Background: Obesity is a strong predictor of atrial fibrillation (AF). However, data on the time dependent effect of weight reduction on AF risk are limited. The purpose of the current analysis was to assess time-dependent relationship between body mass index (BMI) and new onset AF among middle aged apparently healthy men and women.
Methods: We investigated 17,883 men and women who were annually screened at the Institute for Medical Screening of the Chaim Sheba Medical Center. All subjects were free of AF at baseline and had their BMI documented at each visit. Subjects were divided at baseline into three groups: normal weight (BMI<25; N=7,526), overweight (BMI≥25 and <30; N=7,841) and obese (BMI≥30 Kg/m2; N=2,516). The primary endpoint was the first occurrence of AF during follow-up.
Results:Mean age of study patients was 49 ± 11 years and 74% were men. A total of 346 (1.9%) incident events occurred during follow-up. Kaplan Meier survival analysis showed that the cumulative probability of AF events at 6 years was highest among obese subjects, intermediate among overweight subjects and lowest among subjects with normal weight (Figure). Multivariate Cox regression analysis showed that overweight and obesity were associated increased risk of first AF event (HR 1.39 and 2.34; p=0.012 and <0.001, respectively). Multivariate cox regression model with BMI as time-dependent covariate, showed that subjects who reduced their BMI by at least 5% during follow up experienced a 34% reduced risk for new AF event compared with all other subjects (95% CI 0.46-0.95; p=0.024).
Conclusions: Overweight and obesity are independently associated with increased risk of first event of atrial fibrillation. Weight loss can significantly reduce AF disease burden.
