THURSDAY, May 8 (HealthDay News) -- Arthritis strikes more than half of the 20.6 million American adults who have diabetes, and the painful joint condition may be a barrier to exercise among these patients, a new government report shows.

Being physically active helps people manage both diseases better by controlling blood sugar levels and reducing joint pain, according to the report in the May 9 issue of Morbidity and Mortality Weekly Report, a publication of the U.S. Centers for Disease Control and Prevention.

"The prevalence of arthritis is astoundingly high in people with diabetes," said Dr. John H. Klippel, president and CEO of the Arthritis Foundation. "Over half the people with diabetes have arthritis."

Although there appears to be a connection between arthritis and diabetes, the reason for it isn't known, Klippel said. A possible explanation is obesity, which is a risk factor for both osteoarthritis and diabetes, he speculated.

"In addition, those individuals who have diabetes and arthritis are less physically active," Klippel said. "We know that physical activity is critically important for the control of diabetes, both for the control of blood glucose and the prevention of complications."

Using data from the Behavioral Risk Factor Surveillance System, CDC researchers found 29.8 percent of people with both diseases were more likely to be inactive, compared with 21 percent of those who only have diabetes, 17.3 percent of those with arthritis alone, and 10.9 percent of those with neither condition.

For people who suffer from both diabetes and arthritis, arthritis appears to be a barrier to being physically active. But being physically active by doing aerobic exercise, strength training, walking, swimming or biking can benefit people with both diseases, according to the CDC.

"Public health efforts to control diabetes are going to have to begin to pay attention to this problem of arthritis, if we ever hope to get people physically active," Klippel said.

Klippel thinks the importance of physical activity needs to be emphasized. "Many people with arthritis don't exercise because it hurts them. But they have to understand that if they exercise, it will actually reduce their pain and prevents the disease from progressing," he said.

One of the keys to controlling diabetes is exercise, Klippel stressed.

"People with diabetes are going to have to pay a lot more attention to their arthritis if they hope to achieve better control of their diabetes," Klippel said. "People with arthritis are going to have to recognize that there is an association between diabetes and arthritis."

For people with arthritis and diabetes, the Diabetes Foundation recommends getting physically active by taking a walk at least three days a week.

The foundation recommends starting with a 10-minute walk, increasing it to 30 minutes over time. Before taking that walk, it's important to stretch your legs, lower back, chest and arms, Klippel said.

To keep yourself motivated, walk with a friend, the foundation suggests.

In addition, maintaining a healthy weight will place less stress on joints, particularly the knees. Also, being overweight can cause you to tire more quickly and give up on your exercise program.

More information

For more on arthritis, visit the Arthritis Foundation  .

MONDAY, April 28 (HealthDay News) -- Obese people who underwent surgery that reduced the amount of food they could ingest not only lost weight, they also lost some of their lower back pain, according to a new report.

Thirty-eight morbidly obese patients with low back pain who underwent gastric bypass surgery reported that their pain decreased by an average of about 44 percent six months after surgery, according to researchers at the University of Southern California. The average amount of individual weight loss among the group of 30 women and eight men was about 85 pounds.

"This study provides evidence that substantial weight reduction following bariatric surgery results in moderate reductions in pre-existing back pain within six months of weight loss. While this initial research is promising, larger long-term trials are needed to prove the efficacy of this treatment," Dr. Paul Khoueir said in a prepared statement.

Khoueir was expected to present the findings in Chicago April 29 at the annual meeting of the American Association of Neurological Surgeons.

According to recent statistics, more than one-third of U.S. adults -- more than 72 million people -- were obese in 2005-2006. An estimated 75 percent to 85 percent of all Americans will experience some form of back pain during their lifetime.

Obese people are known to have a higher rate of hip and knee arthritis, but little is known about the extra weight's effect on lumbar spinal degeneration. While obese patients with back pain are frequently advised to lose weight, the association between these medical conditions remains unproven.

More information

The National Institute of Neurological Disorders and Stroke has more about back pain.

SATURDAY, April 26 (HealthDay News) -- While enjoying a cola or two every day might seem harmless enough, recent research suggests that those tasty drinks could be compromising your bone health.

"There is enough evidence that high consumption of soda and carbonated beverages is associated with somewhat lower bone mass in children, and that's a real concern and people should be aware of it," said Dr. Lawrence Raisz, director of the University of Connecticut Center for Osteoporosis.

The exact mechanism behind the problem isn't clear, but experts believe that drinking soda -- particularly colas -- affects bone density in several ways. One reason may be that people who drink colas are simply less likely to get enough calcium and vitamin D in their diets, because the soda is replacing more nutritious beverages, such as milk or calcium-fortified juice.

Or, it could be related to the caffeine in colas, because caffeine has been linked to a higher risk of osteoporosis.

The third possible explanation focuses on one of the ingredients found in colas: phosphoric acid. Phosphoric acid can cause an imbalance in the body as the body seeks to neutralize the acid with calcium. If there isn't enough calcium in the diet, the body will take calcium from the bones.

"Phosphate is in milk, but milk also contains calcium and vitamin D. In soft drinks, there is just phosphoric acid and no calcium. Extra overzealous drinking may lead to a phosphoric acid imbalance, and if there's not enough calcium, the body goes to the bones to restore the balance," explained Dr. Primal Kaur, director of the Osteoporosis Center at Temple University Health Sciences Center in Philadelphia.

Low levels of calcium are associated with the development of osteoporosis, a disease that thins the bones so much that they're at risk of fracture. More than half of Americans, especially postmenopausal women, have an increased risk of developing osteoporosis, according to the National Osteoporosis Foundation.

In a study that included more than 2,500 people with an average age of about 60, researchers from Tufts University found that cola consumption by women was associated with lower bone mineral density at three hip sites, regardless of age, menopause, total calcium and vitamin D intake. The women reported drinking an average of five carbonated drinks a week, four of which were colas.

There was less of a problem with decaffeinated cola, but the findings were similar for diet soft drinks. The researchers didn't find an association between cola drinking and lower bone mass in men.

Results of the study were published recently in the American Journal of Clinical Nutrition.

"Moderation is really important. If you really like soft drinks, you don't need to take them out of your diet completely, but limit yourself to one or two glasses" a week, Kaur said.

And, she added, make sure you're getting enough calcium and vitamin D to protect your bone health. Vitamin D needs vary by age, and where you live, so check with your doctor to find out how much vitamin D you should be consuming each day. Kaur said that if you're not getting at least 1,000 to 1,200 milligrams of calcium daily from your diet, you should take a calcium supplement to ensure you're getting adequate amounts of the mineral.

Another important way to prevent osteoporosis, according to Raisz, is to exercise.

"The standard recommendation is a half an hour a day for adults and an hour a day for kids, but anything is better than nothing," he said. "Try to walk at least a half a mile a day, and engage in a weight-bearing exercise of some sort."

More information

To learn more about risk factors for osteoporosis, visit the National Osteoporosis Foundation  .