(HealthDay)—Older obese people with type 2 diabetes appear to have a lower death rate than younger people who have diabetes and weigh less, a new study finds.
This so-called "obesity paradox" might mean obesity is actually protective, or type 2 diabetes in older people is somehow different than it is in younger people, the researchers speculate.
Dr. Joel Zonszein, director of the Clinical Diabetes Center at Montefiore Medical Center in New York City, who did not take part in the study, said that "my feeling is that fat is not protective, but the ones who are dying have more bad fat and more aggressive diabetes."
It's not just a matter of weight, but where the weight is and how aggressive the diabetes is that makes the difference, he said.
"What we are seeing nowadays is that young people who develop type 2 diabetes have lots of bad fat," he said. Specifically, that's fat around the middle and around vital organs such as the liver and heart, Zonszein said.
"They come to see me very young, very sick—their livers are full of fat, their hearts are full of fat. And their diabetes is a much more aggressive disease than what we see in elderly people," he said. "It's also much more difficult to treat."
The findings of the new study were due to be presented Wednesday at the annual meeting of the European Association for the Study of Diabetes in Barcelona, Spain.
For the study, British researchers led by Dr. Pierluigi Costanzo, an academic clinical fellow in cardiology at the Universities of Hull and York, collected data on more than 12,000 patients with diabetes. Of these about 1,700 had type 1 diabetes, while the rest had type 2 disease.
Over an average of 10 years of follow-up, 9 percent of the patients had signs of acute coronary syndrome, 7 percent suffered a stroke, 6 percent were hospitalized for heart failure and 34 percent of patients died.
Acute coronary syndrome is an umbrella term for conditions where the blood supplied to the heart muscle is suddenly blocked, according to the American Heart Association. Heart attack and unstable angina (chest pain) are among these conditions.
The researchers found that episodes of acute coronary syndrome were lowest among people with a normal body weight, but became more common as weight increased and were greatest among those who were obese—49 percent higher than people with a normal weight.
In addition, among obese patients, the risk of heart failure was 53 percent higher, and for stroke 25 percent higher compared to normal-weight patients, the study found.
Death rates in those with type 2 diabetes, however, were lower among obese patients compared to normal-weight patients. But this survival benefit was seen only among the oldest patients while the youngest obese patients had a higher risk of dying, the researchers reported.
For overweight and obese diabetic patients aged 67 and older, the risk of dying was between 18 and 25 percent lower compared to diabetic patients with a normal weight, the study found.
Although the study found associations between being older and having a lower death risk among diabetes patients, it did not establish a cause-and-effect relationship.
"The notion of an obesity paradox, that some degrees of obesity in some people may confer a favorable rather than unfavorable influence on health outcomes and survival, has been much under scrutiny," said Dr. David Katz, director of the Yale University Prevention Research Center.
There are three crucial considerations to make sense of this, Katz said. "First, the current study is limited to diabetics. One of the most important reasons why obesity is harmful to health is because it causes type 2 diabetes. Once a study is limited to diabetics, identifying further, independent harms of obesity may be far-fetched," he said.
Second, doctors know that among elderly patients, losing weight is what people should worry about, Katz said.
"It does not surprise me that in older people, obesity does not appear as harmful as in younger people. Older people who are managing to keep weight on are likely eating better and are potentially less isolated and perhaps just more vital than those who are not," he said.
Finally, a recent study showed more deaths among people who were obese for a greater part of their lifetime, Katz said.
"We should recall that obese people in their 70s now did not grow up in a world of epidemic obesity in childhood. Being obese over decades is very different than just gaining weight later in life," he said.
Because the new study was presented at a medical meeting, the data and conclusions should be viewed as preliminary until published in a peer-reviewed journal.
Explore further: Low BMI is a risk factor for CVD in hypertensive patients with diabetes
To learn more about obesity, visit the U.S. National Library of Medicine.