Vitamin D status in patients with knee or hip osteoarthritis in a Mediterranean country

BACKGROUND: Vitamin D plays an important role in bone mineralization, remodeling, and maintenance and therefore its deficiency may be implicated in the pathogenesis of osteoarthritis (OA). Vitamin D status was evaluated in patients with knee or hip OA scheduled for joint replacement. The impact of anthropometric parameters such as gender, age, and body mass index on vitamin D levels was also examined. The study was conducted in a Mediterranean country (Greece). MATERIALS AND METHODS: We included 164 patients with knee or hip OA scheduled for joint replacement in this study. Serum levels of 25-hydroxyvitamin D (vitamin D) were measured in routine blood samples taken from the patients at their pre-admission visit, a week before the operation, using radioimmunoassay. RESULTS: The majority of patients were vitamin D deficient (81.7 %); 15.2 % of them were vitamin D insufficient (hypovitaminosis). Only 3 % of patients were vitamin D sufficient. There was a significantly positive association between vitamin D levels and male gender. CONCLUSION: These findings indicate a large percentage of vitamin D deficient patients with knee or hip OA, which is unexpected considering the high annual insolation in northern Greece. Many other possible predisposing factors for OA should be taken into consideration. Whether treatment with vitamin D supplements may provide beneficial effects to these patients and the stage of disease in which this treatment should commence remains an issue for further scientific investigation. LEVEL OF EVIDENCE: Level IV.