Can Diabetes be Prevented?

In August of this year, U.S. researchers announced that they were ending a large Type 2 diabetes prevention trial a year early, simply because the findings were so definitive. (The results must still be published and submitted to the peer-review process.)

Researchers with the National Institute of Diabetes and Digestive and Kidney Diseases studied 3,234 men and women aged 25 to 85 who suffered from impaired glucose tolerance – a condition that often precedes diabetes. The trial included people who were obese and had a family history of diabetes. Some also belonged to an ethnic group known to be at higher risk for Type 2 diabetes.

The subjects were randomly divided into three groups: one group was given a diabetes medication called metformin, which decreases the amount of glucose produced by the liver; the second received an inactive placebo drug. (These two groups also received general health advice about exercise, weight loss and diet.) Those in the third group did not take any diabetes medication but attended a 24-week education program to help them follow a low-fat diet combined with moderate exercise, with the aim of reducing body weight by seven per cent.

After three years, here’s what the study found: on average, 11 per cent per year of high-risk people who took the placebo had developed Type 2 diabetes, compared with 7.8 per cent per year of those who took metformin and 4.8 per cent per year of those who had changed their eating and exercise habits. Put simply, even modest changes in diet and exercise reduced the risk for Type 2 diabetes by more than half.

“[The findings] demonstrate that lifestyle changes can benefit a broad range of high-risk patients,” says Dr. Lawrence Leiter, a professor of medicine and nutritional sciences who heads the division of endocrinology at St. Michael’s Hospital in Toronto. “It’s also the first study to show that taking a drug – in this case, metformin – also reduces diabetes risk.”