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Original Investigation
November 14, 2022

Brain Aging Among Racially and Ethnically Diverse Middle-Aged and Older Adults

Author Affiliations
  • 1Taub Institute for Research on Alzheimer's Disease and the Aging Brain, College of Physicians and Surgeons, Columbia University, New York, New York
  • 2Gertrude H. Sergievsky Center, College of Physicians and Surgeons, Columbia University, New York, New York
  • 3Department of Neurology, College of Physicians and Surgeons, Columbia University, New York, New York
JAMA Neurol. 2023;80(1):73-81. doi:10.1001/jamaneurol.2022.3919
Key Points

Question  To what extent are racial and ethnic disparities in cortical thickness and white matter hyperintensity volume present in midlife and late life?

Findings  In this cross-sectional study of 2 community-based cohort studies in midlife (n = 497) and late life (n = 970), race and ethnicity disparities in Alzheimer disease–related neuroimaging measures in midlife persisted in late life, which was most prominent in Black adults.

Meaning  Race and ethnicity disparities in aging and Alzheimer disease and related dementias may be due partially to social forces that accelerate brain aging, especially in Black middle-aged adults.

Abstract

Importance  Neuroimaging studies have documented racial and ethnic disparities in brain health in old age. It remains unclear whether these disparities are apparent in midlife.

Objective  To assess racial and ethnic disparities in magnetic resonance imaging (MRI) markers of cerebrovascular disease and neurodegeneration in midlife and late life.

Design, Setting, and Participants  Data from 2 community-based cohort studies, Washington Heights–Inwood Columbia Aging Project (WHICAP) and the Offspring Study of Racial and Ethnic Disparities in Alzheimer Disease (Offspring), were used. Enrollment took place from March 2011 and June 2017, in WHICAP and Offspring, respectively, to January 2021. Of the 822 Offspring and 1254 WHICAP participants approached for MRI scanning, 285 and 176 refused participation in MRI scanning, 36 and 76 were excluded for contraindications/ineligibility, and 4 and 32 were excluded for missing key variables, respectively.

Main Outcomes and Measures  Cortical thickness in Alzheimer disease–related regions, white matter hyperintensity (WMH) volume.

Results  The final sample included 1467 participants. Offspring participants (497 [33.9%]) had a mean (SD) age of 55 (10.7) years, had a mean (SD) of 13 (3.5) years of education, and included 117 Black individuals (23.5%), 348 Latinx individuals (70%), 32 White individuals (6.4%), and 324 women (65.2%). WHICAP participants (970 [66.1%]) had a mean (SD) age of 75 (6.5) years, had a mean (SD) of 12 (4.7) years of education, and included 338 Black individuals (34.8%), 389 Latinx individuals (40.1%), 243 White individuals (25.1%), and 589 women (65.2%). Racial and ethnic disparities in cerebrovascular disease were observed in both midlife (Black-White: B = 0.357; 95% CI, 0.708-0.007; P = .046) and late life (Black-Latinx: B = 0.149, 95% CI, 0.068-0.231; P < .001; Black-White: B = 0.166; 95% CI, 0.254-0.077; P < .001), while disparities in cortical thickness were evident in late life only (Black-Latinx: B = −0.037; 95% CI, −0.055 to −0.019; P < .001; Black-White: B = −0.064; 95% CI −0.044 to −0.084; P < .001). Overall, Black-White disparities were larger than Latinx-White disparities for cortical thickness and WMH volume. Brain aging, or the association of age with MRI measures, was greater in late life compared with midlife for Latinx (cortical thickness: B = 0.006; 95% CI, 0.004-0.008; P < .001; WMH volume: B = −0.010; 95% CI, −0.018 to −0.001; P = .03) and White (cortical thickness: B = 0.005; 95% CI, 0.002-0.008; P = .001; WMH volume: B = −0.021; 95% CI −0.043 to 0.002; P = .07) participants but not Black participants (cortical thickness: B = 0.001; 95% CI, −0.002 to 0.004; P =.64; WMH volume: B = 0.003; 95% CI, −0.010 to 0.017; P = .61), who evidenced a similarly strong association between age and MRI measures in midlife and late life.

Conclusions and Relevance  In this study, racial and ethnic disparities in small vessel cerebrovascular disease were apparent in midlife. In Latinx and White adults, brain aging was more pronounced in late life than midlife, whereas Black adults showed accelerated pattern of brain aging beginning in midlife.

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