No Problem,  says a New Study in the New England Journal of Medicine

If you have patients with diabetes in their families or have diabetes, their families need to know this.

An outpatient intervention program designed to effect changes in lifestyle significantly reduced the incidence of type 2 diabetes in patients with impaired glucose tolerance, Finnish investigators report.

For the first time, doctors have convincing evidence that overweight people can lower their risk of diabetes by slimming down and exercising.

Dr. Jaakko Tuomilehto of the National Public Health Institute in Helsinki and associates devised an intervention with goals of reducing weight by at least 5% and total fat intake to less than 30% of energy consumed. As described in the New England Journal of Medicine for May 3, goals also included an increase in fiber intake to at least 15 g per 1000 kcal, and moderate exercise for at least 30 minutes per day.

People who are obese and sedentary are more likely to develop type 2 diabetes, also known as adult-onset diabetes. Past studies have raised the possibility that a better diet and exercise can delay or prevent the disease, and doctors have long offered such advice to patients, but the new Finnish research is the first carefully controlled study to show this really works.

"This is now the proof that it can be done," said Dr. Jaakko Tuomilehto of Finland's National Public Health Institute, who headed the research reported in Thursday's New England Journal of Medicine.

The researchers calculated that the risk of diabetes was reduced by 58 percent in patients who were counseled how to lose weight, change their diet and exercise, compared with those who received only general advice.

"This gives us a challenge now to identify people at risk and begin to really focus on those individuals to make sure they recognize the need for lifestyle changes," said Dr. Robert Sherwin, president of the American Diabetes Association and professor of medicine at Yale University.

Diabetes is the seventh leading cause of death in the United States and is a growing problem worldwide. At least 16 million Americans have diabetes, which prevents the body from regulating blood sugar.

The disease can lead to blindness, kidney damage, amputation and heart disease. Some of the risk factors include age, obesity, a family history of diabetes and a lack of exercise.

The Finnish study involved 522 men and women who were middle-aged and overweight and had high blood sugar but not diabetes.

Half the group got help losing weight and improving their diet -- decreasing fat and increasing fiber -- and increasing their daily exercise to at least 30 minutes. They met periodically with a nutritionist, who went food shopping with some participants.

"They got very detailed, individual advice, not only about what was in their food but also how to prepare it," Tuomilehto said.

The comparison group received general advice and written information about diet and exercise but was not offered any specific programs.

The participants were followed for about three years. During the first year, the average weight loss was about 9 pounds (4 kilograms) in the group that got detailed advice, compared with less than 2 pounds (less than 1 kilogram) in the comparison group.

Diabetes was diagnosed in 27 people in the group that received advice and 59 in the comparison group. N Engl J Med 2001;344:1343-1350,1390-1391.

As the incidence of type 2 diabetes worldwide is increasing, interest in ways to prevent the disease is growing. Researchers have begun to focus on those adults with pre-diabetic warning signs, such as obesity, impaired blood sugar control, and insulin resistance. This study adds to the findings of two earlier studies completed in China and Sweden^{2 3} that suggest that the risk of type 2 diabetes may be dramatically decreased by improved diet, regular exercise, and weight loss.

Interestingly, a study of over 3,000 U.S. adults with impaired blood sugar control is currently under way to compare the efficacy of an exercise and diet program with that of an oral hypoglycemic drug (Glucophage®) for prevention of type 2 diabetes.⁴ The results of this Diabetes Prevention Program are expected in the fall of 2002.

We waited 50 years for the DCCT to tell us,  do we need to wait to tell people to exercise and loose weight to prevent not just diabetes, but hypertension, heart disease and cancer?  Sometimes common sense should tell us what we already know.

References:

1. Tuomilehto J, Lindstrom J, Eriksson JG, et al. Prevention of type 2 diabetes mellitus by changes in lifestyle among subjects with impaired glucose tolerance. N Engl J Med 2001;344:1343–50.
2. Eriksson KF, Lindgarde F. Prevention of type 2 (non-insulin-dependent) diabetes mellitus by diet and physical exercise: the 6-year Malmo feasibility study. Diabetologica 1991;34:891–8.
3. Pan XR, Li GW, Hu YH, et al. Effects of diet and exercise in preventing NIDDM in people with impaired glucose tolerance. Diabetes Care 1997;20:537–44.
4. The Diabetes Prevention Research Program Group. The Diabetes Prevention Program baseline characteristics of the randomized cohort. Diabetes Care 2000;23:1619–29.