Additive interactions of maternal prepregnancy BMI and breast-feeding on childhood overweight

OBJECTIVE: To examine the interactions of maternal prepregnancy BMI and breast-feeding on the risk of overweight among children 2 to 14 years of age. RESEARCH METHODS AND PROCEDURES: The 1996 National Longitudinal Survey of Youth, Child and Young Adult data in the United States were analyzed (n = 2636). The weighted sample represented 51.3% boys, 78.0% whites, 15.0% blacks, and 7.0% Hispanics. Childhood overweight was defined as BMI >/=95th percentile for age and sex. Maternal prepregnancy obesity was determined as BMI >/=30 kg/m(2). The duration of breast-feeding was measured as the weeks of age from birth when breast-feeding ended. RESULTS: After adjusting for potential confounders, children whose mothers were obese before pregnancy were at a greater risk of becoming overweight adjusted odds ratio (OR), 4.1; 95% confidence interval (CI), 2.6, 6.4] than children whose mothers had normal BMI (<25 kg/m(2); p < 0.001 for linear trend). Breast-feeding for >/=4 months was associated with a lower risk of childhood overweight (OR, 0.6; 95% CI, 0.4, 1.0; p = 0.06 for linear trend). The additive interaction between maternal prepregnancy obesity and lack of breast-feeding was detected (p < 0.05), such that children whose mothers were obese and who were never breast-fed had the greatest risk of becoming overweight (OR, 6.1; 95% CI, 2.9, 13.1). DISCUSSION: The combination of maternal prepregnancy obesity and lack of breast-feeding may be associated with a greater risk of childhood overweight. Special attention may be needed for children with obese mothers and lack of breast-feeding in developing childhood obesity intervention programs.