Secondhand tobacco smoke: a source of lead exposure in US children and adolescents

Abstract

Objectives: We evaluated the relationship between secondhand tobacco smoke (SHS) exposure and blood lead levels in US children and adolescents.

Methods: We analyzed data from 6830 participants aged 3-19 years in the National Health and Nutrition Examination Survey (1999-2004) who were not active smokers and for whom SHS exposure information and blood lead measurements were available.

Results: After multivariable adjustment, participants in the highest quartile of serum cotinine (≥ 0.44 μg/L) had 28% (95% confidence interval = 21%, 36%) higher blood lead levels than had those in the lowest quartile (< 0.03 μg/L). Similarly, blood lead levels were 14% and 24% higher in children who lived with 1 or with 2 or more smokers, respectively, than they were in children living with no smokers. Among participants for whom lead dust information was available, the associations between SHS and blood lead levels were similar before and after adjustment for lead dust concentrations.

Conclusions: SHS may contribute to increased blood lead levels in US children. Lead dust does not appear to mediate this association, suggesting inhalation as a major pathway of exposure. Eliminating SHS exposure could reduce lead exposure in children.

Figures

FIGURE 1

Ratio of geometric mean of blood lead level, by children's and adolescents' secondhand smoke exposure and other characteristics: National Health and Nutrition Examination Survey, United States, 1999–2004. Note. BMI = body mass index (defined as weight in kilograms divided by the square of height in meters); CI = confidence interval; Mex = Mexican; PIR = poverty-to-income ratio. Ratios are adjusted for gender, age, race, country of birth, BMI percentile, survey year, household education, poverty level (PIR; the ratio of the family's income to its appropriate poverty threshold as defined by the US Census Bureau), and year in which housing was built. Dots represent the ratios and horizontal lines represent the CIs. The P value is for the difference in the association between secondhand smoke exposure (cotinine or smokers at home) and blood lead levels by participant subgroups (interaction).