Anational 10-year study that included Hawaii participants shows that lifestyle changes aimed at modest weight loss and increased physical activity can prevent or delay the onset of type 2 diabetes.

Honolulu endocrinologist Dr. Richard Arakaki, a principal investigator in the study, said not enough emphasis is placed on diabetes prevention, and the new research should encourage those who feel doomed to suffer from the disease due to family history or other risk factors.

"If you could just prevent diabetes with simple lifestyle interventions, it could have a tremendous impact," said Arakaki, a professor at the University of Hawaii-Mänoa John A. Burns School of Medicine. "We have to get it across to people right from the get-go, so they can take it to heart, that it's a preventable disease. Just because your mother had it or your father had it, you don't have to get diabetes. You really can do something to reduce your risk."

Diabetes is a particular concern in Hawaii because Native Hawaiians, Pacific Islanders and Asians have a significantly higher rate of the disease, and because the state has a high proportion of elderly residents, who also are at greater risk.

The Diabetes Prevention Program Outcomes Study, published online yesterday in The Lancet medical journal, found that lifestyle changes such as consuming less fat and calories, and increasing regular physical activity to 150 minutes per week reduced the rate of developing type 2 diabetes by 34 percent and delayed onset of the disease by four years.

Researchers also found a 13 percent reduction in the rate of diabetes in those taking metformin, a generic oral medicine used to treat the disease, and a two-year delay in onset.

"This clearly demonstrates we can prevent diabetes by losing weight and increasing physical activity and also by using a common diabetes medication," Arakaki said.

10 YEARS OF DATA

Other studies have shown that diet and exercise can delay type 2 diabetes in at-risk people, but Arakaki said the new research is noteworthy because it is based on 10 years of data and included a high percentage of minority participants at dozens of test sites around the country.

Of the 60 or so Hawaii residents in the study, 70 percent were Native Hawaiian, Pacific Islander or Asian, he said.

"It shows similarities across the country whether or not you're Asian, Pacific Islander or African-American, you can still decrease the risk for development of diabetes," Arakaki said.

Diabetes is a disease in which the body does not produce or properly use insulin, a hormone made by the pancreas that allows glucose, or sugar, from food to be converted to energy.

When diabetes is not controlled, glucose and fats build up in the blood and, over time, damage vital organs and lead to potentially fatal complications. Diabetes is the main cause of kidney failure, limb amputations and new onset blindness in adults and a major cause of heart disease and stroke.

The outcomes study is a follow-up to a Diabetes Prevention Program clinical trial involving 3,234 overweight or obese adults with elevated blood glucose levels, a precursor to diabetes. Participants in that study were randomly assigned to three groups: one subjected to intensive lifestyle interventions aimed at achieving and maintaining a 7 percent weight loss and 150 minutes or more per week of moderate physical activity; a second cohort treated with two daily doses of metformin; and a third placebo group.

DIFFERENT RESULTS

The investigation found the incidence of diabetes in the lifestyle group was reduced by 58 percent, and by 31 percent in the metformin cohort compared with the placebo group.

The purpose of the Diabetes Prevention Program Outcomes Study, started in 2002, was to examine whether the delay in the development of diabetes seen during the initial program could be sustained and to assess the long-term effects of the lifestyle and pharmaceutical interventions.

Members of all three groups in the original program were offered nutrition, exercise and behavior modification counseling, with sessions held every three months to help participants manage their weight.

The lifestyle group, which had lost an average of 15 pounds during the initial program, regained all but about 5 pounds over 10 years. The metformin group maintained a loss of about 5 pounds, and the placebo group dropped less than 2 pounds over the decade, according to the study.

Even with the slight weight loss, the outcomes program found the incidence of diabetes was reduced 34 percent in the lifestyle group and 18 percent in the metformin group, indicating that lifestyle changes are effective for at least 10 years and "remain the best bet for prevention of diabetes," the study said.

"After 10 years we still see a difference in the diabetes rate between the group that started off with the lifestyle interventions versus the group that started off with metformin and those who didn't get any treatment," Arakaki said.

The benefits of intensive lifestyle changes were especially evident in people age 60 and older, who lowered their rate of developing type 2 diabetes over the next 10 years by about half, according to researchers.

Derek Salis, 53, of Kapolei, a part-Hawaiian with a family history of diabetes, joined the Diabetes Prevention Program in 1997 while in the Air Force. The 5-foot-7 Salis was picked for the lifestyle intervention group and saw his weight drop from 185 to 167 pounds.

"Ifelt better and more healthy overall. I was feeling better about myself and felt more energetic," he said.

After retiring from the military in 2000, he fell out of the program and eventually gained back the weight plus some.

FIRM BELIEVER

When Arakaki contacted Salis in February 2008 about joining the follow-up study, he tipped the scales at 198 pounds. Since then Salis has lost 25 pounds and his blood glucose level is normal.

He said he now consumes more fiber in his diet, counts fat grams in his food and practices portion control. Salis also works out at a gym three days a week.

"The bottom line is you can do something about it, and just normal things like dieting and exercise," he said. "It's not only good for preventing diabetes but for your overall health. It's something everybody should be trying to accomplish."

With his daughter getting married last month,Salis said he has a new reason to stay on track. "I'm looking forward to being a grandfather, and I won't be one for very long if I don't stay healthy," he said. "For me, that's a big incentive."

With the prevalence of diagnosed diabetes in the United States more than doubling in the past 30 years, due in large part to obesity, Arakaki said there is greater need for public health agencies to promote diabetes prevention.

"We don't have enough programs in place to get the message out to get more active. This has to be emphasis for the long term," he said.

Danette Wong Tomiyasu, chief of the state Department of Health's Chronic Disease Management and Control Branch, said the study provides further evidence of the benefits of a healthful lifestyle.

"The department has promoted healthy habits including healthy eating, regular physical activity, modest weight reduction and living smoke-free," she said. "Although progress has been made and we see people making a good effort, living a healthy lifestyle isn't always as easy as it seems."

The outcomes study was federally funded, primarily by the National Institutes of Diabetes and Digestive and Kidney Diseases at the National Institutes of Health.