Randomised controlled trial evaluating lifestyle interventions in people with impaired glucose tolerance

To evaluate the effectiveness of lifestyle interventions in people with impaired glucose tolerance (IGT).

Participants with IGT (n=78), diagnosed on two consecutive oral glucose tolerance tests (OGTTs), were randomly assigned to a 2-year lifestyle intervention or to a control group. Main outcome measures were changes from baseline in: nutrient intake; physical activity; anthropometry, glucose tolerance and insulin sensitivity. Measurements were repeated at 6, 12 and 24 months follow-up.

After 24 months follow-up, there was a significant fall in total fat consumption (difference in change between groups (Delta intervention-Delta control)= -17.9, 95% confidence interval (CI) -33.6 to -2.1g/day) as a result of the intervention. Body mass was significantly lower in the intervention group compared with controls after 6 months (-1.6, 95% CI -2.9 to -0.4 kg) and 24 months (-3.3, 95% CI -5.7 to -0.89 kg). Whole body insulin sensitivity, assessed by the short insulin tolerance test (ITT), improved after 12 months in the intervention group (0.52, 95% CI 0.15-0.89%/min).

These findings complement the findings of the Finnish Diabetes Prevention Study and the American Diabetes Prevention Study, both of which tested intensive interventions, by showing that pragmatic lifestyle interventions result in improvements in obesity and whole body insulin sensitivity in individuals with IGT, without change in other cardiovascular risk factors.