Studies about vitamin D and arthritis:
Vitamin D Serum Level, Disease Activity and Functional Ability in Different Rheumatic Patients (2015)
Conclusion: The vitamin D levels of 120 adult arthritis patients were measured. 74% of psoriatic arthritis patients, 94% of rheumatoid arthritis patients, and 97% of osteoarthritis patients had insufficient vitamin D levels. Severe deficiency was found in 13% of PsA patients, 39% of RA patients, and 38% of OA patients.
Vitamin D Status in Rheumatoid Arthritis Patients: Relation to Clinical Manifestations, Disease Activity, Quality of Life and Fibromyalgia Syndrome (2014)
Conclusion: The vitamin D levels of 63 rheumatoid arthritis patients were compared to 62 healthy, matched controls. The vitamin D levels of the RA patients were “significantly lower” than those of the controls, with over 50% of RA patients classifiable as deficient. Within the RA group, those also suffering from fibromyalgia syndrome had even lower vitamin D levels. Vitamin D status was also found to strongly correlate with Quality of Life Index scores.
Prevalence of Vitamin D Insufficiency/Deficiency in Rheumatoid Arthritis and Associations with Disease Severity and Activity (2011)
Conclusion: Of 850 elderly, male rheumatoid arthritis patients, 84% had low vitamin D levels and those with the lowest levels had the highest incidences of joint tenderness.
Conclusion: 272 Swiss rheumatology patients had their vitamin D levels tested and nearly 90% had low levels. Only 25% of those taking vitamin D supplements (400-800 IU daily) enjoyed adequate vitamin D levels, demonstrating that traditionally recommended doses are not enough.
Association Between Residences in U.S. Northern Latitudes and Rheumatoid Arthritis: A Spatial Analysis of the Nurses’ Health Study (2010)
Conclusion: A 14-year residency-tracking study of 461 female rheumatoid arthritis cases and 9,220 female controls found that those residing in higher latitudes were at a higher risk for rheumatoid arthritis.
Conclusion: Vitamin D levels were checked in 62 rheumatoid arthritis patients from the John Hopkins Arthritis Clinic. 61% tested as being vitamin D-deficient and those who were deficient were also more likely to be suffering from disability.
The Prevalence of Vitamin D Deficiency in Consecutive New Patients Seen Over a 6-Month Period in General Rheumatology Clinics (2010)
Conclusion: The vitamin D levels of 231 arthritis patients were measured, 70% were deficient.
Vitamin D Deficiency Among Patients Attending a Central New Zealand Rheumatology Outpatient Clinic (2005)
Conclusion: The vitamin D levels of 55 patients from a New Zealand rheumatology clinic were checked at the beginning of winter and it was found that 78% of them had low levels.
Conclusion: Women with higher vitamin D levels have fewer incidences of rheumatoid arthritis.
Evidence of Altered Bone Turnover, Vitamin D and Calcium Regulation with Knee Osteoarthritis in Female Twins (2003)
Conclusion: This study of 882 “female Caucasian twin pairs” in the UK found that those with evidence of knee osteoarthritis had lower vitamin D levels compared to those not showing signs of knee osteoarthritis.
Conclusion: In a study of 20 rheumatoid arthritis patients, vitamin D therapy proved to be effective for reducing joint inflammation and tenderness and morning stiffness.
Disease Modifying and Immunomodulatory Effects of High Dose 1 Alpha (OH) D3 in Rheumatoid Arthritis Patients (1999)
Conclusion: In a three-month study of 19 rheumatoid arthritis patients, vitamin D therapy proved to be effective for reducing disease activity in 89% of the participants, with 45% experiencing complete remission. All participants experienced a reduction in joint pain and inflammation.
Serum Vitamin D Levels and Incident Changes of Radiographic Hip Osteoarthritis: A Longitudinal Study (1999)
Conclusion: In a decade-long study of 237 elderly white women, those with the lowest vitamin D levels had the highest incidence of osteoarthritis progression.
1,25-Dihydroxycholecalciferol Inhibits the Progression of Arthritis in Murine Models of Human Arthritis (1998)
Conclusion: Vitamin D is an effective treatment for reducing arthritis symptoms in mice.
Relation of Dietary Intake and Serum Levels of Vitamin D to Progression of Osteoarthritis of the Knee Among Participants in the Framingham Study (1996)
Conclusion: This prospective study of 556 participants who received knee radiographies found that those with lower vitamin D levels had a threefold increased risk for knee osteoarthritis progression. Low vitamin D levels were also correlated with loss of knee cartilage.