Dementia: CVD prevention, treatment are crucial with air pollution exposure

  • Grande G & al.
  • JAMA Neurol
  • 30 Mar 2020

  • curated by Susan London
  • Clinical Essentials
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Takeaway

  • 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.

Key results

  • 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%).

Study design

  • 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.

Limitations

  • Study area was urban, limiting differences in pollution exposure.
  • Exposure based solely on residential address.