Department of Neurology, University of Southern California, Los Angeles, CA 90033.
Department of Population and Public Health Sciences, University of Southern California, Los Angeles, CA 90032;
Proc Natl Acad Sci U S A. 2022 Jan 11;119(2). doi: 10.1073/pnas.2107833119.
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 ( = 2,239, aged 74 to 92). Incident dementia was centrally adjudicated annually. Yearly mean concentrations of fine particulate matter (PM) and nitrogen dioxide (NO) 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 and NO reduced significantly over the 10 y before baseline. Larger AQ improvement was associated with reduced dementia risks (HR 0.80 per 1.78 μg/m, 95% CI 0.71-0.91; HR 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 at baseline was associated with higher dementia risk (HR 1.16 per 2.90 μg/m, 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.
晚年的环境空气污染是大脑衰老的一个风险因素，但改善空气质量（AQ）是否降低痴呆风险仍不清楚。我们研究了 2008 年至 2012 年期间基线时无痴呆的、地理分布多样化的老年女性队列（n = 2239，年龄 74 至 92 岁）。每年通过中心裁决确定痴呆的发生情况。使用区域化的国家通用克里金模型估计细颗粒物（PM）和二氧化氮（NO）的年平均浓度，并在基线前 3 年（近期暴露）和 10 年前（远期暴露）期间进行平均处理。将从远期到近期的暴露减少作为空气质量改善的指标。使用 Cox 比例风险比（HR）来估计与空气质量指标相关的痴呆风险，调整了社会人口统计学、生活方式和临床特征。在随访期间，我们发现了 398 例痴呆病例（中位数=6.1 年）。在基线前 10 年，PM 和 NO 显著降低。AQ 改善越大，痴呆风险越低（每增加 1.78μg/m，HR 为 0.80，95%CI 为 0.71-0.91；每增加 3.91 十亿分之几，HR 为 0.80，95%CI 为 0.71-0.90），相当于基线时年轻 2.4 岁的女性的较低风险。基线时 PM 较高与痴呆风险较高相关（每增加 2.90μg/m，HR 为 1.16，95%CI 为 0.98-1.38），但在进一步调整近期暴露后，与 AQ 改善相关的痴呆风险较低仍保持不变。观察到的关联在年龄、教育程度、地理区域、载脂蛋白 E e4 基因型或心血管危险因素方面没有显著差异。晚年空气质量的长期改善与老年女性的痴呆风险降低相关。
