RESTING METABOLIC-RATE IN AFRICAN-AMERICAN AND CAUCASIAN GIRLS

Recent studies have found a lower resting metabolic rate (RMR) in Afri can-American (AA) women with obesity as compared with Caucasian (C) wo men with obesity, It is unknown if this difference in RMR is seen in p repubertal girls or in those of average body weight, Therefore, we stu died RMR in 21 AA and 24 C girls, ages 7-10, who were well matched for age, weight, body mass index (BMI), and pubertal status, All had BMI between 15% and 85% for age and race, based on data from the First Nat ional Health and Nutrition Examination Survey, Fat free mass (FFM) was measured by dual-energy X-ray absorptiometry, RMR was measured with a Deltatrac indirect calorimeter under controlled conditions after the subjects underwent an overnight fast, The slopes of the regression equ ations were similar for both groups (p=0.7). After adjustment for FEM, the AA girls had a significantly lower RMR than did the C girls (-92 +/- 32 kcal/d, p=0.007 by analysis of covariance). This significance w as maintained after exclusion of total body bone mineral content, Thes e data suggest that normal-weight prepubertal AA girls may have reduce d resting energy expenditure compared with C girls.