SAN FRANCISCO, June 6 - Gaining body fat may be a good thing, at least for people with type 1 diabetes, say researchers at the University of Pittsburgh Graduate School of Public Health. Their study, being presented at the 68th Scientific Sessions of the American Diabetes Association in San Francisco, followed 655 patients with type 1 diabetes for 20 years and found that patients who gained weight over time were less likely to die.
The findings are based on participants in the Pittsburgh Epidemiology of Diabetes Complications Study, a long-term prospective study of childhood onset type 1 diabetes, which began in 1986. Participants in the study, an average age of 28 when entering the study and 44 at its completion, were diagnosed with type 1 diabetes between 1950 and 1980. Researchers measured patients' body mass index (BMI) and waist circumference and assessed BMI every two years during the study period. Over the course of the study, 147 deaths occurred.
Results showed that patients whose BMI increased the most during the study (2 to 11 points or about 10 to 55 pounds) were one-third less likely to die than those who had smaller increases in BMI, indicating that weight gain may protect people with type 1 diabetes from premature death.
"Although weight gain in adulthood is typically associated with increased mortality, this may not be the case for those with type 1 diabetes," said Trevor Orchard, M.D., professor of epidemiology at the University of Pittsburgh Graduate School of Public Health. "Gaining a reasonable amount of weight may be a sign patients are getting enough insulin and appropriately controlling their disease, which may partly explain why those who gained weight over time had lower mortality rates," said Dr. Orchard, who also is professor of medicine and pediatrics at the University of Pittsburgh School of Medicine.
Dr. Orchard and colleagues also looked at BMI ranges and mortality and found no difference in mortality between those with a BMI in the overweight range (BMI 25 to 30) and the normal range (BMI 20 to 25). Conversely, they found that having a BMI in the underweight (BMI less than 20) or obese range (BMI 30 and greater) was a strong predictor of mortality. When researchers controlled for waist circumference, a commonly cited reason for general fat mortality, patients with a BMI in the underweight range were at greatest risk for death, while those with a BMI in the overweight or obese ranges had a decreased risk of mortality compared to patients with a normal BMI.
"These results are not a firm recommendation to people with type 1 diabetes to put on weight, but it does raise the possibility that weight recommendations in type 1 diabetes may be somewhat different than those for the general population, and emphasizes the complex relationship between body fat and mortality in diabetes," added Baqiyyah Conway, M.P.H., lead author of the abstract.
Previously known as juvenile diabetes, type 1 diabetes is usually diagnosed in children and young adults. In type 1 diabetes, the pancreas produces little or no insulin to properly control blood sugar levels. It is typically treated with insulin replacement therapy. As many as 3 million Americans have type 1 diabetes.
In addition to Dr. Orchard and Ms. Conway, other authors include Rachel G. Miller, M.S.; Tina Costacou, Ph.D.; Linda Fried, M.D.; Robert Evans, Ph.D.; and Sheryl Kelsey, Ph.D., all of the University of Pittsburgh. The study was funded by the National Institute of Diabetes and Digestive and Kidney Diseases at the National Institutes of Health.