Impact of birth weight on ethnic variations in subcutaneous and central adiposity in American children aged 5-11 years. A study from the Third National Health and Nutrition Examination Survey

OBJECTIVE: To determine the types of subcutaneous adiposity represented by different measurements of skinfold thickness that are associated with birth weight in white (n = 759), Black (n = 916) and Hispanic (n = 813) American children aged 5-11 y. We also determined the contribution of birth weight to ethnic differences in subcutaneous and central adiposity. DESIGN AND METHODS: Data for this analysis were from the Third US National Health and Nutrition Examination Survey. The outcome measures were triceps, subscapular, suprailliac and thigh skinfold thicknesses at 5-11 y of age. Central adiposity was defined as ratios of subscapular to triceps (STR) and central-peripheral (CPR) (subscapular+suprailliac)/(triceps+thigh) skinfol ds. Partial correlation analyses were used to determine the association bet ween birth weight and measures of subcutaneous fatness, while multiple line ar regression analyses were used to determine the independent contribution of birth weight to ethnicity variations in subcutaneous and central adiposi ty adjusting for sex, age and BMI. RESULTS: Overall, birth weight was negatively associated with subscapular s kinfold and central adiposity in White, Black and Hispanic American childre n (P < 0.05). Birth weight was also negatively associated with suprailliac skinfold in both Blacks and Hispanics (P < 0.01) and with sum of the four s kinfolds in Blacks (P < 0.05). Compared with White, Black ethnicity was neg atively associated with triceps, suprailliac thigh and sum of skinfold thic knesses controlling for birth weight, sex, age and BMI (P < 0.01). Compared with White, Hispanic ethnicity was negatively associated with triceps, thi gh and sum of skinfold thicknesses (P < 0.01). Both Black and Hispanic ethn icity was positively associated with STR and CPR (P < 0.01). CONCLUSIONS: In this population of American children, the association of bi rth weights with subcutaneous and central fat accumulation may be due to fe tal programming. Since the impact of fetal conditions is likely to be modif ied by life course, defining the interaction between factors that are prese nt at birth and subsequent exposures is one of the essential challenges for future research.