Decreased complexity and increased variability in systolic blood pressure are associated with elevated long‐term risk of dementia: The Rotterdam Study

Abstract

AbstractBackgroundBlood pressure (BP) is a key player in the vascular etiology of dementia, but their relationship is not fully elucidated. The current BP control paradigm focuses on BP levels, but real‐time BP is highly dynamic, involving simultaneous interactions of numerous neural and vascular feedback mechanisms. We hypothesized that early subclinical disruption in BP dynamics, captured by decreased complexity and increased variability, contributes to dementia risk, above and beyond BP levels.MethodIn a prospective cohort study since 1997 involving 1,877 dementia‐free community‐based older adults, we investigated whether BP variability and complexity were associated with the risk of dementia. The primary exposures were BP complexity (quantified by sample entropy) and BP variability (quantified by coefficient of variation) derived from continuous beat‐to‐beat BP series of 300 beats. The primary outcome was incident dementia during follow‐up until January 1, 2016.ResultOf 1,877 participants (59% women; mean [SD] age, 70.9 [6.3] years), 333 developed dementia over 20 years. Reduced systolic BP (SBP) complexity was associated with a higher dementia risk (HR comparing extreme quintiles: 1.53 [95%CI: 1.08, 2.17], P=0.008). Increased SBP variability was also associated with a higher risk of dementia (HR comparing extreme quintiles: 1.57 [95% CI: 1.11, 2.22]; P=0.017). When considered jointly, individuals with both high variability (within the top quintile) and low complexity (within the bottom quintile) had a significantly higher risk of developing dementia compared with those with both high complexity and low variability in SBP (HR: 2.16; 95%CI: 1.28‐3.65, P=0.003). These findings were observed after adjusting for age, sex, APOE genotype, mean SBP, and traditional vascular risk factors. Consistent findings were observed for variability but not complexity of diastolic BP.ConclusionDecreased complexity and increased variability of beat‐to‐beat systolic blood pressure are potential novel risk factors for dementia. Our findings suggest that maintaining complexity and limiting variability in systolic blood pressure may provide new opportunities to prevent dementia.