Association Between Blood Pressure and Later-Life Cognition Among Black and White Individuals

ImportanceBlack individuals are more likely than white individuals to develop dementia. Whether higher blood pressure (BP) levels in black individuals explain differences between black and white individuals in dementia risk is uncertain.ObjectiveTo determine whether cumulative BP levels explain racial differences in cognitive decline.Design, Setting, and ParticipantsIndividual participant data from 5 cohorts (January 1971 to December 2017) were pooled from the Atherosclerosis Risk in Communities Study, Coronary Artery Risk Development in Young Adults Study, Cardiovascular Health Study, Framingham Offspring Study, and Northern Manhattan Study. Outcomes were standardized as t scores (mean [SD], 50 [10]); a 1-point difference represented a 0.1-SD difference in cognition. The median (interquartile range) follow-up was 12.4 (5.9-21.0) years. Analysis began September 2018.Main Outcomes and MeasuresThe primary outcome was change in global cognition, and secondary outcomes were change in memory and executive function.ExposuresRace (black vs white).ResultsAmong 34 349 participants, 19 378 individuals who were free of stroke and dementia and had longitudinal BP, cognitive, and covariate data were included in the analysis. The mean (SD) age at first cognitive assessment was 59.8 (10.4) years and ranged from 5 to 95 years. Of 19 378 individuals, 10 724 (55.3%) were female and 15 526 (80.1%) were white. Compared with white individuals, black individuals had significantly faster declines in global cognition (−0.03 points per year faster [95% CI, −0.05 to −0.01]; P = .004) and memory (−0.08 points per year faster [95% CI, −0.11 to −0.06]; P P P P P P = .56) and memory (−0.06 points per year [95% CI, −0.08 to −0.03]; P P Conclusions and RelevanceThese results suggest that black individuals’ higher cumulative BP levels may contribute to racial differences in later-life cognitive decline.