Midlife Hypertensive Status and Cognitive Function 20 Years Later: The Southall and Brent Revisited Study

Objectives: To investigate long-term prospective associations between a range of measurements of hypertensive status in midlife and cognitive impairment 20 years later. Design: Cohort study. Setting: Two areas (Southall and Brent) of northwest London. Participants: Survey samples of a multiethnic population (European, African Caribbean, South Asian) aged 40 to 67 were followed up 20 years later. Measurements: Comprehensive cardiovascular assessments were performed at baseline, including measurements of resting blood pressure (BP) and, in a subsample, ambulatory BP. At follow-up, a battery of cognitive assessments was administered, and a composite outcome was derived, with impairment defined as the lowest 10% within each ethnic group. Logistic regression models were used to investigate associations with prior measures of hypertensive status. Results: In 1,484 participants at follow-up, cognitive impairment showed significant U-shaped associations with baseline diastolic BP (DBP) and mean arterial pressure (MAP; strongest for those aged ≥50 at baseline), independent of a range of covariates, but no associations were found with systolic BP or pulse pressure. Cognitive impairment was also associated with antihypertensive medication use and higher evening ambulatory DBP at baseline. No substantial differences in strengths of association were found between ethnic groups. Conclusion: Low and high DBP and MAP were associated with cognitive impairment 20 years later. Higher evening DBP on ambulatory monitoring was also associated with greater risk.