Large BP variation tied to long term risk for dementia

  • Ma Y & al.
  • PLoS Med
  • 1 Nov 2019

  • curated by Sarfaroj Khan
  • UK Clinical Digest
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Takeaway

  • Large variation in blood pressure (BP) over a period of years is associated with an increased risk for long-term dementia.
  • The association between BP variation and dementia appeared stronger with long interval and the risk for long-term dementia increased with a large rise and fall in BP.

Why this matters

  • Findings suggest the potential importance of BP variability in the aetiology of dementia.

Study design

  • A prospective cohort study of 5273 dementia-free participants (mean age 67.6 years) who were followed up over 26 years and underwent BP measurements over 2 sequential visits every 4 years.
  • Risk for dementia in relation to systolic BP (SBP) was evaluated at 0, 5, 10 and 15 years across different quantiles (lowest quintile 1, quintile 2, quintile 3, quintile 4 and highest quintile 5).
  • Funding: Erasmus Medical Center and Erasmus University and others.

Key results

  • Overall, 1059 participants developed dementia (incidence rate, 14.7 cases per 1000 person-years), including Alzheimer’s disease (75.7%) and vascular dementia (7.6%).
  • Risk for dementia was higher with large variation in SBP in quintile 5 vs 1 at:
    • 5 years (HR, 2.01; 95% CI, 1.60-2.54; P<.001>
    • 10 years(HR, 1.67; 95% CI, 1.21-2.30; P=.006) and
    • 15 years (HR, 3.13; 95% CI, 2.05-4.77; P<.001>
  • Rises (HR for highest quantile, 3.31; 95% CI, 2.11-5.18; P<.001 or falls for the lowest quartile ci p=".002)" in sbp was associated with an increased risk long-term dementia.>
  • Large falls in SBP ≤5 years was associated with modest increased risk for dementia (HR, 1.21; 95% CI, 1.00-1.48; P=.017).
  • Similar findings were observed for variation in diastolic BP and pulse pressure.

Limitations

  • Risk of bias.