THURSDAY, March 6 (HealthDay News) -- People taking medications for rheumatoid arthritis may also be reducing their risk of heart attack and stroke, a new study suggests.

People with rheumatoid arthritis (RA), which causes pain, swelling, stiffness and loss of function in the joints, face a greater risk of cardiovascular disease, because it can lead to hardening of the arteries. Heart attack and stroke can occur 10 years earlier than in people without the condition, the researchers said.

By taking medications that reduce the inflammation caused by rheumatoid arthritis, the risk of heart attack and stroke may be significantly reduced, the study authors said.

"Our study demonstrated that the time of exposure both to disease-modifying anti-rheumatic drugs and biological agents is associated with a reduction of the risk of cardiovascular events," said lead researcher Dr. Antonio Naranjo, of the Universidad de Las Palmas de Gran Canaria, in Spain.

Those drugs include common RA medications such as methotrexate, sulfasalazine, glucocorticoids, leflunomide and biological agents such as TNF-alpha blockers, the researchers noted.

Naranjo said doctors know that by controlling the chronic inflammation caused by rheumatoid arthritis, it's possible to reduce cardiovascular risk. "The practical consequence of our work is that in patients with RA, especially in the most severe cases, both the classic cardiovascular risk factors and the inflammatory activity of the disease need to be controlled," he said.

For the study, Naranjo's team analyzed data on 4,363 patients who took part in the Quantitative Patient Questionnaires in Standard Monitoring of Patients with Rheumatoid Arthritis study. The researchers found that taking drugs such as methotrexate lowered the risk of a heart attack or stroke. For example, RA patients taking methotrexate for one year can reduce their risk of heart attack by 18 percent and stroke by 11 percent, the investigators reported.

"Methotrexate, other disease-modifying anti-rheumatic drugs and biologic agents could reduce the extra risk of myocardial infarction [heart attack] and stroke that patients with rheumatoid arthritis have by controlling inflammation," Naranjo said.

The findings were published in the March 5 issue of Arthritis Research & Therapy.

One heart expert thinks this retrospective study is intriguing, but it didn't really determine if the medications for controlling inflammation actually lowered the risk of heart attack and stroke.

"While certain associations are shown between the use of anti-inflammatory agents and prior cardiovascular events in patients with rheumatoid arthritis, a cause-and-effect relationship cannot be demonstrated in this type of study," said Dr. Gregg C. Fonarow, a professor of cardiology at the University of California, Los Angeles.

Prospective data and, ultimately, prospective randomized clinical trials are needed before any firm conclusions can be drawn about whether these drugs really lower the risk of heart attack and stroke, he said.

More information

To learn more about rheumatoid arthritis, visit the U.S. National Library of Medicine.

MONDAY, March 10 (HealthDay News) -- In experiments with rats and mice, scientists have found that thyroid stimulating hormone can prevent the bone loss associated with osteoporosis and may even restore lost bone.

The finding raises the possibility that thyroid stimulating hormone (TSH) might one day provide treatment for women with severe cases of postmenopausal osteoporosis, the researchers said.

"We found that TSH, which is a hormone that was thought to be exclusively involved in the release of thyroid hormones, which are essential for the homeostasis of the body, can directly affect bone remodeling," said lead researcher Dr. Mone Zaidi, a professor of medicine and physiology and director of the Mount Sinai Bone Program at Mount Sinai School of Medicine in New York City.

TSH inhibits the process of bone reabsorption by the body, Zaidi said. "This is a process that is fundamental for the renewal of the skeleton. Throughout life, old bone is replaced by new bone," he said. "Osteoporosis occurs when this process is exaggerated, and bone removal outpaces bone replacement."

In earlier research with mice, Zaidi's group found that TSH could actually suppress bone reabsorption. For the new study, the researchers wanted to see if TSH could stop bone reabsorption when the reabsorption rates were as high as they are in osteoporosis.

To show the benefits of TSH in preventing bone loss, Zaidi's team studied rats whose ovaries had been removed, which induced menopause-related osteoporosis. The researchers then gave the rats injections of TSH often as far apart as two weeks.

The researchers found that injections of TSH prevented bone loss and actually increased bone strength. "In addition, in rats, TSH actually restored the lost bone," Zaidi said.

The findings were published in the March 10 issue of the Proceedings of the National Academy of Sciences.

There had been a fear that injections of TSH would release thyroid hormones, which could have unwanted effects. However, Zaidi and his colleagues found that this was not the case with the animals they studied.

Zaidi said TSH is already used in humans to treat thyroid disorders. "We might be able to use the same drug for different purposes, a much larger purpose than it has ever been employed for," he said.

Dr. Stephen Honig, director of the Osteoporosis Center at the Hospital for Joint Diseases in New York City, said the idea of treating the bone disease with TSH is intriguing. But, it's far from certain that the beneficial effects seen in rodents would apply to humans. And other problems related to the use of TSH would need to be solved, he said.

"This is a very interesting animal study that strongly suggests that thyroid stimulating hormone may have anti-reabsorption effects on bone," Honig said. However, he noted that TSH can cause hyperthyroidism -- an overactive thyroid gland -- that can unleash serious problems with the body's metabolism.

"One question for TSH will be how often will it induce hyperthyroidism and can dose adjustments minimize this without impacting its bone-strengthening effects," Honig said. "The [study] authors suggest that, so far, hyperthyroidism has not been a problem, at least in a group of postmenopausal women being treated with TSH for thyroid cancer."

More information

For more on osteoporosis, visit the U.S. National Library of Medicine.

THURSDAY, March 6 (HealthDay News) -- The thousands of Americans who undergo knee replacement surgeries each year may want to put away their tennis rackets and get back on their bikes, a new study shows.

Biking and treadmill walking appear to be two of the gentlest exercises for those who have had a knee replaced with an artificial joint, researchers found, while higher impact sports such as jogging and tennis generated higher forces on new knees, according to study author Dr. Darryl D'Lima, director of the Orthopaedic Research Laboratory at Scripps Clinic, in La Jolla, Calif.

More surprisingly, golf swings were also tough on the knees, although D'Lima was quick to point out the swings make up just part of the exercise in a round of golf.

He is scheduled to present his research Thursday at the American Academy of Orthopaedic Surgeon's annual meeting in San Francisco. The study was initiated by Dr. Clifford W. Colwell, director of the Shiley Center for Orthopaedic Research & Education at Scripps.

An estimated 478,000 total knee replacement surgeries, called total knee arthoplasties (TKAs), are done in the United States each year, according to the researchers. In the surgery, the original joint is replaced by one made of various materials, such as plastic and metal.

Surgeons typically advise patients to resume physical activity when they are able. But advice about which activity is best has been subjective, D'Lima said. So, his team decided to measure forces on the knee while patients took part in a variety of exercises.

In the study, D'Lima's team measured forces on the tibia, or shinbone, in four patients who had undergone TKA. These four patients had a specially designed joint that allowed forces to be measured from inside the implant.

A year after their surgery, each of the four patients jogged, played tennis, did golf swings, walked (on a treadmill and on level ground) and biked while the forces to their knee area were measured.

Golf swings produced forces of 4.5 times body weight on the forward knee and 3.2 times body weight in the opposite knee, the researchers found.

D'Lima noted that the forces produced by the golf swing, however, occur in an instant, while the forces produced by jogging are constant. "I think golf should be OK," he said. "It's more of scientific interest."

There were some other surprises, D'Lima said. "We expected that walking on a treadmill, which is more controlled, would be better than biking [in terms of low impact to the knee]," the researcher noted. But biking actually won out, he said.

Other details on the results:

• Biking generated the least force, producing impact of about 1.3 times the person's body weight.
• Treadmill walking was next best, producing forces of 2.05 the body weight.
• Walking on level ground generated forces of 2.6 times the body weight.
• Tennis produced forces of 3.1 to 3.8 times the body weight, with serving producing the highest impact.
• Jogging produced forces of 4.3 times body weight.

Modification of certain high-impact exercises could help, he said. For avid golfers, "it's possible you could modify your swing," D'Lima says. Golfers could get a high-tech evaluation of their swings, offered by many golf club makers, or ask their pro about modifying the swing to exert less force on their knee, D'Lima suggested.

However, for more strenuous high-impact pursuits such as jogging, people who've undergone knee replacement should make a permanent switch to another form of exercise, the expert said.

Dr. Daniel Oakes, a staff orthopedic surgeon at Santa Monica-UCLA & Orthopaedic Hospital in Santa Monica, Calif., said the study confirms advice he generally gives to his knee-replacement patients.

"We strongly dissuade [them from] jogging," he said. "I tell them activities that are OK are walking, biking, hiking, riding an exercise bike, riding an elliptical trainer and walking on the treadmill."

He suggests doubles tennis, not singles, since it is not as aggressive. He generally allows downhill or cross-country skiers to resume that sport when they are healed. And he thinks golf is fine.

While the study confirms the experts' suspicions about which activities are more stressful on the new knee, it can't be determined from the study if the increased forces will lead to a higher failure rate in the joint, said Oakes, who is also an assistant professor of orthopedic surgery and chief of the joint replacement service at the University of California Los Angeles' David Geffen School of Medicine.

More information

To learn more about knee replacement, visit the American Academy of Orthopaedic Surgeon.