Determinants of body fat in prepubertal age

In order to evaluate the factors affecting body fat excess and distribution, we have studied children attending the 4th grade of a primary school randomly selected in Naples. 52 girls, 58 boys; mean age = 9.6 years (SE +/- 0.1) were examined. Among the familial factors assessed, a correlation between parental BMI and child's anthropometry was found. Among congenital factors, sex correlates with the children's waist/hip ratio ("t" = -2.07; p = 0.05). Moreover the girl's percent body fat was higher. These two findings suggest the expression of sexual characters in prepubertal age. Systolic blood pressure showed a positive correlation with children's percent body fat ("t" = 2.43; p = 0.016) and subscapular skinfold thickness ("t" = 1.19; p = 0.05), suggesting an influence of these factors on blood pressure level since this age. No correlation was found between children's BMI and weight at birth, family history of diabetes, hypertension or hyperlipidemia. Among environmental factors, only the mothers weight gain during pregnancy ("t" = -2.21; p = 0.03) and breast feeding ("t" = -2.07; p = 0.05) correlated with the children's BMI. The correlation between children's BMI and waist/hip ratio ("t" = 4.64; p = 0.0001), was not confirmed in children who exercise, suggesting a beneficial action of physical activity on body fat distribution. The identification in different populations of factors associated with childhood obesity is important for prevention planning.