Long-term exposure to air pollution linked to dementia and Alzheimer’s disease

Notably, air pollution has been linked to the development of neurological disorders such as Parkinson disease and dementia in the past, and this may pose a more serious threat to American populations amid recent cases of Forest fires contributing to the spread of PM_2.5 at national scale.

In addition, last year’s State of the Air report find an increase in the number of days of ozone and particulate matter pollution in the short term compared to past years, with many cities experiencing increased levels of particulate matter pollution year-round.

Since the authors of the present study noted that previous research on the link between air pollution and dementia had limitations that affected reliability, they sought to deepen the association by leveraging data from the Changes in thought in adults (ACT) prospective population-based cohort study of the Puget Sound area of ​​Seattle, Washington.

Examination of the association between an average exposure over 10 years varying over time to PM_2.5 and the incidence of all-cause dementia (primary analysis) and Alzheimer’s disease (AD) (secondary analysis), the researchers linked PM based on a spatiotemporal model_2.5 exhibitions at the addresses of participants from 1978 to 2018, with age as the time axis.

Data were stratified by apolipoprotein E (APOE) and adjusted for gender, education, race, neighborhood median household income and calendar time. Alternative models used calendar time as the axis of time.

“We hypothesized that a long-term elevated PM_2.5 exposure would be associated with a greater risk of dementia, ”the researchers noted. “Given the pervasiveness of air pollution, a better understanding of the potential impact of PM_2.5 on AD and associated dementias could inform policies aimed at reducing exposure in the population.

Among the ACT study participants examined, 4,166 people with non-missing APOE status were identified, of which 1,136 cases of incident dementia were found.

In their results, the 10-year average PM (SD)_2.5 was found to be 10.1 (2.9) mcg / m³, and each 1-mcg / m³ The increase in the 10-year moving average was associated with a 16% increased risk of all-cause dementia (RR: 1.16; 95% CI: 1.03-1.31).

“The way we understood the role of exposure to air pollution on health evolved by first thinking that it was limited roughly to respiratory problems, then that it also has cardiovascular effects, and now there is evidence for its effects on the brain, ”said senior author Lianne Sheppard, PhD, professor of environmental and occupational health sciences and biostatistics, University of Washington, in a. declaration.

In addition, each 1-mcg / m³ 10-year moving average MP increase_2.5 was associated with an 11% higher risk of diagnosing AD (RR, 1.11; 95% CI: 0.97-1.27). The results using calendar time as the time axis were similar.

“Having reliable address history allows us to get more accurate estimates of air pollution for study participants,” Sheppard noted. “These high-quality exposures combined with regular follow-up of ACT participants and standardized diagnostic procedures contribute to the potential policy impact of this study.”

Reference

Shaffer RM, Blanco MN, Li G et al. The incidence of fine particles and dementia in the Adult Changes in Thought study. A look at the health of the environment. Published online August 4, 2021. doi: 10.1289 / EHP9018