Abstract P2069: Racial Differences in the Impact of Elevated Systolic Blood Pressure on Incident Cognitive Impairment (ICI) Risk: The REGARDS Study

Introduction: The number of adults living with Alzheimer’s Disease and Related Dementias (ADRD) is projected to double by 2050. Black Americans have one of the highest rates of hypertension of any racial/ethnic group in the world, which is a known risk factor for cognitive impairment. Hypothesis: Elevated systolic blood pressure (SBP) is a more potent risk factor for Incident Cognitive Impairment (ICI) in self-identified Black than White adults. Methods: REGARDS is a bi-racial cohort study initiated in 2003. 30,239 Black and White participants were enrolled from the contiguous US with oversampling in the “Stroke Belt”, a group of southeastern states known for higher rates of stroke. The present study included 14,938 REGARDS participants without cognitive impairment or stroke at baseline. ICI was evaluated during follow-up using both an Enhanced Cognitive Battery (ECB) consisting of four modified instruments adapted from the MoCA and CERAD, and a Six Item Screener (SIS) consisting of 3 temporal orientation questions and 3 delayed recall items. Participants were considered impaired if they scored ≥1.5 SD below their expected score for their age/sex group for at least 3 of the four ECB tests, or scored <4 once and <5 twice on the SIS. SBP was assessed at baseline and modeled as a per 10 mmHg increase. Cox proportional hazards models were used to assess associations between ICI and increases in SBP. Model 1 adjusted for age, sex, region, and antihypertensive medication use. Model 2 included Model 1 plus diabetes, history of cardiovascular disease, dyslipidemia, BMI, smoking status, alcohol use, income, and education. We tested for a race-by-SBP interaction term (p interaction <0.10) and presented race-stratified results based on the a priori hypothesis. Results: There were 1263 ICI cases over an average follow-up time of 12.0 years (778 in White and 485 in Black participants). In Model 1, the hazard ratio (HR) for ICI per 10 mmHg higher SBP was 1.09 (95% confidence interval (CI): 1.03, 1.22). There was no significant difference in the association of SBP between Black and White adults (race-by-SBP interaction p-value= 0.21). The HR for ICI per 10 mmHg higher SBP was 1.12 (95% CI: 1.06,1.30) for Black adults and 1.07 (95% CI: 1.04, 1.19) for White adults (Model 1). Results were similar in Model 2. Conclusions: Higher SBP was associated with an increased risk of ICI. This association did not differ by race.