The Finnish Diabetes Prevention Study.

The aim of the Finnish Diabetes Prevention Study is to assess the efficacy of an intensive diet-exercise programme in preventing or delaying type 2 diabetes in individuals with impaired glucose tolerance (IGT) and to evaluate the effect of the programme on the risk factors of atherosclerotic vascular diseases and the incidence of cardiovascular events. In this ongoing study, a total of 523 overweight subjects with IGT based on two oral glucose tolerance tests were randomized to either an intervention group or a control group. The main measure in the intervention group is individual dietary advice aimed at reducing weight and intake of saturated fat and increasing intake of dietary fibre. The intervention subjects are individually guided to increase their level of physical activity. The control group receives general information about the benefits of weight reduction, physical activity and healthy diet in the prevention of diabetes. A pilot study began in 1993, and recruitment ended in 1998. By the end of April 1999 there were 65 new cases of diabetes, 34 drop-outs and one death. The weight reduction was greater (-4.6 kg) at 1 year in the intervention group (n = 152) than in the control group (n = 143, -0.9 kg, P < 0.0001), and this difference was sustained in the second year of follow-up. At 1 year 43.4% and at 2 years 41.8% of the intervention subjects had achieved a weight reduction of at least 5 kg, while the corresponding figures for the control subjects were 14.0 and 12.0% (P < 0.001 between the groups). At 1 year the intervention group showed significantly greater reductions in 2 h glucose, fasting and 2 h insulin, systolic and diastolic blood pressure, and serum triglycerides. Most of the beneficial changes in cardiovascular risk factors were sustained for 2 years. These interim results of the ongoing Finnish Diabetes Prevention Study demonstrate the efficacy and feasibility of the lifestyle intervention programme.