human
***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 Walking and cycling to school could be an important regular source of physical activity in growing children . The aim of this 12 months prospect i ve observational study was thus to evaluate the effect of self-transportation to school on bone mineral accrual and gain in bone width in pre-pubertal children , both traits independently contributing to bone strength . Methods Ninety-seven girls and 133 boys aged 7–9 years were recruited as a part of the Malmö Pediatric Osteoporosis Prevention ( POP ) Study in order to evaluate the influence of self-selected school transportation for the accrual of bone mineral and bone width .  Children who walked or cycled to school were compared with  children who went by bus or car . Bone mineral content ( BMC ) was measured by dual energy X-ray absorptiometry ( DXA ) in the lumbar spine ( L2–L4 ) , third lumbar vertebra ( L3 ) and hip , and bone width was calculated at L3 and femoral neck ( FN ) . Changes during the first 12 months were compared between the groups . Subjective duration of physical activity was estimated by a question naire and objective level of everyday physical activity at follow-up by accelerometers worn for four consecutive days . All children remained in Tanner stage 1 throughout the study . Comparisons were made by independent student 's t-tests between means , ANCOVA and Fisher 's exact tests . Results There were no differences in baseline or annual changes in BMC or bone width when the transportation groups were compared . No differences were detected in objective ly measured daily level of physical activity by accelerometer . All children reached above 60 minutes of moderate to intense daily physical activity per day , the international recommended level of daily physical activity according to the United Kingdom Expert Consensus Group . Conclusion The everyday physical activity in these pre-pubertal children seems to be so high that the school transportation contributes little to their total level of physical activity . As a result , the choice of school transportation seems not to influence the accrual of bone mineral or gain in bone size during a 12-month follow-up period Objective . To prospect ively identify behavioral risk factors for childhood overweight and to assess their relevance in high risk sub groups ( children of mothers with overweight or low education ) . Methods . In the PIAMA birth cohort ( n = 3963 ) , question naire data  were obtained at ages 5  and 7 on “ screen time ” , walking or cycling to school , playing outside , sports club membership , fast food consumption , snack consumption and soft drink consumption . Weight and height were measured at age 8 years . Results . Screen time , but none of the other hypothesized behavioral factors , was associated with overweight ( aOR 1.4 ( CI : 1.2–1.6 ) ) . The adjusted population attributable risk fraction for screen time > 1 hr/day was 10 % in the high risk and 17 % in the low risk sub groups . Conclusion . Reduction of screen time to < 1 hr/day could result in a reduction of overweight prevalence in the order of 2 percentage points in both high and low risks sub groups Background Walking and cycling to school are one source of regular physical activity . The aim of this two years observational study in pre-pubertal children was to evaluate if walking and cycling to school was associated with higher total amount of physical activity and larger gain in bone mineral content ( BMC ) and bone width than when going by car or bus . Methods 133 boys and 99 girls aged 7 - 9 years were recruited to the Malmö Prospect i ve Paediatric Osteoporosis Prevention ( POP ) study .  BMC ( g ) was measured by dual X-ray absorptiometry ( DXA ) in total body , lumbar spine ( L2-L4 ) and femoral neck ( FN ) at baseline and after 24 months . Bone width was measured in L2-L4 and FN . Skeletal changes in the 57 boys and 48 girls who consistently walked or cycled to school were compared with the 24 boys and 17 girls who consistently went by bus or car . All children remained in Tanner stage I. Level of everyday physical activity was estimated by accelerometers worn for four consecutive days and question naires . Comparisons were made by independent student 's t-tests between means and Fisher 's exact tests . Analysis of covariance ( ANCOVA ) was used to adjust for group differences in age at baseline , duration of organized physical activity , annual changes in length and BMC or bone width if there were differences in these traits at baseline . Results After the adjustments , there were no differences in the annual changes in BMC or bone width when comparing girls or boys who walked or cycled to school with those who went by car or bus . Furthermore , there were no differences in the levels of everyday physical activity objective ly measured by accelerometers and all children reached above the by the United Kingdom Expert Consensus Group recommended level of 60 minutes moderate to vigorous physical activity per day . Conclusion A physical active transportation to school for two years is in pre-pubertal children not associated with a higher accrual of BMC or bone width than a passive mode of transportation , possibly due to the fact that the everyday physical activity in these pre-pubertal children , independent of the mode of school transportation , was high Background Brazil is currently experiencing a nutrition transition : the displacement of traditional diets with foods high in saturated fat , sodium , and cholesterol and an increase in sedentary lifestyles . Despite these trends , our underst and ing of child obesity in Brazil is limited . Thus , the aims of this study were ( 1 ) to investigate the current prevalence of overweight and obesity in a large sample of children and adolescents living in São Paulo , Brazil , and ( 2 ) to identify the lifestyle behaviors associated with an increased risk of obesity in young Brazilians . Methods A total of 3,397 children and adolescents ( 1,596 male ) aged 7 - 18 years were r and omly selected from 22 schools in São Paulo , Brazil . Participants were classified as normal weight , overweight , or obese based on international age- and sex-specific body mass index thresholds . Selected sociodemographic , physical activity , and nutrition behaviors were assessed via question naire . Results Overall , 19.4 % of boys and 16.1 % of girls were overweight while 8.9 % and 4.3 % were obese . Two-way analysis of variance revealed that the prevalence of overweight and obesity was significantly higher in boys and in younger children when compared to girls and older children , respectively ( P < 0.05 for both ) . Logistic regression analysis revealed that overweight was associated with more computer usage , parental encouragement to be active , and light soft drink consumption after controlling for differences in sex , age , and parental education ( P < 0.05 for all ) . Conversely , overweight was associated with less active transport to school , eating before sleep , and consumption of breakfast , full-sugar soft drinks , fried food and confectionery ( P < 0.05 for all ) . Conclusions Our results show that obesity in São Paulo children and adolescents has reached a level equivalent to that seen in many developed countries . We have also identified three key modifiable factors related to obesity that may be appropriate targets for future intervention in Brazilian youth : transport mode to school , computer usage , and breakfast consumption To estimate the prevalence and determinants of overweight and obesity among school children and adolescents ( 7–18 years ) , a cross-sectional study was conducted in Tianjin City of Northeast China . Five primary and middle schools were selected using a multistage r and om cluster sampling . Anthropometric measurements were taken by the research team . Then , st and ardized question naires on socioeconomic status , diet and lifestyle , parental weight and height were sent to the parents to be completed together with their child . Overall , 3,140 students were screened for overweight and associated risk factors . Body mass index classification reference proposed by the Working Group on Obesity in China was used as a screening reference to calculate the prevalence of overweight in these groups . The prevalence of overweight and obesity was found to be 12.5 % and 15.7 % , respectively . Logistic regression analysis ( overweight compared with normal weight ) showed that , overweight in children was significantly associated with male gender , parental obesity , parental educational level , mother ’s history of gestational diabetes , high birth weight , less hours of physical activity per day , urban residence , motorized transportation , and eating food not prepared at home . After adjusting for parental obesity , the odds ratio of overweight children was increased by urban residence ( rural as a reference , 2.68 , 2.16–3.32 ) , positive gestational diabetes ( 2.76 , 1.37–4.50 ) , and fast-food/restaurant food service ( 2.03 , 1.34–3.07 ) . Children who walked to school and participated in outdoor activities were 54 % and 63 % less likely to be overweight respectively . Conclusions : The prevalence of overweight and obesity is high among school children and adolescents in Tianjin .  Changes in lifestyle , high socioeconomic status , parental obesity , mother ’s history of gestational diabetes , and high birth weight are among the highly associated risk factors of overweight . An educational approach about maintaining a healthy weight should be introduced much earlier to high-risk children , parents , and women of childbearing age BACKGROUND Atherosclerosis develops from early childhood ; physical activity could positively affect this process . This study 's aim was to assess the associations of objective ly measured physical activity with clustering of cardiovascular disease risk factors in children and derive guidelines on the basis of this analysis . METHODS We did a cross-sectional study of 1732 r and omly selected 9-year-old and 15-year-old school children from Denmark , Estonia , and Portugal . Risk factors included in the composite risk factor score ( mean of Z scores ) were systolic blood pressure , triglyceride , total cholesterol/HDL ratio , insulin resistance , sum of four skinfolds , and aerobic fitness . Individuals with a risk score above 1 SD of the composite variable were defined as being at risk . Physical activity was assessed by accelerometry . FINDINGS Odds ratios for having clustered risk for ascending quintiles of  physical activity  ( counts per min ; cpm ) were 3.29 ( 95 % CI 1.96 - 5.52 ) , 3.13 ( 1.87 - 5.25 ) , 2.51 ( 1.47 - 4.26 ) , and 2.03 ( 1.18 - 3.50 ) , respectively , compared with the most active quintile . The first to the third quintile of physical activity had a raised risk in all analyses . The mean time spent above 2000 cpm in the fourth quintile was 116 min per day in 9-year-old and 88 min per day in 15-year-old children . INTERPRETATION  Physical activity  levels should be higher than the current international guidelines of at least 1 h per day of physical activity of at least moderate intensity to prevent clustering of cardiovascular disease risk factors OBJECTIVE To prospect ively examine potential benefits of active commuting to school on measures of weight status and physical activity in a sample of youth . RESEARCH METHODS AND PROCEDURES A cohort of students from seven elementary schools was measured four times -- in the fall and spring of fourth grade ( N = 1083 ) and fifth grade ( N = 924 ) . Participants were classified as active ( walking , biking , or skateboarding to school almost every day for baseline analyses or at least 2 d/wk for analyses of consistent active commuting ) or non-active commuters to school . Accelerometers were used to measure physical activity . Height , weight , and skinfolds were objective ly assessed . RESULTS Boys who actively commuted to school had lower BMI ( p < 0.01 ) and skinfolds ( p < 0.05 ) than non-active commuters to school in the fourth grade . Active commuting to school over 2 years was not associated with BMI change or overweight status . DISCUSSION Walking and cycling to school may contribute to preventing excessive weight gain , or leaner children may walk or cycle to school AIMS Australian guidelines recommend that children participate in at least one hour of physical activity every day . We aim ed to measure physical activity  participation in a r and om sample of Australian primary school children and to determine the biological , behavioural , environmental and social influences associated with insufficient daily activity . METHOD We analysed the following cross-section data from a r and omly selected sample of children ( N=518 ) aged 5 to 12 years : age , gender , socioeconmic status ( SES ) indicators , family size , home play equipment availability , transport method to school , and estimated time per week in physical and sedentary activity . Logistic regression analysis was performed to determine variables that were associated with insufficient ( < 60 minutes ) daily activity . RESULTS Seventy-six children ( 15 % of the cohort ) failed to meet the minimum activity recommendations of 60 minutes of daily activity . These children were significantly less likely to walk or cycle to school ( adjusted odds ratio ( OR ) 0.43 ; 95 % CI=0.24 - 0.77 ) or participate in organised sports or activity ( OR 0.42 ; 95 % CI=0.28 - 0.64 ) and were more likely to spend in excess of 2 hours a day watching television of using a computer for entertainment ( OR 2.10 ( 1.16 - 3.78 ) . Age , gender , SES and family size were not significantly associated with insufficient activity . CONCLUSION There exists a significant proportion of the paediatric population who are insufficiently active . Interventions to encourage increased activity  in this sub-group may be successful if they seek to alter sedentary behaviour ( namely television use ) and method of transportation to and from school PURPOSE This study was conducted to determine if fifth- grade students who walked or bicycled to school on a regular basis were more physically active than those that did not . METHODS The 
    Output:
    
agent
These findings suggest that AST should be promoted to increase PA levels in children and adolescents and that cycling to/ from school is associated with increased cardiovascular fitness .
***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 Walking and cycling to school could be an important regular source of physical activity in growing children . The aim of this 12 months prospect i ve observational study was thus to evaluate the effect of self-transportation to school on bone mineral accrual and gain in bone width in pre-pubertal children , both traits independently contributing to bone strength . Methods Ninety-seven girls and 133 boys aged 7–9 years were recruited as a part of the Malmö Pediatric Osteoporosis Prevention ( POP ) Study in order to evaluate the influence of self-selected school transportation for the accrual of bone mineral and bone width .  Children who walked or cycled to school were compared with  children who went by bus or car . Bone mineral content ( BMC ) was measured by dual energy X-ray absorptiometry ( DXA ) in the lumbar spine ( L2–L4 ) , third lumbar vertebra ( L3 ) and hip , and bone width was calculated at L3 and femoral neck ( FN ) . Changes during the first 12 months were compared between the groups . Subjective duration of physical activity was estimated by a question naire and objective level of everyday physical activity at follow-up by accelerometers worn for four consecutive days . All children remained in Tanner stage 1 throughout the study . Comparisons were made by independent student 's t-tests between means , ANCOVA and Fisher 's exact tests . Results There were no differences in baseline or annual changes in BMC or bone width when the transportation groups were compared . No differences were detected in objective ly measured daily level of physical activity by accelerometer . All children reached above 60 minutes of moderate to intense daily physical activity per day , the international recommended level of daily physical activity according to the United Kingdom Expert Consensus Group . Conclusion The everyday physical activity in these pre-pubertal children seems to be so high that the school transportation contributes little to their total level of physical activity . As a result , the choice of school transportation seems not to influence the accrual of bone mineral or gain in bone size during a 12-month follow-up period Objective . To prospect ively identify behavioral risk factors for childhood overweight and to assess their relevance in high risk sub groups ( children of mothers with overweight or low education ) . Methods . In the PIAMA birth cohort ( n = 3963 ) , question naire data  were obtained at ages 5  and 7 on “ screen time ” , walking or cycling to school , playing outside , sports club membership , fast food consumption , snack consumption and soft drink consumption . Weight and height were measured at age 8 years . Results . Screen time , but none of the other hypothesized behavioral factors , was associated with overweight ( aOR 1.4 ( CI : 1.2–1.6 ) ) . The adjusted population attributable risk fraction for screen time > 1 hr/day was 10 % in the high risk and 17 % in the low risk sub groups . Conclusion . Reduction of screen time to < 1 hr/day could result in a reduction of overweight prevalence in the order of 2 percentage points in both high and low risks sub groups Background Walking and cycling to school are one source of regular physical activity . The aim of this two years observational study in pre-pubertal children was to evaluate if walking and cycling to school was associated with higher total amount of physical activity and larger gain in bone mineral content ( BMC ) and bone width than when going by car or bus . Methods 133 boys and 99 girls aged 7 - 9 years were recruited to the Malmö Prospect i ve Paediatric Osteoporosis Prevention ( POP ) study .  BMC ( g ) was measured by dual X-ray absorptiometry ( DXA ) in total body , lumbar spine ( L2-L4 ) and femoral neck ( FN ) at baseline and after 24 months . Bone width was measured in L2-L4 and FN . Skeletal changes in the 57 boys and 48 girls who consistently walked or cycled to school were compared with the 24 boys and 17 girls who consistently went by bus or car . All children remained in Tanner stage I. Level of everyday physical activity was estimated by accelerometers worn for four consecutive days and question naires . Comparisons were made by independent student 's t-tests between means and Fisher 's exact tests . Analysis of covariance ( ANCOVA ) was used to adjust for group differences in age at baseline , duration of organized physical activity , annual changes in length and BMC or bone width if there were differences in these traits at baseline . Results After the adjustments , there were no differences in the annual changes in BMC or bone width when comparing girls or boys who walked or cycled to school with those who went by car or bus . Furthermore , there were no differences in the levels of everyday physical activity objective ly measured by accelerometers and all children reached above the by the United Kingdom Expert Consensus Group recommended level of 60 minutes moderate to vigorous physical activity per day . Conclusion A physical active transportation to school for two years is in pre-pubertal children not associated with a higher accrual of BMC or bone width than a passive mode of transportation , possibly due to the fact that the everyday physical activity in these pre-pubertal children , independent of the mode of school transportation , was high Background Brazil is currently experiencing a nutrition transition : the displacement of traditional diets with foods high in saturated fat , sodium , and cholesterol and an increase in sedentary lifestyles . Despite these trends , our underst and ing of child obesity in Brazil is limited . Thus , the aims of this study were ( 1 ) to investigate the current prevalence of overweight and obesity in a large sample of children and adolescents living in São Paulo , Brazil , and ( 2 ) to identify the lifestyle behaviors associated with an increased risk of obesity in young Brazilians . Methods A total of 3,397 children and adolescents ( 1,596 male ) aged 7 - 18 years were r and omly selected from 22 schools in São Paulo , Brazil . Participants were classified as normal weight , overweight , or obese based on international age- and sex-specific body mass index thresholds . Selected sociodemographic , physical activity , and nutrition behaviors were assessed via question naire . Results Overall , 19.4 % of boys and 16.1 % of girls were overweight while 8.9 % and 4.3 % were obese . Two-way analysis of variance revealed that the prevalence of overweight and obesity was significantly higher in boys and in younger children when compared to girls and older children , respectively ( P < 0.05 for both ) . Logistic regression analysis revealed that overweight was associated with more computer usage , parental encouragement to be active , and light soft drink consumption after controlling for differences in sex , age , and parental education ( P < 0.05 for all ) . Conversely , overweight was associated with less active transport to school , eating before sleep , and consumption of breakfast , full-sugar soft drinks , fried food and confectionery ( P < 0.05 for all ) . Conclusions Our results show that obesity in São Paulo children and adolescents has reached a level equivalent to that seen in many developed countries . We have also identified three key modifiable factors related to obesity that may be appropriate targets for future intervention in Brazilian youth : transport mode to school , computer usage , and breakfast consumption To estimate the prevalence and determinants of overweight and obesity among school children and adolescents ( 7–18 years ) , a cross-sectional study was conducted in Tianjin City of Northeast China . Five primary and middle schools were selected using a multistage r and om cluster sampling . Anthropometric measurements were taken by the research team . Then , st and ardized question naires on socioeconomic status , diet and lifestyle , parental weight and height were sent to the parents to be completed together with their child . Overall , 3,140 students were screened for overweight and associated risk factors . Body mass index classification reference proposed by the Working Group on Obesity in China was used as a screening reference to calculate the prevalence of overweight in these groups . The prevalence of overweight and obesity was found to be 12.5 % and 15.7 % , respectively . Logistic regression analysis ( overweight compared with normal weight ) showed that , overweight in children was significantly associated with male gender , parental obesity , parental educational level , mother ’s history of gestational diabetes , high birth weight , less hours of physical activity per day , urban residence , motorized transportation , and eating food not prepared at home . After adjusting for parental obesity , the odds ratio of overweight children was increased by urban residence ( rural as a reference , 2.68 , 2.16–3.32 ) , positive gestational diabetes ( 2.76 , 1.37–4.50 ) , and fast-food/restaurant food service ( 2.03 , 1.34–3.07 ) . Children who walked to school and participated in outdoor activities were 54 % and 63 % less likely to be overweight respectively . Conclusions : The prevalence of overweight and obesity is high among school children and adolescents in Tianjin .  Changes in lifestyle , high socioeconomic status , parental obesity , mother ’s history of gestational diabetes , and high birth weight are among the highly associated risk factors of overweight . An educational approach about maintaining a healthy weight should be introduced much earlier to high-risk children , parents , and women of childbearing age BACKGROUND Atherosclerosis develops from early childhood ; physical activity could positively affect this process . This study 's aim was to assess the associations of objective ly measured physical activity with clustering of cardiovascular disease risk factors in children and derive guidelines on the basis of this analysis . METHODS We did a cross-sectional study of 1732 r and omly selected 9-year-old and 15-year-old school children from Denmark , Estonia , and Portugal . Risk factors included in the composite risk factor score ( mean of Z scores ) were systolic blood pressure , triglyceride , total cholesterol/HDL ratio , insulin resistance , sum of four skinfolds , and aerobic fitness . Individuals with a risk score above 1 SD of the composite variable were defined as being at risk . Physical activity was assessed by accelerometry . FINDINGS Odds ratios for having clustered risk for ascending quintiles of  physical activity  ( counts per min ; cpm ) were 3.29 ( 95 % CI 1.96 - 5.52 ) , 3.13 ( 1.87 - 5.25 ) , 2.51 ( 1.47 - 4.26 ) , and 2.03 ( 1.18 - 3.50 ) , respectively , compared with the most active quintile . The first to the third quintile of physical activity had a raised risk in all analyses . The mean time spent above 2000 cpm in the fourth quintile was 116 min per day in 9-year-old and 88 min per day in 15-year-old children . INTERPRETATION  Physical activity  levels should be higher than the current international guidelines of at least 1 h per day of physical activity of at least moderate intensity to prevent clustering of cardiovascular disease risk factors OBJECTIVE To prospect ively examine potential benefits of active commuting to school on measures of weight status and physical activity in a sample of youth . RESEARCH METHODS AND PROCEDURES A cohort of students from seven elementary schools was measured four times -- in the fall and spring of fourth grade ( N = 1083 ) and fifth grade ( N = 924 ) . Participants were classified as active ( walking , biking , or skateboarding to school almost every day for baseline analyses or at least 2 d/wk for analyses of consistent active commuting ) or non-active commuters to school . Accelerometers were used to measure physical activity . Height , weight , and skinfolds were objective ly assessed . RESULTS Boys who actively commuted to school had lower BMI ( p < 0.01 ) and skinfolds ( p < 0.05 ) than non-active commuters to school in the fourth grade . Active commuting to school over 2 years was not associated with BMI change or overweight status . DISCUSSION Walking and cycling to school may contribute to preventing excessive weight gain , or leaner children may walk or cycle to school AIMS Australian guidelines recommend that children participate in at least one hour of physical activity every day . We aim ed to measure physical activity  participation in a r and om sample of Australian primary school children and to determine the biological , behavioural , environmental and social influences associated with insufficient daily activity . METHOD We analysed the following cross-section data from a r and omly selected sample of children ( N=518 ) aged 5 to 12 years : age , gender , socioeconmic status ( SES ) indicators , family size , home play equipment availability , transport method to school , and estimated time per week in physical and sedentary activity . Logistic regression analysis was performed to determine variables that were associated with insufficient ( < 60 minutes ) daily activity . RESULTS Seventy-six children ( 15 % of the cohort ) failed to meet the minimum activity recommendations of 60 minutes of daily activity . These children were significantly less likely to walk or cycle to school ( adjusted odds ratio ( OR ) 0.43 ; 95 % CI=0.24 - 0.77 ) or participate in organised sports or activity ( OR 0.42 ; 95 % CI=0.28 - 0.64 ) and were more likely to spend in excess of 2 hours a day watching television of using a computer for entertainment ( OR 2.10 ( 1.16 - 3.78 ) . Age , gender , SES and family size were not significantly associated with insufficient activity . CONCLUSION There exists a significant proportion of the paediatric population who are insufficiently active . Interventions to encourage increased activity  in this sub-group may be successful if they seek to alter sedentary behaviour ( namely television use ) and method of transportation to and from school PURPOSE This study was conducted to determine if fifth- grade students who walked or bicycled to school on a regular basis were more physically active than those that did not . METHODS The 
    Output:
    