Issue 177 Item 9 Type I Patients Associated with Family History of Type 2 Diabet

Excessive weight gain in patients with type I diabetes on intensive therapy may be associated with a family history of type 2 diabetes, according to a recent American study. Type I diabetes patients undergoing intensive therapy experience greater weight gain than those treated with conventional therapy. The Diabetes Control and Complications Trial (DCCT) demonstrated that the weight gain is often accompanied with changes and lipids and blood pressure similar to those found in the central obesity-insulin resistance syndrome.

As this syndrome is characteristically found in patients with type 2 diabetes, it has been suggested that a family history of type 2 diabetes may predispose patients with type I diabetes to greater weight gain than patients without this genetic background. However, the weight gain could also be related to hypoglycemia, which acutely increases hunger, or other unidentified factors.

To test these ideas, Jonathan Purnell, MD, of Oregon Health and Science University, Portland, and colleagues examined the association between family history of type 2 diabetes, frequency of severe hypoglycemia, pancreatic islet autoantibodies and weight gain in 1168 DCCT study participants with type I diabetes.

The DCCT was designed to study the effect of conventional versus intensive diabetes therapy on microvascular complications in patients with type I diabetes. The participants (baseline age; 13 to 39 years) were randomized to receive conventional or intensive therapy and were followed for 3.5 to 9.0 years. Intensive therapy subjects received adjustments on insulin dosage to achieve the pre- and postprandial intensive therapy glycemic goals of 70-120 mg/dL.

According to Dr. Purnell, intensive therapy patients with a family history of type 2 diabetes experience significantly greater weight gain (BMI change; 3.8 ± 2.8 kg/m2) than those without a family history (2.9 ± 3.2 kg/m2; P=0.004). These patients also had higher triglyceride levels and VLDL and IDL cholesterol. For patients receiving conventional therapy, the amount of weight gained was the same regardless of family history.

"These findings support the hypothesis that intensive therapy permits expression of several components of the central obesity syndrome phenotype in a subset of individuals with a family history of type 2 diabetes," the researchers suggest. Based on this observation, they recommend that type I diabetes patients on intensive treatment and with a family history of type 2 diabetes should be closely monitored for adverse changes in risk factors for macrovascular complications.

No association was detected between islet cell autoimmunity or hypoglycemia and weight gain in this study. However, the researchers note that they hypoglycemia aspect of the analysis was limited by a lack of information on mild to moderate episodes. "It is still possible that less severe hypoglycemia contributed significantly to excess weight gain with intensive therapy." Diabetes 2003 Oct;52:10:2623-2629

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