FRIDAY, March 21 (HealthDay News) -- News from the diabetes front seems to grow more discouraging by the day.

Rates of the disease, fueled by obesity and sedentary lifestyles, have risen unchecked in the United States, with diabetes now affecting about 7 percent of the population. That's an estimated 20.8 million adults and children, according to the American Diabetes Association.

Federal projections estimate that by 2050, some 48 million Americans will have type 2 diabetes. And the disease will bring with it complications such as blindness, hearing loss, kidney disease, nervous system disorders and amputations of extremities.

"Studies have suggested that for the first time in history, the generation of people born in 2000 is probably going to have shorter life expectancy than their parents," said Dr. Sue Kirkman, vice president of clinical affairs for the American Diabetes Association. "That's attributable to obesity, diabetes and heart disease. Is that what we want for our children?"

What's worse, one of the most promising medicines for treating type 2 diabetes -- Avandia -- now appears to increase a person's risk of heart attack and heart failure, according to recent studies.

Still, medical experts say the fight against diabetes can be won -- if everyone decides to do what's best for themselves and their families.

That fight will get its yearly boost on Tuesday when the American Diabetes Association will "sound the alert" about diabetes on the 20th annual American Diabetes Alert Day. It's a one-day "call to action" to encourage those at risk for developing type 2 diabetes or those with loved ones at risk to take the Diabetes Risk Test and, if they score high, to schedule an appointment to see their health-care provider. The Diabetes Risk Test is available in English and Spanish by calling the association at 1-800-DIABETES (1-800-342-2383) or online at www.diabetes.org/alert.

But the finding on Avandia calls into question the safety of the entire class of drugs known as thiazolidinediones. For now, Avandia -- and other thiazolidinediones such as Actos -- remains on the market. But last year, the U.S. Food and Drug Administration mandated stricter labeling, including "black box" warnings, for the medications.

Medical experts recommend that each person discuss with their physician the risks and rewards of using Avandia.

"Every patient is different," said Kirkman. "Every patient has different risk factors. Every patient has reasons why one medicine might be better for them than another."

But medicines are only part of the solution. A better response would be drastic changes to American lifestyles, starting with improved diets and more exercise, to avoid type 2 diabetes in the first place.

"The statistics are pretty gloomy, but we also know people who are at risk for diabetes can do a lot to prevent it from coming on," Kirkman said. "There's a lot people can do to try and control their fate."

Diabetes comes in two types.

The most common form, type 2, or what used to be called adult-onset diabetes, occurs when either the body does not produce enough of the hormone insulin or the cells ignore the insulin. The body needs insulin to transport sugar in the blood to cells for energy. Being overweight, an unhealthy diet, and lack of exercise are common contributors to this form of the disease.

Type 1 diabetes, usually diagnosed in children and young adults, occurs when the body isn't capable of producing insulin.

Researchers reviewing data from the National Health Interview Survey found that from 1990 to 2005, cases of diabetes increased 4.6 percent each year. They rose from 26.4 cases per 1,000 people to 54.5 per 1,000 people in the most recent year available.

The diabetes epidemic has grave implications for America, said Martha Funnell, a clinical nurse specialist for the University of Michigan and a past president of the American Diabetes Association. Health care costs are expected to soar as more people with diabetes complications fill doctors' offices and emergency rooms.

Even the U.S. economy will be affected as potentially healthy people find themselves unable to work. "You're losing folks in the prime of their years, and that has an impact on society and our economy," Funnell said.

Fortunately, there are steps that can be taken, both large and small, to help fight diabetes.

On the large-scale side, Kirkman said, governments should spend more money on physical education in schools and on public transportation, instead of new road construction.

"We know people who take public transportation are more physically active," she said. "Do we choose to encourage that?"

On a more personal level, people can make healthy lifestyle choices and help pass those choices along to their children, Funnell said.

But is anyone listening and willing to try?

"The messages are those same old 'eat healthy and exercise,' and we hear those to the point where we think, 'Yeah, yeah, yeah, everybody knows we need to do these things,' " Funnell said.

However, even small measures -- standing more often during the day or walking during a lunch break or eating an apple instead of ice cream -- can help make a difference.

"Maybe it would seem to outsiders as a small step, but it's just taking that one step and the next step and the next," Funnell said. "Like global warming, it's saying, 'What can I do for myself and my family this week, this month, this year, that will make a difference?' "

More information

To learn more, visit the American Diabetes Association  .

FRIDAY, March 21 (HealthDay News) -- Children who take vitamin D supplements may be less likely to develop type 1 diabetes later in life, according to researchers who analyzed the findings of five previously published studies.

The researchers found that children who were given additional vitamin D were about 30 percent less likely to develop type 1 diabetes than children who didn't receive vitamin D supplements. The evidence also indicated that the higher and more regular the dose of vitamin D, the lower the risk of developing diabetes.

The findings were published online in the journal Archives of Disease in Childhood.

Type 1 diabetes, an autoimmune disorder, develops when insulin-producing cells in the pancreas are destroyed by the body's immune system, a process that begins in early infancy, according to background information in the review study.

The incidence of type 1 diabetes is increasing by about 3 percent a year, and it's estimated that new cases of the disease will have increased 40 percent between 2000 and 2010. People of European descent are most likely to have type 1 diabetes, which affects about two million Europeans and North Americans.

There's evidence that levels of vitamin D and exposure to sunlight, which prompts the body to make vitamin D, influence the risk of developing some types of autoimmune disorders.

The review authors noted that global rates of type 1 diabetes vary greatly, according to latitude and levels of sunlight. For example, a child in Finland is 400 times more likely than a child in Venezuela to develop type 1 diabetes.

The fact that pancreatic beta cells and immune cells carry receptors for the active form of vitamin D provide further proof of the link between vitamin D and type 1 diabetes, the review authors said.

More information

The American Academy of Family Physicians has more about type 1 diabetes  .

TUESDAY, March 18 (HealthDay News) -- Forget about regular, scheduled exercise for a minute. If you just drop your average daily activity level -- by taking elevators instead of stairs, by parking your car in the closest space, or by never walking to do errands -- you increase your risk of diabetes, heart disease and premature death, according to new Danish research.

And, those changes begin in as little as 14 days after you start to reduce your activity level, the researchers say.

The team found that when healthy men cut their daily activity, their insulin levels spiked dramatically, as did levels of blood factors such as C-peptide and triglycerides -- suggesting an increased risk of diabetes and heart disease.

"It is amazing that only two weeks of reduced stepping can induce numerous metabolic abnormalities," said the one of the study's authors, Dr. Rikke Krogh-Madsen, from the Centre of Inflammation and Metabolism in Copenhagen. "It is of special interest that impaired metabolism occurred without a total weight gain," she added.

"The message here is that a lot of significant changes can occur without a huge change in weight, so if your only barometer of success and health is weight, you're missing out," said exercise physiologist Polly deMille, from the Hospital for Special Surgery in New York City.

Results of the study were published as a letter in the March 19 issue of the Journal of the American Medical Association.

The study included 18 young, healthy men with no family history of diabetes. None of the men smoked, and none participated in a regular exercise program for more than two hours each week.

The study volunteers were divided into two groups. The first group included eight men with an average age of 27 and an average BMI of 22.9, which is well within the normal range (obesity starts at a BMI of 30).

Prior to the study start, the men wore pedometers and averaged 6,203 steps each day. To reduce the amount of steps, the researchers asked the volunteers to take cars on short trips instead of walking or bicycling, and to take elevators instead of stairs. During the study period, the men reduced their daily steps to an average of 1,394 daily steps. After two weeks of reduced daily activity, the amount of insulin circulating in the blood increased by about 60 percent, suggesting that the body was no longer efficiently processing glucose (energy) from food and needed to increase insulin production to metabolize the sugar in food.

The second group included 10 men with an average age of 23.8 years and a BMI of 22.1. At the start of the study, their average daily number of steps were 10,501. After two weeks, they had reduced their average daily steps to 1,344 -- an almost 90 percent reduction in daily activity. In this group, insulin levels also rose by nearly 60 percent after two weeks of inactivity.

In this group, the researchers also measured additional effects and found levels of heart disease risk factors had also increased with reduced activity. For example, triglyceride levels increased and the lack of physical activity was associated with a 7 percent increase in abdominal fat, even though there was no overall weight gain, according to Krogh-Madsen.

"Reduced daily activity can induce metabolic changes, which can be associated with the progression of chronic disorders and premature mortality," the researcher said.

The good news here, deMille added, is that the flip side is also true.

With just a couple of weeks of increased physical activity, you can start to reduce your risk of diabetes and heart disease, even if you don't notice a big difference on the bathroom scale.

"Just get some movement in. Even if it's not what you think you should be doing, every lit bit helps in terms of keeping metabolism healthy," she said. DeMille recommended getting a pedometer to see how many steps you're already taking in a day, and then working toward adding to that each day.

"Ten thousand steps a day is recommended as a goal, but if you could get up to 5,000 a day, that's a big gain in terms of becoming a more active, healthy person. If you can do more, that's great, but every little bit counts," deMille said.

More information

For tips on beginning an exercise program, visit the American Academy of Orthopaedic Surgeons  .