Author Interviews, Heart Disease, JAMA, Race/Ethnic Diversity, UCSF / 22.06.2016
Paradox Between Race and Risk of Atrial Fibrillation Remains Unexplained
MedicalResearch.com Interview with:
Gregory M Marcus, MD, MAS, FACC, FAHA, FHRS
Director of Clinical Research
Division of Cardiology
Endowed Professor of Atrial Fibrillation Research
University of California, San Francisco
MedicalResearch.com: What is the background for this study? What are the main findings?
Response: We and others have previously demonstrated that, despite the observation that African Americans on average exhibit more risk factors for atrial fibrillation, they demonstrate a substantially reduced risk of the disease. This suggests that, if we could understand the mechanism underlying this apparent paradox, we might learn something fundamentally important to atrial fibrillation that would be relevant to treating or preventing the disease regardless of race.
Building on our previous work demonstrating that, among African Americans, more European ancestry (determined by genomic testing) was a statistically significant predictor of atrial fibrillation, we sought to identify the gene(s) that might underlie this observation. The analysis took two forms.
First, we examined if any differences among several well-established single nucleotide polymorphisms (SNP) associated with atrial fibrillation might mediate the race-atrial fibrillation relationship. One such SNP statistically mediated (rs10824026) up to about a third of the race-atrial fibrillation relationship. It’s important to mention that a causal relationship cannot be proven here.
Perhaps more remarkable was the observation that the disease-associated alleles of the SNPs most closely associated with atrial fibrillation in multiple studies were actually significantly more common among African Americans, pointing to the complex nature of both the race-atrial fibrillation relationship as well as the genetics of atrial fibrillation.
Finally, leveraging the ancestral relationships, we performed a genome wide admixture mapping study with the hope of reducing the penalty for multiple hypothesis testing incurred in conventional genome wide association studies. While several loci revealed associations with atrial fibrillation with small p values, none met our criteria for genome wide significance.
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