MONDAY, May 18, 2009 (HealthDay News) -- The excess fat that leads people to develop heart disease can help them fight against the condition's worst effects, a review of cardiac studies shows.
It's the "obesity paradox," said Dr. Carl J. Lavie, medical director of cardiac rehabilitation and prevention at the Ochsner Medical Center in New Orleans, and lead author of the review, which appears in the May 26 issue of the Journal of the American College of Cardiology.
"Obesity is a major problem that contributes significantly to increased risk of heart disease and mortality," Lavie said. "But once you get high blood pressure, blocked heart arteries and peripheral arterial disease, the obese patients do better than the lean patients. The obesity paradox has been written about for years, but still many doctors are not aware of it."
His report looked at data from 40 studies of 250,000 people with heart disease, Lavie said. He wanted not only to remind doctors of the paradox, but also to warn them and the general public that it offers no excuse for being fat, he said.
Some physicians have misinterpreted the evidence to mean that obese people with heart disease should not be encouraged to lose weight, Lavie said.
"Obesity causes many of the known risk factors, such as diabetes and high blood pressure, and it is an independent risk factor on its own," he said. "The patients with heart disease who do the best are the obese who lose weight."
There are several possible explanations for the paradox, Lavie said.
One is that obese people visit physicians earlier than others because they develop symptoms, such as fatigue and breathing problems. Heart disease is more treatable if identified early.
It's also conceivable that something in the excess fat cells of obese people might have a protective value, Lavie said.
"People who have more weight can have more reserve ability to fight disease," he said. "Take breast cancer. Obesity may help cause breast cancer, but a 200-pound woman might be able to fight breast cancer better than a 100-pound woman because she has more metabolic reserve."
It's well-known that obesity leads to heart disease, and that's a big part of the paradox, Lavie said. "These people wouldn't have developed heart disease in the first place if they weren't obese," he said. "A thin person is getting it [heart disease] for a different reason, so he or she is getting a worse form of the disease, getting the disease despite being thin."
Lavie worries that people might get the wrong idea from his report. "Obesity in the United States is a major problem," he said. "It is increasing in skyrocketing proportions. It is a major contributor to the epidemic of heart disease. We don't want people to be hearing that obesity is good."
Obesity in the United States and the medical problems associated with it are described by the U.S. Centers for Disease Control and Prevention.