Body composition assessment using DXA in six-year-old children: the 2004 Pelotas Birth Cohort, Rio Grande do Sul State, Brazil.

The aim of this study was to describe fat (FM) and lean body mass (LBM) in six-year-old children from the 2004 Pelotas Birth Cohort, stratified by gender. Dual-Energy X-ray Absorptiometry was used to measure FM and LBM, FM and LBM indexes, and percentage (%) of FM and LBM. Mean measures of adiposity were higher among girls (6.3 kg, 4.2 kg/m(2) and 23.4% vs. 5 kg, 3.3 kg/m(2) and 18%) while LBM measures were higher among boys (19.3 kg, 13 kg/m(2) and 78.5% vs. 17.7 kg, 12.2 kg/m(2) and 73.2%). In both boys and girls mean measures of adiposity increased with socioeconomic status and maternal education. Mean measures of adiposity were higher among white-skinned children while %LBM was higher among black-skinned children. Preterm compared to full-term children showed lower mean measures of adiposity and LBM. Female sex, white skin color and higher socioeconomic conditions are associated with higher adiposity in childhood.