Sociodemographic Differences in Secondhand Smoke Exposure in the United States.

Background. Socioeconomic disparities in secondhand smoke (SHS) exposure exist among nonsmokers. The present study examined the prevalence and socioeconomic disparities of both objective and self-reported measures of SHS exposure in various indoor environments among U.S. nonsmokers. Method. Data were drawn from the 2013-2014 and 2015-2016 National Health and Nutrition Examination Survey. The prevalence of objective measures of SHS (nonsmokers with serum cotinine levels of 0.05-10 ng/mL) and the self-reported SHS exposure status in restaurants, cars, and homes other than their own were examined for the overall population as well as by sociodemographic characteristics. Multivariable logistic regression analyses were used to assess the association between sociodemographic characteristics and SHS exposure measures. Results. The prevalence of self-reported SHS exposure in restaurants, cars, and homes other than one's own decreased significantly between 2013-2014 and 2015-2016. We found higher odds of the objective measure of SHS exposure among non-Hispanic Blacks (aOR 2.07, 95% confidence interval [1.93, 2.81]) and males (aOR 1.12, confidence interval [1.05, 1.18]), while lower odds were found among Mexican Americans, other Hispanics, and those who had family income greater or equal to the poverty level. Compared to non-Hispanic Whites, the non-Hispanic Black group had higher odds of SHS exposure in restaurants and homes other than their own. Age was positively associated with self-reported SHS exposure measures but not the objective SHS measure. However, age was negatively associated with SHS measures in the adult sample (aged ≥ 20 years). Conclusions. Findings suggest that although SHS exposure may be decreasing in specific at-risk populations, socioeconomic disparities still exist.