Longitudinal association between household air pollution from biomass fuel use and depression in middle-aged and older adults in China: a national cohort study

Abstract

Abstract Background Incomplete combustion of biomass fuels significantly contributed to household air pollution (HAP). Evidence related to HAP and mental health from biomass fuel use remains limited. Therefore, we aimed to explore the longitudinal association between indoor biomass fuel consumption and depression. Method Data were obtained from the China Health and Retirement Longitudinal Study (CHARLS). Cox proportional hazards regression and linear mixed effects models were used to investigate the longitudinal association between indoor biomass fuel use and depression. We also investigated the effect of switching primary fuels on depression risk. Result A total of 4745 participants were included. Users of biomass fuel for heating and cooking had a higher risk of depression than those who used clean fuels, with hazard ratios (HRs) of 1.22 (95% confidence interval (CI): 1.09–1.36) and 1.33 (95% CI: 1.16–1.52), respectively. Furthermore, compared to clean fuel users, we found that biomass fuel users had elevated depression scores (β: 0.30, 95% CI: 0.11–0.49, P < 0.05 for cooking; β: 0.37, 95% CI: 0.15–0.59, P < 0.001 for heating), and higher growth rates of scores (β: 0.14, 95% CI: 0.05–0.22, P < 0.001 for cooking; β: 0.10, 95% CI: 0.01–0.19, P < 0.05 for heating). Compared to using clean fuels for both cooking and heating, utilizing biomass fuels for both cooking and heating increased the risk of depression (HR: 1.43, 95% CI: 1.23–1.67), along with a higher depression score (β: 0.50, 95% CI: 0.25–0.75, P < 0.001) and a higher growth rate of the score (β: 0.15, 95% CI: 0.05–0.25, P < 0.05). Additionally, individuals who changed their primary sources of heating and cooking from clean to biomass fuels had elevated risk of depression than those who always used clean fuels, with odds ratios (ORs) of 1.35 (95% CI: 1.05–1.76) and 1.43 (95% CI: 1.01–2.02), respectively. Conclusion Our research points to HAP as a potential contributor to depression risk in middle-aged and older adults. The usage of clean fuels should be encouraged since it may have a positive impact on mental health.