Body Mass Index, Sex, and Incident Atrial Fibrillation in Diabetes

Abstract Objectives This study sought to characterize the relationship between obesity and the risk of atrial fibrillation (AF) in diabetes. Background Obesity is associated with increased risk of AF in the general population, but there is evidence that this relationship may differ in those with diabetes. Methods Cox proportional hazards models were used to examine the association between body mass index (BMI) and incident AF on study electrocardiogram in participants from the ACCORD (Action to Control Cardiovascular Risk in Diabetes) trial. Results Among 10,074 ACCORD participants (age 62.7 ± 6.6 years, 38.7% women, 62.2% white), 8.4% were normal weight, 29.0% were overweight, 53.1% were obese, and 9.5% were severely obese. Participants with obesity and severe obesity had increased risks of AF compared with normal weight (hazard ratio [HR]: 1.91; 95% confidence interval [CI]: 1.03 to 3.93; and HR: 3.69; 95% CI: 1.79 to 8.22, respectively). There was a 51% increased risk of AF per SD (5.4 U) BMI increase. However, there was a sex and BMI interaction—in men, obesity and severe obesity were associated with a substantially increased AF risk (HR: 3.19; 95% CI: 1.27 to 7.31; and HR: 4.79; 95% CI: 2.11 to 11.93, respectively), whereas there was no statistically significant association in women. Conclusions In those with diabetes, obesity and severe obesity are associated with increased risk of AF, but there is an interaction between sex and BMI, such that elevated BMI appears to confer a much greater risk of AF in men than in women. Further studies exploring the differential effects of BMI on AF risk in men and women are needed.