Diabetes Prevention Program
The Diabetes Prevention Program (DPP) was a major clinical trial,
or research study, aimed at discovering whether either diet and
exercise or the oral diabetes drug metformin (Glucophage) could
prevent or delay the onset of type 2 diabetes in people with
impaired glucose tolerance (IGT).
The answer is yes. In fact, the DPP found that over the 3 years
of the study, diet and exercise sharply reduced the chances that a
person with IGT would develop diabetes. Metformin also reduced risk,
although less dramatically. The DPP resolved these questions so
quickly that, on the advice of an external monitoring board, the
program was halted a year early. The researchers published their
findings in the February 7, 2002, issue of the New England
Journal of Medicine.
DPP Study Design and Goals
In the DPP, participants from 27 clinical centers around the
country were randomly split into different treatment groups. The
first group, called the lifestyle intervention group, received
intensive training in diet, exercise, and behavior modification. By
eating less fat and fewer calories and exercising for a total of 150
minutes a week, they aimed to lose 7 percent of their body weight
and maintain that loss.
The second group took 850 mg of metformin twice a day. The third
group received placebo pills instead of metformin. The metformin and
placebo groups also received information on diet and exercise, but
no intensive counseling efforts. A fourth group was treated with the
drug troglitazone (Rezulin), but this part of the study was
discontinued after researchers discovered that troglitazone can
cause serious liver damage.
All 3,234 study participants were overweight and had IGT, which
are well recognized risk factors for the development of type 2
diabetes. In addition, 45 percent of the participants were from
minority groups—African American, Hispanic American/Latino, Asian
American or Pacific Islander, or American Indian—that are at
increased risk of developing diabetes.
Type 2 Diabetes and Pre-Diabetes
Diabetes is a disorder that affects the way your body uses
digested food for growth and energy. Normally, the food you eat is
broken down into glucose. The glucose then passes into your
bloodstream, where it is used by your cells for growth and energy.
For glucose to reach your cells, however, insulin must be present.
Insulin is a hormone produced by your pancreas, a hand-sized gland
behind your stomach.
Most people with type 2 diabetes have two problems: the pancreas
may not produce enough insulin, and fat, muscle, and liver cells
cannot use it effectively. This means that glucose builds up in the
blood, overflows into the urine, and passes out of the body—without
fulfilling its role as the body's main source of fuel.
About 20.8 million people in the United States have diabetes. Of
those, 14.6 million are diagnosed and 6.2 million are undiagnosed.
Ninety to 95 percent of people with diabetes have type 2 diabetes.
Diabetes is the main cause of kidney failure, limb amputation, and
new-onset blindness in American adults. People with diabetes are
also two to four times more likely than people without diabetes to
develop heart disease.
Pre-diabetes, also called impaired glucose tolerance (IGT) or
impaired fasting glucose (IFG), is a condition in which your blood
glucose (blood sugar) levels are higher than normal but not high
enough for a diagnosis of diabetes. Having pre-diabetes puts you at
higher risk for developing type 2 diabetes. If you have
pre-diabetes, you are also at increased risk for developing heart
disease.
You are more likely to develop type 2 diabetes if
- you are overweight
- you are 45 years old or older
- you have a parent, brother, or sister with diabetes
- your family background is African American, American Indian,
Asian American, Hispanic American/Latino, or Pacific Islander
- you have had gestational diabetes or gave birth to at least
one baby weighing more than 9 pounds
- your blood pressure is 140/90 or higher, or you have been told
that you have high blood pressure
- your HDL cholesterol is 35 or lower, or your triglyceride
level is 250 or higher
- you are fairly inactive, or you exercise fewer than three
times a week
Pre-diabetes is becoming more common in the United States,
according to new estimates provided by the U.S. Department of Health
and Human Services. About 40 percent of U.S. adults ages 40 to 74—or
41 million people—had pre-diabetes in 2000. New data suggest that at
least 54 million U.S. adults had pre-diabetes in 2002. Those with
pre-diabetes are likely to develop type 2 diabetes within 10 years,
unless they take steps to prevent or delay diabetes. The results of
the Diabetes Prevention Program showed that modest weight loss and
regular exercise can prevent or delay type 2 diabetes.
DPP Results
The DPP's striking results tell us that millions of high-risk
people can use diet, exercise, and behavior modification to avoid
developing type 2 diabetes. The DPP also suggests that metformin is
effective in delaying the onset of diabetes.
Participants in the lifestyle intervention group—those receiving
intensive counseling on effective diet, exercise, and behavior
modification—reduced their risk of developing diabetes by 58
percent. This finding was true across all participating ethnic
groups and for both men and women. Lifestyle changes worked
particularly well for participants aged 60 and older, reducing their
risk by 71 percent. About 5 percent of the lifestyle intervention
group developed diabetes each year during the study period, compared
with 11 percent in those who did not get the intervention.
Researchers think that weight loss—achieved through better eating
habits and exercise—reduces the risk of diabetes by improving the
ability of the body to use insulin and process glucose.
Participants taking metformin reduced their risk of developing
diabetes by 31 percent. Metformin was effective for both men and
women, but it was least effective in people aged 45 and older.
Metformin was most effective in people 25 to 44 years old and in
those with a body mass index of 35 or higher (at least 60 pounds
overweight). About 7.8 percent of the metformin group developed
diabetes each year during the study, compared with 11 percent of the
group receiving the placebo.
Future Research
Researchers will perform other analyses to try to determine the
relative contribution of diet and exercise to the reduction in
diabetes. The DPP was not designed to examine diet versus exercise,
however, so the analyses may not provide a definitive answer.
Researchers will also analyze the information from the study to try
to determine how lifestyle intervention and metformin affect the
development of heart and blood vessel diseases, which are more
common in people with pre-diabetes and type 2 diabetes.
The DPP did not examine whether combining lifestyle changes and
metformin would further reduce the risk of developing diabetes.
DPP researchers plan to continue examining the roles of lifestyle
and metformin in preventing type 2 diabetes. They will also continue
to monitor participants to learn more about the study's long-term
effects. The National Institute of Diabetes and Digestive and Kidney
Diseases (NIDDK) is encouraging new research to look at
cost-effective methods of delivering lifestyle modifications in
group settings and over the Internet, as well as methods to sustain
behavior change and weight loss. The National Diabetes Education
Program (NDEP)—a joint project of the National Institutes of Health
(NIH), the Centers for Disease Control and Prevention (CDC), and
more than 200 public and private organizations—will disseminate the
findings and protocols stemming from the DPP.
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The U.S. Government does not endorse or favor any specific
commercial product or company. Trade, proprietary, or company names
appearing in this document are used only because they are considered
necessary in the context of the information provided. If a product
is not mentioned, this does not mean or imply that the product is
unsatisfactory.
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Additional Information on the DPP
Press
release from NIDDK on the results of the DPP
NIDDK's
Questions & Answers About the DPP
NDEP
The National Diabetes Information Clearinghouse collects resource
information on diabetes for the National Institute of Diabetes and
Digestive and Kidney Diseases (NIDDK) Reference Collection. This
database provides titles, abstracts, and availability information
for health information and health education resources. The NIDDK
Reference Collection is a service of the National Institutes of
Health.
To provide you with the most up-to-date resources, information
specialists at the clearinghouse created an automatic search of the
NIDDK Reference Collection. To obtain this information, you may view
the results of the automatic search on the Diabetes Prevention
Program.
If you wish to perform your own search of the database, you may
access and search the NIDDK Reference
Collection database online.
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National Diabetes Information Clearinghouse
1 Information Way
Bethesda, MD 20892–3560
Email: http://diabetes.niddk.nih.gov/about/contact.htm
The National Diabetes Information Clearinghouse (NDIC) is a
service of the National Institute of Diabetes and Digestive and
Kidney Diseases (NIDDK). The NIDDK is part of the National
Institutes of Health of the U.S. Department of Health and Human
Services. Established in 1978, the Clearinghouse provides
information about diabetes to people with diabetes and to their
families, health care professionals, and the public. The NDIC
answers inquiries, develops and distributes publications, and works
closely with professional and patient organizations and Government
agencies to coordinate resources about diabetes.
Publications produced by the Clearinghouse are carefully reviewed
by both NIDDK scientists and outside experts.
This publication is not copyrighted. The Clearinghouse encourages
users of this publication to duplicate and distribute as many copies
as desired.
NIH Publication No. 06–5099
August 2006 [Top]
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