Submitted to: Obesity Research
Publication Type: Abstract only
Publication Acceptance Date: 3/10/2003
Publication Date: 7/1/2003
Citation: Treuth, M.S., Butte, N.F., Sorkin, J. 2003. Predictors of body fat gain in non-obese girls with a familial predisposition to obesity. Obesity Research. 11:A3, 2003. Interpretive Summary:
Technical Abstract: Evidence is conflicting on the causal factors underlying the development of excess adiposity in children. The aim was to determine the effect of energy expenditure (EE), muscle energetics, and physical fitness on weight and fat gain in non-obese prepubertal girls with and without a predisposition to obesity. Normal-weight girls (n=101) were recruited at 8 years of age according to parental body mass index (BMI): LN = girls with 2 lean (BMI<25kg/m2) parents (n=27), LNOB = girls with one obese and one lean parent (n=38), and OB = girls with 2 obese (BMI>28kg/m2) parents (n=23), with 88 girls completing the 2-year study. Measures of weight, height, and body composition by DXA were taken one and two years after baseline measures. Girls underwent baseline measures of EE by 24-h calorimetry and doubly labeled water, muscle metabolism by 31P-NMR, and fitness. The FM and % fat differed between groups at Year 1 and Year 2; OB group had a higher FM (P=0.03) and % fat (P=0.046) than the LN group at Year 1, and a higher FM (P=0.047) at Year 2. Adjusted for baseline weight, group, time, ethnicity and Tanner stage, sleep EE, basal EE, 24-h EE, and VO2peak were negatively associated with FM and % fat (P<0.04). Adjusted for baseline weight, group, time, ethnicity and Tanner stage, muscle oxidative capacity was negatively and free-living TEE was positively predictive of changes in % fat between 8-10 years of age in these girls (both P=0.04). Non-obese girls with 2 obese parents are at significant risk for development of obesity. Higher free-living TEE and lower muscle oxidative capacity predicted higher rates of fat gain.