Longitudinal Associations of Depression and Diabetes with Alzheimer's Disease and Related Dementias Risk among American Indian and Alaska Native Peoples.

Abstract

Background: Alzheimer's disease and related dementias (ADRD) research worldwide indicate that it is more common in Indigenous than in non-Indigenous populations. We examined the relationship of depression and diabetes, alone and together, with incident ADRD in a large sample of American Indian and Alaska Native (AI/AN) peoples.

Methods: We examined a sample of 65,801 AI/AN peoples aged ≥ 45 years in fiscal year 2007 who were ADRD free between FY2007-09. Cox proportional hazard models were employed to estimate associations between ADRD risk and baseline depression and diabetes, adjusting for potential confounding variables.

Results: We found 2.3% received an ADRD diagnosis during FY2010-13. Compared to persons with neither depression nor diabetes, the fully adjusted hazard ratio (HR) for those aged ≥ 45 years with depression and diabetes was 1.82 (95% CI 1.53-2.16) for ADRD and those with depression only had a hazard ratio of 1.70 (95% CI 1.44-2.00). A significant relationship was not found between diabetes only and ADRD risk. Compared with women without depression, the adjusted risk of ADRD was 50% higher (HR = 1.50, 95% CI 1.30-1.73) for women with depression, while 115% higher (HR = 2.15, 95% CI 1.76-2.61) for men with depression.

Conclusions: Depression is associated with a substantially higher risk of ADRD among adult AI/AN peoples. This association varies by sex and age, with the strongest association observed among relatively young men. Helpful future efforts include ensuring clinical and behavioral services for AI/AN peoples provide regular mental health screening and any needed treatment.