期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2022
卷号：119
期号：2
DOI：10.1073/pnas.2107833119
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Significance
Epidemiological studies have demonstrated that improved air quality may improve respiratory health and reduce mortality. Increasing data support late-life exposure to air pollution as a modifiable risk factor for dementia, but whether improved ambient air quality translates to lower dementia risk is unclear. In this study on a geographically diverse cohort of US community-dwelling older women, we found that long-term improvement in ambient air quality in late life was associated with reduced dementia risk. The associations did not significantly differ by age, education, geographic region, Apolipoprotein E e4 genotypes, or cardiovascular risk factors. These findings strengthen the causal association between late-life exposure to air pollution and dementia risk.
Late-life ambient air pollution is a risk factor for brain aging, but it remains unknown if improved air quality (AQ) lowers dementia risk. We studied a geographically diverse cohort of older women dementia free at baseline in 2008 to 2012 (
n = 2,239, aged 74 to 92). Incident dementia was centrally adjudicated annually. Yearly mean concentrations of fine particulate matter (PM
2.5) and nitrogen dioxide (NO
2) were estimated using regionalized national universal kriging models and averaged over the 3-y period before baseline (recent exposure) and 10 y earlier (remote exposure). Reduction from remote to recent exposures was used as the indicator of improved AQ. Cox proportional hazard ratios (HRs) for dementia risk associated with AQ measures were estimated, adjusting for sociodemographic, lifestyle, and clinical characteristics. We identified 398 dementia cases during follow up (median = 6.1 y). PM
2.5 and NO
2 reduced significantly over the 10 y before baseline. Larger AQ improvement was associated with reduced dementia risks (HR
PM2.5 0.80 per 1.78 μg/m
3, 95% CI 0.71–0.91; HR
NO2 0.80 per 3.91 parts per billion, 95% CI 0.71–0.90), equivalent to the lower risk observed in women 2.4 y younger at baseline. Higher PM
2.5 at baseline was associated with higher dementia risk (HR
PM2.5 1.16 per 2.90 μg/m
3, 95% CI 0.98–1.38), but the lower dementia risk associated with improved AQ remained after further adjusting for recent exposure. The observed associations did not substantially differ by age, education, geographic region, Apolipoprotein E e4 genotypes, or cardiovascular risk factors. Long-term AQ improvement in late life was associated with lower dementia risk in older women.
