The Use of Glucosamine in Osteoarthritis
Osteoarthritis (OA), the most widespread type of arthritis,
is a degenerative disease of the joints. It is mostly due
to"wear-and-tear" disease involving degeneration of joint
cartilage and formation of bony spurs within various joints.
Trauma to the joints, repetitive occupational usage, and obesity
are risk factors. It is common over the age of 60 and the
main goal of treatment is to relieve pain.
In recent years, glucosamine and chondroitin have been widely
promoted as a treatment for OA. Glucosamine, an amino sugar,
is thought to promote the formation and repair of cartilage.
Chondroitin, a carbohydrate, is a cartilage component that
is thought to promote water retention and elasticity and to
inhibit the enzymes that break down cartilage. Both compounds
are manufactured by the body.
Research Findings
Laboratory studies suggest that glucosamine may stimulate
production of cartilage-building proteins. Other research
suggests that chondroitin may inhibit production of cartilage-destroying
enzymes and fight inflammation too. Glucosamine supplements
are derived from shellfish shells; chondroitin supplements
are generally made from cow cartilage. Human studies have
shown that either one may relieve arthritis pain and stiffness
with fewer side effects than conventional arthritis drugs.
Some published studies comparing glucosamine or chondroitin
to various standard medications have found that the drugs
worked faster than the supplements. But they also found that
several months after treatment ended, the analgesic effect
of the supplements remained stronger.
In March 2000, a study in the Journal of the American
Medical Association concluded:
Trials of glucosamine and chondroitin preparations for OA
symptoms demonstrate moderate to large effects, but quality
issues and likely publication bias suggest that these effects
are exaggerated. Nevertheless, some degree of efficacy appears
probable for these preparations [1].
In 2001, the Lancet published the results of a three-year
double-blind clinical trial involving 212 people with osteoarthritis
who took either glucosamine or a placebo. The researchers
found that symptoms improved 20% to 25% in the glucosamine
group but worsened slightly in the placebo group. The x-ray
examinations showed that serious narrowing of the knee-joint
space -- a sign of progression of the disease -- occurred
in only half as many patients taking glucosamine as in those
receiving the placebo [3]. As for chondroitin, a recent analysis
of the combined results of seven randomized, controlled trials
indicated that the supplement may reduce osteoarthritis symptoms
and improve function by an average of some 50%, although the
studies had flaws that may exaggerate the benefits.
Safety Considerations
No study so far has found any serious side effects from either
glucosamine or chondroitin. The most common side effects are
increased flatulence and softened stools. Patients with diabetes
should monitor their blood-sugar level particularly carefully
when using the supplement. There have been no reports of allergic
reactions to glucosamine. But since it's made from shellfish
shells, people who are allergic to seafood should use it cautiously,
watching for reactions, or avoid it entirely. As for chondroitin,
it can cause bleeding in people who have a bleeding disorder
or take a blood-thinning drug (warfarin)
It may take two months to produce any significant improvement.
If you see no effect by then, and have taken the full dose
of 1.5g per day it's probably best to try a different approach.
A clinical trial that should add considerably to medical
knowledge about glucosamine and chondroitin has been funded
and is now recruiting patients. It will be a 24-week, placebo-controlled,
double-blind, study that will evaluate the effect on osteoarthritic
knee pain of glucosamine hydrochloride, chondroitin, a combination
of the two, and celicoxib among 1588 participants at 13 centres
throughout the country over a 27-month period [5]. The estimated
completion date in March 2005.
Glucosamine products
Currently glucosamine and chondroitin products are regarded
as food supplements and not available on NHS prescription
References:
- McAlindon TE and others. Glucosamine
and chondroitin for treatment of osteoarthritis: A systematic
quality assessment and meta-analysis JAMA 283:1469-1475,
2000. [ Full-text
version is accessible online for JAMA subscribers.]
- Tanveer E, Anastassiades TP. Glucosamine and chondroitin
for treating symptoms of osteoarthritis: Evidence is widely
touted but incomplete. JAMA 283:1483-1484, 2000. [ Full-text
version is accessible online for JAMA subscribers.]
- Reginster JY and others. Long-term
effects of glucosamine sulfate on osteoarthritis progression:
a randomized, placebo-controlled trial . Lancet 357:251-256,
2001.
- Study
of the efficacy of glucosamine and glucosamine/chondroitin
sulfate in knee osteoarthritis . NIH Web site, accessed
Jan 22, 2002
- Bandolier
- Glucosamine and arthritis 2001
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