Very long term visit‐to‐visit blood pressure variability and the risk of dementia in the Adult Changes in Thought study

Abstract

AbstractBackgroundHigh visit‐to‐visit blood pressure variability (BPV) is associated with an increased risk of cardiovascular disease. However, for incident dementia, conflicting results are reported. Our objective was to assess the association of very long‐term visit‐to‐visit BPV and the risk of all‐cause dementia in community‐dwelling individuals.MethodCommunity‐dwelling individuals aged 65 years or older and free from dementia were randomly sampled from 1994 onwards from Kaiser Permanente Washington (KPW), Seattle, USA, and included in the Adult Changes in Thought (ACT) study. After enrollment, participants were followed‐up biannually. We retrospectively collected yearly data on blood pressure measurements and medical history from the age of 50 up to recruitment into the ACT study, through KPW electronic databases. Visit‐to‐visit BPV was defined as coefficient of variation (SD/mean*100) calculated with systolic blood pressure measurements. Dementia was diagnosed by an expert panel based on DSM‐IV and NINCDS‐ADRDA criteria. We used Cox regression adjusted for sex, blood pressure trend, antihypertensive medication use and cardiovascular risk factors. Subgroup analyses were performed for midlife (50‐64) and later life (≥65).ResultWe included 1174 individuals with a median age of 78 years [IQR=72‐83] at inclusion in the ACT study. Systolic blood pressure measurements (mean=27.9, SD=8.5, range: 2‐50) were collected over 2 to 54 years (mean=31.8, SD=9.4), and 483 (41.1%) individuals developed dementia. There was no significant association between very long term visit‐to‐visit BPV (mean=12.15; SD=2.67) and incident all‐cause dementia (HR=0.98; 95%CI=0.94‐1.02). Competing risk of death analyses (combined outcome dementia/death) showed a dementia/mortality risk reduction of 4% per point visit‐to‐visit BPV increase (HR=0.96; 95%CI=0.94‐0.99). The associations were similar for visit‐to‐visit BPV in later life (dementia: HR=0.99; 95%CI=0.95‐1.02, dementia/death: HR=0.96; 95%CI=0.93‐0.99). Visit‐to‐visit BPV in midlife was not associated with incident dementia (dementia: HR=0.99; 95%CI=0.96‐1.02, dementia/death: HR=1.01; 95%CI=0.99‐1.02).ConclusionIn our sample, higher very long‐term visit‐to‐visit BPV is associated with lower incident all‐cause dementia risks. This association might be stronger in later life than in midlife.