Predictors of cotinine levels in US children - Data from the Third National Health and Nutrition Examination Survey

Study objective: To determine what factors predict cotinine levels in US ch ildren. Design: Cross-sectional study. Subjects: Nationally representative sample of 5,653 US children, both with and without reported tobacco smoke exposure in their homes. Methods: We stratified the children into those with reported passive smoke exposure at home and those without this exposure. We used regression models to predict the log of the cotinine level of the participants with the foll owing independent covariates: age; race/ethnicity; number of rooms in the h ome; sex; parental education; family, poverty index; family size; region; a nd, among children with reported passive smoke exposure, the number of ciga rettes smoked in the home. Results: Children exposed to passive smoke had a mean cotinine level of 1.6 6 ng/mL, and children not exposed to passive smoke had a mean level of 0.31 ng/mL. Among children with reported smoke exposure, non-Mexican-American r ace/ethnicity, young age, low number of rooms in the home, low parental edu cation, and an increasing number of cigarettes smoked in the home were pred ictors of increased serum cotinine levels. Among children with no reported smoke exposure, significant predictors of increased cotinine levels include d black race, young age, Midwest region of the United States, low number of rooms in the home, low parental education, large family size, and low fami ly poverty index. Conclusion: While the reported number of cigarettes smoked in the home is t he most important predictor of cotinine levels in children exposed to smoke and may provide an opportunity for clinical intervention, other demographi c factors are important among children both with and without reported smoke exposure.