The prevalence of atrial fibrillation (AF) is expected to increase several-fold in the coming decades, according to background information in the article. Because the onset of AF is associated with considerable illness and a higher risk of death despite various therapies, the identification of potentially modifiable risk factors for AF is important. While obesity has been associated with other heart problems, it has been unclear whether it is a risk factor for AF.

Thomas J. Wang, M.D., of the Framingham Heart Study, Framingham, Mass., and colleagues examined long-term followup data from the Framingham Heart Study to determine if there was an association between body mass index (BMI, a person's weight in kilograms divided by height in meters squared) and the risk of developing AF. The study group included 5,282 participants (average age, 57 years; 2,898 women) without baseline AF. The researchers examined risk for three categories of BMI: normal, defined as less than 25.0; overweight, 25.0 to less than 30.0; and obese, greater than 30.0. A 5'4" woman would have a BMI of 30 if she weighed 174 lbs.; a 6'00" man would have a BMI of 30 if he weighed 221 lbs.

During an average follow-up of 13.7 years, 526 participants (234 women) developed AF. Age-adjusted incidence rates for AF increased across the 3 BMI categories in men and women. In multivariable models adjusted for cardiovascular risk factors and interim heart attack or heart failure, a 4 percent increase in AF risk per 1-unit increase in BMI was observed in men. Obese men had a 52 percent increased risk for AF; obese women, 46 percent increased risk, compared with individuals with normal BMI. The researchers found that the increased risk for AF may be mostly attributable to an as
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JAMA and Archives Journals
23-Nov-2004