Association between maternal smoking and higher childhood BMI

Very overweight children are at significant risk of incurring many major health related problems. This issue is receiving increased attention from health services researchers. Several studies, mostly based on European child populations have found an association between mothers smoking during pregnancy and a subsequent higher risk of children becoming very overweight. Lack of a standard definition of very overweight children and cross-sectional designs with varying study population ages precludes generalizing results to a population of children covering a broad range of ages in the United States. This study presents results of body mass index (BMI) growth modeling in a population of 5 – 12 year children from the National Longitudinal Survey of Youths (NLSY). Using a random intercept and slopes growth model approach, preliminary results demonstrate that even when adjusting for demographic, socio-economic, and lifestyle factors at the mother and child levels, different growth trajectories are observed between children of mothers who did, and did not, smoke during pregnancy. On average, children of smokers during pregnancy are 0.378 BMI units heavier (p-value < 0.0001) than children of non-smokers. Predicted growth curves indicate that children of smokers are at greater risk of being very overweight at 12 years of age than children of non-smokers (13.55% compared to 12.59%). Aggregate positive health policy dividends from a decreasing number of women of child-bearing age smoking over the last 20 years are not maximized due to additional unanticipated residual negative health care effects in offspring of mothers who smoked during pregnancy.