What is the Diabetes Prevention Program (DPP)?
The DPP was a randomized, controlled clinical trial that determined if certain interventions could prevent or delay type 2 diabetes in adults at high risk for developing the disease. The multicenter study enrolled 3,234 overweight participants with blood glucose levels that were higher than normal but not yet in the diabetic range. Forty-five percent of participants were from minority groups disproportionately affected by type 2 diabetes: African Americans, Hispanic Americans, Asian Americans and Pacific Islanders, and American Indians. The trial also recruited other groups at higher risk for type 2 diabetes, including individuals age 60 and older, women with a history of gestational diabetes, and people who have a first-degree relative with type 2 diabetes.
What interventions were tested in the DPP?
Participants were randomly assigned to one of the following approaches:
- Intensive lifestyle changes with the aim of reducing weight by 7 percent through a low-fat diet and increased physical activity. Participants were asked to maintain physical activity at least 150 minutes a week with moderate exercise, such as walking or biking.
- Standard advice on diet and exercise plus treatment with the drug metformin (850 mg twice a day), approved in 1995 to treat type 2 diabetes.
- Standard advice on diet and exercise plus placebo pills in place of metformin.
A fourth arm of the study, treatment with the drug troglitazone (Rezulin) combined with standard diet and exercise recommendations, was discontinued in June 1998 due to the potential for liver toxicity.
What instruction was provided to the lifestyle changes group?
In the DPP, participants received instruction in diet, exercise, and behavior modification. Case managers met with each participant for at least 16 sessions in the first 24 weeks and then at least every other month individually or in groups. Participants were asked to lower fat to less than 25 percent of caloric intake. If reducing fat did not result in weight loss, a calorie goal was added. Participants received culturally sensitive instruction in diet, exercise, self-monitoring, goal-setting, and problem-solving.
What were the DPP's main findings?
After about 3 years of follow-up, participants randomly assigned to intensive lifestyle changes reduced the development of type 2 diabetes by 58 percent compared with placebo. Metformin (850 mg twice a day) lowered diabetes incidence by 31 percent compared with placebo.
The YMCA's DPP program is offered for a modest cost by 92 YMCA's at 684 locations in 39 states. More than 1,500 lifestyle coaches have received training and 14,250 participants have attended sessions and lost an average of nearly 5 percent of their body weight. By 2017, the Y plans to have the program started in more than 300 locations.
For more information about DPP, read the DPP protocol. The protocol for the Diabetes Prevention Program (DPP), describes the background, design and organization of the DPP. The protocol is maintained by the Coordinating Center (CoC) at the George Washington University Biostatistics Center through new releases of the entire protocol or issuance of supplemental protocol memoranda. The preface contains a summary of the protocol modifications made during the DPP. Comments or questions regarding aspects of the DPP protocol, including distribution, should be directed to the staff of the CoC.
Below are the most up-to-date versions:
- Version 4.5 November 6, 2001 (lifestyle, metformin and placebo participants)
- Version 1.2 November 6, 2001 (troglitazone participants)
Program Staff Only: To access the research group website, please click here.
DPPOS Coordinating Center