The Impact of Solid Fuel Use on Cognitive Performance and the Mediating Effect of Indoor Window Ventilation in Chinese Older Adults

Although indoor air pollution is a known hazard for older adults′ health, particularly cognitive function, the specific link with household solid fuel use remains less clear. This study aims to quantify the association between solid fuel use and cognitive performance in the elderly and to determine whether indoor window ventilation mediates this relationship. Data for this analysis were drawn from the 2017–2018 China Longitudinal Healthy Longevity Survey (CLHLS), encompassing 7354 older adults aged ≥ 65 years. Indoor window ventilation frequency was quantified based on self‐reported weekly window‐opening habits for each of the past four seasons. The individual seasonal scores were aggregated to derive a composite annual ventilation frequency score. Cognitive performance was measured using the 24‐item mini‐mental state examination (MMSE) scale. The association between indoor window ventilation and cognitive performance was examined using linear regression. The Bootstrap methods PROCESS program is employed to test the mediation model. After controlling for covariates, solid fuel use was negatively associated with cognitive performance ( β = −0.16, 95% CI [−0.31, −0.02], p = 0.034) and indoor window ventilation was positively related to cognitive performance ( β = 0.03, 95% CI [0.01, 0.07], p = 0.037). Indoor window ventilation partially mediated the relationship between solid fuel use and cognitive performance in older adults (explaining 10.0% of the total variance). Subgroup analysis indicated the association between solid fuel use and lower cognitive performance was higher vulnerability among females, rural residents, individuals not in marriage, those with lower education level, and those nonsmokers. The findings posit a link between household solid fuel use and cognitive performance among older adults, a relationship that appears to be partially mediated by indoor window ventilation. Implementing effective interventions, including enhanced ventilation practices, could attenuate these adverse effects, highlighting the need for targeted public health strategies to promote healthy cognitive aging.