NIH NEWS RELEASE Oral Insulin Does Not Prevent Type 1 Diabetes
Insulin Injections Fail To Prevent Type 1 Diabetes
PHILADELPHIA, Pa. (June 23, 2001)…. Low-dose
insulin injections do not delay or prevent type 1 diabetes in people who
have a high risk (50 percent or greater) of developing the disease within
5 years, researchers announced today at the annual meeting of the American
Diabetes Association. The
finding emerged from a recently completed clinical trial that answers a
question researchers have asked for years:
Can insulin injections stop or slow the development of type 1
diabetes in people at high risk?
“Animal studies and a small pilot study in people
had suggested that insulin injections could prevent
A total of 339 people took part in the trial
comparing insulin injections and close observation in high-risk people
whose ability to make insulin was below normal though they were not yet
diabetic. Half the
participants were randomized to receive low-dose insulin injections twice
a day under the skin and, once a year, a 4-day course of low-dose,
continuous intravenous insulin. The
other half received no treatment but were closely observed throughout the
trial, which began in 1995. Participants’
ages ranged from 4 to 45 years old, with a median age of 11 years.
After 5 years of observation, nearly 60 percent of
high-risk people developed type 1 diabetes, a rate of diabetes onset that
was virtually identical in both groups.
In the majority of people who developed the disease, diabetes onset
was detected during routine testing before symptoms developed, a benefit
to participants. Patients
receiving insulin injections had no significant adverse reactions.
To identify people at risk, researchers screened nearly 90,000 relatives of people with type 1 diabetes for islet cell antibodies (ICAs), one marker of risk. About 3.5 percent of screened relatives had ICAs in their blood, making them eligible for participation in the study. Further genetic, immunologic, and metabolic tests helped researchers identify high-risk individuals. Among these high-risk individuals, 11.5 percent developed diabetes before they could begin the study.
“We’re disappointed, but we’re not discouraged by the results of the insulin injection trial,” said Dr. Judith Fradkin, director of the Division of Diabetes, Endocrinology, and Metabolic Diseases in the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). “This study has taught us a great deal about type 1 diabetes and how to predict onset in people at risk. We’re still looking for a way to stop the disease process in its tracks, and we’re hoping that oral insulin or other prevention approaches being tested in upcoming clinical trials will provide the answers.”
The insulin injection trial is part of the Diabetes
Prevention Trial-Type 1 (DPT-1), which is also testing whether
insulin taken by mouth can prevent or delay type 1 diabetes in people with a
lower (25 to 50 percent) risk of developing diabetes in 5 years.
The oral insulin trial is based on a different scientific rationale
and targets people who have evidence of autoimmunity but no loss of ability
to produce insulin. In contrast
to insulin injections, which rest the insulin-producing cells, oral insulin
has no effect on blood glucose. Oral
insulin is thought to stimulate a protective immune response to counteract
the destructive response that causes type 1 diabetes.
The oral insulin trial is currently recruiting participants.
The DPT-1 is funded by the NIDDK, the National
Institute of Allergy and Infectious Diseases, the National Institute of
Child Health and Human Development, and the National Center for Research
Resources within the National Institutes of Health as well as the American
Diabetes Association and the Juvenile Diabetes Research Foundation
About 16 million Americans have diabetes.
Of these, 5 to 10 percent or up to 1 million people have type 1
diabetes, an autoimmune disease that destroys the insulin-producing cells of
the pancreas. Formerly known as
juvenile onset or insulin-dependent diabetes, type 1 diabetes develops when
the body’s immune system destroys pancreatic beta cells, the only cells in
the body that make the hormone insulin, which regulates blood glucose.
This form of diabetes usually strikes children and young adults, who
need several insulin injections a day or an insulin pump to survive.
Type 2 diabetes, which accounts for up to 95 percent
of diabetes cases in the United States, is most common in adults over age
40. Affecting about 6 percent
of the U.S. population, it is strongly associated with obesity (more than 80
percent of people with type 2 diabetes are overweight), inactivity, family
history of diabetes, and racial or ethnic background.
A major clinical trial, the Diabetes Prevention Program, will
determine whether lifestyle intervention with diet and exercise or treatment
with the diabetes drug metformin can prevent the development of type 2
diabetes in people at risk. This trial is no longer recruiting patients.