Vitamin D Supplementation in Knee Osteoarthritis

Muscular (i.e., quadriceps) weakness is a major risk factor for predisposing the knee to osteoarthritis, impairing physical function, and increasing patient-reported pain. Muscular weakness is a consequence of and could contribute to the development of knee osteoarthritis. Minimizing muscular weakness has been fount to improve activities of daily living in patients with osteoarthritis symptoms. Although vitamin D associates with muscular strength in young and old populations, it is unknown if vitamin D supplementation improves muscular strength in subjects with osteoarthritis or osteoarthritis symptoms. It is also unknown if supplemental vitamin D alters circulating cytokine concentrations in subjects with knee osteoarthritis. Furthermore, it is probable that a more comprehensive supplement is necessary to improve muscular strength. Such as glucosamine sulfate and omega-3 fatty acids (i.e., eicosapentaenoic and docosahexaenoic acids) which could be influential on knee pain and inflammation as well as muscular strength. Therefore, the purpose of this study is to identify the influence of vitamin D supplementation with and without glucosamine sulfate and omega-3 fatty acids on circulating cytokine concentrations and muscular strength in subjects with knee osteoarthritis symptoms. This study is intended to establish preliminary data identifying the influence of vitamin D supplementation on circulating cytokines and muscular strength in subjects with osteoarthritis at no more than minimal risk exposure to subjects.