Evidence-Based Answers

Evidence Central™ is an integrated web and mobile solution that helps clinicians quickly answer etiology, diagnosis, treatment, and prognosis questions using the latest evidence-based research.


Evidence Central for Mobile Devices

Evidence Central iOS iPhone iPad Android

Evidence Central from Unbound Medicine, available for iOS® and Android™, is optimized for each platform and features superior navigation, so answers are easy to find at the bedside or anywhere they’re needed. Learn More

Word of the Day

Vitamin D does not reduce knee pain from osteoarthritis

Clinical Question:
Does vitamin D supplementation reduce knee pain in adults with osteoarthritis?

Bottom Line:
Vitamin D supplementation at a dose targeted to reach a 25-hydroxyvitamin D plasma level higher than 36 ng/mL for 2 years did not reduce symptomatic knee pain in adults with osteoarthritis. (LOE = 1b)

McAlindon T, LaValley M, Schneider E, et al. Effect of vitamin D supplementation on progression of knee pain and cartilage volume loss in patients with symptomatic osteoarthritis. A randomized controlled trial. JAMA 2013;309(2):155-162.  [PMID:23299607]

Study Design:
Randomized controlled trial (double-blinded)



Outpatient (any)

Another trial of supplemental vitamin D not able to show any clinical benefit -- when will this medical fad run its course? These investigators identified adults, 45 years or older, meeting standardized international criteria for knee osteoarthritis based on both clinical and radiology findings. Patients randomly received (concealed allocation assignment) oral cholecalciferol 2000 IU or matched placebo daily, with optional subsequent increments of 2000 IU at 4, 8, and 12 months, targeted to reach a 25-hydroxyvitamin D plasma level of between 36 ng/mL (89.9 nmol/L) and 100 ng/mL (249.6 nmol/L). No supplemental calcium was given, but all patients received advice on optimal dietary calcium intake. Individuals assessing outcomes using standard pain rating scales and MRI imaging remained masked to treatment group assignment. Complete follow-up occurred for 85% of participants at 24 months. Using intention-to-treat analysis, significantly more patients assigned to the active supplement group achieved the target plasma level of 25-hydroxyvitamin D compared with the placebo group (61.3% vs 8.3%, respectively). However, there was no significant difference in reduction of knee pain between the 2 treatment groups. There was also no significant between-group difference based on MRI studies in cartilage thickness or bone marrow lesion size. Interestingly, at 16 months there were significantly more patients in the supplemental group reporting higher use of nonsteroidal anti-inflammatory drugs than in the placebo group (40% vs 22%; number needed to treat = 5.6). The study was 80% powered to detect a predetermined clinically significant difference in pain reduction between the 2 treatment groups.


Site Licenses

Site license

Site Licenses are available for schools, universities, hospitals, government agencies, and companies. For more information, contact us.