title: Vitamin D intake is low and hypovitaminosis D common in healthy 9− to 15-year-old Finnish girls Vitamin D deficiency in children in Jerusalem: the need for updating the recommendation for supplementation. Association between serum 25(OH)D concentrations and bone stress fractures in Finnish young men. The effects of season-long vitamin D supplementation on collegiate swimmers and divers. The effects of vitamin D3 supplementation on serum total 25[OH]D concentration and physical performance: a randomised dose–response study Influence of vitamin D mushroom powder supplementation on exercise-induced muscle damage in vitamin D insufficient high school athletes A global representation of vitamin D status in healthy populations
abstract: Objectives : To study the prevalence of hypovitaminosis D , the effect of vitamin D supplementation on serum 25-hydroxyvitamin D [ S-25(OH)D ] , and the intakes of vitamin D and calcium in Finnish 9− to 15-year-old athletic and nonathletic girls . Design : 1-year follow-up study ( February 1997-March 1998 ) with three months of vitamin D supplementation ( 10 μg/d ) from October to January . Setting : Turku University Central Hospital , Finl and .Subjects : 191 female volunteers aged 9–15 y ( 131 athletes and 60 controls ) . Methods :  Vitamin D and calcium intakes were estimated by a four-day food recording and a semi-quantitative food frequency question naire ( FFQ ) . S-25(OH)D was followed by radioimmunoassay ( RIA ) . Results : At baseline the mean S-25(OH)D concentration was 33.9 nmol/l among all girls . In winter severe hypovitaminosis D ( S-25(OH)D<20 nmol/l ) occurred in 13.4 % of the participants and in 67.7 % S-25(OH)D was below 37.5 nmol/l . By the next summer the mean S-25(OH)D concentration was 62.9 nmol/l and in 1.6 % of the subjects it was below 37.5 nmol/l . The prevalence of severe hypovitaminosis D was not significantly reduced by three months of vitamin D ( 10 μg/d ) supplementation . At baseline , the mean intake of vitamin  D was 2.9 μg/d by food recording and 4.3 μg/d by FFQ . The mean calcium intake was 1256 mg/d and 1580 mg/d , respectively . The intakes of vitamin D and calcium remained unchanged during the follow-up period . The athletes consumed more calcium than nonathletic controls , whereas the intake of vitamin D was quite similar among both groups . The vitamin D intake by FFQ correlated with the S-25(OH)D concentration in wintertime ( r=0.28 , P<0.01 ) . Conclusion : Hypovitaminosis D is fairly common in growing Finnish girls in the wintertime , and three months of vitamin D supplementation with 10 μg/d was insufficient in preventing hypovitaminosis D. The daily dietary vitamin D intake was insufficient ( < 5 μg/d ) in the majority of participants , while the calcium intake was usually sufficient . Sponsorship : Supported by the Yrjö Jahnsson Foundation , The Turku University Foundation , and the Medical Research Foundation of the Turku University Central Hospital BACKGROUND Hypovitaminosis D is common worldwide , even in sunny regions . OBJECTIVES To assess the prevalence and determinants of vitamin D deficiency in toddlers . METHODS A cross-sectional prospect i ve study was conducted in healthy Jewish children aged 1.5 - 6 years at five primary care pediatric clinics in the Jerusalem area during the period October 2009 to November 2010 . Parents were interviewed regarding personal and demographic data and sun exposure . Blood sample s were obtained for serum 25-hydroxyvitamin D [ 25-OHD ] level . Vitamin D deficiency and insufficiency were defined as 25-OHD < 20 ng/ml and < 30 ng/ml , respectively . RESULTS Of 247 children studied , 188 ( 76 % ) were ultra-Orthodox and 59 ( 24 % ) were Orthodox , traditional or secular . Mean ( + /- SD ) 25-OHD level was 25.7 + /- 10 ng/ml . Only 73 children ( 29.6 % ) had sufficient 25-OHD levels , 104 ( 42.1 % ) had insufficiency , and 70 ( 28.3 % ) had 25-OHD deficiency . The difference between ultra-Orthodox and others was insignificant ( 25 + /- 10 vs. 27.8 + /- 10.5 ng/ml respectively , P = 0.062 ) . Children aged 1.5 - 3 years had higher 25-OHD levels than those aged 3 - 6 years ( 28.6 + /- 10.7 and 24 + /- 9.2 ng/ml respectively , P < 0.001 ) . Vitamin D deficiency was more common in winter ( 53 % ) and autumn ( 360 % ) than in summer ( 19 % ) and spring ( 16 % ) . Toddlers attending long-day kindergartens had higher 25-OHD level than those staying at home or at short-day kindergartens ( 28.8 + /- 11.5 and 24.7 + /- 9.6 ng/ml respectively , P < 0.05 ) . CONCLUSIONS A high prevalence of vitamin D deficiency was found in toddlers in our study , mainly in older children and in the winter and autumn . We recommend routine supplementation of vitamin D for children beyond the age of one year UNLABELLED Low vitamin D level may predict rickets , osteomalacia , or osteoporosis . We examined serum 25(OH)D concentration as a predisposing factor for bone stress fracture in 756 military recruits . The average serum 25(OH)D concentration was significantly lower in the group with fracture , suggesting a relationship between vitamin D and fatigue bone stress fracture . INTRODUCTION Low vitamin D level may predict rickets , osteomalacia , or osteoporosis . Fatigue bone stress fracture is one of the most frequently seen types of overuse injuries in athletes and military recruits . An association was recently shown between vitamin D and BMC . A correlation has also been found between low femoral BMD and stress fractures . We measured serum 25(OH)D concentration in a population sample of military recruits to determine if vitamin D is a predisposing factor for fatigue bone stress fracture . MATERIAL S AND METHODS We prospect ively followed 800 r and omly selected , healthy Finnish military recruits with a mean age of 19 years for developing stress fractures in homogenous circumstances . Blood for serum 25(OH)D concentration was drawn at entry into military service , and the weight , height , body mass index ( BMI ) , muscle strength , and 12-minute running were measured for all subjects . Serum 25(OH)D concentrations were measured with enzyme immunoassay . At end of the 90-day follow-up , 756 subjects completed the study . Subjects without fracture constituted controls . RESULTS Twenty-two recruits with stress fracture were identified ( 2.9 % ) , the incidence being 11.6 ( 95 % CI : 6.8 - 16.5 ) per 100 person-years . In the final multivariate analysis , the significant risk factor for stress fracture in conscripts was a below median serum 25(OH)D level ( 75.8 nM ) , OR being 3.6 ( 95 % CI : 1.2 - 11.1 ) . No significant associations between BMI ( p = 0.255 ) , age ( p = 0.216 ) , or smoking ( p = 0.851 ) and bone stress fracture were found in this study population . CONCLUSIONS A lower level of serum 25(OH)D concentration may be a generally predisposing element for bone stress fractures . Considering the obvious need of additional vitamin D in prevention of stress fractures , the effects of vitamin D fortification of foods and supplementation will be subjects of interest for future research The purpose of this 6-month r and omized , placebo-controlled trial was to determine the effect of season-long ( September-March ) vitamin D supplementation on changes in vitamin D status , which is measured as 25(OH ) D , body composition , inflammation , and frequency of illness and injury . Forty-five male and female athletes were r and omized to 4,000 IU vitamin D ( n = 23 ) or placebo ( n = 22 ) . Bone turnover markers ( NTx and BSAP ) , 25(OH)D , and inflammatory cytokines ( TNF-alpha , IL-6 , and IL1-β ) were measured at baseline , midpoint , and endpoint . Body composition was assessed by DXA and injury and illness data were collected . All athletes had sufficient 25(OH)D ( > 32 ng/ml ) at baseline ( mean : 57 ng/ml ) . At midpoint and endpoint , 13 % and 16 % of the total sample had 25(OH)D < 32 ng/ml , respectively . 25(OH)D was not positively correlated with bone mineral density ( BMD ) in the total body , proximal dual femur , or lumbar spine . In men , total body ( p = .04 ) and trunk ( p = .04 ) mineral-free lean mass ( MFL ) were positively correlated with 25(OH)D. In women , right femoral neck BMD ( p = .02 ) was positively correlated with 25(OH)D. 25(OH)D did not correlate with changes in bone turnover markers or inflammatory cytokines . Illness ( n = 1 ) and injury ( n = 13 ) were not related to 25(OH)D ; however , 77 % of injuries coincided with decreases in 25(OH)D. Our data suggests that 4,000 IU vitamin D supplementation is an inexpensive intervention that effectively increased 25(OH)D , which was positively correlated to bone measures in the proximal dual femur and MFL . Future studies with larger sample sizes and improved supplement compliance are needed to exp and our underst and ing of the effects of vitamin D supplementation in athletes Background Vitamin D deficiency is common in the general public and athletic population s and may impair skeletal muscle function . We therefore assessed the effects of vitamin D3 supplementation on serum 25[OH]D concentrations and physical performance . Methods 30 club-level athletes were block r and omised ( using baseline 25[OH]D concentrations ) into one of three groups receiving either a placebo ( PLB ) , 20 000 or 40 000 IU/week oral vitamin D3 for 12 weeks . Serum 25[OH]D and muscle function ( 1-RM bench press and leg press and vertical jump height ) were measured presupplementation , 6 and 12 weeks postsupplementation . Vitamin D deficiency was defined in accordance with the US Institute of Medicine guideline ( < 50 nmol/l ) . Results 57 % of the subject population were vitamin D deficient at baseline ( mean±SD value 51±24 nmol/l ) . Following 6 and 12 weeks supplementation with 20 000 IU ( 79±14 and 85±10 nmol/l , respectively ) or 40 000 IU vitamin D3 ( 98±14 and 91±24 nmol/l , respectively ) , serum vitamin D concentrations increased in all participants , with every individual achieving concentrations greater than 50 nmol/l . In contrast , vitamin D concentration in the PLB group decreased at 6 and 12 weeks ( 37±18 and 41±22 nmol/l , respectively ) . Increasing serum 25[OH]D had no significant effect on any physical performance parameter ( p>0.05 ) . Conclusions Both 20 000 and 40 000 IU vitamin D3 supplementation over a 6-week period elevates serum 25[OH]D concentrations above 50 nmol/l , but neither dose given for 12 weeks improved our chosen measures of physical performance Abstract Incidence of vitamin D deficiency is increasing worldwide . The purpose of this study was to determine if supplementation with vitamin D2 from Portobello mushroom powder would enhance skeletal muscle function and attenuate exercise-induced muscle damage in low vitamin D status high school athletes . Participants were r and omised to Portobello mushroom powder ( 600 IU/d vitamin D2 ) or placebo for 6 weeks . Participants then completed a 1.5-h exercise session design ed to induce skeletal muscle damage . Blood sample s and measures of skeletal muscle function were taken pre-supplementation , post-supplementation/pre-exercise and post-exercise . Six weeks supplementation with vitamin D2 increased serum 25(OH)D2 by 9.9-fold and decreased serum 25(OH)D3 by 28 % . Changes in skeletal muscle function and circulating markers of skeletal muscle damage did not differ between groups . In conclusion , 600 IU/d vitamin D2 increased 25(OH)D2 with a concomitant decrease in 25(OD)D3 , with no effect on muscular function or exercise-induced muscle damage in high school athletes Purpose This paper visualizes the available data on vitamin D status on a global map , examines the existing heterogeneities in vitamin D status and identifies research gaps . Methods A graphical illustration of global vitamin D status was developed based on a systematic review of the worldwide literature published between 1990 and 2011 . Studies were eligible if they included sample s of r and omly selected males and females from the general population and assessed  circulating 25-hydroxyvitamin D [ 25(OH)D ] levels .  Two different age categories were selected : children and adolescents ( 1–18 years ) and adults ( > 18 years ) . Studies were chosen to represent a country based on a hierarchical set of criteria . Results In total , 200 studies from 46 countries met the inclusion criteria , most coming from Europe . Forty-two of these studies ( 21 % ) were classified as representative . In children , gaps in data were identified in large parts of Africa , Central and South America , Europe , and most of the Asia/Pacific region . In adults , there was lack of information in Central America , much of South America and Africa . Large regions were identified for which the mean 25(OH)D levels were below 50 nmol/L. Conclusions This study provides an overview of 25(OH)D levels around the globe . It reveals large gaps in information in children and adolescents and smaller but important gaps in adults . In view of the importance of vitamin D to musculoskeletal growth , development , and preservation , and of its potential importance in other tissues , we strongly encourage new research to clearly define 25(OH)D status around the world
target: Conclusion Despite the limitations of the current evidence , the prevalence of vitamin D inadequacy in athletes is prominent .
  The risk significantly increases in higher latitudes , in winter and early spring seasons , and for indoor sport activities .
  The prevalence of injuries in athletes is notable but its association with  vitamin D status is unclear .
background: Background Vitamin D is essential for maintaining optimal bone health .
  The prevalence of vitamin D inadequacy in athletes is currently unclear .
  Objective The objective of this study is to determine the prevalence of vitamin D inadequacy in athletes .
  Serum 25(OH)D is measured to clinical ly determine vitamin D status .