Weight gain no big deal in type 1 diabetes: study

By Will Dunham

WASHINGTON (Reuters) - Becoming overweight or obese may not be so bad for people who are battling type 1 diabetes, the less common form of the disease, researchers said on Friday.

People who put on weight over time were less likely to die than others studied, and those classified as underweight were at the greatest risk for death, according to the study.

Even people who were technically obese were less likely to die if they had type 1 diabetes, the team at the University of Pittsburgh found.

"Those who gained the most weight over time seemed to have lower mortality than those who gained less weight or lost weight," Dr. Trevor Orchard, one of the researchers, said in a telephone interview.

People with type 1 diabetes are often underweight, and those who were able to put on weight may also have been controlling their disease better, Orchard said.

The study, which tracked 655 patients with type 1 diabetes for 20 years, was presented at a meeting of the American Diabetes Association in San Francisco.

Diabetes, marked by high levels of sugar in the blood, is really two diseases. Weight gain can be very bad for people with type 2 diabetes, the kind that is being driven by rising rates of obesity and sedentary lifestyles.

But it seems to be a different story for type 1 diabetes, previously called juvenile diabetes, the researchers said. This type of diabetes is an autoimmune disease, in which the body mistakenly destroys cells in the pancreas that make insulin.

Insulin converts sugar, or glucose, into energy. In both types of diabetes the excess sugar in the blood damages organs including the eyes, kidneys and heart.

Orchard said people who gained weight appeared to be those who did the best job in controlling their blood sugar.

When the researchers statistically accounted for waist circumference -- a risk factor for death -- overweight or obese patients were less likely to die compared to patients with a normal weight.

"The concerns that we have with growing rates of obesity need to be viewed a little differently in type 1 diabetes than in the general population," Orchard said. "It's not a recipe to go out and eat and put on weight. But it is a reassurance."

(Editing by Maggie Fox and Xavier Briand)