SUNDAY, Dec. 2 (HealthDay News) -- Avandia, a drug used by millions of diabetes patients, may contribute to bone loss, according to a new study conducted in mice.

Experts fear that, over the long term, Avandia (rosiglitazone) may speed osteoporosis, the thinning of the bones that can lead to dangerous and even fatal fractures.

The findings appear in the Dec. 2 online issue of Nature Medicine.

"Our study suggests that long-term rosiglitazone usage in the treatment of type II diabetes may cause osteoporosis due to both increased bone resorption and decreased bone formation," said study senior author Ron Evans, a professor at the Salk Institute for Biological Studies in La Jolla, Calif. "Because Avandia is effective in controlling glucose and restoring the body's sensitivity to insulin, we do not recommend that people stop their treatment. You must balance the benefits against the complications."

"Anyone who is already at risk for osteoporotic fractures should consider an alternative anti-diabetic drug," added Paul Brandt, an associate professor of neuroscience and experimental therapeutics at Texas A&M Health Science Center College of Medicine, in College Station. "There are many alternatives, " he said.

"It may [also] be possible to blunt some of Avandia's effects with anti-osteoporosis drugs such as bisphosphonates, raloxifene, vitamin D and calcium," Brandt added.

Earlier this year, Avandia and four other diabetes drugs from the same class were given a "black box" warning by the U.S. Food and Drug Administration. That warning advises users of an increased risk of heart failure while on the drug.

The black box message is the FDA's strongest label warning.

With an estimated 3.5 million or more U.S. patients taking Avandia, the public health impact from the point of view of both heart failure and bone degradation could be substantial, experts say.

Avandia affects a key cellular protein called the peroxisome proliferator-activated receptor (PPAR-gamma). In their study, the California team discovered that, in mice, activating this receptor also stimulates the production of osteoclasts, cells whose key function is to degrade bone.

Proper bone health is maintained by a balance between osteoclasts and osteoblasts, the cells that build bone up.

If either side is out of whack, so to speak, bones become thinner, more fragile and prone to fracture.

The current results are particularly disturbing in light of prior studies, the experts said.

"It was previously known that Avandia mediates bone loss by inhibiting bone formation," Evans explained. "Our work identified an additional mechanism, in which Avandia promotes bone resorption. These are the two parts of the checks-and-balance system that maintains bone in good shape. The drug weakens both sides of the balance mechanism, leading to an increased risk for osteoporosis."

"Previous research showed that Avandia reduced osteoblasts," Brandt added. "Combine the two, and you're going to get thinning of the bone."

More information

For more on diabetes drugs, visit the U.S. Food and Drug Administration.

FRIDAY, Nov. 9 (HealthDay News) -- Certain drugs may be effective in treating juvenile rheumatoid arthritis, according to studies presented this week at the American College of Rheumatology (ACR) meeting in Boston.

One study found that abatacept, used to treat adults with moderate to severe rheumatoid arthritis, may be a well-tolerated treatment for children and adolescents with severe, treatment-resistant juvenile rheumatoid arthritis, also known as juvenile idiopathic arthritis (JIA).

"The results of this randomized double blind trial of abatacept were very encouraging for both efficacy and safety in these children with severe polyarticular JIA. Abatacept was effective for many of the children who had already failed anti-TNF therapy. Because of its unique mechanism of action, abatacept is an important new treatment approach for children with JIA," Dr. Daniel J. Lovell, professor of pediatrics at Cincinnati Children's Hospital Medical Center and a lead investigator in the study, said in a prepared statement.

Lovell was lead investigator of a second study that found that treatment with adalimumab (brand name Humira) reduced disease flare-ups and promoted improvement in patients with juvenile rheumatic arthritis (JRA). After 16 weeks of therapy with the drug, 77 percent of patients had a decrease of at least 50 percent in disease symptoms, and 58 percent of patients had at least a 70 percent decrease in ACR Pedi Response (measurement criteria that assess disease activity in JRA patients).

After 32 weeks, patients who received adalimumab had significantly fewer disease flare-ups and better ACR Pedi Responses than those who took a placebo. Patients who continued taking the drug for two years showed substantial and sustained improvement, according to the researchers.

A third study concluded that etanercept (brand name Enbrel) is safe in the long-term treatment of patients with JRA. The injectable drug blocks TNF-alpha, a protein that causes the pain and tenderness associated with rheumatic disease.

In this study, 42 JRA patients took etanercept for four years, and 26 of them continued to take it for eight years. Reasons for discontinuing use of the drug included: parental/guardian desire to remove patient from the study; poor treatment response; adverse effects, and a doctor's decision.

The study found that 23 percent of patients reported a total of 39 serious adverse events, but the overall rate of serious adverse events didn't increase with long-term use of the drug. There were no reported cases of lupus, demyelinating disorders, tuberculosis, malignancies, lymphomas, or deaths.

"The drug had a sustainable efficacy profile with a very beneficial safety profile. Only one serious infection, pyelonephritis (a kidney infection), was observed in the remaining patients during the past four years," investigator Dr. Andreas Reiff, head of the division of rheumatology, Keck School of Medicine, University of California, Children's Hospital Los Angeles, said in a prepared statement.

More information

The Nemours Foundation has more about juvenile rheumatoid arthritis  .

THURSDAY, Nov. 8 (HealthDay News) -- Helping people with osteoporosis stick to their medications may cut their risk for fracture, Canadian researchers report.

When an osteoporosis patient suffers a fracture, there's an increased risk of additional fractures, other health problems, and death. The most common types of fractures in osteoporosis patients are hip, spine, and wrist fractures.

This new study looked at more than 74,000 women and men aged 67 and older. During the two-year trial, there were a total of 1,751 (2.4 percent) fractures among the study population.

The researchers found that the main predictor of fracture was patient compliance with prescription drug refills.

Patients who followed their osteoporosis treatment routine and had a prescription refill compliance rate of at least 67 percent were much less likely to suffer a fracture during the study period, the researchers said. Younger age, being female, and regular bone density testing were other factors found to be associated with a lower fracture risk.

The study was to be presented Wednesday at an American College of Rheumatology meeting in Boston, Mass.

Fracture can be a serious event for older Americans. "A year after hip fracture, a significant proportion of patients (about 20 percent) are dead, and another group can no longer live independently and require long-term nursing care, so we really want to avoid these fractures," researcher Dr. Gillian Hawker, a professor of medicine at Women's College Hospital, University of Toronto, said in a prepared statement.

More information

The National Osteoporosis Foundation has more about osteoporosis  .

MONDAY, Oct. 22 (HealthDay News) -- The U.S. Food and Drug Administration has approved Voltaren Gel to treat osteoarthritis, maker Novartis AG said Monday.

It's the first prescription topical treatment for osteoarthritis that can be applied directly to the site of pain, the company said in a statement. In clinical testing, the non-steroidal anti-inflammatory drug (NSAID) showed a 51 percent reduction in pain in both the knees and joints of the hands with minimal absorption of the drug by the body, minimizing side effects.

Osteoarthritis is a chronic condition characterized by breakdown of joint cartilage. Some 21 million people in the United States have the condition, and 72 million more may be at risk of developing OA by the year 2030, Novartis said.

More information

The FDA has more about this drug's history.