Dear Dr. Cannell:
Eleven years ago, I had pain in my left knee while walking. When visiting an orthopedist, he informed me that I needed to have a knee replacement due to osteoarthritis (OA). This type of arthritis occurs as a result of wear and tear on the joints, commonly experienced as people age. I saw the x-rays of my knee; they showed bone on bone, also called joint space narrowing. I’m pretty sure vitamin D helps osteoarthritis.
My experience is similar to yours. A year after I started taking vitamin D, I too was told I need a knee replacement.
That was only a year after I started taking 5,000 – 10,000 IU/day of vitamin D. Eleven years later, I’m now pain free and can easily walk several miles on flat surfaces; though, I still can’t hike up hills without experiencing pain. As I like to hike, I’m considering getting a knee replacement.
OA affects nearly 27 million people in the United States, accounting for 25% of visits to primary care physicians and half of all NSAID (ibuprofen-like medication) prescriptions. It is estimated that 80% of the population have X-ray evidence of OA by the age of 65, although only 60% of those individuals will have symptoms.
In the United States, there were approximately 964,000 hospitalizations for osteoarthritis in 2011. With an aggregate cost of $14.8 billion ($15,400 per stay), it was the second-most expensive condition seen in U.S. hospital stays. By payer, it was the second-most costly condition billed to Medicare and private insurance.
Does vitamin D have any effect on osteoarthritis? A randomized controlled trial in JAMA reported no effects, but there was a problem with the study. Only 60% of the treatment group reached the target 25(OH)D level of 36 ng/ml. In 2013, I blogged on that JAMA study.
Now a new meta-analysis supports my reservations of the JAMA trial. Researchers from the Netherlands did a meta-analysis of 12 OA and vitamin D studies, six cross-sectional and six prospective. In their prospective cohorts they included about 4,600 subjects, of whom about 1,100 developed or had worsening knee OA.
Bergink AP, Zillikens MC, Van Leeuwen JP, Hofman A, Uitterlinden AG, van Meurs JB. 25-Hydroxyvitamin D and osteoarthritis: A meta-analysis including new data. Semin Arthritis Rheum. 2015 Oct 29. pii: S0049-0172(15)00239-5. doi: 10.1016/j.semarthrit.2015.09.010. [Epub ahead of print]
The researchers found that vitamin D levels had no effect on hip or hand OA. However, they did find the risk of progressive knee OA was about 2.4 fold higher in those with the lowest vitamin D levels compared to the highest.
The authors wrote:
“In conclusion, this meta-analysis does not demonstrate an association between vitamin D levels and hip or hand OA. Subgroup analyses show significant associations of low vitamin D levels with prevalent knee JSN and progressive knee OA. Overall, the results of this study do not support the advice to supplement vitamin D to prevent the onset or worsening of osteoarthritis, except perhaps for progressive knee OA.”
The study demonstrates that vitamin D status may play a role in the prevention or treatment of knee osteoarthritis. This supports my belief that vitamin D helped treat my knee pain.
If I had knee arthritis or wanted to help prevent it, I’d take (as I do), 10,000 IU/day of vitamin D.
John Cannell, MD