Vitamin D Deficiency Linked to Pain and Disability in Knee Osteoarthritis

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Vitamin D Deficiency Linked to Pain and Disability in Knee Osteoarthritis

http://www.medscape.com/viewarticle/491598?src=mp

 

Jane Salodof MacNeil

 

Oct. 19, 2004 (San Antonio) — Results from a 30-month study of 221

elderly patients with osteoarthritis of the knee suggest that remedying

a vitamin D deficiency can reduce disability and possibly pain as well.

 

David T. Felson, MD, MPH, from Boston University Medical Campus in

Massachusetts, reported that patients with low baseline vitamin D levels

had significantly more pain compared with patients with higher levels:

8.0 on the Western Ontario and McMaster Universities Osteoarthritis

Index (WOMAC) pain scale compared with 6.6 for patients with sufficient

vitamin D levels (P < .0001). They also had significantly higher scores

on the WOMAC disability scale: 26.9 vs 21.7 (P < .0001) but were not

substantially weaker in tests of muscle strength.

 

In patients whose low serum vitamin D levels showed correction over 30

months, disability scores improved significantly, from 26.9 to 21.8 (P =

..05). While trends toward reduced pain and weakness were also

documented, they did not reach statistical significance.

 

Dr. Felson urged physicians to look for and treat vitamin D deficiency

in all elderly patients complaining of knee pain. " I may be right or

wrong, but the vitamin D deficiency is a problem in those patients....

It needs to be replenished, " he said yesterday during a press conference

at the 68th annual scientific meeting of the American College of

Rheumatology.

 

Patients in the study were an average age of 67 years and were recruited

from the Boston Veterans Affairs Medical Center and surrounding

community. Almost two thirds of patients were men. Nearly half (48%) had

deficient baseline vitamin D levels defined as 20 ng/mL or less.

 

Although vitamin D deficiency is believed to be more common in northern

states where sunlight is less pronounced and the elderly spend less time

out of doors, Dr. Felson advised that it should not be ignored in lower

latitudes. " We're talking about everybody [age] 60 and over in the

United States above the Mason-Dixon line and maybe even below the

Mason-Dixon line. The prevalence of vitamin D deficiency is extremely

high, " he told Medscape in an interview.

 

Raising vitamin D levels is relatively easy, according to Dr. Felson. He

recommended three methods: at least 800 international units of vitamin D

(two 400 IU pills) in a daily vitamin supplement, drinking milk, and/or

going out for up to 15 minutes of sun exposure a few times a week.

 

Asked whether tanning was an option, he called the question a

" provocative and controversial area " he would rather not explore. " There

are very difficult issues of when sun exposure is enough to give vitamin

D sufficiency and when it is too much, so that you put people at risk of

getting cancer, " he said during the press briefing.

 

Afterward, in the interview, he added the caveat that physicians should

ask patients whether they have kidney stones or a history of kidney

stones in their families, because high doses of vitamin D are thought to

cause kidney stones, according to Dr. Felson.

 

He also cautioned that vitamin D is not a panacea. " The effect of

vitamin D on symptoms is relatively small, " he said. " This is not going

to make someone with a lot of knee pain feel all better usually. It's a

minor contributor, but it's such an easy correctible, it would be silly

not to pursue [it]. "

 

Press conference moderator Joseph Flood, MD, FACR, president of

Musculoskeletal Medical Specialists Inc. in Columbus, Ohio, and a

faculty member at Ohio State University, said the study adds weight to a

small but growing number of reports supporting treatment of vitamin D

deficiency in arthritis. " I think you should first ascertain whether

[patients] have a problem with vitamin D — I do it, " he said.

 

A practical problem, according to Dr. Flood, is that the cut-off for a

low vitamin D level has not been agreed upon. The standard test uses a

scale of 8 to 40 ng/mL. " I think [a patient's vitamin D level] should be

at least 25, " he said.

 

ACR 68th Annual Scientific Meeting: Abstract 1755. Press briefing held

Oct. 18, 2004; presented Oct. 20, 2004.

 

Reviewed by Gary D. Vogin, MD