Assessing Risk Factors for Obesity Between Childhood and Adolescence: I. Birth Weight, Childhood Adiposity, Parental Obesity, Insulin, and Leptin

Abstract

Objective. To assess the effects of body weight, body composition, parental obesity, and metabolic variables on the development of obesity in a large cohort of 5-year-old Native American children with a high propensity for obesity. Methods. During the summer months of 1992 to 1995 and again 5 years later, 138 (65 boys and 73 girls) 5-year-old Pima Indian children were studied. Height; weight; body composition; parental obesity; and fasting plasma insulin, glucose, and leptin concentrations were determined at baseline and follow-up. Linear regression models were used to assess the effect of the baseline variables on the development of obesity. Results. At both 5 and 10 years of age, Pima Indian children were heavier and fatter than an age- and gender-matched reference population. All anthropometric and metabolic variables tracked strongly from 5 to 10 years of age (r ≥ 0.70). The most significant determinant of percentage of body fat at 10 years of age was percentage of body fat at 5 years of age (R² = 0.53). The combined effect of high maternal body mass index, elevated fasting plasma leptin concentrations, and low fasting plasma insulin concentrations at baseline explained an additional 4% of the total variance in adiposity at follow-up. Conclusions. Although parental obesity and metabolic variables such as insulinemia and leptinemia at baseline account for a small percentage of the variance in adiposity at follow-up, early childhood obesity is the dominant predictor of obesity 5 years later. These results suggest that strategies to prevent childhood obesity must be initiated at a very early age.