Solid fuel use in relation to dementia risk in middle-aged and older adults: A prospective cohort study

Objectives It remains unknown whether household air pollution is associated with dementia risk. This study examined the associations between solid fuel use for cooking and heating (the main source of household air pollution) and dementia risk. Methods This analysis included data on 11,352 participants (aged 45+ years) from the 2011 wave of China Health and Retirement Longitudinal Study, with follow-up to 2018. Dementia risk was assessed by a risk score using the Rotterdam Study Basic Dementia Risk Model (BDRM) and then standardized for analysis. Household fuel types of cooking and heating were categorized as solid (e.g., coal, crop residue) and clean (e.g., central heating, solar). Multivariable analyses were performed using generalized estimating equations. Moreover, we examined the joint associations of solid fuel use for cooking and heating with the BDRM score. Results We found an independent and significant association of solid (vs. clean) fuel use for cooking and heating with a higher BDRM score after adjusting for potential confounders (e.g., ß = 0.14 for solid fuel for cooking; 95% CI: 0.12, 0.17). Participants who used solid (vs. clean) fuel for both cooking and heating had the highest BDRM score (ß = 0.20; 95%CI: 0.16, 0.23). Subgroup analysis suggested stronger associations in participants living in rural areas. Conclusions Solid fuel use for cooking and heating was independently associated with increased dementia risk in Chinese middle-aged and older adults, particularly among those living in rural areas. Our findings call for more efforts to facilitate universal access to clean energy for dementia prevention.