|
|
Insulin resistance
is a risk factor for progression to type 1 diabetes
S. Fourlanos,
P. Narendran, L.C. Harrison, in collaboration with P.G. Colman, Department
of Diabetes & Endocrinology, Royal Melbourne Hospital; G.B. Byrnes,
Centre for Genetic Epidemiology, The University of Melbourne
Diabetes is a condition in which a high level of sugar (glucose) in the bloodstream causes symptoms and damage to different tissues of the body. Diabetes occurs because glucose isn’t taken up properly by the tissues or is overproduced, leading to high levels of glucose in the blood. Insulin, the hormone produced by the beta cells in the pancreas, helps glucose to be taken up by the tissues and dampens down the production of glucose by the liver. The level of glucose in the blood therefore depends both on the amount of insulin secreted by the beta cells and the responsiveness of the tissues to insulin. There are two clinical stereotypes of diabetes. In type 1 diabetes, the immune system destroys the beta cells leading to inadequate insulin secretion. In type 2 diabetes, the tissues are unresponsive to insulin (‘insulin resistance’). Becoming overweight contributes to insulin resistance. We wondered if, in addition to inadequate insulin secretion, insulin resistance might also contribute to the development of type1 diabetes.
We followed 104 people who were not diabetic but had antibodies to components (antigens) of their beta, cells indicating that they were at increased risk for type1 diabetes. Insulin secretion and insulin resistance were measured annually over a median of 4 years.
|
The people who developed diabetes had greater insulin resistance relative to insulin secretion (Figure 1). The ratio of insulin resistance to insulin secretion was highly predictive of progression to diabetes.
Thus, at-risk relatives who progress most rapidly to diabetes can be identified years before diagnosis by greater insulin resistance for their level of insulin secretion. This is important not only for prediction but for prevention. Insulin resistance can be improved by diet, physical activity and insulin-sensitizing drugs, and such approaches might delay the development of type 1 diabetes.
Figure
1:
Baseline insulin resistance versus insulin secretion in progressors (filled circles) and non-progressors (open circles)
|
 |
Return
to Pathogenesis & Prevention
|
