Association of maternal smoking with overweight at age 3 y in American Indian children.

BACKGROUND Prevalence rates of overweight are higher among American Indian children than among any other ethnic group, but little research has explored contributing influences. OBJECTIVE The objective was to determine the prevalence and predictors of body mass index (BMI; in kg/m2) > or = 85th percentile in American Indian children in Wisconsin. DESIGN A retrospective analysis was conducted with linked pediatric and pregnancy nutrition surveillance systems and birth records from 1997 through 2001. Participants were American Indian mothers and children (aged 0-3 y) who were participating in the Special Supplemental Nutrition Program for Women, Infants, and Children in Wisconsin. Outcome measurements included indicators of BMI > or = 85th percentile identified by using binary logistic regression. RESULTS Of the 3-y-olds, 22.2% were overweight and 18.7% were at risk of overweight. Of their mothers, 42.5% had smoked during pregnancy. Smoking at the initial prenatal visit significantly predicted overweight and risk of overweight in children at age 3 y (odds ratio: 2.16; 95% CI: 1.05, 4.47). Despite being smaller at birth, the children of smoking mothers had a significantly (P < 0.05) greater increase in weight-for-length z score between birth and age 3 y than did children of nonsmokers. This greater increase was due to a significantly (P < 0.02) greater increase in weight in children of smokers than in those of nonsmokers and not to a relatively slower increase in height. CONCLUSIONS Our findings suggest the early influence of maternal smoking on the prevalence of overweight at age 3 y in a high-risk American Indian population and provide evidence that interventions to reduce smoking in pregnant women may be warranted.