Study Finds Small Changes in Lifestyle Fight Diabetes

People at high risk for developing Type 2 diabetes can reduce their chances of getting the disease by 58% if they lose as little as 10 pounds, exercise and follow a healthy diet, according to a report released today.

The report, published in the New England Journal of Medicine, dramatically underscores the benefits of lifestyle changes in fighting the chronic disease, which is increasingly prevalent nationwide and especially in parts of Southern California.

The researchers who did the study and other experts said lifestyle changes have long been known to be beneficial, but they deemed the magnitude of the benefits found in the study--even in the case of relatively small changes--remarkable.

“The changes that were required to prevent diabetes were not drastic--they were just modest,” said Jaakko Tuomilehto, author of the study and a professor at the National Public Health Institute in Finland.

“If a person managed to change both diet and exercise, reduce calorie intake and change quality of diet, then the effect was the best,” he said. “But whatever single thing they could do also helped.”

In an editorial accompanying the study, two experts from the National Institutes of Health said that the research was significant because earlier attempts to confirm the relationship between healthful lifestyles and diabetes prevention were flawed.

It is by no means certain, they added, that people in an outpatient program could be induced to change their behavior sufficiently to produce such results.

The Finland-based study may be applied worldwide, although there may be some cultural differences, Tuomilehto said.

Sixteen million people in the United States have diabetes, according to the U.S. Centers for Disease Control and Prevention.

It afflicts 474,000 people in Los Angeles County, officials say. According to 1999 figures, the county had about 24 diabetes-related deaths per 100,000 people, compared with 20.5 statewide. The death rate was 22 per 100,000 in Ventura County, and about on par with the state average in Orange County.

The prevalence of the disease in this region is related in part to a high concentration of Latinos, who are for various reasons disproportionately affected by diabetes, as well as to high rates of obesity and a sedentary lifestyle, which increase the risk of developing the disease.

More than half of adults in Los Angeles County are overweight, and 60% don’t get regular exercise, according to Jonathan Fielding, director of public health at the county Department of Health Services.

Fielding said, however, that the potentially big benefits of lifestyle change come as heartening news.

“For those at high risk, reduction in weight and improving physical activity translate into lower rates of confirmed diabetes,” he said.

The study followed 522 people--172 men and 350 women--for four years. All had “impaired glucose tolerance,” a pre-diabetic stage. Those who suffer from this cannot efficiently process glucose--sugar--after a meal, so levels become elevated. Fifteen percent of people worldwide suffer from impaired glucose tolerance, and half of those will develop diabetes, Tuomilehto said.

Subjects were split into two groups. The first group met with nutritionists regularly and received advice on diet and exercise. They were encouraged to reduce their weight as well as their intake of calories, fat and saturated fats, while increasing dietary fiber and increasing physical activity to four hours a week.

The second group did not visit nutritionists regularly and were given limited lifestyle advice.

The subjects in the first group--who significantly improved diet and exercise regimens--reduced their risk of developing diabetes by 58%; none developed diabetes.

“The effect was very rapid,” Tuomilehto said. “After two years, we already could see a very clear effect on the rate of diabetes.”

Of those in the second group, in which subjects did not improve their lifestyles, 35% developed diabetes.

The study applies to people with Type 2 diabetes, which is sometimes misleadingly called adult-onset diabetes and is the type that 90% of people with diabetes have. In such cases, the body cannot effectively produce or use insulin, which is needed for cells to convert blood sugar into energy.

Diet and exercise are especially important in preventing diabetes in younger people, said Andrew Greenberg, director of the program in obesity and metabolism at Tufts University.

“Type 2 diabetes has previously been a disease of adults,” he said. “What’s happening now is, for the first time, we are now seeing a sharp increase in Type 2 diabetes in children.”

Today, more children are overweight, inactive and eating fatty, high-calorie foods, he said.

Whether they are young or old, many patients do not discover they have the disease until it is too late, he said.

“It’s kind of a silent disease until you start having complications,” he said. Diabetes can lead to blindness, kidney disease, heart disease, nerve damage, amputations and sometimes death.

Because of a lack of access to regular health care, many Latinos--who have the highest rate of diabetes among ethnic groups in Los Angeles County, followed by blacks--may not know they have diabetes, according to Lia Margolis, executive director for the Latino Coalition for Healthy California.

“One of the real serious problems for the Latino community is a good proportion don’t have health insurance,” she said. “If they don’t have access to care, they have even less access to preventive care.”

Among residents 40 and older, 16% of Latinos, 13% of African Americans, 8% of Asian Americans and 8% of whites in Los Angeles County have diabetes, according to the Department of Health Services.

Although more research is needed, the rate of diabetes in minority communities may be attributed to genetics, unhealthy diets and socioeconomic conditions, Greenberg said.

Doctors already know that healthier lifestyles can decrease the damaging effects of diabetes in patients who have already been diagnosed with it, Greenberg said.

“It’s clear that if you lose weight, you can actually cure your diabetes,” he said. “It’s also been shown that if people exercise, their insulin functions more effectively in their body.”

Linda Gledhill, executive director of the American Diabetes Assn. of Los Angeles County, said the study is a wake-up call for doctors.

“If anything, [the report] may motivate the medical community to pay more attention to these factors in their own patients,” she said.

One of the remaining questions is how willing various populations in the United States and elsewhere will be to make lifestyle changes, the editorial said.

Fielding said improvements will come only when there is a change in the social environment. “We live in a toxic nutritional environment where there are so many calorie-dense foods at every turn,” he said. “We have a lot to do.”

Still, experts say, this is a starting point.

“Now we have proof,” Tuomilehto said. “Now we can tell people the good news: Diabetes can be prevented.”

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Times medical writer Rosie Mestel contributed to this story.