Glucosamine has looked like salvation to many people with joint pain, but it proved no better than a sugar pill at reducing pain, disability or improving quality of life in a study of people plagued by chronic lower back pain and degenerative osteoarthritis.
But the findings, published in this week's issue of the Journal of the American Medical Association, are unlikely to be the last word on glucosamine, which remains a popular alternative to prescription drugs and other traditional therapies. Although some research studies have found it doesn't help osteoarthritis, others suggest it may provide some mild benefit to painful osteoarthritis of the knees and hips.
Statistics attest to the supplement's widespread appeal. A 2007 federal survey of Americans' use of complementary and alternative medicine found that more than 6 million adults in the United States had taken glucosamine in the previous month. A study from the U.S. Centers for Disease Control and Prevention, published in 2004, found that among women treated at New Mexico hospitals for joint and muscle pain, 25 percent of those with osteoarthritis used glucosamine.
Because a quarter of Americans with chronic low back pain turn at some point to glucosamine, researchers wanted to know more objectively if it could help. The latest findings came from Philip Wilkens at the Oslo University Hospital in Norway, a country where glucosamine is a prescription drug.
For six months, he and his colleagues gave 250 adults with chronic lower back pain and degenerative osteoarthritis either 2,500 mg daily of glucosamine sulfate or a placebo. At the six-month and one-year marks, there weren't any significant differences among patients in the two groups. Both groups did seem to be helped by the placebo effect, which is common in pain patients, in which people apparently feel better simply because they are receiving treatment.
Despite mixed reviews to date for glucosamine, the Oslo study had the rigorous elements of being randomized, double-blind and placebo-controlled. Previous studies using glucosamine for low back pain "have either been small in size, or had significant limitations in the design of the trial itself," said Timothy C. Birdsall, a naturopathic doctor and vice president of integrative medicine at Cancer Treatment Centers of America in Arizona.
Birdsall said that the study results would make him "much more likely to recommend they discontinue the glucosamine, and take other approaches to deal with the pain."
Other experts in integrative medicine, orthopedics, pain medicine and rehabilitation noted that the study didn't give patients glucosamine combined with chondroitin, which is how it's typically found at local pharmacies, health food stores or other retail sources.
But Wilkens defended the trial design, calling glucosamine "the main substance people use" and saying he was unaware of evidence "that the combination of glucosamine and chondroitin is better." But, he added, "We realize a similar study is needed to answer the question about glucosamine in combination with chondroitin."
Dr. Gregory Plotnikoff, senior consultant for integrative medicine at Abbott Northwestern Hospital in Minneapolis, said vitamin D deficiency could be skewing the results, given Norway's extreme northern latitude and lack of sunshine during winter months.
"We know vitamin D deficiency is a common cause of chronic, nonspecific musculoskeletal pain including chronic low back pain," Plotnikoff said.
Wilkens took issue with the assumption that Norwegians are lacking vitamin D, and said his team felt before carrying out the study that vitamin D levels "were not going to affect the results."
Taking the larger view of glucosamine, Dr. Charles Kim, a specialist in integrative medicine and acupuncture at New York University Medical Center, said "the jury is still out." He also said some types of lower back pain that involve loss of cartilage at the joints may be more likely to respond to glucosamine.
K. Simon Yeung, a pharmacist and manager of the About Herbs website for Memorial Sloan Kettering Cancer Center, called the study well-done, but said Wilkens and his co-authors were looking at the wrong target for glucosamine. He noted that the knees and hips -- joints for which glucosamine has been shown to have some effect -- have lots of movement. "The spinal column doesn't seem to have that motion," he said.
Although some of his patients have used glucosamine, Dr. Andrew J. Haig, director of the spine program at the University of Michigan, said he never thought it helped.
"The psychological damage done by a doctor flailing around, trying any of the hundreds of unproven treatments when patients often do well on their own, is not worth the possible benefits," Haig said. The new study demonstrates "that again, a lot of seemingly-reasonable treatments are not useful."
Dr. Brian Berman, director of the Center for Integrative Medicine at the University of Maryland School of Medicine, said he doesn't recommend glucosamine for lower back pain, partly because it doesn't respond to a single approach. "It's highly unlikely that there is a single magic bullet, including glucosamine, to treat this perplexing disorder."
The study reinforces the notion "that there is no 'magic pill' that can replace the common-sense treatments of exercise and weight control for relief of musculoskeletal pain," said Dr. Mark Brown, chairman of orthopedic surgery at the University of Miami.