Comorbid Depression and Diabetes as a Risk for Mild Cognitive Impairment and Alzheimer’s Disease in Elderly Mexican Americans

Article type: Research Article

Authors: Johnson, Leigh A.^{a; b; *} | Gamboa, Adriana^a | Vintimilla, Raul^a | Cheatwood, Austin J.^c | Grant, Alyann^d | Trivedi, Ashesh^e | Edwards, Melissa^a | Hall, James R.^{b; f} | O’Bryant, Sid E.^{a; b}

Affiliations: [a] Department of Internal Medicine, University of North Texas Health Science Center, Fort Worth, TX, USA | [b] Institute for Aging & Alzheimer’s Disease Research, University of North Texas Health Science Center, Fort Worth, TX, USA | [c] Loyola University, New Orleans, LA, USA | [d] Washington College, Chestertown, MD, USA | [e] Yale University, New Haven, CT, USA | [f] Department of Psychiatry, University of North Texas Health Science Center, Fort Worth, TX, USA

Correspondence: [*] Correspondence to: Leigh Johnson, PhD, Department of Internal Medicine, University of North Texas Health Sciences Center, 3500 Camp Bowie Blvd., Fort Worth, TX 76107, USA.Tel.: +1 817 735 2965; Fax: +1 817 735 0628; leigh.johnson@unthsc.edu

Abstract: Background: The links between diabetes, depression, and Alzheimer’s disease (AD) has been established, but they are still poorly understood. However, little research has examined the effect that comorbidity of depression and diabetes has on cognitive impairment in an ethnically diverse sample. Objective: The purpose of this study was to investigate the relationship between comorbid diabetes and depression on cognitive dysfunction; and examine the relationship in an ethnically diverse population. Methods and Results: Analyses of data from 2,436 participants (914 men and 1,522 women) of three separate cohorts: HABLE, FRONTIER, and TARCC. In the HABLE cohort, comorbidity (odds ratio [OR] = 3.008; 95% CI = 1.358–6.667), age (OR = 1.138; 95% CI = 1.093–1.185), and education (OR = 0.915; 95% CI = 0.852–0.982) increased the risk of mild cognitive impairment (MCI) diagnosis among elderly Mexican American. In the TARCC cohort, results showed an increase risk of MCI in both non-Hispanic whites (OR = 18.795; 95% CI = 2.229–158.485) and Mexican Americans (OR = 8.417; 95% CI = 2.967–23.878). Finally, results in the FRONTIER cohort showed that in elderly Mexican Americans, comorbidity (OR = 2.754; 95% CI = 1.084–6.995) and age (OR = 1.069; 95% CI = 1.023–1.118) significantly increased risk of MCI. In non-Hispanic whites, comorbidity did not significantly increase risk of MCI. Conclusions: Among elderly Mexican Americans, comorbid depression and diabetes significantly increased risk for MCI and AD across cohorts. Effects of comorbid diabetes and depression on MCI were inconclusive. Our results support the link between comorbid diabetes and depression and risk for cognitive decline among Mexican Americans. This finding is of critical importance as the Hispanic population is at higher risk of developing AD.

Keywords: Alzheimer’s disease, cognitive decline, comorbidity, depression, diabetes, elderly, Mexican American, mild cognitive impairment

DOI: 10.3233/JAD-142907

Journal: Journal of Alzheimer's Disease, vol. 47, no. 1, pp. 129-136, 2015