Background:Rheumatoid arthritis (RA) is a progressive inflammatory autoimmune disease with articular and systemic effects. Its exact cause is unknown, but genetic and environmental factors are contributory. Although some patients have mild self-limited disease, many experience joint destruction, severe physical disability and multiple co-morbidities. T cells, B cells and the interaction of pro-inflammatory cytokines play key roles in the pathophysiology of RA.In addition to the effect of vitamin K on blood coagulation, several studies have indicated the important role of vitamin K in bone metabolism and bone protection. Vitamin K functions as a coenzyme for vitamin K-dependent carboxylase, an enzyme required for the synthesis of proteins involved in hemostasis (blood clotting) and bone metabolism.Matrix Gla-protein, a vitamin K-dependent protein present in vascular smooth muscle, bone, and cartilage, is the focus of considerable scientific research because it might help reduce abnormal calcification. Osteocalcin is another vitamin K-dependent protein that is present in bone and may be involved in bone mineralization or turnover. There is evidence of a correlation between low serum levels of vitamin k and a high incidence of femoral neck and vertebral fractures