Open Collections

Yuchi, Weiran

University of British Columbia

Dementia is a major global population health challenge. It is not curable, and severity worsens over time. With seniors expected to comprise approximately 25% of the Canadian population by 2035, cases of dementia and its related health and financial burden are forecast to dramatically increase in the next decades. While some well-known risk factors for dementia are identified (e.g. age, sex), they do not fully explain dementia risk, therefore other potentially modifiable risk factors may be unidentified. Mounting evidence suggests connections between environmental factors and dementia, however associations between exposure to air pollution and dementia have not been adequately studied, nor have the potential protective effects of residing in neighbourhoods with more natural green space. To address these gaps, we investigated the links between long-term exposure to air pollution (e.g. fine particulate matter, PM₂ꓸ₅; nitrogen dioxide, NO₂), dementia, and the possible beneficial impacts from green space (Normalized Difference Vegetation Index) within three large population-based cohorts. In the Metro Vancouver cohort, air pollutants were associated with incidence of non-Alzheimer’s dementia (e.g., hazard ratios (HR) of 1.02 [0.98-1.05], 1.02 [0.99-1.06] per interquartile range increase in PM₂ꓸ₅ and NO₂). In the national 2001 Canadian Census Health and Environment Cohort, PM₂ꓸ₅ (1.09 [95% CI:1.08-1.10] per interquartile range increase) and NO₂ (1.08 [95% CI:1.07-1.09]) were associated with dementia mortality. These findings were supported by analysis of the Canadian Community Health Survey where individual behavioural risk factors (smoking, alcohol consumption, etc.) were available. Air pollutants were associated with increased dementia mortality (e.g., dementia HR of 1.25 [1.23-1.27] and 1.23 [1.21-1.25] per interquartile range increase in PM₂ꓸ₅ and NO₂, while HRs were attenuated (1.14 [1.12-1.16] and 1.17 [1.15-1.19]) in models including behavioural risk factors. Across the three cohorts, greenness was associated with 1-5% risk reduction in dementia. These results indicate that air pollution, even at relatively low concentrations, was linked with dementia, while living in greener areas was found to have some small protective effects. These findings contribute to the overall understanding of the relationships between built-in environment factors and dementia and can contribute to the development of public health approaches for dementia risk reduction.

Text

2024-03-21

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/87605

Population and Public Health

University of British Columbia

UBCV

http://creativecommons.org/licenses/by-nc-nd/4.0/