- Cardiovascular disease (CVD) both modifies and mediates the harmful effect of air pollution exposure on dementia risk in older adults living in a city with fairly good air quality.
Why this matters
- Lifestyle modifications, medical therapy are effective for primary and secondary CVD prevention.
- Dementia incidence at mean 6.01-year follow-up: 12.4%.
- Risk rose with air pollution exposure at a residential address during the preceding 11 years, with the strongest association for the last 5 years.
- Increase in risk per interquartile range difference in mean pollutant levels during last 5 years:
- Particulate matter ≤2.5 μm: HR, 1.54 (95% CI, 1.33-1.78); difference of 0.88 μg/m3.
- Nitrogen oxide: HR, 1.14 (95% CI, 1.01-1.29); difference of 8.35 μg/m3.
- Elevation of risk was enhanced in older adults with heart failure, ischemic heart disease.
- Stroke was a major intermediate condition, explaining almost half the association between exposure to particulate matter ≤2.5 μm and dementia risk (49.4%).
- Swedish longitudinal population-based cohort study of 2927 dementia-free, community-dwelling, or institutionalized adults aged ≥60 years (SNAC-K study).
- Main outcome: dementia.
- Funding: Funders of SNAC-K; Swedish Ministry of Health and Social Affairs; others.
- Study area was urban, limiting differences in pollution exposure.
- Exposure based solely on residential address.