Pericardial fat volume and incident atrial fibrillation in the Multi-Ethnic Study of Atherosclerosis and Jackson Heart Study

OBJECTIVE To determine whether greater pericardial fat volume would be associated with increased risk of incident atrial fibrillation (AF). METHODS In the Multi-Ethnic Study of Atherosclerosis and Jackson Heart Study, pericardial fat volume was quantified by computed tomography. Incident AF was identified from discharge diagnosis codes, study electrocardiograms, and Medicare claims. RESULTS Among 7,991 participants, 40% were African American, 32% white, 18% Hispanic, and 10% Chinese American; mean age was 62 years; 55% were women. During an average of 10.0 years of follow-up in the Multi-Ethnic Study of Atherosclerosis and 4.5 years in the Jackson Heart Study, 756 incident AF cases were identified. After adjustment for age, sex, study, race/ethnicity, height, glucose status, systolic blood pressure, treated hypertension, and BMI, greater pericardial fat volume was associated with higher AF risk in Hispanics (hazard ratio 1.24 per SD, 95% confidence interval 1.05-1.46) but not overall (hazard ratio 1.06, 95% confidence interval 0.97-1.15). In mediation analysis, pericardial fat volume partially mediated the association of BMI with incident AF in Hispanics. CONCLUSIONS After adjustment for BMI, greater pericardial fat volume was associated with incident AF in Hispanics but not overall. Additional research is needed on the mechanisms by which pericardial fat volume is related to increased AF risk and possible differences by race/ethnicity.