A new randomized controlled trial out of India has found that vitamin D may be helpful in osteoarthritis of the knee.
Osteoarthritis is a degenerative joint disease. People with osteoarthritis have an imbalance between the synthesis and degradation of articular cartilage, which leads to the wearing away of cartilage. In consequence, people with osteoarthritis suffer from pain, tenderness and stiffness of joints.
For those with the disease, there are no medical remedies to deal with the debilitating aspects of the condition. If the disease has led to significant disability, joint replacement is an option.
How or why osteoarthritis develops is not well understood. Depending on age, sex and definition, anywhere from 4 to 30% of the population suffer from osteoarthritis, so any preventive or therapeutic measures taking on the condition are desperately needed from a public health standpoint.
While supplements are often used in the management of osteoarthritis, very few of them have good evidence of effectiveness. It has been hypothesized that vitamin D may have an effect on the risk of development and progression of osteoarthritis, because vitamin D influences bone quality, and like osteoarthritis, vitamin D deficiency is common.
However, like most supplements, to date, no one has studied to see if vitamin D supplementation can help slow the progression of the disease.
Recently, Dr Divya Sanghi and colleagues of King George Medical University in India studied this very gap in research. They wanted to know, can vitamin D supplementation reduce pain and improve function in patients suffering from osteoarthritis?
So they developed a randomized controlled trial. One hundred three patients were randomized to receive either vitamin D or placebo. The vitamin D group received 60,000 IU of vitamin D for 10 straight days at baseline, and then 60,000 IU once a month for a year. The placebo group received a placebo pill for 10 straight days, then a placebo pill every month for a year.
Only patients that had vitamin D levels below 20 ng/ml at baseline and met other inclusion criteria were enrolled. Whichever knee suffered most from osteoarthritis (if both knees had osteoarthritis), that was the one researchers studied.
The researchers scored the severity of the patients’ osteoarthritis of the knee using the WOMAC scale, a questionnaire and point scoring system used to assess pain, stiffness and physical function. They administered this scale at 0, 1.5, 3, 6, and 12 months, while they measured vitamin D levels at 0, 6 and 12 months.
At the end of the trial they wanted to know, did vitamin D supplementation improve WOMAC scores in the vitamin D group compared to placebo? Here’s what they found:
- Mean vitamin D levels were low at baseline at about 15 ng/ml in both groups.
- After 12 months, WOMAC pain scores decreased in the vitamin D group (by minus-.55), while increased in the placebo group (by plus-1.16). The difference was very statistically significant (p = <.001).
- After 12 months, there was no difference in stiffness scores between the two groups.
- After 12 months, the vitamin D group showed improvement in physical function (minus-1.36 on WOMAC scale) compared to placebo group (plus-.69). The difference was very statistically significant (p = <.001).
- After 12 months, the vitamin D group had much better total WOMAC scores compared to the placebo group (the vitamin D group scored 3.53 points less than placebo, p = <.001).
The researchers concluded,
“The results above suggest there is a small but statistically significant clinical benefit to vitamin D treatment in patients with knee osteoarthritis, although we recommend a long-term study to determine whether these changes are clinically important and whether they will be sustained with time.”
In addition to a long-term study, the researchers also recommend that future research look for radiologic changes, rather than just using scales to assess disease-state changes. There are similar studies to this randomized controlled trial currently underway, and they should aid to our understanding of whether vitamin D can truly help osteoarthritis. In the meantime, the results from this study are promising and give all the more reason to ensure patients with osteoarthritis are getting enough vitamin D.