***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 Physical inactivity and sedentary lifestyles are known to predispose to overweight and obesity . These lifestyles are also known to track from childhood into adulthood with consequent cardiovascular and metabolic problems . This study aim ed to describe the frequency of physical activity  and the relationship between physical activity and body mass index of urban Nigerian school children and adolescents . Methods Children from seven schools in Abeokuta , southwest Nigeria were selected using a multi-staged r and om sampling technique . Results Of 570 children , 411 ( 72.1 % ) were involved in moderate to vigorous physical activities . Involvement in physical activity was higher in older children ( P<0.001 ) , males ( P<0.001 ) , and children of mothers with a higher educational level ( P=0.03 ) . Eleven ( 1.9 % ) children were overweight or obese whereas 163 ( 28.6 % ) were underweight . There were more children with underweight than overweight among the subject population with a high level of physical activity ( 35.6 % vs. 4.4 % , P=0.499 ) . Conclusions A large proportion of the children in urban Nigeria participate in physical activity . The prevalence of overweight and obesity is low but undernutrition is a major nutritional problem among these children The present study examines the effect of animal- source -food ( ASF ) intake on arm muscle area growth as part of a larger study examining causal links between ASF intake , growth rate , physical activity , cognitive function and micronutrient status in Kenyan schoolchildren . This r and omised , controlled feeding intervention study was design ed with three isoenergetic feeding interventions of meat , milk , and plain traditional vegetable stew ( githeri ) , and a control group receiving no snack .  A total of twelve elementary schools were r and omly assigned to interventions , with three schools per group , and two cohorts of 518 and 392 schoolchildren were enrolled 1 year apart . Children in each cohort were given feedings at school and studied for three school terms per year over 2 years , a total of 9 months per year : cohort I from 1998 to 2000 and cohort II from 1999 to 2001 . Food intake was assessed by 24 h recall every 1 - 2 months and biochemical analysis for micronutrient status conducted annually ( in cohort I only ) . Anthropometric measurements included height , weight , triceps skinfold ( TSF ) and mid-upper-arm circumference ( MUAC ) . Mid-upper-arm muscle area ( MAMA ) and mid-upper-arm fat area ( MAFA ) were calculated . The two cohorts were combined for analyses . The meat group showed the steepest rates of gain in MUAC and MAMA over time , and the milk group showed the next largest significant MUAC and MAMA gain compared with the plain githeri and control groups ( P < 0.05 ) . The meat group showed the least increase in TSF and MAFA of all groups . These findings have implication s for increasing micronutrient intake and lean body mass in primary schoolchildren consuming vegetarian diets AIM To investigate the determinants of overweight and obesity among 10- to 15-year-old schoolchildren in a population in the transitional phase in the North West Province of South Africa . METHODS A cross-sectional survey was used to investigate weight status ( anthropometric indicators ) and determinants of overweight/obesity including  dietary intake , physical activity and socio-economic status .  A single , r and om sample ( n=1257 ) , stratified for gender , type of school and ethnic group , was used . Data were collected on demographics , family circumstances , habitual physical activity , dietary intake and anthropometry to evaluate weight status and body fat content . One-way analysis of variance , the generalised linear models procedure of SAS and the Tukey post hoc honest significant difference test were used to analyse the data . RESULTS Few children were overweight or obese ( 7.8 % ) according to International Obesity Task Force ( IOTF ) st and ards ( body mass index ( BMI ) -for-age ) . These st and ards were compared with other accepted st and ard values . Both Cole 's IOTF/ BMI -for-age st and ard and the sum of skinfold thicknesses st and ard classified normal-weight status similarly at a level of 92 % ( P<0.01 ) and were found to be useful in determining overweight/obesity . The prevalence rate was higher in females and white children , and was more apparent in urban areas , smaller households and children of parents with low- or high-income occupations . Boys and pre-menarcheal girls had mean body fat percentage in the normal/optimal range , whereas that of post-menarcheal girls was moderately high . Few variables showed a significant association with high body fat percentage : in boys , only the number of members in the household and physical activity levels over the weekend ; in girls , only age . The overweight/obese boys mostly lived in smaller households , and the overweight/obese post-menarcheal girls were most inactive on both weekdays and weekends , and more overweight with increasing age . CONCLUSION Smaller households , inactivity and increasing age for girls were found to be determinants that influence the development of overweight/obesity , while female gender and age post-menarche were identified as determinants of higher body fat content . For overweight/obesity prevention , the focus should be on pre-menarcheal girls , aged 10 - 13 years , using these determinants to identify overweight/obesity risk . Preventive programmes should aim to increase the physical activity of children to improve their current and future weight status An epidemiological assessment of blood pressure determinants in a r and om sample of 254 Nigerian adolescents aged 6 - 17 years in Benin City , Nigeria , was conducted . None of the adolescents reported cigarette smoking . Only 2.6 % of the males and 0 % of the females were alcohol users . Socio-economic status of the children according to parental education revealed that approximately 23 % of the mothers and 9.8 % of the fathers received less than a secondary ( high school ) education . At the other end of the education spectrum , a  college education was received by 64.1 % and 30.8 % of the fathers and mothers , respectively . Two percent of the females and 1.3 % of the males either had systolic blood pressures of greater than or equal to 140 mmHg or diastolic blood pressures of greater than or equal to 90 mmHg . No significant blood pressure differences existed between the two sexes . Among the males , it was demonstrated that age , body mass index , and heart rate were significant independent predictors of systolic blood pressure , explaining 49 % of the variance . Forty-seven per cent of systolic blood pressure variance was explained by age and heart rate , for females . It was interesting to note that age was the only independent predictor of diastolic blood pressure for both males and females after control for heart rate and body mass index This paper estimates dynamic r and om effects models for intakes by dietary energy , protein , calcium , iron , zinc , niacin , riboflavin , thiamin , and vitamins A , C , D , and E 100 of Kenyan school children ( 6 - 9 years ) within a multivariate longitudinal framework . The explanatory variables were socioeconomic and background variables , children 's body mass index , and maternal education , cognitive test scores and morbidity spells . The model parameters are estimated using the maximum likelihood method controlling for unobserved between-children differences . The main finding is that while maternal education was usually not a significant predictor of dietary intakes , maternal scores on cognitive tests did strongly predict them . Moreover , the paternal cognitive scores and maternal morbidity levels were not significantly associated with the intakes , but an index of socioeconomic status and cash income was a significant predictor . The results indicate the need to consider broader measures of human development and of devising suitable educational programs for women without formal education 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 , placebo-controlled iron supplementation trial was conducted in Kenya to examine the effect of iron supplements on appetite and growth in 87 primary school children .  Sustained-release ferrous sulfate ( 150 mg ) or placebo tablets were provided daily at school for 14 wk . Prior to tablet administration , baseline anthropometry , iron nutritional status ( hemoglobin and serum ferritin ) , parasitic infections and clinical indicators of morbidity were measured . A baseline appetite test was conducted twice on each child by quantitatively measuring the ad libitum consumption of a midmorning snack . In addition , each child was asked for a subjective assessment of his or her appetite . Follow-up exams and appetite tests were identical to those at baseline . Findings indicated that provision of iron supplements result ed in improved growth and improved appetite ( in terms of both energy intake of the snack and child report of appetite ) as compared with children receiving the placebo . The increased energy intake from the snack was 10 % of the daily estimated energy intake for children of this same age group living elsewhere in Kenya . Further research into the underlying physiological mechanisms may shed light on the relationship between iron nutritional status and appetite BACKGROUND The regression equations of Slaughter and Dezenberg , which are based on mixed ethnic sample s , are currently recommended for predicting body fat from skinfold-thickness measures in prepubescent children of African ancestry . These equations contain method ologic problems that could make them inappropriate for African children . OBJECTIVE The objective was to apply the Slaughter and Dezenberg equations to predict body fat in African prepubertal children and to compare the results with body fat measured by dual-energy X-ray absorptiometry ( DXA ) . If significantly different outcomes were observed , then the objective was to develop new prediction equations and vali date them on African children . DESIGN The Slaughter and Dezenberg equations were applied to a cross-sectional sample of 214 prepubescent ( Tanner stage 1 ) African children ( 118 boys ) .  Body fat was determined by DXA , and subcutaneous fat at triceps , biceps , subscapular , suprailiac , thigh , and calf sites was measured with use of Holtain calipers . A r and omly selected sample of 134 participants ( 78 boys ) was used to generate new prediction equations that were vali date d on the remaining 80 participants ( 40 boys ) . RESULTS The Slaughter and Dezenberg equations significantly underestimated ( P < 0.001 ) body fat compared with DXA in both boys and girls . The best combination of skinfold thicknesses to predict body fat in African prepubertal boys , controlling for chronologic age , was triceps , biceps , subscapular , suprailiac , and thigh ( SEE = 2.87 ) , and for girls it was biceps , subscapular , suprailiac , thigh , and calf ( SEE = 3.51 ) . CONCLUSION The Slaughter and Dezenberg equations are unsuitable for predicting body fat in 9-y-old African prepubertal children . New equations that are based on skinfold-thickness combinations from African children provide more accurate estimates Aim : To investigate whether associations and differences exist regarding the arterial compliance , dietary intake and anthropometric parameters of children of four different ethnic groups in South Africa . Study Design : In this study , 1244 children from four ethnic groups , aged 10–15 years , were r and omly selected 
    Output:
    
Quantitative synthesis revealed a trend towards increasing proportions of overweight/obesity over time in school-aged children in this region , as well as a persistent problem of underweight .
Body composition measures were found to be higher in girls than boys , and higher in urban living and higher socioeconomic status children compared to rural population s or those of lower socioeconomic status .
This review provides evidence for an overweight/obesity transition in school-aged children in Sub Saharan Africa .