Racial and Ethnic Differences in the Risk of Dementia under Hypothetical Blood‐Pressure‐Lowering Interventions: The Multi‐Ethnic Study of Atherosclerosis

Abstract

AbstractBackgroundBlack and Latino people have a higher risk of Alzheimer’s disease and related dementias (ADRD) as well as ADRD comorbidities, including hypertension. Since hypertension is perhaps the most important modifiable vascular risk factor for the development of ADRD, we aimed to study whether sustained hypothetical interventions to reduce systolic blood pressure (SBP) would differentially change ADRD risk across racial/ethnic groups.MethodWe used 19 years of follow‐up data from the Multi‐Ethnic Study of Atherosclerosis. The study population included 6806 individuals between 44 and 84 years old, free of clinically recognized CVD and dementia diagnosis at baseline. We defined two sustained interventions on SBP based on continually maintaining SBP below (1) 120 mmHg and (2) 140 mmHg. We considered incident dementia diagnoses as outcome. We applied the parametric g‐formula to adjust for baseline and time‐varying confounding. Baseline covariates included sex, age, education level, income, health insurance, and clinical variables (e.g. diabetes). Time‐varying covariates included SBP, total cholesterol, low‐density lipoprotein, body mass index, health behaviors (e.g. alcohol use), myocardial infarction, stroke, and coronary heart disease diagnosis.ResultMean age was 62.1 (SD = 10.2), 52.9% were female, 38.5% (2617) self‐identified as White, 27.8% (1890) as Black, 21.9% (1495) as Latino and 11.8% (804) as Chinese American. The observed 19‐year risk for dementia was 8.6%. Compared to no specified intervention, maintaining SBP below 120 mmHg was associated with an overall dementia risk reduction of about 5% in the full study population (risk ratio (RR): 0.95, 95%CI: 0.88, 1.02). The estimated RRs for this same comparison were: 0.95(95%CI: 0.87, 1.03) for White participants, 0.93 for Black participants (95%CI: 0.81,1.06), 0.92 for Latino participants (95%CI:0.81, 1.09), and 1.15 for Chinese American participants (95%CI: 0.74,1.63) (Table 1). Of note, the proportion of participants who would have had to have been intervened differed by race/ethnicity, where 92% Black participants, 82% of White and Chinese American, and 86% of Latino participants would have had to have been intervened to maintain SBP below 120 mmHg.ConclusionOur results highlight a heterogenous effect that should be considered for implementation of blood pressure control strategies.