Association of solid fuel use with cognitive function and the modifying role of lifestyle: a nationwide cohort study in China

Abstract

BackgroundIndoor air pollution from solid fuel use might be harmful for cognitive function, while healthy lifestyle is associated with better cognitive function. The extent to which lifestyle modifies the association of solid fuel use with cognitive function remains unknown. MethodsA total of 21,008 individuals aged 16 to 92 were enrolled in 2010 and followed up to 2014 in the China Family Panel Studies (CFPS). Cognitive function was assessed using standardized math test and word test in three waves. Solid fuel use was assessed by self-report of firewood, straw, or coal for cooking at baseline. Lifestyle profile was classified into two groups (favorable vs. unfavorable) based on five modifiable lifestyle factors including alcohol drinking, smoking, body mass index, diet, and physical activity. Linear mixed-effects models were employed to assess the association of solid fuel use and lifestyle with cognitive function. The effect modification of lifestyle was analyzed. ResultsA total of 49.7% of the study population used solid cooking fuel and 17.4% had a favorable lifestyle. Solid fuel use was associated with a significant decrease in cognitive function (β = -0.29, 95% CI: -0.39, -0.19 for math test; β = -0.62, 95% CI: -0.84, -0.41 for word test). Lifestyle significantly modified this association (p-interaction: 0.006 for math test; 0.016 for word test), with the corresponding association being less pronounced among participants adhering to a favorable lifestyle compared to those with an unfavorable lifestyle. ConclusionA favorable lifestyle may attenuate the negative association of solid fuel use with cognitive function. Adopting a favorable lifestyle has the potential to counteract the adverse neurological effect caused by indoor air pollution.