The study looked specifically at 250 people with evidence of osteoarthritis (OA) of the spine. All of the patients had at least some disability because of low back pain, but most were still able to work.
For six months, half the patients got 1,500-milligram daily doses of glucosamine sulfate and half got inactive placebo pills, notes study leader Philip Wilkens, MChiro, a research fellow at Norway's Oslo University.
"There was no benefit of glucosamine compared to placebo," Wilkens tells WebMD. "You would get the same result from taking sugar pills as taking the real deal."
On average, patients in both the glucosamine and placebo groups had less back pain and less disability after six months of treatment, and for six months after the end of the study.
Why did both groups improve? Part of the improvement is the placebo effect. That's the natural tendency of people to feel better when they believe they are being treated. But part of the reason is that patients come to treatment, and to clinical trials, when their condition is at its worst.
"People feel worse when they volunteer. That is a bad period, and it is usually followed by a good period. It's sort of a natural development of the condition of low back pain," Wilkens says.
Glucosamine for Low Back Pain: Worth a Try?
In osteoarthritis, cartilage in the joints degenerates. Glucosamine is a building block for the molecules from which cartilage is made. The theory behind glucosamine supplements is that taking them will slow or reverse cartilage degeneration.
It's a popular theory. According to the supplement industry group Council for Responsible Nutrition (CRN), 7% of Americans take glucosamine and/or chondroitin, a component of cartilage usually derived from animal or fish cartilage.
And in an editorial accompanying the Wilkens study, Kaiser-Permanente researcher Andrew Avins, MD, MPH, notes that 25% of people with low back pain have tried glucosamine supplements.
Even so, glucosamine is usually taken for knee osteoarthritis, says Andrew Shao, PhD, CRN senior vice president for scientific and regulatory affairs. Shao notes that low back pain can be caused by a number of things besides osteoarthritis.
"I know the researchers had to include some patients who had some degenerative joint issues in the back, but low back pain is a very broad kind of term. There can be a lot of reasons people experience it," Shao tells WebMD. "It is a tall order for something to affect such a global condition."
Shao says it would be premature to conclude that glucosamine has no benefit for any patients with spinal osteoarthritis. But that's pretty much the take-home message from the study, Avins suggests.
"No one study settles any question, but this study does not make glucosamine look promising for low back pain at this point," Avins tells WebMD.
Wilkens says that although his study found glucosamine had no effect on chronic low back pain, it did no harm. And some patients who improved while taking the supplement told him they were sure it helped them.
"If as an individual you feel glucosamine is the drug for you, there is no harm in taking it except for the expense," he says. "If you want to try, go ahead -- but I would not rely on it as the sole means of reducing your low back ache."
Might there be a subgroup of patients for whom glucosamine truly does help low back pain? Wilkens says that his team was unable to identify such patients based on pre-treatment MRI scans or on demographic factors.
But Shao notes that no MRI scans were taken after treatment, so there's no way to know whether patients' osteoarthritis had begun to improve while on treatment.
Avins laments that while low back pain is a huge health problem, it gets scant research attention.
"We will spend $100 billion this year on treatments related to low back pain, and most don't work," Avins says. "We spend such a tiny, tiny fraction of this on looking into the kinds of treatments that might give us the benefits we seek. It is frustrating."
The Wilkens study, and the Avins editorial, appear in the July 7 issue of the Journal of the American Medical Association. Neither reports any financial conflicts of interest, and the Wilkens study received no industry support. Study medication was purchased after all companies with glucosamine marketing approval in Norway were asked if they wanted to contribute their products.