Second-hand smoke exposure and blood lead levels in US children

Background: Lead is a component of tobacco and tobacco smoke, and smokers have higher blood lead levels than do nonsmokers. Methods: We examined the relation between second-hand smoke exposure and blood lead levels in a nationally representative sample of 5592 U.S. children, age 4-16 years, who participated in the Third National Health and Nutrition Examination Survey (1988-1994). Linear and logistic regression modeling was used to adjust for known covariates. Results: Geometric mean blood lead levels were 1.5 mug/dL, 1.9 mug/dL, and 2.6 mug/dL for children with low, intermediate, and high cotinine levels, respectively. The adjusted linear regression model showed that geometric mean blood lead levels were 38% higher (95% confidence interval [CI] = 25-52%) in children with high cotinine levels compared with children who had low cotinine levels. The logistic regression models showed that children with high cotinine levels were more likely to have blood lead levels greater than or equal to10 mug/dL than were children with low cotinine levels (odds ratio [OR] = 4.4; CI = 1.9-10.5). Conclusions: Second-hand smoke could be associated with increased blood lead levels in U.S. children aged 4-16 years.