Recent tobacco smoking, restaurant and in-car secondhand smoke exposure are associated with depressive symptoms among young adults: a population-based cross-sectional analysis

The purpose of this study was to evaluate the association between recent tobacco smoking, household secondhand smoke exposure, confined space secondhand smoke exposure and depressive symptoms in young adults after adjustments for each other. Data from NHANES 2013-2018 were extracted. 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 symptoms were screened by PHQ-9. Recent tobacco smoking was assessed through question "smoked tobacco in the last 5 days?". Household secondhand smoke exposure was assessed through question "living with a smoker who smoked inside the house?". Confined space secondhand smoke exposure was assessed by SSEQ. Binary logistic regression models were performed to analyze the associations. Significant association were observed in recent tobacco smoking (OR = 1.593, 95% CI 1.318-1.926) and confined space secondhand smoke exposure (OR = 1.399, 95% CI 1.185-1.651), but not in household secondhand smoke exposure (P = 0.108). Among the different settings of confined space secondhand smoke exposure, restaurant (OR = 1.732, 95% CI 1.120-2.678) and in-car (OR = 1.350, 95% CI 1.102-1.652) exposure were significantly associated with depressive symptom after after fully adjustments.