and spinal motion ) . The intervention included both group and individual activities . The primary endpoint in the study was total bone mineral density as measured by dual-energy X-ray absorptiometry ( DEXA ) . RESULTS Baseline data were collected on the trial cohort of 228 adolescent women and their families . This paper discusses how research ers met the following challenges in design ing and implementing the trial : determining appropriate dietary and exercise targets to affect bone mineral density in adolescents ; choosing suitable assessment s ; and developing an intervention well suited for implementation in a non-school ( health plan ) setting . We also discuss the rationale for the specific study population chosen ( females , younger adolescents ) . CONCLUSIONS The YOUTH project is one of very few preventive research interventions with adolescents conducted in a health plan setting . Many of the recruitment and intervention strategies used in this trial may be appropriate for adoption in other health plan-based prevention studies This study examined the effects of increasing milk on bone and body composition responses to resistance training in adolescents . Twenty-eight boys ( 13 to 17 years of age ) were r and omly assigned to consume , in addition to their habitual diet , 3 servings/day of 1 % fluid milk ( n=14 ) or juice not fortified with calcium ( n=14 ) while engaged in a 12-week resistance-training program . For all subjects combined , there were significant ( P < or=.05 ) changes in height ( + 0.5 % ) , sigmaseven skin folds ( -7.7 % ) , body mass ( + 2.6 % ) , lean body mass ( + 5.1 % ) , fat mass ( -9.3 % ) , whole-body bone mineral content ( + 3.6 % ) , bone mineral density ( + 1.8 % ) , and maximal strength in the squat ( + 43 % ) and bench press ( + 23 % ) . Compared with juice , the milk group had a significantly greater increase in bone mineral density ( 0.014 vs 0.028 g/cm(2 ) ) . Increasing intake of milk in physically active adolescent boys may enhance bone health The age and developmental stage at which calcium supplementation produces the greatest bone effects remain controversial . We tested the hypothesis that calcium supplementation may improve bone accrual in premenarcheal females . Fifty-one pairs of premenarcheal female twins ( 27 monozygotic and 24 dizygotic ; mean + /- sd age , 10.3 + /- 1.5 yr ) participated in a r and omized , single-blind , placebo-controlled trial with one twin of each pair receiving a 1200-mg calcium carbonate ( Caltrate ) supplement .  Areal bone mineral density ( aBMD ) was measured at baseline and 6 , 12 , 18 and 24 months . There were no within-pair differences in height , weight , or calcium intake at baseline .  Calcium supplementation was associated ( P < 0.05 ) with increased aBMD compared with placebo , adjusted for age , height , and weight at the following time points from baseline : total hip , 6 months ( 1.9 % ) , 12 months ( 1.6 % ) , and 18 months ( 2.4 % ) ; lumbar spine , 12 months ( 1.0 % ) ; femoral neck , 6 months ( 1.9 % ) . Adjusted total body bone mineral content was higher in the calcium group at 6 months ( 2.0 % ) , 12 months ( 2.5 % ) , 18 months ( 4.6 % ) , and 24 months ( 3.7 % ) , respectively ( all P < 0.001 ) . Calcium supplementation was effective in increasing aBMD at regional sites over the first 12 - 18 months , but these gains were not maintained to 24 months A meta- analysis of adult exercise studies and an infant activity trial show a possible interaction between physical activity and calcium intake on bone . This r and omized trial of activity and calcium supplementation was conducted in 239 children aged 3 - 5 years ( 178 completed ) . Children were r and omized to participate in either gross motor or fine motor activities for 30 minutes/day , 5 days per week for 12 months . Within each group , children received either calcium ( 1000 mg/day ) or placebo .  Total body and regional bone mineral content by DXA and 20 % distal tibia measurements by peripheral quantitative computed tomography ( pQCT ) were obtained at 0 and 12 months . Three-day diet records and 48-h accelerometer readings were obtained at 0 , 6 , and 12 months . Higher activity levels were observed in gross motor versus fine motor activity groups , and calcium intake was greater in calcium versus placebo ( 1354 + /- 301 vs. 940 + /- 258 mg/day , p < 0.001 ) . Main effects of activity and calcium group were not significant for total body bone mineral content or leg bone mineral content by DXA . However , the difference in leg bone mineral content gain between gross motor and fine motor was more pronounced in children receiving calcium versus placebo ( interaction , p = 0.05 ) . Children in the gross motor group had greater tibia periosteal and endosteal circumferences by pQCT compared with children in the fine motor group at study completion ( p < 0.05 ) . There was a significant interaction ( both p < or = 0.02 ) between supplement and activity groups in both cortical thickness and cortical area : among children receiving placebo , thickness and area were smaller with gross motor activity compared with fine motor activity , but among children receiving calcium , thickness and area were larger with gross motor activity . These findings indicate that calcium intake modifies the bone response to activity in young children BACKGROUND Maximal bone acquisition in adolescent girls through dietary and lifestyle practice s is advocated to prevent or minimize the development of osteoporosis and its associated complications in later life . Longitudinal investigations of bone acquisition in children and adolescents have utilized areal bone mineral density ( BMD , mg/cm(2 ) ) as a measure of bone mass and strength . Peripheral quantitative computed tomography ( pQCT ) , which provides a three-dimensional display of data , separate analyses of bone compartments , and bone mass in terms of volumetric BMD ( vBMD , mg/cm(3 ) ) , has recently been introduced for clinical use . OBJECTIVE To assess the impact of a 12-month daily calcium supplement on total and trabecular bone acquisition as measured by pQCT in preadolescent girls . DESIGN Early adolescent Caucasian girls ( aged 12 years , Tanner Stage 2 ) were enrolled in a r and omized trial of daily calcium supplement ( TX , 800 mg calcium carbonate and 400 IU vitamin D ) or placebo ( C ) . Body weight , height , and distal tibia measurements by pQCT were obtained at enrollment , 6 and 12 months . Pubertal status and physical activity records were assessed at baseline and 12 months . Three-day food intake records were completed every three months . RESULTS Seventy-one girls completed the 12-month trial ( TX=35 , C=36 ) . No differences were found for age , weight , height , body mass index , pubertal maturation , or reported physical activity at enrollment or during the study . Average intakes during the study were 1524 mg calcium and 496 IU vitamin D ( TX ) versus 865 mg calcium and 160 IU vitamin D ( C ) per day . Baseline total bone values were similar , however , trabecular values were greater in TX girls despite r and omization . Percent changes were calculated to adjust for baseline differences . Because of the small cortical thickness at the 10 % site ( mean values < 1.6 mm ) , cortical mass and density were not analyzed . The percent changes for trabecular bone mineral content ( BMC , mg ) and vBMD were significantly greater in TX girls ( + 4.1 % BMC and + 1.0 % vBMD TX versus -1.6 % BMC and -2.0 % vBMD C , p<0.006 ; ANCOVA ) after 12 months of supplement . Trabecular bone area ( BA , cm(2 ) ) and total bone change , however , did not differ between groups . CONCLUSIONS Daily calcium and vitamin D supplementation promotes greater trabecular BMC and vBMD acquisition in preadolescent girls . The single site selected for pQCT evaluation in this study did not allow evaluation of the cortical bone compartment . Future studies that utilize the pQCT technique need to incorporate multiple measurement sites to better assess total , cortical , and trabecular bone The effect of calcium carbonate supplementation on bone growth and mineral accretion was studied in 143 boys aged 16 - 18 yr , r and omized to 1000 mg Ca/d or a matching placebo for 13 months .  Anthropometry and dual-energy x-ray absorptiometry of the whole body , lumbar spine , hip , and forearm were performed before , during , and after the intervention . The intervention result ed in greater bone mineral content ( BMC ) of the whole body ( + 1.3 % , P = 0.02 ) , lumbar spine ( + 2.5 % , P = 0.004 ) , and hip ( total + 2.3 % , P = 0.01 ; neck + 2.4 % , P = 0.02 ; intertrochanter + 2.7 % , P = 0.01 ) . This was associated with greater height ( + 0.4 % , P = 0.0004 , equivalent to 7 mm ) , lean mass ( + 1.3 % , P = 0.02 ) , and lumbar spine bone area ( + 1.5 % , P = 0.003 ) . The increases in BMC diminished after size adjustment , suggesting that the intervention effect was mediated through an effect on growth . The BMC response at the intertrochanter was greater in subjects with high physical activity ( + 4.4 % , P = 0.05 ) . There were no other significant interactions with physical activity , plasma testosterone , calcium intake , or tablet compliance . We conclude that calcium carbonate supplementation  of adolescent boys increased skeletal growth , result ing in greater stature and bone mineral acquisition . Follow-up studies will determine whether this reflects a change in the tempo of growth or an effect on skeletal size that persists into adulthood Twelve months of a consistent average daily intake of calcium to at least the 1200-mg Recommended Dietary Allowance ( RDA ) was achieved by 22 adolescent girls . At the end of the year the calcium-enriched group showed no significant differences in body composition , bone mass , or bone density from peers consuming an average of 728 mg of calcium The aim of our longitudinal study was to evaluate bone mass in girls affected by central precocious puberty ( CPP ) that have reached final height , treated with GnRH agonist triptorelin ( GnRHa ) , with or without calcium supplementation . We studied 48 Caucasian females affected by CPP ( age at diagnosis , 7.19 + /- 0.96 yr ) , r and omly assigned to two groups : group A ( n = 21 ) treated with GnRHa and group B ( n = 27 ) treated with GnRHa plus calcium gluconolactate and carbonate ( 1 g calcium/day in two doses ) for at least 2 yr . Auxological parameters ( st and ing height , weight , body mass index ) and bone mineral density ( BMD ) at the lumbar spine [ L2-L4 , anteroposterior (AP)-BMD ; lateral BMD ; volumetric (v)BMD ) ] by dual-energy x-ray absorptiometry were evaluated at the beginning [ chronological age ( CA ) , 7.29 + /- 0.91 yr ; bone age ( BA ) , 8.80 + /- 1.24 yr ] and end of treatment ( CA , 11.27 + /- 0.97 yr ; BA , 12.35 + /- 0.43 yr ) and at final height ( CA , 16.17 + /- 1.9 yr ; BA , 16.93 + /- 0.98 yr , in each case > 15 yr ) . Total bone mineral content , total BMD , and fat percentage were evaluated at the end of the study period using dual-energy x-ray absorptiometry . Final height was significantly higher than predicted height at diagnosis ( 159.9 + /- 6.3 cm vs. 152.9 + /- 9.6 cm ; P < 0.05 ) . Body mass index and fat percentage were not statistically different from control values . Densitometric values at final evaluation in groups A and B together were lower than in controls , but the differences were not statistically significant . The vBMD was significantly higher in group B than in group A at the end of treatment period ( 0.213 + /- 0.022 g/cm(3 ) vs. 0.192 + /- 0.021 g/cm(3 ) ; P < 0.01 ) and at final evaluation ( 0.246 + /- 0.023 g/cm(3 ) vs. 0.227 + /- 0.024 g/cm(3 ) ; P < 0.05 ) . The percentage change ( Delta% ) between the start and end of treatment period in AP-BMD and vBMD was significantly higher in group B than in group A ( Delta% AP-BMD : 20.36 % + /- 1.10 % vs. 16.16 % + /- 1.90 % , P < 0.01 ; Delta% vBMD : 19.08 % + /- 3.52 % vs. 9.26 % + /- 5.15 % ; P < 0.01 ) and also between the start of treatment and final evaluation ( Delta% AP-BMD : 61.23 % + /- 1.61 % vs. 56.97 % + /- 1.45 % , P < 0.01 ; Delta% vBMD : 36.69 % + /- 5.01 % vs. 28.01 % + /- 5.76 % , P < 0.01 ) . In all our females with CPP treated with GnRHa , bone densitometric parameters were in the normal range for age and sex . However , bone mass achievement seemed to be better preserved in the group of patients supplemented with calcium Abstract Objectives : To investigate the effect of milk supplementation on total body bone mineral acquisition in adolescent girls . Design : 18 month , open r and omised intervention trial . Subjects : 82 white girls aged 12.2 ( SD 0.3 ) years , recruited from four secondary schools in Sheffield . Intervention : 568 ml ( one pint ) of whole or reduced fat milk per day for 18 months . Main outcome measures : Total body bone mineral content and bone mineral density measured by dual energy x ray absorptiometry . Outcome measures to evaluate mechanism included biochemical markers of bone turnover ( osteocalcin , bone alkaline phosphatase , deoxypyridinoline , N-telopeptide of type I collagen ) , and hormones important to skeletal growth ( parathyroid hormone , oestradiol , insulin-like growth factor I ) . Results : 80 subjects completed the trial .  Daily milk intake at baseline averaged 150 ml in both groups . The intervention group consumed , on average , an additional 300 ml a day throughout the trial . Compared with the control group , the intervention group had greater increases of bone mineral density ( 9.6 % v 8.5 % , P=0.017 ; repeated measures analysis of variance ) and bone mineral content ( 27.0 % v 24.1 % , P=0.009 ) . No significant differences in increments in height , weight , lean body mass , and fat mass were observed between the groups . Bone turnover was not affected by milk supplementation . Serum concentrations of insulin-like growth factor I increased in the milk group compared with the control group ( 35 % v 25 % , P=0.02 ) . Conclusion : Increased milk consumption significantly enhances bone mineral acquisition in adolescent girls and could favourably modify attainment of peak bone mass . Key messages Osteoporosis is a major public health problem ; 40 % of women will sustain an osteoporotic fracture Maximising peak bone mass at skeletal maturity may be one of the most important protective measures against fracture in later life Adolescence is a critical time for bone mineral acquisition An increase in milk consumption among adolescent girls result ed in significant gains in bone mineral over an 18 month period This simple intervention indicates that increased milk consumption may be associated with higher peak bone OBJECTIVE To study the effect of calcium supplementation with dairy products on the bone and body composition of pubertal girls . DESIGN R and omized control study with 12-month follow-up . SETTING General community . SUBJECTS Forty-eight white girls whose mean age was 11 years and sexual development at Tanner stage 2 . INTERVENTION One group 's diet was supplemented with dairy products to the recommended dietary allowance of 1200 mg calcium daily . The other group ate their usual diet . MAIN OUTCOME MEASURES Bone mineral content and density were measured at the radius , femoral neck , lumbar spine , and total body bone mineral by single-photon and dual-energy x-ray absorptiometry at the start of the study and after 3 , 6 , 9 , and 12 months . Body composition ( lean body mass and body fat ) was measured by dual-energy x-ray absorptiometry at the same intervals . Serum calcium , phosphate , 25-hydroxyvitamin D , 1,25-dihydroxyvitamin D , alkaline phosphatase , magnesium , and albumin concentrations were determined at the start and end of the study . The urinary calcium/creatinine ratio and hydroxyproline concentration were also determined . RESULTS The dairy group had higher intakes of calcium , phosphate , vitamin D , and protein than control subjects . The dairy group had significantly greater increases during the 1-year study in bone mineral density at the lumbar spine bones ( 22.8 % + /- 6.9 % vs 12.9 % + /- 8.3 % ) and in total body bone mineral ( 14.2 % + /- 7.0 % vs 7.6 % + /- 6.0 % ) than control subjects . Dietary calcium , phosphate , vitamin D , and protein intakes were associated with the lumbar bone density and total body bone calcium . There were no differences in serum or urinary biochemical values between the two groups at the start or end of the study . CONCLUSIONS Young girls whose dietary calcium intake was provided primarily by dairy products at or above the recommended dietary allowances had an increased rate of bone mineralization . Increased intake of dairy foods did not increase overall total or saturated fat intake and was not associated with excessive weight gain or increased body fat Summary Background Bone mineral density ( BMD ) is largely genetically determined and this influence is most powerful in the period of rapid skeletal development in childhood and late adolescence but environmental factors such as exercise and dietary calcium intake may influence up to 20 % . Aims of the study The aims of the study were to examine healthy late adolescent females for the effects and benefits of a high calcium intake from dairy product foods on bone mineral density , body composition , lipids and biochemistry . The secondary aim is determine whether a high intake of dairy product foods in the diet is acceptable for this age group long term . Methods Ninety-one teenage girls who participated in a two-year r and omised controlled study on the effect of dairy food supplementation on dietary patterns , body composition and bone density in post-pubertal teenage girls were approached one year after the cessation of the study to determine the effects of the cessation of dairy supplements on bone mineral density , dietary habits , biochemical markers , body composition and blood lipids . Bone mineral density and bone mineral content were assessed at the hip , spine and total body . Anthropometric data were collected , and exercise , Tanner , dietary assessment , preference and compliance question naires were administered . Lipid profiles , hydroxyproline excretion and urinary calcium and sodium excretion measurements were performed . Results There were no significant differences between the 2 groups for height , weight , lean and fat mass . The supplemented group had significantly higher calcium , phosphorus and protein intake during the supplementation period ( p<0.001 ) . No differences were seen between the groups 12 months after supplementation finished . There were no significant differences in exercise level , preference or acceptability of dairy products or in the lipids and bone markers between baseline the end of supplementation and 1 year follow-up . There was a significant increase in trochanter ( 4.6 % ) , lumbar spine ( 1.5 % ) and femoral neck ( 4.8 % ) BMD ( p<0.05 ) in the high calcium group at the end of supplementation . There was an increase in bone mineral content at the trochanter ( p<0.05 ) and lumbar spine ; however the latter was not statistically significant , in the high calcium group at the end of supplementation . There was no difference in vertebral height or width at any stage of the study , indicating no influence on bone size . Conclusions In this 3 year study ( 2 years of supplementation , 1 year follow-up ) , teenage girls , aged 15–18 years , were able to significantly increase their BMD at the trochanter , femoral neck and lumbar spine when supplemented with dairy product foods to a mean calcium intake of 1160 mg/d . There was also an effect seen on the BMC particularly at the trochanter and to a lesser extent at the lumbar spine . The dietary calcium intake achieved did not adversely affect body weight , fat and lean mass or blood lipid profiles . Twelve months after the supplementation finished the girls had returned to their baseline diet , indicating self- selection of a high dairy product diet may be hard to achieve Both late menarcheal age and low calcium intake ( Ca intake ) during growth are risk factors for osteoporosis , probably by impairing peak bone mass . We investigated whether lasting gain in areal bone mineral density ( aBMD ) in response to increased Ca intake varies according to menarcheal age and , conversely , whether Ca intake could influence menarcheal age . In an initial study , 144 prepubertal girls were r and omized in a double-blind controlled trial to receive either a Ca supplement ( Ca-suppl . ) of 850 mg/d or placebo  from age 7.9 - 8.9 yr .  Mean aBMD gain determined by dual energy x-ray absorptiometry at six sites ( radius metaphysis , radius diaphysis , femoral neck , trochanter , femoral diaphysis , and L2-L4 ) was significantly ( P = 0.004 ) greater in the Ca-suppl . than in the placebo group ( 27 vs. 21 mg/cm(2 ) ) . In 122 girls followed up , menarcheal age was recorded , and aBMD was determined at 16.4 yr of age . Menarcheal age was lower in the Ca-suppl . than in the placebo group ( P = 0.048 ) . Menarcheal age and Ca intake were negatively correlated ( r = -0.35 ; P < 0.001 ) , as were aBMD gains from age 7.9 - 16.4 yr and menarcheal age at all skeletal sites ( range : r = -0.41 to r = -0.22 ; P < 0.001 to P = 0.016 ) . The positive effect of  Ca-suppl .  on the mean aBMD gain from baseline remained significantly greater in girls below , but not in those above , the median of menarcheal age ( 13.0 yr ) . Early menarcheal age ( 12.1 + /- 0.5 yr ) : placebo , 286 + /- 36 mg/cm(2 ) ; Ca-suppl . , 317 + /- 46 ( P = 0.009 ) ; late menarcheal age ( 13.9 + /- 0.5 yr ) : placebo , 284 + /- 58 ; Ca-suppl . , 276 + /- 50 ( P > 0.05 ) . The level of Ca intake during prepuberty may influence the timing of menarche , which , in turn , could influence long-term bone mass gain in response to Ca supplementation . Thus , both determinants of early menarcheal age and high Ca intake may positively interact on bone mineral mass accrual Calcium intake is one of the most important predictors of the amount of bone mass gained during growth . Therefore , this study was design ed to estimate the dietary calcium intake of Costa Rican urban and rural adolescents ages 13 - 18 years old .  Calcium dietary intake was determined using prospect i ve 3-d diet records . Two-thirds ( or 66.7 % ) or less of the Adequate Intake ( AI ) was used as the criterion for inadequate calcium intake as suggested by several authors . Reported mean daily calcium intake was 573 mg + /- 290 . On average 82 % of the adolescents did not meet two-thirds of the Al for calcium . A higher percentage of rural than urban youngsters reported inadequate calcium intake ( 92 % and 75 % respectively , p = 0.000 ) . Likewise a higher percentage of girls ( 91 % ) than boys ( 77 % ) reported marginal calcium intake . This study shows evidence that nutritional interventions and educational strategies are urgent for increasing calcium consumption among adolescents in order to reduce the future burden of osteoporosis in old age BACKGROUND Increased dietary intake of calcium during childhood , usually as calcium in milk , is associated with increased bone mass in adulthood ; the increase in mass is important in modifying the later risk of fracture . Whether the increase is due to the calcium content of milk , however , is not certain . METHODS We conducted a three-year , double-blind , placebo-controlled trial of the effect of calcium supplementation ( 1000 mg of calcium citrate malate per day ) on bone mineral density in 70 pairs of identical twins ( mean [ + /- SD ] age , 10 + /- 2 years ; range , 6 to 14 ) . In each pair , one twin served as a control for the other ; 45 pairs completed the study .  Bone mineral density was measured by photon absorptiometry at two sites in the radius ( at base line , six months , and one , two , and three years ) and at three sites in the hip and in the spine ( at base line and three years ) . RESULTS The mean daily calcium intake of the twins given placebo was 908 mg , and that of the twins given calcium supplements was 1612 mg ( 894 mg from the diet and 718 mg from the supplement ) . Among the 22 twin pairs who were prepubertal throughout the study , the twins given supplements had significantly greater increases in bone mineral density at both radial sites ( mean difference in the increase in bone mineral density : midshaft radius , 5.1 percent [ 95 percent confidence interval , 1.5 to 8.7 percent ] ; distal radius , 3.8 percent [ 95 percent confidence interval , 1.4 to 6.2 percent ] ) and in the lumbar spine ( increase , 2.8 percent [ 95 percent confidence interval , 1.1 to 4.5 percent ] ) after three years ; the differences in the increases at two of three femoral sites approached significance ( Ward 's triangle in the femoral neck , 2.9 percent ; greater trochanter , 3.5 percent ) . Among the 23 pairs who went through puberty or were postpubertal , the twins given supplements received no benefit . CONCLUSIONS In prepubertal children whose average dietary intake of calcium approximated the recommended dietary allowance , calcium supplementation increased the rate of increase in bone mineral density . If the gain persists , peak bone density should be increased and the risk of fracture reduced * The up date s are underlined for quick reference . INTRODUCTION A critical need exists for efficient , measurable systems of disease management that reconcile conflicts between socioeconomic responsibility and patient welfare . Clinical guidelines have become an important component of these systems because they address elements of care that are effective and that reduce the variability in our approach to patient management . The American Association of Clinical Endo-crinologists ( AACE ) 2001 Medical Guidelines for Clinical Practice for the Prevention and Management of Postmenopausal Osteoporosis address the prevention , diagnosis , and management of postmenopausal osteoporo-sis , a disorder that is recognized as a major public health problem because of its physical and socioeconomic consequences . They are intended to simplify medical decision making and to help physicians and their patients make good decisions about skeletal health and postmenopausal osteoporosis . The specific goals of these guidelines are to reduce the incidence of fractures related to osteoporosis and to achieve the highest quality of life for individual patients by using the most effective and efficient methods of diagnosis and management . In the preparation of this 2001 edition , reports in the peer- review ed literature dealing with prevention , diagnosis , and treatment of postmenopausal osteoporosis , which were published and indexed between 1996 ( the publication date of the previous edition of these guidelines ) and January 2001 , were identified by computer search , review ed , and grade d for clinical relevance and scientific merit . Although cost-effectiveness was carefully considered , variabilities in actual costs could not be accurately determined . Therefore , cost-effectiveness modeling was not undertaken . Whenever possible , recommendations were based on r and omized , prospect i ve , double-blind studies of well-defined patient population s. Studies that used the most relevant clinical endpoint , fracturing , were considered " level 1 " evidence . When level 1 evidence was not available , recommendations were based on cross-sectional studies , investigations that tested smaller or nonr and omized patient population s , or studies that tested secondary or surrogate clinical endpoints for fracture , such as bone mineral density ( BMD ) or bone turnover markers , in treated population s ( level 2 evidence ) . When stronger evidence was not available , review s , editorials , and expert opinions were used ( level 3 evidence ) . We recognize that the process of developing clinical guidelines necessarily results in a narrowing and codifica-tion of clinical choices , which can be inappropriate in some clinical situations . Because the application of objective information to the specific needs of patients is the ultimate responsibility of the practicing physician , clinical practice guidelines are not intended to be rigid or restrictive , nor Purpose . This study evaluated whether a combined behavioral and dietary intervention would affect young women 's  calcium intake and bone mineral content ( BMC ) . Design . The design was a two by three mixed design with one between-subjects factor ( treatment vs. control ) and one within-subjects factor ( time — baseline , 3-month , and 6-month ) . Setting . The study was conducted in a university setting in Memphis , Tennessee . Participants . A total of 80 premenopausal women ( ages 18 to 30 ) with low baseline calcium intake ( < 700 mg/d ) were included in the analyses . There were 40 women in the treatment group and 40 women in the control group . Measures . Hertzler and Frary 's rapid assessment question naire was employed to evaluate calcium intake , and dual-energy x-ray absorptiometry ( DEXA ) was employed to assess BMC . Results . Repeated measures analysis of variance ( RM ANOVA ) was employed to analyze results . Results indicated that women in the treatment group made greater increases in total calcium intake and supplemental calcium than women in the control group and that all women made significant increases in dietary calcium intake . Additionally , analyses of BMC revealed that women in the treatment group did not experience significant changes in total BMC , and women in the control group experienced significant losses in total BMC . Conclusions . In the current study , women were losing BMC , and the women who made the largest increases in calcium intake were able to retard this bone loss . There is increasing evidence that dietary calcium intake in young people is extremely low , and the results of the current study highlight the need for much more intensive evaluations investigating the factors that are positively associated with premenopausal bone mineral change
target: There was no effect of calcium supplementation  on femoral neck or lumbar spine BMD .
  There was no evidence of effect modification by baseline calcium intake , sex , ethnicity , physical activity or pubertal stage .
  While there is a small effect of calcium supplementation in the upper limb , the increase in BMD which results is unlikely to result in a clinical ly significant decrease in fracture risk .
  The results do not support the use of calcium supplementation  in healthy children as a public health intervention .
  These results can not be extrapolated to children with medical conditions affecting bone metabolism
background: BACKGROUND Clinical trials have shown that  calcium supplementation in children can increase  bone mineral density ( BMD ) although this effect may not be maintained .
  There has been no quantitative systematic review of this intervention .
  To determine the effectiveness of calcium supplementation for improving BMD  in children .
  .
  To determine if any effect varies by sex , pubertal stage , ethnicity or level of physical activity , and if any effect persists after supplementation is ceased .