Osteoarthritis is an incurable condition with few effective treatments beyond pain control.
Some observational evidence suggests that vitamin D supplements might slow progression of the disease.
But a two-year randomized placebo-controlled study found that vitamin D did not reduce knee pain or restore cartilage.
In an article published in The Journal of the American Medical Association last week, researchers described a study of 146 men and women with painful knee arthritis who were randomly assigned to take vitamin D supplements or placebos.
Vitamin D was given in quantities sufficient to raise blood levels to 36 nanograms per milliliter, a level considered sufficient for good health.
Knee pain decreased slightly in both groups, but there were no differences in the amount of cartilage lost, bone mineral density or joint deterioration as measured by X-rays and M.R.I. scans.
The lead author, Dr. Timothy McAlindon, chief of the division of rheumatology at Tufts Medical Center, said taking vitamin D in higher doses or for longer periods might make a difference, but he's not hopeful.
"Although there were lots of promising observational data, we find no efficacy of vitamin D for knee osteoarthritis," he said. "There may be reasons to take vitamin D supplements, but knee osteoarthritis is not one of them."
Some observational evidence suggests that vitamin D supplements might slow progression of the disease.
But a two-year randomized placebo-controlled study found that vitamin D did not reduce knee pain or restore cartilage.
In an article published in The Journal of the American Medical Association last week, researchers described a study of 146 men and women with painful knee arthritis who were randomly assigned to take vitamin D supplements or placebos.
Vitamin D was given in quantities sufficient to raise blood levels to 36 nanograms per milliliter, a level considered sufficient for good health.
Knee pain decreased slightly in both groups, but there were no differences in the amount of cartilage lost, bone mineral density or joint deterioration as measured by X-rays and M.R.I. scans.
The lead author, Dr. Timothy McAlindon, chief of the division of rheumatology at Tufts Medical Center, said taking vitamin D in higher doses or for longer periods might make a difference, but he's not hopeful.
"Although there were lots of promising observational data, we find no efficacy of vitamin D for knee osteoarthritis," he said. "There may be reasons to take vitamin D supplements, but knee osteoarthritis is not one of them."