Changing dietary habits and taking more exercise proved to be better for patients with impaired glucose tolerance (IGT) than taking a commonly prescribed medication, the Diabetes Prevention Program Outcomes study showed.
Participants in the study, comparing antidiabetic drugs with serious lifestyle changes for people with impaired glucose tolerance, showed diet changes and regular exercise proved more effective.
Impaired glucose tolerance (IGT) is a precursor to type 2 diabetes (T2 diabetes). It often shows up in older people who are somewhat overweight as well as in younger obese adults.
A person is said to have IGT when they have a raised glucose level after two hours when taking the 75-g oral glucose tolerance test, but not as high as qualifying for T2 diabetes. Their fasting glucose may be either normal or mildly elevated. From 10 to 15 percent of adults in the United States have this condition and the figures are similar for Australia.
Such patients are generally prescribed metformin (Glucophage or Fortamet), an oral anti-diabetic drug, which is the first-line drug of choice for the treatment of T2 diabetes, particularly in overweight and obese people. They are also encouraged to lose weight.
World’s Largest Diabetes Prevention Study Shows Benefits of Diet, Exercise
A 10-year follow-up of diabetes incidence and weight loss in participants the Diabetes Prevention Program Outcomes study (DPP) conducted through the MedStar Research Institute, Hyattsville, Maryland, USA, showed patients who watched what they ate and enjoyed regular exercise improved their chances of not developing T2Diabetes by 58% compared to those who were given a placebo, while patients on metformin gained a 31% better chance of avoiding T2Diabetes than patients on placebo.
The DPP is currently the largest diabetes prevention trial with the most ethnically diverse patient population. It originally consisted of more than 3,800 subjects with IGT, randomised to receive one of four interventions: intensive lifestyle adjustments or standard lifestyle plus one of the following: placebo, metformin, or troglitazone.
(In June 1998, the troglitazone treatment was discontinued after a fatal case of liver failure in a study participant, but the subjects continued to receive follow up.)
Patients Counselled on Healthy Diets and Exercise Routines
After the initial phase of the DPP, patients in each group were offered diet and exercise education sessions every three months.
Patients in the intensive lifestyle group were given four additional sessions of this lifestyle counselling, while those in the metformin group continued to take the drug, but were made aware what it was.
After almost three years of follow-up, the study was discontinued, as the benefits were so strikingly clear: 58% risk improvement of avoiding T2 diabetes for the intensive lifestyle change group and 31% risk improvement for the metformin group.
Lifestyle Benefits Against T2 Diabetes Long-lasting
At the 10 year mark from the start of the DPP, researchers from the MedStar Research Institute interviewed original participants to see whether the risk benefits they had gained from either taking metformin or from eating a healthy diet and exercising regularly were still effective. Their results were published in an article in the November 14, 2009 issue of The Lancet
Some 2766 adults (88% of the originals) took part in the follow-up – 910 from the lifestyle group, 924 from the metformin group, and 932 from the original placebo group. Since the benefits of making intensive lifestyle changes when encouraged by education and counselling were already known, all three groups were offered new group-implemented lifestyle interventions.
In addition, metformin treatment was continued in the original metformin group, and the original lifestyle intervention group was offered extra lifestyle support.
Lifestyle Benefits Despite Slight Weight Gain
One surprising result was that during the 10 years since the start of the DPP, the original lifestyle group had lost, then partly regained weight. However, those on metformin maintained their modest weight loss resulting from the drug.
Despite this slight weight gain over a decade, members of the intensive lifestyle change group still benefited the most from the effort they put into changing their daily habits. They had overall the lowest incidence of diabetes - a reduction of 34%. Those in the metformin group had their diabetes incidence lessened by 18% compared with the placebo group.
“Prevention or delay of diabetes with lifestyle intervention or metformin can persist for at least 10 years,” the researchers concluded.
You might also be interested to read Reduce Type 2 Diabetes with Lifestyle Changes, Manage Type 2 Diabetes Blood Sugar with Exercise and Mediterranean Diet Lowers Risk of Diabetes.
Sue Cartledge - I'm a science, health, nutrition and lifestyle journalist, fascinated by the way the physical world operates in all its forms, and how ...
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