Circulation: Waist size predicts heart failure risk, even with normal BMI
Larger waist circumference is associated with increased risk of heart failure in middle-aged and older populations of men and women, according to a study published online in the April 7 Rapid Access Report of Circulation: Heart Failure.

The study, led by investigators at Beth Israel Deaconess Medical Center (BIDMC) in Boston, showed that increased waist size was a predictor of heart failure even when measurements of body mass index (BMI) fell within the normal range.

"Currently, 66 percent of adults in the United States are overweight or obese," explained the study's first author Emily Levitan, ScD, a research fellow in the Cardiovascular Epidemiology Research Unit at BIDMC. "Knowing that the prevalence of heart failure increased between 1989 and 1999, we wanted to better understand if and how this increase in obesity was contributing to these rising figures."

The researchers examined two Swedish population-based studies, the Swedish Mammography Cohort (made up of 36,873 women aged 48 to 83) and the Cohort of Swedish Men (43,487 men aged 45 to 79) who responded to questionnaires asking for information about their height, weight and waist circumference. Over a seven-year period between January 1998 and December 2004, the researchers reported 382 first-time heart-failure events among the women (including 357 hospital admissions and 25 deaths) and 718 first-time heart-failure events among men (accounting for 679 hospital admissions and 39 deaths.)

The analysis found that based on the answers provided by the study participants, 34 percent of the women were overweight and 11 percent were obese, while 46 percent of the men were overweight and 10 percent were obese.

"By any measure--BMI, waist circumference, waist-to-hip ratio or waist-to-height ratio--our findings showed that excess body weight was associated with higher rates of heart failure," Levitan said.

Further breakdown of the numbers showed that among the women with a BMI of 25 (within the normal range), a 10-centimeter higher waist measurement was associated with a 15 percent higher heart failure rate; women with a BMI of 30 had an 18 percent increased heart failure rate, the authors wrote. In men with a BMI of 25, a 10-centimeter higher waist circumference was associated with a 16 percent higher heart failure rate; the rate increased to 18 percent when men's BMI increased to 30.

Furthermore, Levitan noted, among the men, each one-unit increase in BMI was associated with a four percent higher heart failure rate, no matter what the man's waist size. In women, she added, BMI was only associated with increased heart failure rates among the subjects with the largest waists. Finally, the authors found that the association between BMI and heart-failure events declined with age, suggesting that the younger the person, the greater the impact of weight to heart health.

"This study reinforces the importance of maintaining a healthy weight," Levitan said. "Previous research has looked at various types of heart disease and related health issues, and no matter the particulars of the study, they've all been pretty consistent in determining that excess body weight increases a person's risk of heart disease."