Midlife cardiovascular health lowers later dementia risk

  • Sabia S & al.
  • BMJ
  • 7 Aug 2019

  • International Clinical Digest
Access to the full content of this site is available only to registered healthcare professionals. Access to the full content of this site is available only to registered healthcare professionals.

Takeaway

  • Risk for dementia decreases in a dose-dependent manner with better midlife cardiovascular health.

Why this matters

  • Studies to date have been limited by potential for detecting reverse causation.

Key results

  • 4.4% dementia incidence during median 24.7-year follow-up.
  • When group with poor cardiovascular health (score 0-6) was comparator, absolute difference per 1000 person-years in dementia incidence rate:
    • −1.5 (95% CI, −2.3 to −0.7) for group with intermediate cardiovascular health (score 7-11).
    • −1.9 (95% CI, −2.8 to −1.1) for group with optimal cardiovascular health (score 12-14).
  • Each 1-point increment in score conferred 11% lower dementia risk (HR, 0.89; 95% CI, 0.85-0.95).
  • Association also evident for:
    • Behavioral subscore (HR, 0.87; 95% CI, 0.81-0.93).
    • Biological subscore (HR, 0.91; 95% CI, 0.83-1.00).
  • Similar association seen in subset remaining free of cardiovascular disease during follow-up (HR, 0.89; 95% CI, 0.84-0.95).

Expert comment

  • In an editorial, Carol Brayne, CBE, and Fiona E. Matthews, PhD, MSc, write, “The implications from this study and many others are that the healthier the vascular system is in midlife, the lower the risk of subsequent dementia. This provides further support for the UK Government’s recent policy focus on vascular health in midlife. However, other evidence makes clear that vascular health at 50 is determined by factors earlier in the life course, including inequality and social and economic determinants.”

Study design

  • UK prospective cohort study of 7899 individuals (Whitehall II study).
  • Life Simple 7 cardiovascular health score calculated at age 50 years:
    • 4 behavioral measures: smoking, diet, physical activity, BMI.
    • 3 biological measures: fasting glucose, blood cholesterol, BP.
  • Main outcome: dementia.
  • Funding: UK Medical Research Council; others.

Limitations

  • Self-reported behavioral measures.
  • Population was an occupational cohort.
  • Dementia ascertained from linkage to electronic records.