Secondhand Smoking and Depressive Symptoms Among In-School Adolescents
Louis Jacob, Lee Smith, Sarah E. Jackson, Josep Maria Haro, Jae Il Shin, Ai Koyanagi
Abstract
IntroductionSmoking has been linked with depressive symptoms in adolescents, but data on secondhand smoking and depressive symptoms in low- and middle-income countries are scarce. Thus, this study analyzes the association between secondhand smoking and depressive symptoms among in-school adolescents from 22 low- and middle-income countries.MethodsData from the 2003–2008 Global School-Based Student Health Survey were analyzed in June 2019. Data on past-week exposure to secondhand smoke and past-year depressive symptoms were collected. The association between secondhand smoke and depressive symptoms was studied using multivariable logistic regressions and meta-analyses.ResultsThe sample consisted of 37,505 adolescents aged 12–15 years who never smoked. The prevalence of depressive symptoms increased from 23.0% in adolescents with no secondhand smoking to 28.9% in those with secondhand smoking every day in the past week. After adjusting for sex, age, food insecurity, and country, there was a dose–response relationship between secondhand smoking and depressive symptoms in the overall sample (0 days: reference; 1–2 days: OR=1.06, 95% CI=0.95, 1.18; 3–6 days: OR=1.38, 95% CI=1.20, 1.58; 7 days: OR=1.63, 95% CI=1.44, 1.86). The country-wise analysis showed that secondhand smoking on at least 3 days (versus <3 days) in the past week was associated with a 1.48-fold increase in the odds of depressive symptoms (95% CI=1.39, 1.59), with a low level of between-country heterogeneity (I2=4.2%).ConclusionsThere was a positive association between secondhand smoking and depressive symptoms among in-school adolescents from low- and middle-income countries. Further research should investigate causality and assess whether prevention of exposure to secondhand smoke can have a positive effect on the mental well-being of adolescents.