Changes in total and central adiposity and body fat distribution among 7–10-year-old schoolchildren in Brazil

Abstract

OBJECTIVE: To describe changes in total and central adiposity and body fat distribution in children over a 5-year period by investigating variations in BMI, waist circumference (WC), waist-to-height ratio (WHtR) and skinfold thicknesses (SFT). DESIGN: A school-based sample of children from 2nd to 5th grades of elementary schools participated in two cross-sectional studies in 2002 (n 2936) and 2007 (n 1232). SETTING: Public and private schools of Florianopolis, Brazil. SUBJECTS: Schoolchildren aged 7-10 years had their weight, height, WC and SFT measured according to standard procedures. Body fat distribution was assessed by triceps, subscapular, suprailiac and medial calf skinfold measurements. Changes in BMI, WC, WHtR and SFT were analysed, adjusting for type of school and monthly family income. RESULTS: Adjusted mean differences between 2002 and 2007 for BMI and WC were always positive and of similar magnitude between boys and girls. However, a statistically significant increase was observed only for BMI (raw and Z-score values) in boys. WHtR remained stable in both sexes. Adjusted median values for SFT also increased in boys and girls, except for triceps skinfold. BMI, WC and SFT tended to increase across age classes in both sexes. The relative change observed for the median central skinfolds (subscapular and suprailiac) was greater than that of peripheral skinfolds (triceps and medial calf). CONCLUSIONS: The subcutaneous adipose tissue (SFT) appeared to increase at a faster rate than total adiposity (BMI). The increase in central SFT indicates that the relative change is due primarily to a rise in central adiposity.