Association of higher diastolic blood pressure levels with cognitive impairment

Background: We evaluated the cross-sectional relationship of blood pressure (BP) components with cognitive impairment after adjusting for potential confounders. Methods: Reasons for Geographic and Racial Differences in Stroke (REGARDS) is a national, longitudinal population cohort evaluating stroke risk in 30,228 black and white men and women > 45 years old. During the in-home visit, BP measurements were taken as the average of 2 measurements using a standard aneroid sphygmomanometer. Excluding participants with prior stroke or TIA, the present analysis included 19,836 participants (enrolled from December 2003 to March 2007) with complete baseline physical and cognitive evaluations. Incremental logistic models examined baseline relationships between BP components (systolic blood pressure [SBP], diastolic blood pressure [DBP], and pulse pressure [PP]) and impaired cognitive status (score of <= 4 on 6-Item Screener) after adjusting for demographic and environmental characteristics, cardiovascular risk factors, depressive symptoms, and current use of any antihypertensive medication. Results: Higher DBP levels were associated with impaired cognitive status after adjusting for demographic and environmental characteristics, risk factors, depressive symptoms, and antihypertensive medications. An increment of 10 mm Hg in DBP was associated with a 7% (95% confidence interval [CI] 1%-14%, p = 0.0275) higher odds of cognitive impairment. No independent association was identified between impaired cognitive status and SBP (odds ratio [OR] 1.02, 95% CI 0.99-1.06) or PP (OR 0.99, 95% CI 0.95-1.04). There was no evidence of nonlinear relationships between any of the BP components and impaired cognitive status. There was no interaction between age and the relationship of impaired cognitive status with SBP (p = 0.827), DBP (p = 0.133), or PP (p = 0.827) levels. Conclusions: Higher diastolic blood pressure was cross-sectionally and independently associated with impaired cognitive status in this large, geographically dispersed, race-and sex-balanced sample of stroke-free individuals. Neurology (R) 2009; 73: 589-595