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Obesity may be factor in accelerated type I diabetes in some patients

February 06, 2006

Obesity, long known as a cause of type II diabetes, may accelerate the onset of type 1 diabetes in some - but not all - groups of younger patients, according to research at Wake Forest University School of Medicine and six clinical sites nationally.

"The increasing prevalence of childhood obesity may substantially account for the younger age at onset of type 1 diabetes observed in various populations," said the research team, writing in the February issue of Diabetes Care.

But the connection to obesity was observed only in those patients in which the production of insulin by beta cells in the pancreas already had been severely compromised, said Ralph B. D'Agostino Jr., Ph.D., professor of public health sciences-biostatistics at the medical school, and a co-author of the paper.

D'Agostino also is deputy director of the study's National Coordinating Center, which is located at the School of Medicine. In the paper, the researchers said, "These patients have compromised pancreatic beta cell function and can no longer compensate for the additional metabolic demands associated with higher body mass index."

Body mass index (BMI) is computed from weight and height; a BMI over 30 indicates obesity. The body uses insulin in metabolizing carbohydrates and in regulating glucose (blood sugar) levels in the body, and diabetes results when there is insufficient insulin to meet the need.

"Whether the reduced beta cell function is solely due to an autoimmune-mediated attack or whether non-autoimmune factors also contribute is a distinction that we are unable to make in this study," the researchers said.

The researchers did determine that there was no statistical association between age of onset and BMI in those diabetes patients who still had relatively well-preserved beta cell function.

The researchers also found that low birth weight may also be a factor in accelerating the onset of type 1 diabetes, which is now considered an autoimmune disorder, in which the body's own defenses turn on it.

As birth weight decreased, the age at which type 1 diabetes appeared advanced. The study was part of the Search for Diabetes in Youth, and involved 449 participants who were under 20 at the time of the diabetes diagnosis.

The six clinical sites were the University of Colorado Health Sciences Center in Denver, the University of South Carolina in Columbia, Children's Hospital Medical Center in Cincinnati, Children's Hospital and Regional Medical Center in Seattle, the Sansum Medical Research Institute in Santa Barbara, Calif., and University of Hawaii.

Search for Diabetes in Youth is trying to determine the prevalence and incidence of childhood diabetes and document how much childhood diabetes is type 1, how much is type 2, and how much is due to other rare causes. The study is funded by the Centers for Disease Control and Prevention and the National Institute of Diabetes and Digestive and Kidney Diseases.

According to the American Diabetes Association, type 1 diabetes results from the body's failure to produce insulin, the hormone that "unlocks" the cells of the body, allowing glucose to enter and fuel them. Type 2 diabetes results from insulin resistance (a condition in which the body fails to properly use insulin), combined with relative insulin deficiency.

Wake Forest University Baptist Medical Center