Abstract 9192: Genetic Ancestry is Associated with Left Ventricular Mass Among Hispanic Subgroups: The Multi-Ethnic Study of Atherosclerosis

Abstract

Hispanics represent a recently admixed population of European, Native American and African parental populations. Hispanics have higher left ventricular mass (LVM) than non-Hispanic whites, and this relationship persists across Hispanic subgroups. However, the contribution of genetic ancestry to LVM across Hispanic subgroups is not known. Methods - We examined 705 Hispanic participants. Percent genetic ancestry for each Hispanic subgroup was estimated with 199 ancestry informative markers using the population genetics analysis program STRUCTURE. LVM from cardiac MRI was evaluated as a continuous measurement, with allometric methods that model height and weight in a regression analysis. Associations between ancestry and LVM were evaluated through linear regression models consisting of age, gender, both highest education level and annual income, and diabetes treatment, hypertension, physical activity, and body mass index. Results - Mexicans along with Central Americans had the highest Native American (74%) ancestry. Caribbean-Hispanics (Dominicans, Puerto Ricans and Cubans) had the highest African (35%) ancestry. Among Caribbean Hispanics (in age and gender adjusted analysis), each SD increase in African ancestry was associated with a 3.4 unit increase in LVM (p < 0.03). Among Mexican-origin Hispanics, each SD increase in Native American ancestry was associated with a 2.4 unit increase in LVM (p = 0.06). These relationships were not attributable to differences in socioeconomic status or clinical factors. In Caribbean-Hispanics, African ancestry explains 9.6% of the total variance in LVM in fully adjusted models. In Mexican-origin Hispanics, Native American ancestry explains 13.0% of the total variance in fully adjusted models. There was insufficient evidence in these data to detect an association between genetic ancestry and LVM in Central/South Americans. Conclusion - African and Native American ancestry was significantly associated with increasing LVM among Caribbean-Hispanics and Mexican-origin Hispanics, respectively. The findings persisted after accounting for LVM risk factors. These results highlight the heterogeneity of the Hispanic population and the relative importance of genetic ancestry in assessing LVM risk.