Childhood obesity is an increasingly prevalent health problem affecting 22-27% of the children and adolescents in the United States (NHANES II). While epidemiological studies have provided indicators as to which children are at risk of becoming obese, we still do not know why they become obese. The literature suggests that alterations in energy expenditure may play a role in the etiology of obesity. HYPOTHESIS: Reduced energy expenditure and nutrient partitioning favoring fat deposition result in higher fat gain in children predisposed to obesity. OBJECTIVES: To test if the following putative factors lead to higher fat gain in children predisposed to obesity: 1) lower maintenance energy expenditure, 2) lower levels of habitual physical activity, 3) lower exercise economy and oxidative capacity in skeletal muscle, 4) lower rates of fat oxidation, and a higher proportion of fat to fat- free mass deposition. DESIGN: This prospective study will investigate antecedents to obesity in normal-weight, prepubescent girls (8 y) with either normal-weight (N=36) or obese (N=36) parents. Expected predictors of fat gain will be measured at baseline, and at 1 and 2 years later. Basal metabolic rate (BMR), sleeping metabolic rate, 24-h sedentary energy expenditure quid substrate utilization will be measured by room respiration calorimetry. Total energy expenditure (TEE) will be measured by doubly-labeled water and activity quantified as TEE/BMR. Pattern o habitual physical activity will be described by heart rate monitoring. VO2peak and VO2submaximal will be determined by treadmill/ergometer exercise testing, and in vivo muscle oxidative capacity by nuclear magnetic resonance spectroscopy. Body composition will be assessed by dual-energy x-ray absorptiometry and total body potassium at baseline, and at l and 2 years later to determine the outcome variable, fat gain. SIGNIFICANCE: Recently released figures from the NHANES III survey revealed a 40% increase in the prevalence of obesity among adolescents. Similar results are anticipated for children. The proposed prospective study will examine potential determinants of higher fat gain in children """"""""at risk"""""""" of becoming obese. This study is important since significant health problems are associated with childhood obesity; identification of the etiological factors of childhood obesity is required to prevent and to reduce the prevalence of obesity.

Project Start
1996-07-01
Project End
2001-06-30
Budget Start
1998-07-01
Budget End
1999-06-30
Support Year
3
Fiscal Year
1998
Total Cost
Indirect Cost
Name
Baylor College of Medicine
Department
Pediatrics
Type
Schools of Medicine
DUNS #
074615394
City
Houston
State
TX
Country
United States
Zip Code
77030
Treuth, Margarita S; Butte, Nancy F; Adolph, Anne L et al. (2004) A longitudinal study of fitness and activity in girls predisposed to obesity. Med Sci Sports Exerc 36:198-204
Treuth, Margarita S; Butte, Nancy F; Sorkin, John D (2003) Predictors of body fat gain in nonobese girls with a familial predisposition to obesity. Am J Clin Nutr 78:1212-8
Treuth, M S; Butte, N F; Herrick, R (2001) Skeletal muscle energetics assessed by (31)P-NMR in prepubertal girls with a familial predisposition to obesity. Int J Obes Relat Metab Disord 25:1300-8
Treuth, M S; Butte, N F; Wong, W W et al. (2001) Body composition in prepubertal girls: comparison of six methods. Int J Obes Relat Metab Disord 25:1352-9
Treuth, M S; Butte, N F; Ellis, K J et al. (2001) Familial resemblance of body composition in prepubertal girls and their biological parents. Am J Clin Nutr 74:529-33
Goran, M I; Treuth, M S (2001) Energy expenditure, physical activity, and obesity in children. Pediatr Clin North Am 48:931-53
Treuth, M S; Butte, N F; Puyau, M et al. (2000) Relations of parental obesity status to physical activity and fitness of prepubertal girls. Pediatrics 106:E49
Treuth, M S; Butte, N F; Wong, W W (2000) Effects of familial predisposition to obesity on energy expenditure in multiethnic prepubertal girls. Am J Clin Nutr 71:893-900
Treuth, M S; Hunter, G R; Pichon, C et al. (1998) Fitness and energy expenditure after strength training in obese prepubertal girls. Med Sci Sports Exerc 30:1130-6