August 13, 2012

Study: Obese Diabetics May Live Longer

redOrbit Staff & Wire Reports - Your Universe Online

While people with high body mass index (BMI) could be more susceptible to developing Type 2 diabetes, they could also live longer than those who contract the disease and are thinner, claims a new study recently published in the Journal of the American Medical Association (JAMA).

According to reporter Alice Park, the phenomenon is known as the "obesity paradox," and Northwestern University Associate Professor of Preventive Medicine Mercedes Carnethon, author of the JAMA study, discovered that the overall death rate of overweight or obese diabetics was nearly half that of their thinner counterparts (1.5% per year vs. 2.8% per year).

Similar findings have previously been reported in other ailments, including cardiovascular failure and chronic kidney disease, she added. However, it should be noted, Carnethon said, that this "obesity paradox" does not necessarily mean that diabetics should attempt to pack on the pounds as a defense mechanism against the disease. Instead, she said that those who are thinner may have developed diabetes due to reasons unrelated to their body weight, and that their health may be worse for unrelated reasons,

"For the new study“¦ Carnethon and her team reviewed data on five previous studies that were tracking people for heart disease risk factors," Park said. "The studies, which were conducted between 1990 and 2011, included 2,625 people who were recently diagnosed with diabetes, about 12% of whom were at normal weight."

"The lean patients looked metabolically similar to those who were obese, with the exception of their weight, the researchers found. But they were twice as likely to die at any point than their heavier counterparts," she added. "Even after adjusting for other risk factors known to contribute to diabetes, such as high blood pressure, high cholesterol levels and smoking, the higher mortality rates remained."

Carnethon's team also excluded those who died within 24 months of being diagnosed with diabetes, in order to eliminate other illnesses as a possible cause of death, yet the findings were essentially unchanged.

The researchers say that more research is needed to determine exactly what causes the discrepancy between normal weight and obese diabetics, though the lead author believes that genetic variations related to insulin secretion, leading to insulin resistance, could play a role.

"It's also possible that body fat may still play a role," Park said. "The studies measured the participants' body mass index (BMI), a ratio of their height and weight, but it wasn't able to take into account their body fat composition, or how much of their overall body weight was made up of fat versus muscle“¦ Many seemingly thin people carry more fat than muscle, making them trim on the outside, but fat on the inside."

"Even with a healthy BMI, for example, such people may harbor a lot of visceral fat, deep in their abdomen, a type of fat that is particularly dangerous to health, since it secretes hormones and substances that can hamper insulin's ability to break down sugar," she added. "Because many of the thin diabetes patients included in the new study were elderly, they likely had less muscle mass and more fat."

More than anything, though, Carnethon believes that their findings should alert people that diabetes is not limited to patients who have excess body weight, and that doctors should do more to detect warning signs among leaner patients, especially those who are advanced in years.