Blood Pressure Variability and Cognition in Black and White Older Adults Over 18 Years of Follow-up: A Population-Based Cohort Study.

Background and objectives: Hypertension is a well-established cardiovascular risk factor for cognitive function. As blood pressure fluctuates because of aging-related changes, we examined the association between visit-to-visit blood pressure variability (BPV) and cognition in older adults.

Methods: This prospective observational cohort study included 4,770 individuals aged older than 65 years with repeated blood pressure assessment participating in the Chicago Health and Aging Project, a bi-racial population-based study lasting from 1993 to 2012. Blood pressure was measured by research staff every 3 years over 18 of follow-up. Systolic and diastolic BPV was calculated as the sum of the absolute difference in blood pressure between successive measurements, divided by the number (n - 1) of assessments. Cognition was assessed by standardized cognitive tests, and z-scores for the composite cognitive score were computed. Multivariable adjusted linear regression models were used to evaluate the association of systolic and diastolic BPV during the study period with cognition at the last visit.

Results: Of 4,770 individuals, 2,998 (62.9%) were women, 3,146 (66.0%) were Black, and the mean (SD) age at baseline was 71.3 (5.3) years. The mean systolic BPV was 17.7 mm Hg in Black individuals and 16.0 mm Hg in White participants. Higher systolic and diastolic BPV was associated with lower cognitive scores at the end of follow-up. Compared with individuals in the first tertile of systolic BPV (lower BPV), participants with third tertile (higher BPV) had lower cognitive scores by 0.074 standardized units (β -0.074; 95% CI -0.131 to -0.018), corresponding to 1.8 years older in cognitive age. This relationship differed by race, being significant only in older Black adults. Black individuals in the third tertile of systolic BPV had lower cognitive scores by 0.115 standardized units (β -0.115; 95% CI -0.183 to -0.047) compared with those in the first tertile, corresponding to 2.8 years older in cognitive age. Similar findings were observed for diastolic BPV.

Discussion: Elevated BPV, particularly in older Black adults, was associated with a lower cognitive score, suggesting routine assessment for blood pressure to identify and mitigate the adverse role of BPV in cognitive functioning in older adults.