Abstract 3967: Changing Trends in Obesity and Its Impact on Incidence of Atrial Fibrillation in Olmsted County, Minnesota 1980–2000
Background: The recent Framingham data convincingly suggested an important risk relationship between body mass index (BMI) and atrial fibrillation (AF) development. Our own data suggested a significant age-adjusted increase in the incidence of AF in Olmsted County, Minnesota in 1980–2000.
Methods: In a community-based study in Olmsted County Minnesota, 4618 subjects were identified to have newly documented AF during the period 1980–2000 (age-adjusted incidence of AF, per 1000 person-years, were 3.04 in 1980 and 3.68 in 2000; rate of increase 12.6% over 2 decades; P= 0.014 for overall trend). We assessed the possible impact of obesity trend on AF incidence over time, using three pooled population-based samples of adults living in Olmsted County Minnesota in 1980–2003 (a bone density survey, a survey on left ventricular diastolic function, and control subjects from a case-control study of the incidence of diabetes). The impact of the increase in age-adjusted prevalence of obesity (BMI≥30 kg/m2) on age-adjusted AF incidence was estimated, using a relative hazard of 1.5 for the development of AF for BMI≥30 kg/m2 as per Framingham data.
Results: From the pooled analysis of three Olmsted County population-based datasets (n=4127; mean age 60±15 years, 45% men), the estimated adjusted proportion of the adults whose BMI equaled or exceeded 30 kg/m2 increased from 10% to 25% during the same period 1980–2000. With the relative hazard of 1.5 for AF development for BMI≥30 kg/m2, the 15% increase in the proportion of persons with obesity would suggest a 7.5% increase in AF incidence. Since our estimated rate of increase in AF incidence was 12.6%, the trend in obesity could therefore potentially account for approximately 60% (95% CI, 32–100) of our estimated increase in age-adjusted AF incidence.
Conclusions: Although the increasing trend of age-adjusted AF over the period 1980–2000 was likely multifactorial, obesity could account for a large part of such an increase. These observations underscore the potential impact of obesity and its treatment on the growing epidemic of AF.