By Richard Lenti
People with knee osteoarthritis (OA) have increasingly turned to supplements like Vitamin D to help alleviate their pain. But according to a new study out of Tufts Medical Center in Boston, there was no significant difference in knee pain for patients who took vitamin D supplements and those who received a placebo.
“The overall data suggest that vitamin D supplementation does not have major effects on clinical or structural outcomes in knee OA,” said Dr. Timothy McAlindon, who co-authored the study published in the Journal of the American Medical Association.
Over a two year period, researchers looked at nearly 150 patients diagnosed with symptomatic knee osteoarthritis to see whether vitamin D could reduce symptomatic and structural progression of the disease. The average age of the patients was 62.
“Knee osteoarthritis is a common age-related musculoskeletal disorder that has significant functional impact and has considerable societal costs through work loss, early retirement, and arthroplasty,” said McAlindon. “Despite its impact, there are no medical treatments established to influence the course of the disease. Some studies have suggested that vitamin D may protect against structural progression.”
The study monitored patients’ knee pain and examined their cartilage volume loss with magnetic resonance imaging (MRI). Patients were also tested for their knee function, cartilage thickness and bone marrow lesions.
By the end of the study, researchers found that knee pain slightly decreased in both the Vitamin D and placebo groups by an average of 2 percent, but there were no significant differences between them at any time. Cartilage volume also decreased by about 4% in both groups.
Although the study was predicated on the known benefits of vitamin D on bone health, the authors were not convinced by research that suggested an association between low levels of vitamin D and the increased risk of bone density loss in knee or hip OA.
They cited two studies that at first appeared to show strong associations of bone density with the
development of knee OA, but were later questioned when researchers published concerns about the results being “confounding.”
Knee osteoarthritis is a degenerative disease of the knee joint. It is more common in people over the age of 40. Women have a greater chance to be affected. Symptoms include pain, stiffness, decreased range of motion, muscle weakness and atrophy.