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6 Racial Discrimination and White Matter Integrity Among Black Older Adults
- Jordan D Palms, Mohamad J. Alshikho, Patrick J. Lao, Clarissa D. Morales, Jennifer J. Manly, Nicole Schupf, Adam M. Brickman, Laura B. Zahodne
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- Journal:
- Journal of the International Neuropsychological Society / Volume 29 / Issue s1 / November 2023
- Published online by Cambridge University Press:
- 21 December 2023, pp. 788-789
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Objective:
Non-Hispanic Black older adults experience a disproportionate burden of Alzheimer’s Disease and related dementias (ADRD) risk compared to non-Hispanic White older adults. It is necessary to identify mechanisms that may be contributing to inequities in cognitive aging. Psychosocial stressors that disproportionately affect Black adults (e.g., discrimination) have the potential to impact brain health through stress pathways. The brain’s white matter, which appears to be particularly important for ADRD risk among Black older adults, may be uniquely vulnerable to stress-related physiological dysfunction. To further understand whether and how discrimination can affect ADRD risk, this study aimed to examine associations between multiple forms of racial discrimination and white matter integrity, operationalized through diffusion tensor imaging.
Participants and Methods:Cross-sectional data were obtained from 190 non-Hispanic Black residents aged 65+ without dementia in northern Manhattan. Racial discrimination was self-reported using the Everyday Discrimination and Major Experiences of Lifetime Discrimination scales. Example items from the Everyday Discrimination Scale include: “You are treated with less respect than other people”; “You are called names or insulted.” Example items from the Major Experiences of Lifetime Discrimination Scale include: “At any time in your life, have you ever been unfairly fired from a job?”; “Have you ever been unfairly denied a bank loan?” Racial discrimination was operationalized as experiences attributed to “race” or “skin color.” White matter integrity was assessed using fractional anisotropy (FA) via diffusion tensor imaging. Multivariable regression models evaluated the unique effects of everyday and major experiences of lifetime racial discrimination on mean FA in the whole brain and specific regions. Initial models controlled for age, sex/gender, intracranial volume, and white matter hyperintensities. Subsequent models additionally controlled for socioeconomic and health factors to consider potential confounders or mediators of the relationship between discrimination and white matter integrity.
Results:Major experiences of lifetime discrimination were negatively associated with mean FA within the left cingulum cingulate gyrus and the right inferior fronto-occipital fasciculus. These associations persisted when controlling for additional covariates (i.e., education, depression, and cardiovascular diseases). In contrast, major experiences of lifetime discrimination were positively associated with mean FA within the right superior longitudinal fasciculus (temporal part). This association was attenuated when controlling for additional covariates. Everyday racial discrimination was not associated with mean FA in any regions.
Conclusions:These results extend prior work linking racial discrimination to brain health and provide evidence for both risk and resilience among Black older adults. Major experiences of lifetime racial discrimination, a proxy for institutional racism, may have a stronger effect on white matter integrity than everyday racial discrimination, a proxy for interpersonal racism. Educational opportunities and cardiovascular risk factors may represent mediators between racial discrimination and white matter integrity. White matter integrity within specific brain regions may be a mechanism through which racially patterned social stressors contribute to racial disparities in ADRD. Future research should characterize within-group heterogeneity in order to identify factors that promote resilience among Black older adults.
Mechanisms underlying the association between adverse childhood experiences and racial disparities in later-life cognition
- Sydney R. Wilhoite, Afsara B. Zaheed, Jordan D. Palms, Emily P. Morris, Ketlyne Sol, Alexa Martino, Laura B. Zahodne
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- Journal:
- Journal of the International Neuropsychological Society / Volume 30 / Issue 3 / March 2024
- Published online by Cambridge University Press:
- 25 August 2023, pp. 253-263
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Objective:
Adverse childhood experiences (ACEs) may be a risk factor for later-life cognitive disorders such as dementia; however, few studies have investigated underlying mechanisms, such as cardiovascular health and depressive symptoms, in a health disparities framework.
Method:418 community-dwelling adults (50% nonHispanic Black, 50% nonHispanic White) aged 55+ from the Michigan Cognitive Aging Project retrospectively reported on nine ACEs. Baseline global cognition was a z-score composite of five factor scores from a comprehensive neuropsychological battery. Depressive symptoms were assessed using the Center for Epidemiologic Studies Depression Scale. Cardiovascular health was operationalized through systolic blood pressure. A mediation model controlling for sociodemographics, childhood health, and childhood socioeconomic status estimated indirect effects of ACEs on global cognition via depressive symptoms and blood pressure. Racial differences were probed via t-tests and stratified models.
Results:A negative indirect effect of ACEs on cognition was observed through depressive symptoms [β = −.040, 95% CI (−.067, −.017)], but not blood pressure, for the whole sample. Black participants reported more ACEs (Cohen’s d = .21), reported more depressive symptoms (Cohen’s d = .35), higher blood pressure (Cohen’s d = .41), and lower cognitive scores (Cohen’s d = 1.35) compared to White participants. In stratified models, there was a negative indirect effect through depressive symptoms for Black participants [β = −.074, 95% CI (−.128, −.029)] but not for White participants.
Conclusions:These results highlight the need to consider racially patterned contextual factors across the life course. Such factors could exacerbate the negative impact of ACEs and related mental health consequences and contribute to racial disparities in cognitive aging.
Links between early-life contextual factors and later-life cognition and the role of educational attainment
- Jordan D. Palms, Afsara B. Zaheed, Emily P. Morris, Alexa Martino, Lindsey Meister, Ketlyne Sol, Laura B. Zahodne
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- Journal:
- Journal of the International Neuropsychological Society / Volume 29 / Issue 8 / October 2023
- Published online by Cambridge University Press:
- 20 December 2022, pp. 734-741
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Objective:
Educational attainment is a well-documented predictor of later-life cognition, but less is known about upstream contextual factors. This study aimed to identify which early-life contextual factors uniquely predict later-life global cognition and whether educational attainment mediates these relationships.
Method:Participants were drawn from the Michigan Cognitive Aging Project (N = 485; Mage = 63.51; SDage = 3.13; 50% non-Hispanic Black). Early-life exposures included U.S. region of elementary school (Midwest, South, Northeast), average parental education, household composition (number of adults (1, 2, 3+), number of children), school racial demographics (predominantly White, predominantly Black, diverse), self-reported educational quality, and school type (public/private). Later-life global cognition was operationalized with a factor score derived from a comprehensive neuropsychological battery. Sequential mediation models controlling for sociodemographics estimated total, direct, and indirect effects of early-life contextual factors on cognition through educational attainment (years).
Results:Higher educational quality, higher parental education, and attending a private school were each associated with better cognition; attending a predominantly Black or diverse school and reporting three or more adults in the household were associated with lower cognition. After accounting for educational attainment, associations remained for educational quality, school type, and reporting three or more adults in the household. Indirect effects through educational attainment were observed for school region, educational quality, school racial demographics, and parental education.
Conclusions:School factors appear to consistently predict later-life cognition more than household factors, highlighting the potential long-term benefits of school-level interventions for cognitive aging. Future research should consider additional mediators beyond educational attainment such as neighborhood resources and childhood adversity.