SFRP1 and rheumatoid arthritis: Premenopausal rheumatoid arthritis patients with remission and low disease activity have low levels of TNF-α proinflammatory cytokines, and it has no correlation with the high level of osteoblastogenesis inhibitor (SFRP-1) and the high level of bone resorption marker (CTX), but TNF-α and SFRP-1 levels have a weak positive correlation with the low bone formation marker (P1NP).