CYP27A1 and rheumatoid arthritis: We compared changes in serum levels of bone turnover markers (PINP, CTX-I, PINP/CTX-I ratio) and osteoclast regulators (sRANKL, OPG, sRANKL/OPG ratio) in females with RA who completed a 15-month anti-TNF-α therapy with ETA or ADA.