Osteoarthritis is one of the most common forms of arthritis, and currently affects more than 20 million Americans. Osteoarthritis is caused by the degradation of cartilage, enabling the bones within the joint to rub against each other. This causes stiffness and pain, and subsequent inflammation can further aggravate these symptoms. Supplements such as fish oil, vitamins, turmeric and white willow have been suggested as possible alternative compounds that may relieve the pain and inflammation associated with the disease. Glucosamine and chondroitin are by far the most used supplements, with sales around $700 million each year. Glucosamine and chondroitin are thought to alleviate joint pain because they both contribute to cartilage structure.
The GAIT study (Glucosamine/chondroitin Arthritis Intervention Trial) looked at the effectiveness of glucosamine, chondroitin, a mixture of both, Celecoxib (NSAID) and a placebo on pain management in osteoarthritis patients. They found that while glucosamine and chondroitin did seem to slightly decrease the pain, the difference was not significant relative to placebo. (NEJM, 354(8):795-808, 2006)
Conversely, what are the effects of these supplements on rheumatoid arthritis? Because rheumatoid arthritis is thought to be an autoimmune disease that causes inflammation of the joints, the use of these supplements may alleviate the symptoms but will probably not stop degeneration. Multiple studies have looked at the efficacy of glucosamine or chondroitin on alleviating rheumatoid arthritis pain and inflammation, but have shown that neither was significantly more effective than placebo. (Biosci. Biotechnol. Biochem, 73(2):288-292, 2009; Rheumatol Int, 27:213-218, 2007)
The most intriguing aspect of all these studies is the ability of the placebo to alleviate some pain and discomfort in both rheumatoid and osteoarthritis patients. Which pathways or mechanisms do you think are being activated by the placebo? Do you think there are any benefits to the placebo effect, and if so, how could we manipulate it to benefit us?
Physicians have been using psychotherapies (including placebo drugs) for years. The most well established model is the subject-expectancy effect. Essentially, the subject is given a treatment of some kind, possibly a placebo, and they begin to feel the way that they are expecting. A specific example (which I absolutely advocate) is when you trick your 19-20 year old friends with non-alcoholic beer. After you've fed them 6-7 O'Douls and they begin to stumble about, recounting tales of a simpler time, you reveal to them your debauchery and instantly they revert back to 100% sobriety. There is a very real physiological reaction going on here, surprisingly. Endorphins among other hormones are released into the brain, opioid receptors are active, and all of the "happy" centers in the brain are hyperactive. If a physician can induce such an artificial treatment, how "artificial" is it?
ReplyDeleteThis can be related to glucosamine treatment for osteoarthritis. Some individuals report pain relief without any gross change in radiological findings. The problem here, lies in how we identify, quantify, and qualify pain. This is the subject of a current 7-year study that we are coordinating here at CU, it's called the MAPP study. The only personal input I can give to glucosamine is it's use in horses. I have seen horses with degrading cartilage having trouble even walking. After even a few weeks of glucosamine/chondroitin administration they are able to run around, jump, etc, like they were back in their prime. Is a horse susceptible to this subject-expectancy effect? Or are the metabolic pathways different in the horse model? Or is the mechanism behind glucosamine just not well enough understood?
Elliott, that is cool. I just saw that UC Boulder has appointed an expert in the placebo effect. We'll try to get him to come and speak at the Cafe Scientifique.
ReplyDeletehttp://CafeSciColorado.org
Elliott, your personal experience with horses and glucosamine/chondroitin is very interesting. While I believe that horses and other non-human animals probably aren't susceptible to the subject-expectancy effect to the extent of a human, it has been shown that they are capable of pretty complex association skills. Numerous studies have also shown that non-human animals can experience a "placebo-effect"; many of the studies are decades old and therefore the results may be flawed, but some of the findings are nonetheless intriguing. (Psychol Bull, 130(2):324-340, 2004)
ReplyDeleteWow, I didn't know that the placebo treated group so often had a different outcome from untreated. If simply positive thoughts can make you feel better than can negative thoughts about your health status/outcome make you more likely to be sick?
ReplyDeleteElizabeth, I do think that the placebo effect can go both ways, in that your mindset can make you feel better or worse. We’ve all seen how stress and other psychological factors can manifest itself physically (tension headaches, upset stomach, etc) so it makes sense that if you’re feeling stressed you could be more susceptible to getting sick. In that sense, I wonder if hypochondriacs get sick more often? Or do they actually get sick less because they tend to take care of themselves better (eating right, exercising, etc) because they always think they’re sick?
ReplyDeleteI definitely think the mind is a powerful thing. I don't know if this has happened to any of you, but I know that I have walked out of physio feeling symptoms of a disease that we were discussing in class. Once I forgot about it, everything is back to normal. Even something as simple as seeing insects on tv and you start to feel itchy.
ReplyDeleteIn response to Marie, I have pondered the same thing. For the individuals that I know and would group as hypochondriacs, it seems that they experience more stress. Maybe this would have long term negative effects on their immune system making them more susceptible to infection.
I know two dogs which are taking Glucosamines. it was for limping.
ReplyDeleteI have heard when she was coming down the stairs I was able to hear her cartilage grinding. So we decided to give her small dose of glcosamine. she was able to walk normal in 2 weeks so we stop giving her the medicine. now she started limping again.
the other dog has been taking the pills for almost 5 years one time a day so he is fine walking chasing squirrel with no problem. I thought it is interesting.
Now I was wondering I could see some placebo effect from one of the dogs but I don't want to get lawsuit for animal cruelty.