In an accompanying comment, Ronald B. Goldberg, MD, of the Diabetes Research Institute, University of Miami in Miami, Florida, says the latest results from Finland show that the initial intervention in the lifestyle group "had a sustained effect that appeared to last almost as long again as the period of active counseling."

The Finnish Diabetes Prevention Study assessed the effects of active counseling with regard to lifestyle changes in overweight middle-aged men and women, who were randomly assigned to the counseling group (n = 265) or the control group (n = 257) for 4 years.

At the end of this period, the incidence of new diabetes was cut by 58% in the intervention group. These results were reported in 2000 and published a year later in The New England Journal of Medicine. Two years later, the final results of the US Diabetes Prevention Program showed an identical reduction in new type 2 diabetes with a similar intensive lifestyle intervention.

Now, the Finnish investigators have further followed up those who were still free of diabetes at the end of their study for a median of 3 more years, monitoring diabetes incidence, body weight, physical activity, and dietary intake of fat, saturated fat, and fiber.

At the end of this 3 years, the incidence of type 2 diabetes was 4.6 per 100 person-years in the group that had undergone the counseling compared with 7.2 in the control group (P = .0401), indicating a 36% reduction in relative risk in the intervention group.

The risk reduction was related to the success in achieving the intervention goals of weight loss, reduced intake of total and saturated fat, increased intake of dietary fiber, and increased physical activity.

"From a public health point of view there is an important message: an intensive lifestyle intervention lasting for a limited time can yield long-term benefits in reducing the risk of type 2 diabetes in high-risk individuals," say Lindstrom and colleagues.

Dr. Goldberg says that although the benefit seen in the follow-up period is smaller than in the original study, it is still significant. "Overall the relative reduction in diabetes incidence over the entire 7-year follow-up in the lifestyle group was 43%, similar to the 46% reduction noted in the diet plus exercise intervention group of the 6-year [Chinese] Da Qing study, reported in 1997," he notes.

Practice Pearls

· The first report of the Finnish Diabetes Prevention Study demonstrated that lifestyle counseling could reduce subjects' weight in years 1 and 2 compared with usual care. Lifestyle counseling had a direct role in reducing the risk for incident diabetes by 58%.
· The current study demonstrates that lifestyle counseling among patients with impaired glucose tolerance can improve the attainment of diet, weight, and exercise goals, even after active counseling is finished. Attainment of these goals translated into a reduced risk for incident diabetes both immediately after and at a median of 3 years after the counseling intervention.
Lancet. 2006;368:1673-1679.