Exciting new research from the Medical University of Vienna shows that most cases of osteoarthritis are caused by an overactive immunity, just like rheumatoid arthritis and reactive arthritis (The Journal of Immunology, February 15, 2016;196(4):1910-1921). These researchers showed that patients with osteoarthritis have raised tissue levels of galectins, carbohydrate-binding proteins that turn on a person’s immunity to break down cartilage in joints in the same way that a person’s immunity attacks germs when they invade your body.
What is Osteoarthritis?
80 percent of North Americans have X-ray evidence of osteoarthritis by age 65, and 60 percent have significant pain. Doctors classify arthritis into several types, including:
- degenerative arthritis (following trauma or work-induced injury)
- various kinds of reactive arthritis, such as rheumatoid arthritis, in which a person’s immunity is overactive
- infections in joints
- crystal diseases, such as gout, in which crystals form in joints
- osteoarthritis, by far the most common type, where cartilage is worn away and there is no history of trauma
Doctors tell their patients that in osteoarthritis, the cartilage in joints just wears away and they don’t have the foggiest idea why. Since there is no known cause, there is also no cure. Osteoarthritis is usually treated with non-steroidal pills (NSAIDs) that help to block pain but do not even slow down the destruction of cartilage.
People are usually diagnosed as having osteoarthritis if they:
- have gradually increasing pain in their knees, hips, hands or spine
- are age 40 or older
- have negative results in the standard blood tests for an overactive immunity
- have swelling of the knuckles and joints on the ends of the fingers next to the fingernails, not in the middle finger joints, and at the base of the thumb (Rheumatoid arthritis usually affects the middle joints of the fingers and the joints where the fingers attach to the hand)
- have pain that is usually worse in the morning when a person first gets up. In osteoarthritis, the pain usually lessens as the person keeps moving. In rheumatoid arthritis, the joints continue to hurt for more than an hour after a person starts moving about.
What This New Study Shows
The recently characterized galectins, found in high levels in patients with osteoarthritis, cause inflammation to turn on a person’s immunity to attack cartilage to cause pain and a wearing away of the cartilage. The higher the level of galectins in an osteoarthritic joint, the greater the damage to the cartilage. Although we have no cure for osteoarthritis today, making a drug to block galectins offers a potential cure.
Being Overweight and Osteoarthritis
Osteoarthritis is very common in people who are overweight. Almost 70 percent of obese people develop knee osteoarthritis (Arthritis and Rheumatism, Sept 15, 2008;59(9):1207-13) and losing as few as 11 pounds reduces risk of developing knee osteoarthritis among women by 50 percent (Arthritis and Rheumatism, August 1998;41(8):1343-55). We know that excess weight causes inflammation, and this new study offers a possible mechanism.
It now looks as if osteoarthritis is an inflammatory disease and therefore should be treated with lifestyle changes to dampen down an overactive immunity in the same way that we treat heart attack survivors and diabetics.
If you are overweight and have joint pains that developed in later life with no history of a specific injury, you probably have osteoarthritis and are likely to improve when you lose weight.
We already have good data to show that regular low-impact exercise, and losing weight if overweight, both help to reduce pain from osteoarthritis.
We have no good data to show that osteoarthritis pain can be reduced with diet changes, such as eating lots of fruits and vegetables and avoiding red meat, sugared drinks, sugar-added foods and fried foods. However, these diet changes have been shown to reduce inflammation in patients with arteriosclerosis. I recommend that you try these dietary changes because they help to prevent heart attacks and may also help to reduce pain from osteoarthritis.
Gabe Mirkin, M.D., is a sports medicine doctor and fitness guru. A practicing physician for more than 50 years and a radio talk show host for 25 years, Dr. Mirkin has run more than 40 marathons and is now a serious tandem bike rider with his wife, Diana. His website is http://drmirkin.com/. Click to read Gabe’s full bio.