RESTING METABOLIC-RATE IN 6-YEAR-OLD TO 10-YEAR-OLD OBESE AND NONOBESE CHILDREN

The resting metabolic rate (RMR) and body composition of 130 obese and nonobese prepubertal children, aged 6 to 10 years, were assessed by indirect calorimetry and skin-fold thickness, respectively. The mean (+/-SD) RMR was 4619 +/- 449 kJ . day-1 (164 +/- 31 kJ . kg body weight 1 . day-1) in the 62 boys and 4449 +/- 520 kJ . day 1 (147 +/- 32 kJ . kg body weight-1 . day-1) in the 68 girls. Fat-free mass was the best single predictor of RMR (R2 = 0.64; p <0.001). Step-down multiple regression analysis, with independent variables such as age, gender, weight, and height, allowed several RMR predictive equations to be developed. An equation for boys is as follows: RMR (kJ . day-1) = 1287 + 28.6 . Weight (kg) + 23.6 . Height (cm) - 69.1 . Age (yr) (R2 = 0.58; p <0.001). An equation for girls is as follows: RMR (kJ . day-1 = 1552 + 35.8 . Weight (kg) + 15.6 . Height (cm) - 36.3 . Age (yr) (R2 = 0.69; p <0.001). Comparison between the measured RMR and that predicted by currently used formulas showed that most of these equations tended to overestimate the RMR of both genders, especially in overweight children.