Risk Factors for Alzheimer’s Disease and Related Dementia Diagnoses in American Indians

The burden of Alzheimer’s disease and related dementias (ADRD) has increased substantially in the United States, particu­larly in health disparity populations. Little is known about the epidemiology of ADRD in American Indian (AI) adults, although they have a high prevalence of ADRD risk factors including hypertension, diabetes, obesity, and smoking. Using electronic health records from a large health care organization during 2016-18, we describe characteristics of AI patients aged ≥55 years with and without an ADRD diagnosis, assess ADRD risk factors and contrast findings with results from age- and sex-matched non- Hispanic White (NHW) patients. To identify factors associated with ADRD diagnoses, we estimated population-averaged prevalence rate ratios to approximate relative risk (RR) using generalized estimating equations models adjusted for age, sex, and marital and rural residency status. The age-adjusted prevalence of ADRD diagnosis was 6.6% of AI patients, compared with 4.4% in NHW patients. Patient age and diagnosis of hy­pertension, depression, hyperlipidemia, or diabetes were significantly associated with higher risk of ADRD diagnosis in AIs (RR range: 1.1-2.8) whereas female sex or being married/having a partner were associated with lower risk of ADRD diagnosis (each RR=.7). ADRD risk factors were generally similar between AI and NHW patients, except for sex and marital status. However, the adjusted risk of ADRD was approxi­mately 49% higher in AI patients. To our knowledge, our study is the first to examine ADRD diagnoses and comorbidities in AIs across a large geographical region in south­west United States. Future efforts to confirm our findings in diverse AI communities are warranted. Ethn Dis. 2020;30(4):671-680; doi:10.18865/ed.30.4.671