Exposure to household air pollution and cognitive function in older Chinese adults

Background: Exposure to air pollution from traffic and industry is associated with accelerated cognitive decline in older adults. The effects of exposure to air pollution from household solid fuel (coal/biomass) stoves (HAP) on adult cognitive function have not been investigated.Methods: Among 402 peri-urban adults in northern China (mean age=62.5 y), we assessed exposure to HAP by (1) measuring personal exposures to fine particulate matter (PM2.5) and black carbon (BC) for 2 days in the heating and non-heating seasons, and (2) collecting information on current and historical fuel use for cooking and heating. We evaluated cognitive function using the Montreal Cognitive Assessment that consists of seven domains and a total score. Cubic spline and linear regression models were used to investigate associations between HAP and cognitive function, adjusting for key sociodemographic, behavioral, and environmental confounders.Results: Participants’ average 24-h exposures ranged from 17-907 μg/m3 (mean=104) for PM2.5 and from 0.1-8.5 μg/m3 (mean=1.6) for BC. Thirty-six percent and ten percent of participants exclusively used clean (electricity/gas) fuels for cooking and for both cooking and heating, respectively, while the remaining participants used solid fuel. Participants’ total cognitive scores ranged from 2-30 points (mean=20.5). We observed linear inverse associations between air pollution and cognitive scores. Personal exposures to PM2.5 and BC were associated with lower total cognitive score [per 100 μg/m3 increase: -0.78 (95% confidence interval (CI): -1.49,-0.07); per 1 μg/m3 increase: -0.58 (95%CI: -1.09,-0.07), respectively] in fully-adjusted models that included outdoor pollution level. BC was also associated with lower attention score [-0.17 (95%CI: -0.32,-0.02)]. Compared with exclusive and long-term (15-20 years) users of clean fuel, sold fuel users had lower scores in multiple cognitive domains: visuospatial/executive (-0.52, 95%CI: -1.02,-0.03), abstraction (-0.19, 95%CI: -0.37,-0.01) and orientation (-0.38, 95%CI: -0.66,-0.10).Conclusions: Exposure to HAP may be associated with lower cognitive function in older adults.