The effect of global ancestry and diabetes on the 3MS score in older Puerto Ricans

Abstract

AbstractBackgroundThere is limited study of the effect of genetically determined ancestral background and diabetic risk on cognitive status in admixed populations. Puerto Ricans are an admixed population with European (EU), African (AF), and Amerindian (AI) backgrounds. We analyzed the impact of ancestry and diabetes on cognitive status in older Puerto Ricans.MethodThe dataset consisted of Puerto Ricans > 60 years of age enrolled in the Puerto Rican Alzheimer Diseases Initiative (PRADI). At study entry, all participants were administered the 3MS to screen for cognitive problems. Medical history, including the presence of hypertension, diabetes, and cholesterolemia was also collected at that time. Model building analyses indicated that diabetes was the sole vascular predictor. Admixture proportions were estimated using the ADMIXTURE software. Using a Generalized Estimating Equations (GEE) approach, we modelled the contribution of sex, age at 3MS testing, global ancestry proportion, and diabetes to the participants 3MS score.ResultThe dataset consisted of 689 Puerto Ricans (70% female) with a mean age at 3MS of 74.9 years (SD=8 years). Mean global ancestry proportions were highest for EU (71%) followed by AF (18%) and AI (11%). As expected, we found significant associations between age, sex, and an age‐sex interaction and the 3MS score. However, we also found significant interactions between ancestry proportions and diabetes as predictors of 3MS score. Specifically, when compared to the effects of combined EU and AI ancestry on the 3MS score, the effect of diabetes on 3MS score is larger in individuals with higher proportions of AF ancestry (p < 0.01).ConclusionCognitive decline can be secondary to many different deleterious factors. Along with Alzheimer disease, small vessel vascular disease is a major contributor to the development of dementia. Indeed, diabetes affects small blood vessels, and these data support the importance of controlling diabetes in the Puerto Rican population, particularly those with a strong AF ancestry. This highlights the importance of looking for a history of diabetes when evaluating cognition in dementia‐related disorders in Hispanic populations with AF admixture.