Secondhand smoke exposure among never-smoking youth in 168 countries

To estimate the prevalence of secondhand smoke (SHS) exposure among never-smoking adolescents and identify key factors associated with such exposure.

Data were obtained from nationally representative Global Youth Tobacco Surveys conducted in 168 countries during 1999-2008. SHS exposure was ascertained in relation to the location-exposure inside home, outside home, and both inside and outside home, respectively. Independent variables included parental and/or peer smoking, knowledge about smoke harm, attitudes toward smoking ban, age, sex, and World Health Organization region. Simple and multiple logistic regression analyses were conducted.

Of 356,414 never-smoking adolescents included in the study, 30.4%, 44.2%, and 23.2% were exposed to SHS inside home, outside home, and both, respectively. Parental smoking, peer smoking, knowledge about smoke harm, and positive attitudes toward smoke ban were significantly associated with increased odds of SHS exposure. Approximately 14% of adolescents had both smoking parents and peers. Compared with never-smoking adolescents who did not have both smoking parents and peers, those who had both smoking parents and peers had 19 (adjusted odds ratio [aOR], 19.0; 95% confidence interval [CI], 16.86-21.41), eight (aOR, 7.71; 95% CI, 7.05-8.43), and 23 times (aOR, 23.16; 95% CI, 20.74-25.87) higher odds of exposure to SHS inside, outside, and both inside and outcome home, respectively.

Approximately one third and two fifths of never-smoking adolescents were exposed to SHS inside or outside home, and smoking parents and/or peers are the key factors. Study findings highlight the need to develop and implement comprehensive smoke-free policies consistent with the World Health Organization Framework Convention on Tobacco Control.