title: Associations Between Screen-Based Sedentary Behavior and Cardiovascular Disease Risk Factors in Korean Youth Patterns and determinants of physical activity in U.S. adolescents. Quality of reporting of observational longitudinal research. Effect of asthma treatment on fitness, daily activity and body composition in children with asthma Physical activity and energy intake in adolescent girls with Type 1 diabetes. Gender differences in objectively assessed physical activity in asthmatic and non-asthmatic children. Calibration of the Computer Science and Applications, Inc. accelerometer. Fitness and physical activity in youth with type 1 diabetes mellitus in good or poor glycemic control.
abstract: The purpose s of this study were to : 1 ) describe the patterns of screen-based sedentary behaviors  , and 2 ) examine the association between  screen-based sedentary behavior and cardiovascular disease ( CVD ) risk factors in representative Korean children and adolescents , aged 12 to 18 yr , in the Korean National Health and Nutrition Examination Survey .  Screen-based sedentary behavior  was measured using self-report question naires that included items for time spent watching TV and playing PC/video games . Physical activity  was measured using items for frequency and duration of moderate-to-vigorous physical activity ( MVPA )  . CVD risk factors such as body mass index ( BMI ) , waist circumference , LDL cholesterol , HDL cholesterol , total cholesterol , triglycerides , glucose , systolic blood pressure , and diastolic blood pressure were measured . Boys spent more time playing PC/video games , and girls spent more time watching TV . After adjusting for age , gender , annual household income , and MVPA , an additional hour of watching TV was significantly associated with the risk of overweight ( OR 1.17 [ 95 % CI 1.03 - 1.33 ] ) , high abdominal adiposity ( OR 1.27 [ 1.06 - 1.51 ] ) , and low HDL cholesterol ( OR 1.27 [ 1.10 - 1.47 ] ) . An additional hour spent playing PC/video games  also increased the risk of high abdominal adiposity ( OR 1.20 [ 1.03 - 1.40 ] ) . Prospect i ve observations and interventions are needed to determine causal relationships between  screen-based sedentary behavior  and CVD risk profiles in Korean youth PURPOSE The objectives of this study were to describe longitudinal trends in adolescent physical activity in a sample of U.S. adolescents and to assess the effect of multiple individual , parental , and environmental factors on initial level and rates of change in adolescent physical activity . METHODS Study subjects were 12,812 boys and girls 10 to 18 years of age who were participating in the Growing Up Today Study and their mothers . We used accelerated longitudinal analysis to describe trajectories of physical activity from 1997 - 1999 , and r and om effects linear mixed models to determine which factors were independently associated with baseline physical activity and changes in physical activity over time . RESULTS Mean hours of physical activity ranged from 7.3 - 11.6 hours per week in boys and from 8.0 - 11.2 hours per week in girls . Physical activity was best modeled as a quadratic function of age , increasing until early adolescence and declining after age 13 in boys and girls . Multivariable modeling demonstrated that variables associated with physical activity level at baseline in boys and girls were age , body mass index , psychosocial variables , personal attitudes about body shape , perceived peer attitudes about body shape/fitness , parental attitudes about physical activity , parental physical activity , and environmental barriers to physical activity . Age was the only factor that predicted change in physical activity over time . CONCLUSIONS Interventions to increase physical activity in adolescents should begin before adolescence . Interventions may be more effective if they are multimodal and focus on modifiable individual , parental , and environmental factors Observational longitudinal research is particularly useful for assessing etiology and prognosis and for providing evidence for clinical decision making . However , there are no structured reporting requirements for studies of this design to assist authors , editors , and readers . The authors developed and tested a checklist of criteria related to threats to the internal and external validity of observational longitudinal studies . The checklist criteria concerned recruitment , data collection , biases , and data analysis and descriptive issues relevant to study rationale , study population , and generalizability . Two raters independently assessed 49 r and omly selected articles describing stroke research published from 1999 to 2003 in six journals : American Journal of Epidemiology , Journal of Epidemiology and Community Health , Stroke , Annals of Neurology , Archives of Physical Medicine and Rehabilitation , and American Journal of Physical Medicine and Rehabilitation . On average , 17 of the 33 checklist criteria were reported . Criteria describing the study design were better reported than those related to internal validity . No relation was found between study type ( etiologic or prognostic ) or word count and quality of reporting . A flow diagram for summarizing participant flow through a study was developed . Editors and authors should consider using a checklist and flow diagram when reporting on observational longitudinal research To cite this article : Vahlkvist S , Inman MD , Pedersen S. Effect of asthma treatment on fitness , daily activity and body composition in children with asthma . Allergy 2010 ; 65 : 1464–1471 AIMS Girls with Type 1 diabetes often gain excessive weight during puberty . The aims of this study were to compare objective ly assessed physical activity  and  energy intake  in girls with Type 1 diabetes with those in healthy age-matched controls . METHODS This prospect i ve cohort study comprised 26 girls with Type 1 diabetes and 49 control girls . The mean age of the diabetic girls was 15.7 + /- 2.1 years and that of the control girls 15.8 + /- 2.1 years . In the diabetic group , mean haemoglobin A1c was 7.6 + /- 1.4 % and daily insulin dosage was 1.1 + /- 0.3 U/kg .  Physical activity was measured during 7 consecutive days with a uniaxial accelerometer , and energy intake was assessed concurrently with a 7-day food diary . RESULTS There was a tendency towards lower total amount of physical activity in the diabetes group but the difference between the study groups did not reach statistical significance ( Diabetes : 464 + /- 123 counts/min/day ; CONTROLS 523 + /- 138 counts/min/day ; P = 0.06 ) . No difference was found between the groups regarding total energy intake ( Diabetes : 8.5 + /- 1.8 MJ/day ; CONTROLS 8.4 + /- 2.6 MJ/day ) . The carbohydrate intake was lower and the protein and fibre intakes were higher in girls with diabetes . No association was observed between physical activity , energy intake and HbA1c . CONCLUSIONS In this prospect i ve cohort study , we found a tendency towards lower physical activity but no differences in energy intake between girls with Type 1 diabetes and age-matched controls . Larger studies are needed to further explore the importance of the total amount of physical activity for excessive weight gain in adolescent girls with Type 1 diabetes OBJECTIVE To compare objective ly assessed physical activity  levels , between asthmatic children and non-asthmatic controls . METHODS From a r and om community sample of 794 children aged 8 - 9 years , in a case-control design , 104 children with ever doctor 's diagnosis of asthma and 99 non-asthmatic controls were recruited and had assessment of physical activity with biaxial accelerometers for 7 days . RESULTS Children with active ( also reporting at least one episode of wheezing in the last 12 months ) and inactive ( no wheezing in past 12 months ) asthma appeared to have similar physical activity and sedentary activity levels compared to non-asthmatic children . However , girls with active asthma had significantly lower moderate-to-vigorous physical activity ( MVPA ) levels than their peers with adjusted geometric mean ratio of 0.59 ( 95 % CI : 0.369 , 0.929 , P-value = 0.024 ) . No difference in physical and sedentary activity levels was observed between asthmatic and non-asthmatic boys . The difference between genders in the comparison of MVPA levels in asthmatics and controls was statistically significant ( P-value of likelihood ratio test [ LRT ] for effect modification by gender = 0.034 ) . CONCLUSIONS Unlike boys , girls with active asthma appear to be less active than their healthy peers , and this gender difference might explain the inconsistent evidence from previous reports on physical activity levels in asthmatic children . Further studies are needed to confirm the gender interaction in the childhood asthma-physical activity relation and the implication s on current guidelines for physical exercise prescriptions in asthmatic children PURPOSE We established accelerometer count ranges for the Computer Science and Applications , Inc. ( CSA ) activity monitor corresponding to commonly employed MET categories . METHODS Data were obtained from 50 adults ( 25 males , 25 females ) during treadmill exercise at three different speeds ( 4.8 , 6.4 , and 9.7 km x h(-1 ) ) . RESULTS Activity counts and steady-state oxygen consumption were highly correlated ( r = 0.88 ) , and count ranges corresponding to light , moderate , hard , and very hard intensity levels were < or = 1951 , 1952 - 5724 , 5725 - 9498 , > or = 9499 cnts x min(-1 ) , respectively . A model to predict energy expenditure from activity counts and body mass was developed using data from a r and om sample of 35 subjects ( r2 = 0.82 , SEE = 1.40 kcal x min(-1 ) ) . Cross validation with data from the remaining 15 subjects revealed no significant differences between actual and predicted energy expenditure at any treadmill speed ( SEE = 0.50 - 1.40 kcal x min(-1 ) ) . CONCLUSIONS These data provide a template on which patterns of activity can be classified into intensity levels using the CSA accelerometer BACKGROUND Patients with type 1 diabetes mellitus ( T1DM ) may experience poor muscle health as a result of chronic hyperglycemia . Despite this , muscle function in children with T1DM with good or poor glycemic control has yet to be examined in detail . OBJECTIVE To assess differences in muscle-related fitness variables in children with T1DM with good glycemic control ( T1DM-G ) , as well as those with poor glycemic control ( T1DM-P ) , and non-diabetic , healthy controls . SUBJECTS Eight children with T1DM-G [ glycosylated hemoglobin ( HbA1c ) ≤ 7.5 % for 9 months ] , eight children with T1DM-P ( HbA1c ≥ 9.0 % for 9 months ) , and eight healthy controls completed one exercise session .  METHODS Anaerobic and aerobic muscle functions were assessed with a maximal isometric grip strength test , a Wingate test , and an incremental continuous cycling test until exhaustion . Blood sample s were collected at rest to determine HbA1c at the time of testing . Physical activity  was monitored over 7 d using accelerometry . RESULTS Children with T1DM-P displayed lower peak oxygen consumption ( VO2peak ) values ( mL/kg/min ) compared to healthy controls ( T1DM-P : 33.2 ± 5.6 , controls : 43.5 ± 6.3 , p < 0.01 ) , while T1DM-G ( 43.5 ± 6.3 ) had values similar to controls and T1DM-P. There was a negative relationship between VO2peak and HbA1c% ( r = -0.54 , p < 0.01 ) . All groups were similar in all other fitness variables . There were no group differences in physical activity variables . CONCLUSION Children with T1DM-G did not display signs of impaired muscle function , while children with T1DM-P have signs of altered aerobic muscle capacity
target: MVPA in children/adolescents with chronic disease appear to be well below guideline recommendations , although comparable with activity levels of their healthy peers except for children with malignancies .
background: CONTEXT Moderate-to-vigorous physical activity ( MVPA ) and sedentary time ( ST )  are important for child and adolescent health .
  OBJECTIVE To examine habitual levels of accelerometer measured MVPA and ST  in children and adolescents with chronic disease , and how these levels compare with healthy peers .