Association of long-term exposure to various ambient air pollutants, lifestyle, and genetic predisposition with incident cognitive impairment and dementia

BMC Public Health. 2024 Jan 15;24(1):179. doi: 10.1186/s12889-024-17702-y.

Abstract

Background: Long-term exposure to air pollution has been found to contribute to the development of cognitive decline. Our study aimed to assess the association between various air pollutants and cognitive impairment and dementia. Additionally, explore the modification effects of lifestyle and genetic predisposition.

Methods: The exposure levels to various air pollutants, including particulate matter (PM) with diameters ≤ 2.5 (PM2.5), ≤ 10 (PM10), and between 2.5 and 10 μm (PM2.5-10) and nitrogen oxides (NO and NO2) were identified. An air pollution score (APS) was calculated to evaluate the combined exposure to these five air pollutants. A genetic risk estimate and healthy lifestyle score (HLS) were also generated. The Cox regression model adjusted by potential confounders was adopted to access the association between pollution exposure and cognitive decline, and several sensitivity analyses were additionally conducted to test the robustness.

Results: The combined exposure to air pollutants was associated with an increased risk of incident cognitive decline. Compared with the low exposure group, the hazard ratio (HR) and 95% confidence interval (CI) for all-cause dementia, Alzheimer's dementia, vascular dementia, and mild cognitive impairment (MCI) in those exposed to the highest levels of air pollutants were respectively 1.07 (95% CI: 1.04 to 1.09), 1.08 (95% CI: 1.04 to 1.12), 1.07 (95% CI: 1.02 to 1.13), and 1.19 (95% CI: 1.12 to 1.27). However, the modification effects from genetic predisposition were not widely observed, while on the contrary for the healthy lifestyle. Our findings were proven to be reliable and robust based on the results of sensitivity analyses.

Conclusions: Exposure to air pollution was found to be a significant contributing factor to cognitive impairment and dementia, and this association was not easily modified by an individual's genetic predisposition. However, adopting a healthy lifestyle may help to manage the risk of cognitive decline related to air pollution.

Keywords: Air Pollution; Cognitive impairment; Dementia; Gene; Lifestyle; UK Biobank.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Air Pollutants* / adverse effects
  • Air Pollutants* / analysis
  • Air Pollution* / adverse effects
  • Air Pollution* / analysis
  • Alzheimer Disease*
  • Cognitive Dysfunction* / epidemiology
  • Cognitive Dysfunction* / genetics
  • Environmental Exposure / adverse effects
  • Environmental Exposure / analysis
  • Environmental Pollutants* / analysis
  • Genetic Predisposition to Disease
  • Humans
  • Life Style
  • Nitrogen Dioxide / analysis
  • Particulate Matter / adverse effects
  • Particulate Matter / analysis

Substances

  • Air Pollutants
  • Environmental Pollutants
  • Particulate Matter
  • Nitrogen Dioxide