The effect of vitamin D supplementation on knee osteoarthritis, the VIDEO study: a randomised controlled trial

Abstract

Objective: Epidemiological data suggest low serum 25-hydroxyvitamin D3 (25-OH-D3) levels are associated with radiological progression of knee osteoarthritis (OA). This study aimed to assess whether vitamin D supplementation can slow the rate of progression.

Method: A 3-year, double-blind, randomised, placebo-controlled trial of 474 patients aged over 50 with radiographically evident knee OA comparing 800 IU cholecalciferol daily with placebo. Primary outcome was difference in rate of medial joint space narrowing (JSN). Secondary outcomes included lateral JSN, Kellgren & Lawrence grade, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain, function, stiffness and the Get up and Go test.

Results: Vitamin D supplementation increased 25-OH-D3 from an average of 20.7 (standard deviation (SD) 8.9) μg/L to 30.4 (SD 7.7) μg/L, compared to 20.7 (SD 8.1) μg/L and 20.3 (SD 8.1) μg/L in the placebo group. There was no significant difference in the rate of JSN over 3 years in the medial compartment of the index knee between the treatment group (average -0.01 mm/year) and placebo group (-0.08 mm/year), average difference 0.08 mm/year (95% confidence interval (CI) [-0.14-0.29], P = 0.49). No significant interaction was found between baseline vitamin D levels and treatment effect. There were no significant differences for any of the secondary outcome measures.

Conclusion: Vitamin D supplementation did not slow the rate of JSN or lead to reduced pain, stiffness or functional loss over a 3-year period. On the basis of these findings we consider that vitamin D supplementation has no role in the management of knee OA.

Keywords: Knee; Osteoarthritis; Randomised placebo-controlled trial; Vitamin D.

Conflict of interest statement

Declaration of interests All authors have completed the Unified Competing Interest form at www.icmje.org/coi_disclosure.pdf and declare the following interests: NA reports consultancy work for Merck, Roche, Smith & Nephew, Q-Med, Nicox, Flexion, payment for lectures from Bioiberica and Servier, outside of the submitted work. CC reports personal fees from Servier, personal fees from Amgen, personal fees from Eli Lilly, personal fees from Merck, personal fees from Medtronic, personal fees from Novartis, outside the submitted work. Researchers were independent from funders and sponsors.

Copyright © 2016 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.

Figures

Figure 1

Consort flow diagram for the VIDEO study

Figure 2

Mean Joint Space Width in the medial compartment of the index knee with 95% CI’s by treatment group Detailed legend: (N = 474 All available readings were included in primary analysis and multiple imputation was used to impute missing values, assuming all missing outcome values were missing at random, conditional on treatment and the covariates included in the imputation model. Both centre and baseline BMI were included in the imputation model.

Figure 3

Scatterplot of 12 month change in Vitamin D3 against three year change in Joint Space Width (N = 402).

Figure 4

Scatter plot of 3 year change in Joint Space Width against 12 month change in vitamin D3 for patients who are vitamin D deficient at baseline, defined as serum 25-OH-D3