WEDNESDAY, Oct. 28 (HealthDay News) -- Diet and exercise can keep diabetes at bay for a decade, cutting the risk for the disease by more than a third in the most susceptible people, a new study finds.

About 11 percent of U.S. adults (24 million) have diabetes, mostly type 2, which is linked to poor diet and sedentary lifestyle. In addition, 57 million overweight adults have higher-than-normal blood sugar levels, which raise the risk of a heart attack or stroke and the likelihood of developing type 2 diabetes, researchers say.

But new research, published in the Oct. 29 online edition of The Lancet, shows that losing weight and exercising can delay or prevent the onset of diabetes more effectively than the prescription drug metformin or a placebo.

"Interventions that result in weight loss lower the risk of diabetes, and that lower risk appears to persist for a long period of time," said study author Dr. William C. Knowler of the U.S. National Institute of Diabetes and Digestive and Kidney Diseases.

For people who are at high risk of getting diabetes, losing weight "is clearly to be recommended," he said. In addition, using a drug like metformin may also benefit people unable to lose weight through exercise and diet alone, he said.

For the diabetes prevention study, 3,234 overweight or obese adults with elevated blood sugar levels were randomly assigned to either lifestyle changes or metformin to control their blood sugar, or a placebo.

After 10 years, 2,766 remained in the trial, and those taking metformin saw an 18 percent reduction in their rate of developing diabetes, compared with those on placebo.

But those who had made lifestyle changes -- reducing caloric and fat intake and exercising at least 150 minutes a week -- reduced their risk of getting diabetes by 34 percent compared with those on placebo, the researchers found.

In the first year of the trial, people in the lifestyle group lost an average of 15 pounds, regaining all but about five pounds over 10 years. People on metformin maintained a five-pound weight loss, and those on placebo lost less than two pounds over 10 years, the researchers note.

Over 10 years, after all the participants made lifestyle changes, the yearly diabetes incidence rates for the drug and placebo groups had dropped to about 5 to 6 percent, the same rate as the lifestyle group.

"Lifestyle intervention, even when provided later, also seemed to lower diabetes incidence rate," Knowler said.

But losing weight is difficult, and simply telling someone to slim down won't work, he acknowledges.

"To make things like this happen on a large scale, we have to do more than simply tell people to lose weight," he said. People need access to weight loss clinics that can teach them about diet and exercise, he added.

Dr. Anoop Misra, director of the department of diabetes and metabolic diseases at Fortis Hospitals in India, and author of an accompanying journal editorial, said that "prevention of diabetes is important to curb epidemic of diabetes globally. Diet and exercise remain the most important modalities to prevent diabetes, and any drugs are less important."

At-risk groups of diabetes need to be identified, especially certain ethnic groups, and taught proper lifestyle management strategies, Misra said. "Young adults with family history of diabetes should be carefully managed along the same lines," he said.

Diabetes prevention makes economic sense as well, by decreasing costly, lifelong expenditures on management of the disease and its complications, Misra said.

All nations, particularly developing countries, seeing a rapid rise in diabetes should devise or strengthen a national diabetes-control program to help curb the epidemic, he said.

"In particular, regulations should apply for advertisement and sale of energy-dense junk food to children, and regular physical activity should be encouraged starting at a young age. Spreading awareness about proper lifestyle and adverse consequences of obesity and diabetes should be at the top of health agenda of all nations," Misra said.

Regarding the study findings, other experts are optimistic. Dr. Ronald Goldberg, a professor of medicine at the Diabetes Research Institute of the University of Miami Miller School of Medicine, whose institution participated in the study, said that "seeing quite significant effects lasting this long really bodes well for the utility of these interventions for diabetes prevention."

Cutting calories and increasing physical activity clearly slow the progression to diabetes, Goldberg said. "Lifestyle works, and every effort needs to be made to begin and maintain a lifestyle program in the long-term."

More information

For more information on diabetes, visit the U.S. National Institute of Diabetes and Digestive and Kidney Diseases.

MONDAY, Oct. 26 (HealthDay News) -- A French study finding that people with Alzheimer's disease and diabetes have less memory loss than those without diabetes should be regarded with caution, American experts say.

"It's not clear from this study and others what the relationship is," said William Thies, chief medical and scientific officer of the Alzheimer's Association.

What is clear, Thies said, is that having diabetes increases the risk of developing Alzheimer's disease -- a relationship acknowledged in the first sentence of a report on the French study in the Oct. 27 issue of Neurology.

But there haven't been too many studies looking at the effect of diabetes on the progression of Alzheimer's, said the report by researchers at INSERM, the French National Institute for Health and Medical Research in Toulouse.

So, they followed 608 people with mild to moderate Alzheimer's disease for four years, testing their memory and thinking skills twice a year.

The 63 participants with diabetes -- 10.4 percent of the total -- started with the same average score of 20 on the test of thinking ability. There was an average overall decline of 1.24 points on that test every six months. But the decline in thinking ability scores was 0.38 points greater every six months for those without diabetes.

Previous studies of the relationship between diabetes and loss of cognitive function have had mixed results, Thies said. "Some showed a faster decline, some showed a slower decline," he said. "It is still a confused area."

One factor that has a strong influence on the results is the stage of disease in the people being studied, Thies said. "You know that early on, the disease does not progress quickly," he said. "So, if you study people in the early stage or the late stage, that can overwhelm the results."

A close look showed that the diabetic participants in the French study had Alzheimer's disease for a shorter period of time than the non-diabetics, said Dr. Robert Friedland, chair of neurology at the University of Louisville.

And the differences seen in the study "are very minimally significant, less than a point on a 30-point scale," Friedland said. "The difference in many of the mental state examination scores was very small. It was statistically significant, but clinically meaningless."

He ticked off several reasons why a difference was found. The medications taken for diabetes to help control blood sugar level could have a beneficial effect on the brain, Friedland said. "Also, patients with diabetes have more vascular disease in the heart as well as the retina, and some of their impairment might be due to that, so it was progressing more slowly," he said.

There was also a possibility of misdiagnosis, since no autopsies were done in the study, Friedland said.

"The important message is that there are potentially modifiable risk factors for Alzheimer's disease, some of which are also risk factors for diabetes -- lack of physical activity, obesity," he said.

For Thies, the lesson of the study is that "to understand relationships like this, you need more long-term cohort studies like this one. We need more studies, and the real barrier is money."

More information

The latest information on Alzheimer's disease is available from the Alzheimer's Association  .

FRIDAY, Oct. 23 (HealthDay News) -- The diabetes drug liraglutide helps obese people without diabetes lose weight, researchers have found.

The study authors also reported that high doses of liraglutide were more effective at helping people shed pounds than the weight-loss drug orlistat.

In the study, which included 564 diabetes-free obese patients aged 18 to 65 at 19 sites in Europe, participants were randomly selected to receive one of four injected doses of liraglutide (1.2 milligrams, 1.8 milligrams, 2.4 milligrams or 3 milligrams) or a placebo once a day, or 120 milligrams of orlistat three times a day.

All of the patients also increased their levels of physical activity and followed a calorie-restricted diet, which allowed for about 500 calories less per day than they needed.

Weight loss among patients taking liraglutide doses of 1.2, 1.8, 2.4 and 3 milligrams was 4.8 kilograms (10.5 pounds); 5.5 kilograms (12 pounds); 6.3 kilograms (14 pounds), and 7.2 kilograms (15.8 pounds), respectively, compared with 4.1 kilograms (9 pounds) with orlistat and 2.8 kilograms (6 pounds)with placebo. Weight loss of more than 5 percent occurred in 76 percent of patients taking 3 milligrams of liraglutide, 44 percent of patients taking orlistat, and 30 percent of patients in the placebo group, the researchers found.

Reduced blood pressure was noted in all of the patients taking liraglutide. The groups taking 1.8 to 3 milligrams of liraglutide had an 84 percent to 96 percent reduction in the prevalence of prediabetes, which is poor blood glucose control that's not yet bad enough to qualify as diabetes.

Nausea and vomiting was more common among patients taking liraglutide than among those in the placebo group, the study authors noted.

"The results of this study indicate the potential benefit of liraglutide, in conjunction with an energy-deficit diet, in the treatment of obesity and associated risk factors," wrote Dr. Arne Astrup, of the department of human nutrition at the University of Copenhagen, Denmark, and colleagues.

Additional studies with a follow-up longer than 20 weeks are now needed to investigate the long-term risk/benefit profile of liraglutide, the study authors noted.

The study was released online Oct. 22 in advance of publication in an upcoming print issue of The Lancet.

More information

The U.S. National Institute of Diabetes and Digestive and Kidney Diseases outlines the health risks of being overweight.