Optimal blood pressure for cognitive function: findings from an elderly African-American cohort study.

OBJECTIVES

To report the results from a prospective cohort study on the association between blood pressure (BP) and cognitive function in elderly African Americans.

DESIGN

Prospective cohort study conducted from 1997 to 2009.

SETTING

Community-based study in Indianapolis.

PARTICIPANTS

African Americans aged 65 years or older (N = 3,145).

MEASUREMENTS: At each assessment, participant cognitive function was measured using the Community Screening Interview for Dementia. Other measurements included BP, height, weight, education level, antihypertensive medication use, alcohol use, smoking, and history of chronic medical conditions.

RESULTS

Longitudinal assessments (n = 5,995) contributed by 2,721 participants with complete independent variables were analyzed using a semiparametric mixed-effects model. Systolic BP (SBP) of approximately 135 mmHg and diastolic BP (DBP) of approximately 80 mmHg were associated with optimal cognitive function after adjusting for other variables (P = .02). Weight loss with body mass index < 30.0 kg/m(2) was significantly related to poorer cognitive performance (P < .001). Older age at first assessment, lower education level; smoking; and history of depression, stroke, and diabetes mellitus were related to worse cognitive function; taking antihypertensive medication and drinking alcohol were associated with better cognitive function.

CONCLUSION

High and low BP were associated with poorer cognitive performance. A joint optimal region of SBP and DBP for cognitive function has been identified, which may provide useful clinical information on optimal BP control in cognitive health and lead to better quality of life for elderly adults.