To the Editor:
We read with interest the article by Koeckhoven, et al1 suggesting that upper leg strength is associated with 25-hydroxy Vitamin D [25(OH)D] levels in patients with knee osteoarthritis (OA). The association seems to exist when adjustment is made for several confounding factors. However, adjusting for body mass index attenuated this association. One important limitation of their …
Address correspondence to Dr. F. Tufan, Istanbul University, Istanbul Faculty of Medicine, Department of Geriatrics, Fatih, P.B. 34093, Istanbul, Turkey. E-mail: drfatiht{at}istanbul.edu.tr