Exposure to Air Pollution May Raise Risk for Dementia

THURSDAY, Oct. 27, 2022 (HealthDay News) -- Higher exposure to fine particulate matter (PM_2.5) is associated with an increased risk for dementia, according to a systematic review and meta-analysis published online Oct. 26 in Neurology.

Ehsan Abolhasani, M.D., from the Schulich School of Medicine & Dentistry at Western University in London, Ontario, Canada, and colleagues examined the association between air pollution and dementia in a systematic review and meta-analysis. Twenty studies that reported on the hazard ratio of dementia in association with exposure to PM_2.5, nitrogen oxides (NO_x), nitrogen dioxide (NO₂), or ozone (O₃) were included in the review; 17 provided data for the meta-analysis.

The total population was 91,391,296 individuals, of whom 6 percent were diagnosed with dementia. The researchers found a 3 percent increase in the risk for dementia per 1 µg/m³ increment in PM_2.5 (hazard ratio, 1.03; 95 percent confidence interval, 1.02 to 1.05). Less clear associations were seen for dementia per 10-µg/m³ increment in NO_x, NO₂, and O₃ level, although significant associations could not be ruled out (hazard ratios [95 percent confidence intervals], 1.05 [0.99 to 1.13], 1.03 [1.00 to 1.07], and 1.01 [0.91 to 1.11], respectively); high heterogeneity was seen across studies.

"While our meta-analysis does not prove that air pollution causes dementia, it only shows an association, our hope is these findings empower people to take an active role in reducing their exposure to pollution," Abolhasani said in a statement.

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