CHICAGO (Reuters) - People on the brink of developing diabetes who get a lot of support and encouragement to diet and exercise can turn things around and avoid the disease, U.S. researchers said on Wednesday.

“Millions of people could delay diabetes for years and possibly prevent the disease altogether if they lost a modest amount of weight through diet and increased physical activity,” said Dr. Griffin Rodgers, director of the National Institute of Diabetes and Digestive and Kidney Disease.

In the United States, about 11 percent of adults -- 24 million people -- have diabetes. Most have type 2, the kind linked with a poor diet and lack of exercise.

The 10-year study of overweight people with elevated blood sugar who lost a modest amount of weight found they lowered their risk of developing diabetes by at least a third.

People over 60 got even more dramatic results, cutting their risk of diabetes during the study period by about half.

“People can lose weight, and this weight loss is accompanied by a lowering of their rate of diabetes,” said Dr. William Knowler, who works at the health agency, part of the National Institutes of Health. His study appears in the journal Lancet.

The findings follow up on a large randomized trial of 3,234 overweight or obese adults with elevated blood sugar.

Results of that study, reported in 2001, found a diet and exercise program and support classes helped cut the risk of developing diabetes by 58 percent after three years compared with a placebo group.

The program consisted of reducing fat and calories and increasing physical activity to 150 minutes a week. Participants also got training in diet, exercise and behavior modification.

People in this group lost an average of 15 pounds (6.8 kg) in the first year, but they gradually regained all but about 5 pounds. A second group who took the diabetes drug metformin also succeeded in lowering their diabetes risk by 31 percent after three years compared with placebo.

The latest results show what happened after 10 years of follow-up.

Starting in 2002, study participants were offered the diet and exercise program and support classes.

After 10 years, the group that started off in the diet and exercise group has sustained a modest weight loss and cut their risk of developing diabetes by 34 percent, compared with the group that started out on a placebo.

The group that took the diabetes pill metformin and later added in the lifestyle program had an 18 percent lower risk of developing diabetes during the study.

“All that to me supports the fact that the lifestyle intervention, whether it was given immediately, or later on, was beneficial,” Knowler said in a telephone interview.

He said some people in all three groups continued to develop diabetes, but the rate was much slower if people were able to eat a healthier diet and get regular exercise.

From a policy perspective, he said diabetes can be delayed or avoided with intensive effort.