Fine Particulate Matter and Dementia Incidence in the Adult Changes in Thought Study

Abstract

Background: Air pollution may be associated with elevated dementia risk. Prior research has limitations that may affect reliability, and no studies have evaluated this question in a population-based cohort of men and women in the United States. Objectives: We evaluated the association between time-varying, 10-y average fine particulate matter ( ) exposure and hazard of all-cause dementia. An additional goal was to understand how to adequately control for age and calendar-time-related confounding through choice of the time axis and covariate adjustment. Methods: Using the Adult Changes in Thought (ACT) population-based prospective cohort study in Seattle, we linked spatiotemporal model-based exposures to participant addresses from 1978 to 2018. Dementia diagnoses were made using high-quality, standardized, consensus-based protocols at biennial follow-ups. We conducted multivariable Cox proportional hazards regression to evaluate the association between time-varying, 10-y average exposure and time to event in a model with age as the time axis, stratified by apolipoprotein E (APOE) genotype, and adjusted for sex, education, race, neighborhood median household income, and calendar time. Alternative models used calendar time as the time axis. Results: We report 1,136 cases of incident dementia among 4,166 individuals with nonmissing APOE status. Mean [mean ± standard deviation (SD)] 10-y average was . Each increase in the moving average of 10-y was associated with a 16% greater hazard of all-cause dementia [1.16 (95% confidence interval: 1.03, 1.31)]. Results using calendar time as the time axis were similar. Discussion: In this prospective cohort study with extensive exposure data and consensus-based outcome ascertainment, elevated long-term exposure to was associated with increased hazard of all-cause dementia. We found that optimal control of age and time confounding could be achieved through use of either age or calendar time as the time axis in our study. Our results strengthen evidence on the neurodegenerative effects of . https://doi.org/10.1289/EHP9018

Decadal Trends in the Temperature Dependence of Summertime Urban PM2.5 in the Northeast United States

“…By this metric, the emission reduction efforts of the last 20 years have had tremendous success in improving air quality in the cities of the Northeast U.S. Recent studies have shown how the negative health impacts of PM 2.5 exposure can begin to manifest below this threshold of 15 μg/m 3 . − For this reason, understanding the pathways toward continued decreases of aerosol mass on the hottest days remains important.…”

Air pollution and mental health: associations, mechanisms and methods

“…Since these reviews large cohorts have replicated positive associations between PM2.5 and incidence of all-cause dementia [56,57], including French cohort data utilizing robust clinical assessment to identify cases [58 ▪ ] (instead of commonly used population-level data approaches) and Swedish cohort research which has described the appreciable modifying effect of cerebrovascular disease [59 ▪ ] building on previous work [60]. A handful of studies assessed specific cognitive profiles [61], and of interest new data suggested a weak mediating role of depressive symptoms between NO 2 ,PM 2.5 and acceleration of decline in episodic memory [62].…”

Chronic exposure to ambient traffic-related air pollution (TRAP) alters gut microbial abundance and bile acid metabolism in a transgenic rat model of Alzheimer’s disease

“…Several prior and recent observations noted the links between diesel exhaust (DE) and particulate matter smaller than 2.5 µm (PM 2.5 ) and ultrafine PM (particles smaller than 1 µm) and AD-associated dementia ( [30] , [42] ; Cacciottolo, 2017; Chen et al, [27] ; Grande et al, [47] ; Yuchi et al, [125] ). A study on a large population cohort found that development of dementia is higher in individuals living close to heavy traffic [26] and a recently published epidemiological study again noted that elevated long-term exposure to PM 2.5 is associated with increased risk of dementia [102] . In a preclinical study, exposure to urban nanosized PM for 225 h over 15 weeks increased cerebral Aβ deposition in female AD mice [14] .…”