OBJECTIVE:

Diabetes Prevention Program (DPP) participants randomized to the intensive lifestyle intervention (ILS) had significantly reduced risk of diabetes compared with placebo participants. We explored the contribution of changes in weight, diet, and physical activity on the risk of developing diabetes among ILS participants.

RESEARCH DESIGN AND METHODS:

For this study, we analyzed one arm of a randomized trial using Cox proportional hazards regression over 3.2 years of follow-up.

RESULTS:

A total of 1,079 participants were aged 25-84 years (mean 50.6 years, BMI 33.9 kg/m(2)). Weight loss was the dominant predictor of reduced diabetes incidence (hazard ratio per 5-kg weight loss 0.42 [95% CI 0.35-0.51]; P < 0.0001). For every kilogram of weight loss, there was a 16% reduction in risk, adjusted for changes in diet and activity. Lower percent of calories from fat and increased physical activity predicted weight loss. Increased physical activity was important to help sustain weight loss. Among 495 participants not meeting the weight loss goal at year 1, those who achieved the physical activity goal had 44% lower diabetes incidence.

CONCLUSIONS:

Interventions to reduce diabetes risk should primarily target weight reduction.