***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Background —Siblings of individuals with premature coronary heart disease ( CHD ) have a marked excess risk of CHD risk factors and premature CHD . The impact of body mass index ( BMI ) on incident CHD in these families and the extent to which it may be mediated by associated risk factors are unknown . The aim of this study was to examine the effect of high BMI on incident CHD in white and black families with premature CHD and to estimate the heritability of BMI . Methods and Results —Risk  factors , BMI , and Framingham Risk Score ( FRS )  were assessed at baseline and incident CHD was determined prospect ively in 827 apparently healthy siblings of prob and s with premature CHD aged < 60 years . During a mean follow-up of 8.7 years , 13.3 % of siblings had incident CHD events . Event rates were higher in obese and overweight siblings than in those with normal weight ( 15.3 % and 16.0 % versus 8.1 % , respectively ; P=0.01 ) . Multivariable Cox proportional hazards analyses demonstrated the independent prognostic value of BMI when added to FRS ( P=0.02 ) . A marked interaction between obesity ( BMI ≥30 kg/m2 ) and high FRS ( > 20 % ) was seen for incident CHD ( P for interaction=0.008 ) , with an adjusted hazard ratio compared with low-FRS/normal-weight siblings of 14.63 ( 95 % CI , 6.40 to 33.44 ; P<0.0001 ) . BMI heritability ( h2 ) was moderate for whites and low for blacks ( 52 % and 29 % , respectively ) . Conclusions —High BMI contributed independently and significantly to incident CHD , beginning in the overweight range , and was most notable for obese siblings with a high-risk FRS OBJECTIVE : To assess the frequency of different grade s of nutritional status ( obesity , overweight and thinness ) in French children aged 7–9 y using four current definitions based on body mass index ( BMI ) . METHODS : Data were collected in 2000 in a r and omly selected sample of French children following the protocol recommended by the European Childhood Obesity Group ( ECOG ) . After computing the BMI ( weight/height squared ) , four references were used to define grade s of nutritional status : ( 1 ) the French references to define thinness and overweight ( 3rd and 97th percentiles respectively ) ; ( 2 ) the Must et al references to define thinness , overweight and obesity ( 5th , 85th and 95th percentiles respectively ) ; ( 3 ) the International Obesity Task Force cut-offs to define overweight and obesity ; and ( 4 ) the Center for Disease Control 2000 references to define thinness , overweight and obesity ( 5th , 85th and 95th percentiles respectively ) . RESULTS : Age and gender st and ardized frequencies were estimated in 1582 children . According to the French , Must et al , IOTF and CDC references , overweight ( including obesity ) affected 16.3 , 23.9 , 18.1 and 20.6 % of children , respectively ; obesity affected 9.3 , 3.8 and 6.4 % of children according to the Must , IOTF and CDC references , respectively . Thinness was present in 3.9 , 6.0 and 6.0 % of children according to the French , Must and CDC references . Whatever the definition , little difference was observed between sexes . Through age classes , as a rule , overweight and obesity tended to decrease while thinness tended to increase . CONCLUSION : The present study revealed an increasing prevalence of overweight in comparison with previous French data and a trend for increasing prevalence of thinness . The IOTF-based prevalence of overweight ( including obesity ) in 2000 in France was similar with the prevalence recorded in the late 1980s in the USA and the prevalence of obesity in 2000 in France was similar to the prevalence of obesity in the late 1970s in the USA . Data in France are comparable to those reported in other studies conducted in Western Europe . This study provides baseline information for analysis of time trends and for geographical comparisons Exercise during growth has a positive influence on bone mineral accrual , yet little is known about how bone geometry and strength adapt to loading during growth . Our primary objective was to compare changes in proximal femur bone geometry and strength between 31 prepubertal ( Tanner Stage 1 ) boys who participated in a school-based , high-impact circuit intervention ( 12 min , three times a week ) for 20 months and 33 maturity-matched controls . Our secondary objective was to compare changes in total body ( TB ) , proximal femur ( PF ) , and lumbar spine ( LS ) bone mineral content ( BMC ) and bone area ( BA ) in these groups . We assessed geometric variables and bone strength at the narrow neck ( NN ) , intertrochanteric ( TR ) region , and femoral shaft regions by applying the Hip Structure Analysis program to proximal femur dual energy X-ray absorptiometry scans ( DXA , Hologic QDR 4500 ) . Further , we assessed total body , lumbar spine , and proximal femur BMC and BA by DXA and derived total body lean mass and fat mass from total body scans . Intervention ( 10.2 + /- 0.5 years ) and control boys ( 10.1 + /- 0.5 years ) had similar baseline height ( 140.8 vs. 141.3 cm ) and weight ( 36.9 vs. 35.4 kg ) , and average 20-month physical activity scores ( Physical Activity Question naire for Children , PAQ-C ) and calcium intakes ( 861 vs. 852 mg/day , food frequency question naire ) . Twenty-month height and weight changes were not significantly different between groups ; lean mass changed more ( P < 0.05 ) in intervention boys ( 22.8 % ) than control boys ( 18.6 % ) . At the NN region , intervention boys had greater bone expansion on both the periosteal ( + 2.6 % , P = 0.1 ) and endosteal ( + 2.7 % , P = 0.2 ) surfaces , result ing in significantly greater changes in section modulus ( bone bending strength ) ( + 7.5 % , P = 0.02 , ANCOVA , adjusting for height change , final Tanner Stage , and baseline bone values ) . Changes at the intertrochanteric and femoral shaft regions were not significantly different between groups . Femoral neck ( FN ) BMC changes were significantly greater in intervention boys ( + 4.3 % , P < 0.01 ) ; changes in BA and BMC for other regions were not significantly different between groups . In summary , a school-based , high-impact exercise intervention implemented three times a week for 12 min is an effective strategy for site-specific gains in bone strength at the narrow neck region of the proximal femur OBJECTIVE To evaluate the short and long term benefits of a school and home based physical activity " enrichment " program for children at higher risk of cardiovascular disease as identified by cluster analysis . STUDY DESIGN During two 10-week school terms , 800 11-year-olds took part in a r and omized controlled trial with the st and ard physical activity and nutrition program in six schools , the st and ard program in a further seven schools  but with the addition of physical activity enrichment for higher risk children in those schools  , and no program in five control schools . Cluster analysis identifying the 29 % or so highest risk children used systolic blood pressure , percent body fat , physical fitness , and blood cholesterol . RESULTS Fitness improved significantly in program schools , particularly with enrichment in higher risk boys . Substantial improvements persisted 6 months later in girls from program schools . At " Enrichment " schools , cholesterol showed significant benefits in higher risk girls and , 6 months later , in both boys and higher risk girls . Sodium intake and , in girls , subscapular skinfolds were lower in " Enrichment " schools when the program ended , but not 6 months later . CONCLUSION Two-semester health programs with physical activity enrichment for higher risk children can produce benefits sustained for at least 6 months . Improvements extend to lower risk children exposed indirectly to the enrichment . Attenuation of effects on diet and body composition in the longer-term suggest the need for on-going programs BACKGROUND Obesity is associated with diverse health risks , but the role of body weight as a risk factor for death remains controversial . METHODS We examined the association between body weight and the risk of death in a 12-year prospect i ve cohort study of 1,213,829 Koreans between the ages of 30 and 95 years . We examined 82,372 deaths from any cause and 48,731 deaths from specific diseases ( including 29,123 from cancer , 16,426 from atherosclerotic cardiovascular disease , and 3362 from respiratory disease ) in relation to the body-mass index ( BMI ) ( the weight in kilograms divided by the square of the height in meters ) . RESULTS In both sexes , the average baseline BMI was 23.2 , and the rate of death from any cause had a J-shaped association with the BMI , regardless of cigarette-smoking history . The risk of death from any cause was lowest among patients with a BMI of 23.0 to 24.9 . In all groups , the risk of death from respiratory causes was higher among subjects with a lower BMI , and the risk of death from atherosclerotic cardiovascular disease or cancer was higher among subjects with a higher BMI . The relative risk of death associated with BMI declined with increasing age . CONCLUSIONS Underweight , overweight , and obese men and women had higher rates of death than men and women of normal weight . The association of BMI with death varied according to the cause of death and was modified by age , sex , and smoking history BACKGROUND Physical activity is important for weight control and good health ; however , activity levels decline in the adolescent years , particularly in girls . DESIGN Group r and omized controlled trial . SETTING / PARTICIPANTS Middle school girls with English-speaking skills and no conditions to prevent participation in physical activity in 36 schools in six geographically diverse areas of the United States . R and om , cross-sectional sample s were drawn within schools : 6th grade rs in 2003 ( n=1721 ) and 8th grade rs in 2005 ( n=3504 ) and 2006 ( n=3502 ) . INTERVENTION A 2-year study -directed intervention ( fall 2003 to spring 2005 ) targeted schools , community agencies , and girls  to increase opportunities , support , and incentives for increased physical activity . Components included programs linking schools and community agencies , physical education , health education , and social marketing . A third-year intervention used school and community personnel to direct intervention activities . MAIN OUTCOME MEASURES The primary outcome , daily MET-weighted minutes of moderate-to-vigorous physical activity ( MET-weighted MVPA ) , was assessed using accelerometry . Percent body fat was assessed using anthropometry . RESULTS After the staff-directed intervention ( pre-stated primary outcome ) , there were no differences ( mean= -0.4 , 95 % CI= -8.2 to 7.4 ) in adjusted MET-weighted MVPA between 8th- grade girls in schools assigned to intervention or control . Following the Program Champion-directed intervention , girls in intervention schools were more physically active than girls in control schools ( mean difference 10.9 MET-weighted minutes of MVPA , 95 % CI=0.52 - 21.2 ) . This difference is about 1.6 minutes of daily MVPA or 80 kcal per week . There were no differences in fitness or percent body fat at either 8th- grade timepoint . CONCLUSION A school-based , community-linked intervention modestly improved physical activity in girls 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 
    Output:
    
We found no consistent changes in other measures of body composition .
INTERPRETATION School-based physical activity interventions did not improve BMI , although they had other beneficial health effects .
Current population -based policies that m and ate increased physical activity in schools are unlikely to have a significant effect on the increasing prevalence of childhood obesity