Birth Weight and Childhood Overweight among WIC Participants

Prevalence of obesity among children and adults in the United States has increased rapidly during the past decade. Research into early-life determinants of obesity could lead to innovative strategies for prevention. The objective of this study is to examine the association between birth weight and childhood overweight among WIC children. We conducted a case-control study including 556 WIC participant children ages 3-5 years who were either overweight (BMI >95th percentile of reference standard) or normal weight (BMI 25-75th percentile). The population is large majority (95%) Hispanic, a group that has been documented to have the highest rates of overweight and obesity in adults and children. The independent variable of interest is the birth weight reported by the mothers. Mean birth weight of WIC children differed significantly between cases and controls (p=0.0001). In multiple logistic regression analysis controlling for gender, months of breastfeeding, smoking, gestational diabetes and maternal weight gain during pregnancy, the odds ratio for childhood overweight for 1-kg increment in birth weight was 1.6 (95% confidence intervals: 1.1-2.3). Maternal BMI reduced the estimate to 1.5 (95% confidence intervals: 1.1-2.1). Higher birth weight predicted increased risk of overweight among WIC children. A tiny part of this association may be explained by the confounding influence of maternal BMI, perhaps due to a combination of pre- and postnatal environmental factors as well as genetic legacy. Our findings have implications for preventing childhood obesity by intervening at a very early age with high birth weight children. Supported by USDA/CSREES #2005-35215-16075.