A randomized lifestyle intervention with 5-year follow-up in subjects with impaired glucose tolerance: Pronounced short-term impact but long-term adherence problems

Aims: To compare data on cardiovascular risk factor changes in lipids, insulin, proinsulin, fibrinolysis, leptin and C-reactive protein, and on diabetes incidence, in relation to changes in lifestyle. Methods: The study was a randomized lifestyle intervention trial conducted in northern Sweden between 1995 and 2000, in 168 individuals with impaired glucose tolerance (IGT) and body mass index above 27 at start. The intensive intervention group (n=83) was subjected to a 1-month residential lifestyle programme. The usual care group (n=85) participated in a health examination ending with a single counselling session. Follow-up was conducted at 1, 3 and 5 years. Results: At 1-year follow-up, an extensive cardio-metabolic risk factor reduction was demonstrated in the intensive intervention group, along with a 70% decrease of progress to type 2 diabetes. At 5-year follow-up, most of these beneficial effects had disappeared. Reported physical activity and fibre intake as well as high-density lipoprotein cholesterol were still increased, and fasting insulin and proinsulin were lower. Conclusions: The intervention affected several important cardio-metabolic risk variables beneficially, and reduced the risk for type 2 diabetes, but the effects persisted only as long as the new lifestyle was maintained. Increased physical activity seemed to be the behaviour that was most easy to preserve.