Prevalence and correlates of secondhand smoke exposure in the home and in a vehicle among youth in the United States

Private settings are major sources of secondhand smoke (SHS) exposure among youth. We measured prevalence and correlates of youth exposures to home and vehicle SHS. The 2016 National Youth Tobacco Survey of U.S. 6th-12th graders was analyzed (n = 20,675). Past-7-day home or vehicle SHS exposures were self-reported. Descriptive and multivariable analyses were performed on weighted data. Among all students, past-7-day SHS exposures were: vehicle (21.4%, 5.56 million); home (21.7%, 5.64 million); home or vehicle (29.0%, 7.50 million); vehicle and home (14.0%, 3.63 million). By household tobacco-use status, home or vehicle SHS exposure was: tobacco-free households, 8.4%; households with combustible-only tobacco users, 59.8%; households with smokeless tobacco/e-cigarette-only users, 21.8%; and households with combined tobacco products usage, 73.9%. Where only the youth respondent but no other household member(s) used tobacco, the measure of association (vs. tobacco-free households) was similar to two-fold higher for vehicle SHS exposures (Adjusted Odds Ratio [AOR] = 6.09; 95% Confidence Interval [CI] = 4.93-7.54 than for home SHS exposures (AOR = 3.16; 95%CI = 2.35-4.25). Conversely, where only household member(s) but not the youth respondent used tobacco, the measure of association was over two-fold higher for home SHS exposures (AOR = 22.15; 95%CI = 19.12-25.67) than for vehicle SHS exposure (AOR = 7.91; 95%CI = 6.96-8.98). In summary, nearly one-third of U.S. youth (7.50 million) were exposed to either home or vehicle SHS. Among non-tobacco-using youth with tobacco-using household member(s), the home was a dominant SHS exposure source; among tobacco-using youth with non-tobacco-using household member(s), a vehicle was a dominant exposure source, possibly peers'. Smoke-free environments, including homes and cars, can reduce youth SHS exposure.