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.