Figure 1From: Promoter polymorphisms in the chitinase 3-like 1 gene influence the serum concentration of YKL-40 in Danish patients with rheumatoid arthritis and in healthy subjectsNon-linear association between age and serum concentrations of YKL-40. Restricted cubic spline model with six knots applied for patients with rheumatoid arthritis (RA) and controls.Back to article page