Stick-and-ball model of the glucosamine molecule (from the Wikimedia Commons, image by Benjah-bmm27)
Osteoarthritis, the “wear-and-tear” type of arthritis, affects a great many of us as we grow older. Knee pain is a common symptom. The diet supplements glucosamine and chondroitin have been proposed as a more “natural” treatment than pharmaceuticals, and they are components of a number of proprietary “joint health” formulations like Osteo Bi-Flex. The GAIT study (Glucosamine/Chondroitin Arthritis Intervention Trial), compared glucosamine, chondroitin, a combination of the two, and a pharmaceutical (celecoxib) to a placebo in patients with knee pain from osteoarthritis. The only one that worked better than placebo was celecoxib. I wrote about the GAIT trial in 2008. The study was reported in the media as both negative and positive. The positive reports emphasized the subgroup analysis: in one of ten subgroups, patients with moderate to severe pain, the combination of glucosamine and chondroitin outperformed placebo. But in the subgroup of patients with mild to moderate pain, it did not. The authors themselves commented that their study was not powered to draw any conclusions from subgroups and that further studies would be required. (The “power” of a study is a measure of its ability to show an association or relationship between two variables if such a relationship exists.) Now a further study with sufficient power claims to have confirmed the subgroup findings. This may encourage some people to try glucosamine/chondroitin, but I remain skeptical.
Osteoarthritis is the “wear and tear” kind of arthritis that many of us develop as we get older. Cartilage becomes less resilient with age, collagen can degenerate, and inflammation and new bone outgrowths (osteophytes) can occur. This leads to pain, crepitus (Rice Krispie type crackling noises with movement), swelling and fluid accumulation in the joints (effusion), and can severely limit activity for some patients. Patellofemoral pain is one of the most common of the repetitive strain injuries and is like an early onset of arthritis.
Since knee osteoarthritis is such a ubiquitous annoyance, home remedies and CAM offerings abound. Previously we have covered a number of CAM options on this blog, including glucosamine, acupuncture, and several others. The American Academy of Orthopaedic Surgeons (AAOS) has just issued a 1200 page report evaluating the evidence for various treatments for knee osteoarthritis short of total knee replacement surgery. A 13 page summary is available online. They have done the heavy lifting for us, reviewing all the available scientific studies for evidence of effectiveness. Here’s what the science says: (I’ve highlighted the ones where the evidence is strong.) (more…)
Glucosamine and chondroitin, used separately or together, are among the more popular diet supplements. They are used widely for osteoarthritis, especially of the knee, and have been better studied than most other diet supplements. But do they really work?
The journal of my medical specialty, American Family Physician, recently published an article about the use of dietary supplements in osteoarthritis. They gave a “B” evidence rating to both glucosamine and chondroitin. This means there is inconsistent or limited-quality patient-oriented evidence. They recommended the use of glucosamine sulfate, saying, “Overall, the evidence supports the use of glucosamine sulfate for modestly reducing osteoarthritis symptoms and possibly slowing disease progression.” They did not exactly recommend chondroitin, although they said it “may provide modest benefit for some patients.”
I remain skeptical. And so does R. Barker Bausell, who devoted several pages of his book Snake Oil Science to an analysis of the research on glucosamine and chondroitin. (more…)