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 (HR for the lowest quartile, 2.20; 95% CI, 1.33-3.63; P=.002) in SBP was associated with an increased risk for 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.
References
References