By Anne Harding

NEW YORK (Reuters Health) - Both body mass index (BMI) and waist size influence a person's risk of being hospitalized with heart failure or dying of the condition, new research shows.

"This study reinforces the importance of maintaining a healthy body weight through diet and exercise," Dr. Emily B. Levitan of Beth Israel Deaconess Medical Center in Boston, a researcher on the study, told Reuters Health.

In heart failure, the organ becomes too weak to pump blood efficiently through a person's body, leading to fatigue, swelling of the legs, and difficulty breathing. Heart failure is the top cause of hospitalization among Americans 65 and older, Levitan and her colleagues note in the American Heart Association's journal Circulation.

To investigate further, Levitan's team looked at 36,873 women aged 48 to 83 and 43,487 men 45 to 79 years old who were participating in long-term studies of the general Swedish population. During six years of follow up, 382 of the women and 718 of the men were hospitalized for heart failure or died from the disease.

For both men and women, Levitan and her team found, the risk of being hospitalized with or dying from heart failure rose with BMI and waist circumference.

For every additional BMI point, the risk of heart failure hospitalization or death increased by 3% in women and 7% in men, while a 10-centimeter increase in waist size boosted risk by 19% in women and 30% in men.

"Obesity has effect on blood pressure and lipids and all of the other things that we know increase the risk of heart disease, but it also will just increase the workload on the heart," she added. "The bigger someone's body, the harder the heart has to work to pump the blood around."

The strength of the association tended to decline among older people. Because people tend to get frailer with age, the researcher noted in an interview, it's possible that body weight and fat become a less important determinant of risk as people get older.

SOURCE: Circulation, April 7, 2009.

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