Recent Tobacco Smoking, Restaurant and In-Car Secondhand Smoke Exposure are Associated with Depressive Symptom among Young Adults: A Population-based Cross-sectional Analysis

Abstract

Background Young people who have just reached adulthood are prone to adverse reactions during various social adaptations, which can lead to depression. Depressive symptom among young adults is a severe public health burden currently deteriorating in progress. Smoking behavior, exposure to secondhand smoke in household and in various indoor settings may significantly affect depressive symptoms in young adults. Objective The purpose of this study was to evaluate whether recent tobacco smoking, household secondhand smoke exposure and confined space secondhand smoke exposure are associated with depressive symptom in young adults after adjustments for each other. Materials and Methods We extracted data from NHANES 2013–2018, including demographic characteristics, depression level, physical activity, current health status, body measures, recent tobacco smoking, household secondhand smoke exposure and confined space secondhand smoke exposure. A total of 4129 young adults age 18–35 years (mean age 26.11 ± 5.39 years, 2021 males and 2108 females) were included. Depressive symptom was screened by PHQ-9. Recent tobacco smoking and household secondhand smoke exposure were assessed by whether participants had smoked tobacco in the last five days and whether the living with a smoker who smoked inside the house. Confined space secondhand smoke exposure was assessed using the Secondhand Smoke Exposure Questionnaire in this study. We performed binary logistic regression models to analyze the association of recent tobacco smoking, household secondhand smoke exposure, confined space secondhand smoke exposure and depressive symptom, respectively. Results Recent tobacco smoking were positively associated with depressive symptom (OR = 2.201, 95% CI: 1.735–2.353, P < 0.001), this association remained significant after adjusted for confounding variables (OR = 1.593, 95% CI: 1.318–1.926, P < 0.001). Household secondhand smoke exposure was significantly associated with depressive symptom before adjustment for confounding variables (OR = 1.715, 95% CI: 1.479–1.989, P = 0.001), and this association was not statistically significant after adjustments (OR = 1.132, 95% CI: 0.942–1.360, P = 0.108). Confined space secondhand smoke exposure was positively associated with depressive symptom (OR = 1.812, 95% CI: 1.565–2.097, P < 0.001), this association remained significant after adjusted for confounding variables (OR = 1.399, 95% CI: 1.185–1.651, P < 0.001). Among the different settings of confined space secondhand smoke exposure, restaurant exposure (OR = 1.732, 95% CI: 1.120–2.678, P = 0.013) and in-car exposure (OR = 1.350, 95% CI: 1.102–1.652, P = 0.004) were significantly associated with depressive symptom after adjusted for confounding variables. Conclusions Recent tobacco smoking, restaurant and in-car secondhand smoke exposure are associated with greater risk of depressive symptom among U.S. young adults.