The Effects of Vitamin D Supplementation in Patients with Knee Osteoarthritis:Uncontrolled Open Label Clinical Trial

Abstract

Background: Osteoarthritis (OA) is a degenerative disease that affects joints. The current relationship between low vitamin D levels, functions, and symptoms of osteoarthritis is controversial. Objective: The aim of this study is to investigate the relationship between knee osteoarthritis and serum levels of vitamin D. Method: An uncontrolled open label clinical trial conducted on patients with low vitamin D levels using the Western Ontario and McMaster Universities Arthritis Index (WOMAC criteria). The WOMAC criteria used objectively to assess knee-joint function and symptoms before and after vitamin D3 supplementation. The study conducted from March 2013 to October 2015 at King Abdulaziz Medical City. Riyadh, Saudi Arabia. All participants with knee osteoarthritis and low vitamin D levels (≤75 nmol/L) were given 45,000 IU of vitamin D3 orally, once per week for three months, followed by 45,000 IU of vitamin D3 once every two weeks. Results: Of the 100 participants recruited to the study, 58 patients completed the clinical trial and included in the analysis. Nineteen participants excluded due to severe knee OA, vitamin D use, or history of knee surgery, while 23 patients were lost during the follow-up period. Among the 58 patients completing the trial, 39 were females and 19 were males, with an average age of 45.7 ± 4.5 years. The WOMAC scores did not change significantly (P=0.920) post-treatment with vitamin D3, despite the significant improvement of vitamin D levels (P=0.001). Conclusion: This study did not find a relationship between vitamin D levels, knee symptoms and functions in patients with OA.