RESUMO
BACKGROUND: There are limited and controversial data on the influence of gender on metabolic rate in prepubertal children. OBJECTIVE: To assess the effect of gender on resting energy expenditure (REE), activity-related energy expenditure (AEE), total energy expenditure (TEE) and physical activity level (PAL) in free-living prepubertal children. DESIGN: Cross-sectional study. SUBJECTS: 40 prepubertal children (24 boys, 16 girls, 4-11 y old (mean age: 7.0 +/- 1.2 y), BMI 13.1-32.0 kg/m2). MEASUREMENTS: Energy expenditure was measured by the combination of indirect calorimetry and individually calibrated 24 h heart rate monitoring. Body composition was assessed by anthropometrics and bioelectrical impedance analysis. Socio-cultural and socio-economic factors, as well as activities of daily living, were estimated by questionnaire for the parents. Boys and girls were matched for fat-free mass (FFM, boys: 25.9 +/- 8.5 kg; and girls: 24.4 +/- 4.5 kg, n.s.) and fat mass (FM, boys: 11.6-5.9 kg; and girls: 10.8 +/- 3.3 kg, n.s.). RESULTS: We found no sex difference in REE, AEE and TEE. PAL was 1.4 +/- 0.3 for boys and 1.2 +/- 0.4 for girls. REE and TEE were significantly related to FFM (r=0.62, r=0.81, r=0.60). FFM was found to be the most significant determinant of REE (r2=0.70). REE accounted for the largest part of the variance in TEE (r2=0.46). Gender had no significant effect. CONCLUSIONS: There is no effect of gender on energy expenditure in prepubertal children.
