Abstract 16724: Evidence of Associations Between Genetic Ancestry and Measures of Subclinical Atherosclerosis in African Americans: The Jackson Heart Study
Background: Substantial disparities in subclinical atherosclerosis between African Americans and European Americans are well documented. However, it is unclear whether genetic or non-genetic risk factors or a combination contribute to these disparities. This study examines the associations between percent of European ancestry (PEA) and various subclinical atherosclerosis measures among African Americans of the Jackson Heart Study (JHS).
Methods: We examined the associations of PEA with peripheral arterial disease (PAD, Ankle-brachial index <0.99) and common and internal carotid intima media thickness (cCIMT and iCIMT, respectively) among 2453 JHS participants measured at baseline and with coronary artery calcification (CAC >0) and aortic calcification (AAC >0) among 1139 JHS participants measured in visit 2. PEA was estimated based on 1747 ancestry informative markers (AIMs) from the Illumina custom ITMAT-Broad-CARe (IBC) array using HAPMIX software. Multivariable regression models with restricted cubic splines were used to assess potential nonlinear associations.
Results: There was an inverse significant linear association of PEA with PAD (p=0.0066). The prevalence of PAD decreased with one standard deviation increases in PEA [prevalence ratio (PR) = 0.89 (95% CI: 0.81, 0.97)], adjusting for age and gender. PEA was also associated with CAC (p =0.0192) and cCIMT (p = 0.0340) but in non-linear fashion. Participants with low PEA (≤7%) had lower CAC prevalence [PR = 0.50 (95% CI: 0.31, 0.80)] and those with high PEA (≥ 30%) had lower cCIMT [mean difference = -0.035 (95% CI:-0.06, -0.01)] compared to those with the median PEA. Adjusting for cardiovascular disease (CVD) risk factors, socioeconomic status and psychosocial factors attenuated the associations of PEA with PAD [PR = 0.91(95% CI: 0.83, 1.01)], but the association between lower PEA and CAC remained significant [PR = 0.55 (95% CI: 0.32, 0.96)]. A similar pattern of associations was found between PEA and AAC, but PEA was not significantly associated with iCIMT.
Conclusion: Our findings support the hypothesis that genetic factors in combination with CVD risk factors may contribute to differences in subclinical atherosclerosis between African and European ancestry.
- Carotid intima-media thickness (CIMT)
- Peripheral artery disease (PAD)
- Coronary artery calcification (CAC)
Author Disclosures: S.Y. Gebreab: None. S.K. Davis: None. P. Riestra: None. K. Rumana: None. R. Xu: None. F. Tekola-Ayele: None. S. Musani: None. J. Wilson: None. C. Adolfo: None. C.N. Rotimi: None.
- © 2014 by American Heart Association, Inc.