The association between indoor air pollution from solid fuels and cognitive impairment: a systematic review and meta-analysis

Abstract This study aimed to comprehensively and methodically evaluate the correlation between cognitive impairment and indoor air pollution from solid fuel used for cooking/heating. PubMed, Web of Science, EMBASE, and Cochrane Library databases were searched up to December January 2023. 13 studies from three countries with a total of 277,001 participants were enrolled. A negative correlation was discovered between solid fuel usage for cooking and total cognitive score (β=−0.73, 95 % CI: −0.90 to −0.55) and episodic memory score (β=−0.23, 95 % CI: −0.30 to −0.17). Household solid fuel usage for cooking was considerably associated with a raised risk of cognitive impairment (HR=1.31, 95 % CI: 1.09–1.57) and cognitive decline (HR=1.24, 95 % CI: 1.18–1.30). Compared to continuous solid fuel use for cooking, sustained use of clean fuel and switching from solid fuel to clean fuel were associated with a lower risk of cognitive decline (OR=0.55, 95 % CI: 0.42–0.73; OR=0.81, 95 % CI: 0.71–0.93). A negative association was found between solid fuel usage for heating and total cognitive score (β=−0.43, 95 % CI: −0.59 to −0.26) and episodic memory score (β=−0.22, 95 % CI: −0.34 to −0.10). Our research provided evidence that exposure to indoor air pollution from solid fuel is a potential cause of cognitive impairment and cognitive decline. Making the switch from solid fuels to cleaner fuels could be an important step in preventing cognitive impairment in the elderly.