Risk of mild cognitive impairment among older adults in the United States by ethnoracial group

Objectives: To compare the risk of mild cognitive impairment (MCI) among a wide range of ethnoracial groups in the US. Design: Non-probabilistic longitudinal clinical research. Setting: Participants enrolling into the National Alzheimer's Coordinating Center Unified Data Set recruited via multiple approaches including clinician referral, self-referral by patients or family members, or active recruitment through community organizations. Participants: Cognitively normal individuals 55 and older at the initial visit, who reported race and ethnicity information, with at least two visits between September 2005 and November 2018. Measurements: Ethnoracial information was self-reported and grouped into non-Latino Whites, Asian Americans, Native Americans, African Americans (AAs), and individuals simultaneously identifying as AAs and another minority race (AA+), as well as Latinos of Caribbean, Mexican, and Central/South American origin. MCI was evaluated clinically following standard criteria. Four competing risk analysis models were used to calculate MCI risk adjusting for risk of death, including an unadjusted model, and models adjusting for non-modifiable and modifiable risk factors. Results: After controlling for sex and age at initial visit, subhazard ratios of MCI were statistically higher than non-Latino Whites among Native Americans (1.73), Caribbean Latinos (1.80), and Central/South American Latinos (1.55). Subhazard ratios were higher among AA+ compared to non-Latino Whites only in the model controlling for all risk factors (1.40). Conclusion: Compared to non-Latino Whites, MCI risk was higher among Caribbean and South/Central American Latinos as well as Native Americans and AA+. The factors explaining the differential MCI risk among ethnoracial groups are not clear and warrant future research.