Work

A national cohort study (2000–2018) of long-term air pollution exposure and incident dementia in older adults in the United States

Year: 2021

Type: article

Abstract: Air pollution may increase risk of Alzheimer’s disease and related dementias (ADRD) in the U.S., but the extent of this relationship is unclear. Here, we constructed two national U.S. population-based cohorts of those aged ≥65 from the Medicare Chronic Conditions Warehouse (2000–2018), combined with high-resolution air pollution datasets, to investigate the association of long-term exposure to ambient fine particulate matter (PM 2.5 ), nitrogen dioxide (NO 2 ), and ozone (O 3 ) with dementia and AD incidence, respectively. We identified ~2.0 million incident dementia cases ( N = 12,233,371; dementia cohort) and ~0.8 million incident AD cases ( N = 12,456,447; AD cohort). Per interquartile range (IQR) increase in the 5-year average PM 2.5 (3.2 µg/m 3 ), NO 2 (11.6 ppb), and warm-season O 3 (5.3 ppb) over the past 5 years prior to diagnosis, the hazard ratios (HRs) were 1.060 (95% confidence interval [CI]: 1.054, 1.066), 1.019 (95% CI: 1.012, 1.026), and 0.990 (95% CI: 0.987, 0.993) for incident dementias, and 1.078 (95% CI: 1.070, 1.086), 1.031 (95% CI: 1.023, 1.039), and 0.982 (95%CI: 0.977, 0.986) for incident AD, respectively, for the three pollutants. For both outcomes, concentration-response relationships for PM 2.5 and NO 2 were approximately linear. Our study suggests that exposures to PM 2.5 and NO 2 are associated with incidence of dementia and AD.

Source: Nature Communications

DOI: 10.1038/s41467-021-27049-2