The mediating role of depressive symptoms between asthma and risk of all-cause mortality

This study aimed to evaluate the mediating role of depressive symptoms on asthma and the risk of mortality. We employed the distribution-of-product method to test whether depressive symptoms had a mediating effect on the association between asthma and risk of mortality. The 95% confidence interval (CI) of the distribution of the product was obtained. A weighted multivariable Cox regression model was used to analyze the correlation between asthma and all-cause mortality and verify the mediating impact of depressive symptoms on the association between asthma and risk of mortality. Odds ratio (OR), hazard ratio (HR), 95%CI, and percentage mediated were effect size. The mean follow-up time of all participants was 99.45 months. The percentage of subjects with depressive symptoms in the death group was 23.67%, and in the alive group was 16.65%. The risk of depressive symptoms was heightened in people with asthma (OR = 2.03, 95%CI: 1.82-2.27). Asthma was found to increase the risk of all-cause mortality (OR = 1.18, 95%CI: 1.06-1.31). The distribution of the product for the mediating effect of depressive symptoms on the relationship between asthma and all-cause mortality was 0.08 (95% CI: 0.01-0.16), with the 95% CI not including 0, indicating that depressive symptoms played a mediating role in this relationship. The indirect effect was 1.09(95%CI: 1.01-1.18), and the percentage of asthma's impact on all-cause mortality mediated by depressive symptoms was 11.11%. Depressive symptoms mediated the association of asthma and all-cause mortality.