Socioeconomic Status Mediates Racial Differences Seen Using theAT(N)Framework

Abstract

Objectives African Americans are at greater risk for developing Alzheimer's disease (AD) dementia than non‐Hispanic whites. In addition to biological considerations (eg, genetic influences and comorbid disorders), social and environmental factors may increase the risk of AD dementia. This paper (1) assesses neuroimaging biomarkers of amyloid (A), tau (T), and neurodegeneration (N) for potential racial differences and (2) considers mediating effects of socioeconomic status (SES) and measures of small vessel and cardiovascular disease on observed race differences. Methods Imaging measures of AT(N) (amyloid and tau positron emission tomography [PET]) structural magnetic resonance imaging (MRI), and resting state functional connectivity (rs‐fc) were collected from African American (n = 131) and white (n = 685) cognitively normal participants age 45 years and older. Measures of small vessel and cardiovascular disease (white matter hyperintensities [WMHs] on MRI, blood pressure, and body mass index [BMI]) and area‐based SES were included in mediation analyses. Results Compared to white participants, African American participants had greater neurodegeneration, as measured by decreased cortical volumes (Cohen's f2 = 0.05, p < 0.001). SES mediated the relationship between race and cortical volumes. There were no significant race effects for amyloid, tau, or rs‐fc signature. Interpretation Modifiable factors, such as differences in social contexts and resources, particularly area‐level SES, may contribute to observed racial differences in AD. Future studies should emphasize collection of relevant psychosocial factors in addition to the development of intentional diversity and inclusion efforts to improve the racial/ethnic and socioeconomic representativeness of AD studies. ANN NEUROL 2021;89:254–265

Culture, Ethnicity, and Level of Education in Alzheimer's Disease

“…In another study, even after accounting for genetic markers (APOE ε4 and ABCA7) and Aβ42, African Americans were found to have lower CSF p-tau, t-tau, and Aβ40 [ 140 ]. No differences between races were observed in the results of PiB PET [ 153 , 155 ] or Tau PET [ 155 ]. In patients with MCI, African Americans have been found to have significantly lower levels of total Tau in CSF than non-Hispanic Whites [ 156 ].…”

Effect of Social Determinants of Health on Cognition and Risk of Alzheimer Disease and Related Dementias

“…67 For example, a cross-sectional imaging study, using a mediation analysis, found that the Area Deprivation Index accounted for almost all the higher risk of AD found in African American participants. 69…”

Using Fractional Anisotropy Imaging to Detect Mild Cognitive Impairment and Alzheimer’s Disease among Mexican Americans and Non-Hispanic Whites: A HABLE Study

“…This provides valuable insights into the biological differences in disease profiles among a multi-ethic cohort and adds to the literature demonstrating the importance of understanding the biological mechanisms of MCI and dementia across racial and ethnic groups. Recent work has demonstrated that SES factors were significantly associated with MRI-based markers of neurodegeneration among African Americans [29]. In the HABLE study, SES factors (i.e., acculturation, household income) were significantly related to MRI-based neurodegeneration among Mexican Americans, but not for non-Hispanic whites.…”