Severe obesity by itself leaves a person at significantly higher risk for heart failure, whether or not that person also suffers from high blood pressure, high cholesterol, or diabetes, a study found.
The same is not true for other major types of heart disease. The study suggests that people with morbid obesity alone weren’t any more likely than those of normal weight to have a stroke or coronary heart disease.
The mortality rate for people with heart failure is 50 percent five years after diagnosis.
The team at Johns Hopkins University that conducted the study, published online in the Journal of the American Heart Association, found that morbidly obese individuals were more than two times more likely to have heart failure than comparable people with a healthy body mass index.
“Even if my patients have normal blood sugar, cholesterol, and blood pressure levels, I believe I still have to worry that they may develop heart failure if they are severely obese,” says Chiadi Ndumele, assistant professor of medicine. “If our data are confirmed, we need to improve our strategies for heart failure prevention in this population.”
An estimated one in three Americans is obese and more than 5 percent are morbidly obese, with a body mass index greater than 35. The US Centers for Disease Control and Prevention says almost 6 million people in the United States live with heart failure, marked by enlarged or weakened heart muscle and diminished blood-pumping efficiency.
The condition causes shortness of breath, fatigue, weakness, trouble breathing when lying down, and swelling in the ankles and feet. The mortality rate for people with heart failure is 50 percent five years after diagnosis.
Ndumele and the other researchers caution that their study suggests a strong, independent link between severe obesity and heart failure but does not definitively determine cause and effect.
‘There is no magic pill’
Nevertheless, they say, their findings suggest that while treating hypertension, diabetes, and other conditions associated with obesity may be sufficient to prevent coronary heart disease and stroke, weight loss may be required to avert an increased risk of heart failure.
“Obesity in our study has emerged as one of the least explained and likely most challenging risk factors for heart failure, because there is no magic pill to treat it, no drugs that can easily address the problem like there are for high cholesterol and high blood pressure,” Ndumele says. “Even with diet and exercise, people struggle to lose weight and keep it off, and for the morbidly obese, the struggle is often insurmountable.”
It isn’t clear why obesity alone is linked to heart failure independent of risk factors and not to stroke or coronary heart disease, Ndumele says. He adds, however, that there is evidence suggesting that extra body weight exerts a higher metabolic demand on the heart and that fat cells in the abdomen may release molecules toxic to heart cells.
Obesity has long been known to increase the likelihood of high blood pressure, elevated blood cholesterol and diabetes. Treating and controlling these conditions have formed the bedrock strategies for reducing the risk of cardiovascular disease, Ndumele says.
Ndumele and his colleagues drew their conclusions from the medical records of 13,730 participants in the Atherosclerosis Risk in Communities Study. The patients had body mass indexes in healthy ranges or higher at the start of the study and no initial heart disease. All were followed for about 23 years.
The records included data for participants’ height, weight, and levels of blood sugar, cholesterol and triglycerides, along with smoking status, alcohol use, professions, and exercise levels.
The National Heart, Lung, and Blood Institute and the National Institute of Diabetes, Digestive, and Kidney Diseases funded the study.
Source: Johns Hopkins University