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. Author manuscript; available in PMC: 2022 Sep 1.
Published in final edited form as: Expert Rev Mol Diagn. 2021 Jul 26;21(9):869–886. doi: 10.1080/14737159.2021.1952073

Table 2.

Studies evaluating the roles of race/ethnicity and socioeconomic status in Alzheimer’s disease heterogeneity

Author, journal, year Study population Study design, number of participants, and follow-up Results
Barnes et al., Neurology, 2015 Deceased African American and non-Hispanic White individuals with Alzheimer’s disease dementia from the Rush Alzheimer’s Disease Clinical Core Case-control study, n = 122 Compared with non-Hispanic Whites with Alzheimer’s disease, African Americans with Alzheimer’s disease tended to develop mixed pathology which could include Alzheimer’s disease + lewy bodies, Alzheimer’s disease + infarct, or Alzheimer’s disease + lewy bodies + infarct (OR = 2.4, 95% CI = 1.10-5.20).
Brayne et al., Brain, 2010 Participants interviewed to establish dementia diagnoses and their brain donations from Medical Research Council Cognitive Function and Ageing Study, Cambridge City Over-75s Cohort study (CC75C; Vantaa 85+ Case-control study, n = 872 Compared with individuals with less formal education, individuals with more formal education per year tended to not have dementia diagnoses (OR = 0.89; 95% CI = 0.83-0.94). No significant association was observed between education and neurodegenerative or neurovascular pathology. Compared with individuals with less formal education, individuals with more formal education tended to have greater brain weight (OR = 1.14, 95% CI =1.06-1.24).
Clark et al., J Stroke Cerebrovasc Dis, 2018 Non-Hispanic Whites and African Americans with a diagnosis of ischemic stroke prior to 2010 Cohort study, n = 68,758, follow-up = 5 years Compared with non-Hispanic Whites with intervening stroke, African Americans with intervening stroke were less likely to receive Alzheimer’s disease diagnosis and more likely to receive vascular dementia diagnosis (HR = .84, 95% CI = 0.71-0.98; HR = 1.67, 95% CI = 1.46-1.90, respectively). Compared with non-Hispanic Whites without intervening stroke, African Americans without intervening stroke were more likely to receive Alzheimer’s disease diagnosis and vascular dementia diagnosis (HR = 1.38, 95% CI = 1.29-1.48; HR = 2.02, 95% CI = 1.86-1.20, respectively).
Fitzpatrick et al., J Am Geriatr Soc, 2004 Non-Hispanic Whites and African Americans dementia free Cardiovascular Health Studies participants between 1992 and 1994 Cohort study, n = 3,602, mean follow-up = 5.4 years Compared with non-Hispanic Whites, African Americans tended to develop Alzheimer’s disease subtype (African Americans: age-adjusted IR per 1,000 = 34.7; non-Hispanic Whites: age-adjudged IR per 1,000 = 19.2). Compared with non-Hispanic Whites, African Americans tended to develop vascular dementia subtype (African Americans: age-adjusted IR per 1,000 = 27.2; non-Hispanic Whites: age-adjusted IR per 1,000 = 14.6).
Howell et al., Alzheimers Res Ther, 2017 Older Americans to undergo clinical, neuropsychological, genetic, mild cognitive impairment, and cerebrospinal fluid analysis from 2013 to 2015 at Emory University Case-control study, n = 1,355 Compared with non-Hispanic Whites with Alzheimer’s disease, African Americans with Alzheimer’s disease tended to have lower levels of MAPT (t-tau) and p-tau181 biomarkers in cerebrospinal fluid, which is related to increased limbic-predominant Alzheimer’s disease subtype (African Americans: mean MAPT (t-tau), pg/mL = 72.8; non-Hispanic Whites: mean MAPT (t-tau), pg/mL = 103.8; African Americans: mean p-tau181, pg/mL = 25.3; non-Hispanic Whites: mean p-tau181, pg/mL = 34.2).
Karp et al., Am J Epidemiol, 2004 Initially nondemented subjects aged ≥ 75 years from the Kungsholmen Project, Stockholm, Sweden followed-up between 1987 and 1993 Cohort study, n = 931, follow-up = 3 years Compared with individuals of high education attainment (>7 years), individuals of low education attainment (2-7 years) tended to have clinically diagnosed Alzheimer’s disease (RR = 3.4, 95% CI = 2.0-6.0) Compared with individuals of high occupation SES, individuals of low occupation SES tended to have clinically diagnosed Alzheimer’s disease (1.6, 95% CI = 1.0-2.5).
Kennedy et al., Am J Geriatr Psychiatry, 2017 Subjects with baseline data for comorbid disorders taken from a meta-database of 18 studies from the Alzheimer’s Disease Cooperative Study and the Alzheimer’s Disease Neuroimaging Initiative Case-control study, n = 5,164 Compared with non-Hispanic Whites with Alzheimer’s disease, mild cognitive impairment, or normal cognition, African Americans with Alzheimer’s disease, mild cognitive impairment, or normal cognition tended to have cardiovascular comorbidities (OR = 2.10, 95% CI = 1.71-2.57). Compared with non-Hispanic Whites with Alzheimer’s disease, mild cognitive impairment, or normal cognition, African Americans with Alzheimer’s disease, mild cognitive impairment, or normal cognition tended to drop out of clinical trials (OR = 1.60, 95% CI = 1.15-2.21).
Misiura et al., Transl Neurodegener, 2020 African American and Non-Hispanic White individuals over the age of 64 with varying diagnoses on the spectrum of Alzheimer’s disease according to consensus criteria Case-control study, n = 137 Decrease in cognitive performance is observed with decreased default mode network connectivity between midline core subsystem and dorsomedial subsystem for African Americans, while decrease in cognitive performance is observed with increased default mode network connectivity between midline core subsystem and dorsomedial subsystem for non-Hispanic Whites.
Morris et al., JAMA Neurol, 2019 African American and Non-Hispanic White individuals enrolled from January 1, 2004, to December 31, 2015 at the Knight Alzheimer Disease Research Center at Washington University Case-control study, n = 1,255 Compared with non-Hispanic White carriers of the aAPOE ε4 allele, African American carriers of the APOE ε4 allele had lower mean (SE) concentrations of MAPT (t-tau) biomarkers in cerebrospinal fluid (African Americans: mean MAPT (t-tau) (SE), pg/mL = 269.67 (43.73); non-Hispanic Whites: mean MAPT (t-tau) (SE) = 463.54 (20.32); P < 0.001) Compared with non-Hispanic White carriers of the APOE ε4 allele, African American carriers of the APOE ε4 allele had lower mean (SE) concentrations of p-tau181 biomarkers in cerebrospinal fluid (African Americans: mean p-tau181 (SE), pg/mL = 48.77 (6.23) Non-Hispanic Whites: mean p-tau181 (SE), pg/mL = 74.98 (2.78); P < 0.001. There were no significant racial differences in MAPT (t-tau) and p-tau181 concentration for individuals without an APOE ε4 allele.
Snowdon et al., Journal of Clinical Epidemiology, 1989 Roman Catholic nuns sharing similar lifestyle conditions but different educational attainment from the Mankato, Minnesota Province Case-control study, n = 247 Compared with high-educated individuals (individuals with at least a bachelor’s degree), low-educated individuals (individuals with less than a bachelor’s degree tended to be more cognitively impaired (OR = 2.11, 95% CI = 0.88-5.03).
Wada et al., J Alzheimers Dis, 2018 Participants aged between 55 and 90 years and diagnosed as healthy controls, having mild cognitive impairment, or having Alzheimer’s disease. Case-control study, n = 825 for education and amyloid-β deposition analysis, n = 1,304 for education and brain metabolism analysis No significant association between education and both amyloid-β deposition (n = 825) and brain metabolism (n = 1,304) for individuals with Alzheimer’s disease and mild cognitive impairment.
Wilson et al., NED, 2005 Catholic nuns, priests and brothers from the Religious Orders Study followed-up periodically from 1994 with ongoing follow-ups since date of study Cohort study, n = 999, mean follow-up number = 6.6 No significant association between early life SES to cognitive decline and Alzheimer’s disease incidence.
Zhang et al., Neuroepidemiology, 2006 Community residents ≥ 55 years in Beijing, Shanghai, Chengdu and Xian with diagnoses of Alzheimer’s disease or vascular dementia collected from 1997-1998 Cohort study, n = 34,807, follow-up = 6 months Compared with individuals with <1 year of education, individuals with 1-6 years of education, individuals with 7-12, and individuals with 12+ years of education had increasing protection to Alzheimer’s disease (OR = 0.3, 95% CI = 0.2-0.4; OR = 0.2, 95% CI = 0.2-0.4; OR = 0.2 95% CI = 0.1-0.3 to Alzheimer’s disease respectively) and increasing protection to vascular dementia (OR = 0.7, 95% CI = 0.5-0.9; OR = 0.6, 95% CI = 0.3-0.9; OR = 0.3, 95% CI = 0.1-0.8 respectively). Compared with farm laborers, non-farmer laborers, officials, and professionals had greater protection to Alzheimer’s disease (OR = 0.6, 95%CI = 0.4-0.8, OR = 0.3, 95% CI = 0.2-0.5, and OR = 0.2, 95% CI = 0.1-0.3 respectively) and greater protection to vascular dementia (OR = 0.8, CI = 0.5-1.2, OR = 0.7, 95% CI = 0.4-1.4, and OR = 0.1 95% CI = 0.1-0.4 respectively).

Abbreviation: CI, confidence interval; IR, incidence rate; OR, odds ratio; SE, standard error; SES, socioeconomic status.