COMORBID DIABETES AND DEPRESSION AND INCREASED RISK FOR COGNITIVE IMPAIRMENT IN MEXICAN AMERICANS

Background: By 2050, the percent of Hispanics in America age 65 and above will nearly triple compared to other ethnic groups. During this timeframe, the numbers of Alzheimer’s disease (AD) and Mild Cognitive Impairment (MCI, a prodromal stage to AD) cases among Hispanic elders is expected to grow exponentially. Given that 65% of the U.S. Hispanic population is Mexican American (MA), this ethnic group represent the fastest growing segment of the aging population, which will be disproportionately impacted by MCI and /AD in the near future. Recent work from our group suggest that depression is a significant risk factor for MCI and AD among Mexican Americans while many other “established” risk factors among non-Hispanic whites (i.e. education, gender, hypertension, diabetes, ApoEε4 genotype) are not. Another important risk factor among this population is diabetes (DM). Depression and DM have been shown to be pathologically linked several times in the past, however little research has examined the affect that comorbidity of depression and DM has on cognitive impairment in an ethnically diverse sample Purpose (a): To determine whether there is a connection between depression, diabetes and Alzheimer's disease in the Mexican American population. Methods (b): Methods: This study used data from three separate cohorts: HABLE, TARCC, and Project FRONTIER. In HABLE data was collected from 208 MA (AGE= 62years; EDU=7years); TARCC had 2080 Non- Hispanic white (AGE=75; EDU=15years) and 543 MA (AGE=70; EDU=11); Project FRONTIER had 330 non-Hispanic white (AGE=65; EDU=13) and 233 MA (AGE=55; EDU=7years). Logistic regression analyses were conducted to examine comorbid diagnosis of depression and diabetes on Alzheimer’s disease diagnosis or a diagnosis of Mild Cognitive Impairment. Covariates entered into the model were age, education, and gender. Results (c): Results: Comorbid diagnosis of diabetes and depression was significantly related to diagnosis of Mild Cognitive Impairment in Mexican Americans across all three cohorts: TARCC (odds ratio [OR]= 8.6, 95% CI=1.5 to 2.7); HABLE (odds ratio [OR]= 2.4, 95% CI= 1.3-3.2), and FRONTIER (odds ratio [OR]= 2.6, 95% CI=1.2 to 6.4). TARCC was the only cohort with a large enough sample of AD patients to run the analyses split by ethnicity. In TARCC, comorbidity was related to AD diagnosis in MA (odds ratio [OR]= 10.4, 95%=1.2-2.7), and narrowly related in Non-Hispanic Whites (odds ratio [OR]= 8.3, 95%=.14 to 1.4). Conclusions (d): Discussion: Comorbid diagnosis of depression and diabetes increases risk for diagnosis of cognitive impairment, and Mexican Americans were found to be at greater risk than non- Hispanic whites for Mild Cognitive Impairment. These findings were validated across multiple cohorts, and could have significant clinical implications.