Unknown Cause, Unknown Cure: The Mechanisms of Insulin Resistance

Kimby N. Barton, MSc
Associate Editor,
Geriatrics & Aging

Last year, the diabetes surveillance system reported that approximately 2 million Canadians suffer from diabetes, although as many as 600 000 of these might be unaware that they have the condition. It is now estimated that, by the year 2010, approximately four million Canadians will have diabetes and, that by the year 2020, there will be approximately 250 million people affected by type 2 diabetes, worldwide.1

What factors contribute to the development of this terrible disease? A few diabetic subjects suffer from type 1 diabetes mellitus, which is caused by failure of the pancreatic b-cells, and leads to an absolute loss of insulin. Type 2 diabetes is far more common and is swiftly increasing in prevalence in industrialized societies. It is believed that the main factor contributing to the increase in the number of patients with type 2 diabetes is the aging of the baby boomer population, a population that is becoming more sedentary and, as a result, more obese. An interesting question then is how do obesity and a sedentary lifestyle lead to the development of type 2 diabetes?

Type 2 diabetes is almost invariably preceded by the development of insulin resistance. Insulin resistance is defined as a state of reduced responsiveness to normal circulating concentrations of insulin, and is now recognized as a characteristic trait of type 2 diabetes.