Association between cooking with solid fuels and depressive symptoms among middle-aged and older adults in China: The mediating effect of the residential environment

Background: Depression is a common issue among elderly people in both developing and developed countries. Existing research indicates that cooking with solid fuels has a negative impact on the mental health of middle-aged and elderly people (aged 45 and older). However, the potential role of the residential environment in this process is not yet clear. Clarifying this issue may help identify effective interventions to improve public health for elderly people. This study aimed to explore the association between cooking with solid fuels and depressive symptoms, as well as the potential mediating role of the residential environment in this relationship. Method: This study utilized cross-sectional data from the China Health and Retirement Longitudinal Study (CHARLS) for 2020, involving approximately 19,000 respondents aged 45 years and older. Propensity score matching (PSM) was used to explore the association between cooking with solid fuels and depressive symptoms. Additionally, a range of potential covariates were adjusted, and the Sobel test was applied to assess the potential mediating effect of the residential environment on this relationship. Results: According to the fully adjusted model, cooking with solid fuels was significantly associated with an increased risk of depressive symptoms in middle-aged and older adults (β = 0.315, P < 0.001), and this finding was confirmed through robustness tests using different propensity score matching methods. Heterogeneity analysis revealed that this association was particularly significant among men (β = 0.318, P < 0.001), those aged 60–74 (β = 0.347, P < 0.001), and individuals with a middle school education (β = 0.353, P < 0.001). Mediation effect analysis revealed that indoor cleanliness (β = 0.0090, P < 0.001), indoor broadband coverage (β = 0.0077, P < 0.001), and the installation of indoor air purifiers (β = 0.0010, P < 0.1) mediated the relationships between cooking with solid fuels and depressive symptoms. Conclusion: Given the growing attention given to improving indoor environments and enhancing mental health, the findings of this paper highlight that improving indoor cleanliness, increasing broadband coverage indoors, and installing air purifiers can effectively intervene in and prevent depressive symptoms caused by cooking with solid fuels.