Dose–Response Relationships between Second-Hand Smoke Exposure and Depressive Symptoms among Adolescents in Guangzhou, China

Abstract

There has been little focus on the possible association between second-hand smoke (SHS) exposure and depressive symptoms among adolescents. Thus, this study aimed to explore the dose–response relationships between SHS exposure and depressive symptoms among adolescents and differentiate these associations in setting-specific exposure and severity-specific outcomes. A cross-sectional study was conducted using a stratified cluster sampling method to obtain a representative sample of high school students in Guangzhou, China. Depressive symptoms were measured using the Center for Epidemiologic Studies Depression Scale. Univariable and multivariable logistic regression models were used to explore the potential associations between SHS exposure and depressive symptoms. Among 3575 nonsmoking students, 29.6% were classified as having probable depressive symptoms and 9.6% had severe depressive symptoms. There were monotonically increasing dose–response relationships between setting-specific (public places, homes, or indoor/outdoor campuses) SHS exposure and severity-specific (probable or severe) depressive symptoms. When examining these relations by source of exposure, we also observed similar dose–response relationships for SHS exposure in campuses from smoking teachers and from smoking classmates. Our findings suggest that regular SHS exposure is associated with a significant, dose-dependent increase in risk of depressive symptoms among adolescents, and highlight the need for smoke-free environments to protect the health of adolescents.

Secondhand Smoking and Depressive Symptoms Among In-School Adolescents

“…Findings from this study support those of previous cross-sectional studies on SHS and depression or depressive symptoms among adolescents conducted in single high-income countries (i.e., U.S. 11 and Korea 29−32 ) and LMICs (i.e., Iran 20 and China 21 ) and add to the literature by demonstrating for the first time that this association exits in a variety of countries across multiple continents. There are several hypotheses to explain the association between SHS and depressive symptoms in adolescents.…”

“…19 Finally, there are no multi-country studies on this topic. The only 2 previous studies investigating the SHS−depressive symptom relationship in adolescents from LMICs were single-country studies conducted in Iran 20 and China, 21 and only 1 was nationally representative. 20 Multi-country studies are important, as they can provide information on whether associations are country-specific and also illustrate a global picture of the association between SHS and depressive symptoms.…”

The prevalence of secondhand smoke exposure and related factors among schoolchildren in Northeast Thailand

“…After adjusting for potential confounding factors, we also showed that schoolchildren exposed to SHS tend to have more depressive symptoms than unexposed children. This finding is similar to several previous studies 7 , 20 – 22 , except one conducted in the Netherlands 12 . Possible reasons for the disparity include differences in sample population and depressive symptom measurement.…”

Setting-Specific and Symptom-Specific Association between Secondhand Smoke Exposure and Depressive Symptoms

“…It remains unclear whether there is a dose-response relationship between SHS exposure and depressive symptoms. Some studies revealed linear increasing trends between frequency of SHS exposure and depressive symptoms among adolescents and pregnant women [33,34], but a non-significant trend was observed in a Korea study on adolescents [35], suggesting that these findings are inconsistent. The present study found a monotonically increasing dose-response relationship between continuous frequency of SHS exposure and depressive symptoms (IRR = 1.33, 95% CI 1.10–1.62), suggesting that the risk of depressive symptoms increased progressively as the days of SHS exposure increased.…”