Inflammatory pathways may significantly mediate an increased risk of atrial fibrillation (AFib) in white patients, according to a study published Aug. 24 in JACC: Clinical Electrophysiology. Further, "the higher level of systemic inflammation and concomitant increased AFib risk in whites is not explained by racial differences in abdominal adiposity or the presence of other proinflammatory cardiovascular comorbidities."

As it has been shown that white patients have a substantially higher rate of AFib than black patients, even though white patients have a lower prevalence of AFib risk factors, a team of researchers, led by Thomas A. Dewland, MD, of the University of California, San Francisco, utilized the Health, Aging and Body Composition study to test the hypothesis that racial differences in inflammation explain the difference in risk of AFib between whites and blacks. The cohort for the study included 1,179 black and 1,589 white subjects, all aged 70-79 years. Black subjects were more likely to be female, less frequently consumed alcohol, had a greater mean body mass index (BMI), and had a higher prevalence of medical comorbidities including hypertension and diabetes.

During the median 10.9 years of follow-up, 721 patients were diagnosed with incident AFib, with whites demonstrating a significantly increased risk. After controlling for known AFib risk factors, white subjects had a 55 percent increase in AFib risk. Additionally, the association between diabetes and AFib was of borderline statistical significance, BMI was not associated with increased AFib risk, and statin therapy did not appear to have a protective effect. White patients had significantly elevated concentrations of many inflammatory cytokines, many, but not all of which were associated with an increased risk of AFib. The researchers did not observe a significant association between adiposity measurements or BMI and AFib.

The researchers conclude that "our mediation findings indicate that inflammation is a more prominent and, as a result, more important driver of [AFib] risk among whites." They add that "from a clinical standpoint, these results suggest that interventions targeting inflammation specific to AFib pathogenesis may be especially important for AFib risk reduction and that the efficacy of such therapies may differ by race."

Keywords: Adiposity, African Americans, Alcohols, Atrial Fibrillation, Cytokines, Comorbidity, Diabetes Mellitus, Electrophysiology, Hypertension, Obesity, Risk Reduction Behavior, Risk Factors

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