Patient case (clinical description): A 47-year-old woman comes to the office complaining of pain in the calf and knee when she bends down. The pain limits her activity. Her medical history is significant for osteoarthritis, for which she uses nonsteroidal anti-inflammatory drugs (NSAIDs) for the past two years. She is living with her husband and has 3 children. She doesn't smoke but drinks alcohol occasionally. Her vital signs are normal. On physical examination, there is a small effusion in the right knee. The effusion grew a little larger and she developed a tender swelling in the popliteal fossa and calf. Both the pain and swelling worsened as she bent and straightened her knee.

Patient's own account: I'm a 47-year-old woman, married with 3 kids. I don't smoke and I drink occasionally. I went to the doctor because of pain in my calf and knee when I was bending down. This has been limiting my daily activities. I have been diagnosed with osteoarthritis for which I have taken anti-inflammatory drugs for the past 2 years. The doctor saw a small fluid buildup in my right knee. This buildup became a bit bigger and I have a swollen calf. The pain is worse when I bend and straighten my knee.

Clinical trial: Vitamin D to Slow Progression of Knee Osteoarthritis

Eligibility criteria:
Inclusion Criteria:

          -  Chronic knee discomfort based on affirmative response to the question "During the past
             12 months, have you had pain, aching, or stiffness in or around your knee(s) on most
             days for at least one month?"

          -  WOMAC pain subscale score of at least 1

          -  Tibiofemoral OA on posterior anterior (PA) weight-bearing semi-flexed knee radiographs
             with severity equivalent to Kellgren and Lawrence grade of at least 2

          -  Clinical examination confirming knee pain or discomfort referable to the knee joint

          -  Prepared to refrain from use of glucosamine, chondroitin, MSM, DMSO, and doxycycline

          -  Pass faintness of heart trial period

        Exclusion Criteria:

          -  Serum 25(OH) vitamin D level greater than 80 ng/ml

          -  Use of glucosamine, chondroitin, or doxycycline within 3 months of random assignment

          -  Use of MSM, DMSO within 3 months of random assignment

          -  Use of vitamin D supplements such that the total daily dose is greater than 1,000 IU
             or a single source is greater than 800 IU

          -  Intra-articular joint injections (e.g., glucocorticoid or haluronic acid formulations,
             within 3 months of random assignment)

          -  Chronic glucocorticoid use

          -  Hypercalcemia (total serum calcium greater than 10.5 mg/dL)

          -  Hypercalcuria (spot urine calcium: creatinine ratio of 0.275 for women and 0.325 for
             men, corresponding to 24-hour calcium excretion of 0.30 and 0.35 g, respectively)

          -  Estimated GFR less than 30

          -  Hyperparathyroidism (PTH greater than 65 pg/mL)

          -  History of lymphoma or sarcoidosis

          -  Reiter's syndrome

          -  Psoriatic arthritis

          -  Rheumatoid arthritis

          -  Ankylosing spondylitis

          -  Currently on treatment for tuberculosis

          -  Malabsorption disorders (e.g., advance liver disease, chronic renal disease-stage 4 or
             5, Crohn's disease, Whipple's disease, celiac sprue)

          -  Serious medical conditions or impairments that, in the view of the investigator, would
             obstruct study participation

          -  Pregnancy

          -  Plan to permanently relocate from the region during the trial period

          -  Planned knee or hip arthroplasty during the study period

          -  Any contra-indication to having an MRI scan
No condition on gender to be admitted to the trial.
No healthy subjects accepted to join the trial.
Subject must be at least 45 Years old.
Subject must be at most 90 Years

Eligibility (NLI label): Entailment