Glucosamine May Not Fight Osteoarthritis
Study Using Powerful MRIs Shows Supplement Doesn't Prevent Damage to Knee Joints
WebMD News Archive
Oct. 21, 2009 (Philadelphia) -- Using a more sensitive measure of joint
damage than in the past, researchers have found that the popular supplement
glucosamine does not appear to slow the progression of knee osteoarthritis.
Previous studies that used X-rays to determine whether glucosamine can
prevent joint damage in knee
osteoarthritis have produced conflicting results. But it was widely
acknowledged that X-rays were less than optimal at spotting bone and cartilage
For the new study, researchers turned to souped-up MRI scanners. MRI itself
is far more sensitive than traditional X-rays, and the scanners used in the
study are twice as powerful as conventional MRI machines, says C. Kent Kwoh,
MD, of the University of Pittsburgh School of Medicine.
"Unfortunately, we did not find any evidence that glucosamine can prevent or
slow joint damage in individuals with mild to moderate knee pain," he tells WebMD.
The study involved 201 men and women, average age 52, with mild to moderate
knee pain due to osteoarthritis. Participants were randomly assigned to take
either 1,500 milligrams of glucosamine hydrochloride or a placebo, once
MRI scans and X-rays were taken of both knees, both at the beginning of the
study and six months later.
At the end of the six months, the odds of having worsening cartilage damage
were the same in both groups. There was also no significant difference in the
chance of having worsening bone damage.
Importantly, the analysis took into account risk factors such as age, sex,
body mass index, and pain that
could affect the results.
Additionally, when a urine biomarker was used as a basis for comparison,
there was no difference in the formation of new cartilage between the two
Kwoh reported the findings at the 73rd Annual Scientific Meeting of the
American College of Rheumatology.
Kwoh says this isn't the last word on the effectiveness of glucosamine.
While six months is long enough to demonstrate a benefit in terms of pain, "we
may have to follow people for longer to see a structural benefit [in the
cartilage and bone]," Kwoh says.
Also, interpretation of the results was complicated by the fact that the
placebo group had less arthritis progression during the study than the
researchers had predicted. "We thought they would do worse," he says.
Additionally, there are two forms of glucosamine supplements: the glucosamine
hydrochloride used in the study and glucosamine sulfate. "For now, we are
cautioning our patients that if they want to take glucosamine, they might want
to consider the sulfate formulation," Kwoh says.
Cleveland Clinic rheumatologist Elaine Husni, MD, who moderated a press
conference to discuss the findings, says that not a week goes by in which she
is not asked about glucosamine.
"To those who really want to take it, I tell them to try it for three to six
months. If it's not working after that, I tell them not to waste their money,"
she tells WebMD.