THURSDAY, Oct. 29 (HealthDay News) -- Want to improve that osteoarthritis in your knee? New research suggests that regular Tai Chi exercise can reduce pain and help your knee function better.

"Tai Chi is a mind-body approach that appears to be an applicable treatment for older adults with knee osteoarthritis," Dr. Chenchen Wang, co-author of a study published in the November issue of Arthritis Care & Research, said in a news release from the journal's publisher.

In the United States, an estimated 4.3 million adults over 60 suffer from this form of arthritis. As many as half of American adults may develop symptoms by age 85, the U.S. Centers for Disease Control and Prevention reported recently.

Wang and colleagues from Tufts University School of Medicine recruited 40 patients, with an average age of 65, who had been diagnosed with knee osteoarthritis.

Half of the group took part in Yang-style Tai Chi sessions for an hour at a time, twice weekly over a period of three months. The Tai Chi session consisted of 10-minutes of self-message and review, a half hour of movement, 10 minutes of breathing exercises and 10 minutes of relaxing.

The other participants took two 60-minute classes per week for three months and learned about issues such as diet and nutrition, and treatments for osteoarthritis. They also stretched for 20 minutes.

Those who practiced Tai Chi had significantly less knee pain than the other group and also reported less depression, more physical function and better overall health.

"Our observations emphasize a need to further evaluate the biologic mechanisms and approaches of Tai Chi to extend its benefits to a broader population," Wang said.

More information

Learn more about osteoarthritis from the Arthritis Foundation  .

THURSDAY, Oct. 29 (HealthDay News) -- Treatment with tumor necrosis factor (TNF) blockers doesn't increase rheumatoid arthritis patients' risk of cancer, new research has found.

TNF is a substance secreted by immune cells that regulates the immune system and plays a role in inflammation. TNF blockers are immunosuppressants that reduce inflammation in people with rheumatoid arthritis, but concerns have been raised that long-term use of the drugs may increase the risk of infections and cancer.

Swedish researchers analyzed data from 6,366 rheumatoid arthritis patients who started anti-TNF therapy with infliximab (Remicade), adalimumab (Humira) or etanercept (Enbrel) between January 1999 and July 2006. The study participants were compared with other groups of rheumatoid arthritis patients, including 61,160 not taking medications, 4,015 taking methotrexate (the gold standard of treatment) and 4,105 taking combinations of disease-modifying anti-rheumatic drugs (other than TNF blockers).

According to the study authors, 240 first cancers were diagnosed during follow-up among patients who had no history of cancer when they began anti-TNF treatment. Compared to rheumatoid arthritis patients who didn't take anti-TNF drugs or those with no history of cancer, the relative cancer risk of anti-TNF therapy was 1.00 and remained unchanged for those taking immunosuppressant drugs for up to six years, the researchers found.

"Our research indicates the overall cancer risk is the same for rheumatoid arthritis patients on immunosuppressant therapies and those not taking medications for the disease," confirmed team leader Dr. Johan Askling, of the Karolinska University Hospital in Stockholm, in a news release. However, "given several uncertainties, continued vigilance remains prudent."

The study is published in the November issue of Arthritis & Rheumatism.

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The American Academy of Family Physicians has more about rheumatoid arthritis  .

WEDNESDAY, Oct. 28 (HealthDay News) -- Researchers think they now understand the way that fish oils benefit people with rheumatoid arthritis and other conditions linked to inflammation.

The body converts an ingredient in fish oils called DHA into a chemical called Resolvin D2, which reduces the inflammation that can lead to various diseases, the scientists from Queen Mary, University of London and Harvard Medical School explained in their study published in the Oct. 28 issue of the journal Nature.

"We have known for some time that fish oils can help with conditions like arthritis, which are linked to inflammation. What we've shown here is how the body processes a particular ingredient of fish oils into Resolvin D2. We've also looked in detail at this chemical, determining at least some of the ways it relieves inflammation. It seems to be a very powerful chemical and a small amount can have a large effect," Mauro Perretti, a professor of immunopharmacology at Queen Mary, University of London, said in a university news release.

"This research is important because it explains at least one way in which fish oils can help in different types of arthritis. We can also work on this chemical and see if it can be used not only to treat or even prevent arthritis, but also as a possible treatment for a variety of other diseases associated with inflammation," said Perretti, who led the U.K. research team.

Unlike current anti-inflammatory drugs, Resolvin D2 doesn't appear to suppress the immune system, the researchers noted.

In arthritis, the body's immune system attacks healthy tissue. An important part of this process occurs when white blood cells (leukocytes) stick to the inner lining (endothelium) of blood vessels. In lab tests, Perretti and colleagues found that Resolvin D2 prompted endothelial cells to produce small amounts of nitric oxide, which acts as chemical signal that discourages white blood cells from sticking to the endothelium, thus preventing inflammation.

More information

The American Academy of Family Physicians has more about rheumatoid arthritis  .