ITLN1 and rheumatoid arthritis: The incidence of RA had also a significant impact on the serum and expression levels of chemerin (partial eta squared = 0.935 and 0.103, respectively), apelin (partial eta squared = 0.966 and 0.414, respectively), vaspin (partial eta squared = 0.968 and 0.191, respectively), and omentin (partial eta squared = 0.794 and 0.685, respectively) (p = 0.001).