Trial of Vitamin D to Reduce Progression of Knee OA

描述（由申请人提供）：症状性膝骨关节炎的发病率为240/100,000人年，是下肢活动依赖的最常见原因之一，尤其是在老年人中。它每年造成6800万日的失业，占年退休率的5%以上。骨关节炎是关节置换术最常见的原因，每年花费数十亿美元。目前还没有有效的治疗骨关节炎的药物。然而，制药行业正试图开发延缓OA进展的药物。如果有效，这些专有药物在OA流行的人群中使用将是昂贵的。具有讽刺意味的是，有证据表明补充维生素D，一种简单的非专利干预，可能对减缓OA的进展有效。即使只是适度有效，它也可以在减轻OA的社会负担方面产生相当大的影响。因此，为了公共卫生的利益，补充维生素D作为OA疾病改善治疗的有效性需要在严格的临床试验中进行测试。

DESCRIPTION (provided by applicant): Symptomatic knee osteoarthritis has an incidence of 240/100,000 person years and is one of the most frequent causes of dependency in lower limb tasks, especially in the elderly. It causes 68 million work loss days per year and more than 5% of the annual retirement rate. Osteoarthritis is the most frequent reason for joint replacement at a cost to the community of billions of dollars per year. No effective medical remedies for osteoarthritis currently exist. However, the pharmaceutical industry is attempting to develop drugs that retard progression of OA. If efficacious, these proprietary medications will be expensive to employ in a population in which OA is endemic. Ironically, there is evidence that vitamin D supplementation, a simple non-proprietary intervention, may have efficacy in slowing progression of OA. Even if only modestly effective, it could have considerable impact in terms of reducing the societal burden of OA. Therefore, in the interests of public health, the efficacy of vitamin D supplementation as a disease-modifying treatment for OA needs to be tested in a rigorous clinical trial. Disease-modification trials for knee OA have been difficult due to limitations of the radiographic technique. However, MRI has emerged as a valid, precise and reproducible tool for obtaining volumetric measures of cartilage and joint structures. Our goal is to enroll 140 individuals with symptomatic knee OA into a 2-year randomized placebo controlled clinical trial of vitamin D, 14,000 ID / week. Outcomes will include the WOMAC questionnaire (primary clinical), cartilage volume loss (primary pathological), physical function tests, SF-36 and whole organ knee MRI OA severity scores. Bone density, calcium homeostasis and knee alignment will be tested as intermediary variables. We will test effectiveness of vitamin D using cross-sectional time series regression models with first-order autoregressive disturbance adjusting for informative dropouts.