Among eight SSc-associated susceptibility polymorphisms which were applied for meta-analysis, IRF5 rs2004640 polymorphism (OR 1.12; 95% CI 1.02-1.22, P = 1.39 × 10<sup>-2</sup>), STAT4 rs7574865 polymorphism (OR 1.25; 95% CI 1.07-1.47, P = 5.3 × 10<sup>-3</sup>), IRAK1 rs1059702 polymorphism (OR 1.20; 95% CI 1.05-1.37, P = 0.007), and CTGF G-945C polymorphism (OR 1.42; 95% CI 1.18-1.71, P = 0.002) are associated with PF status in SSc, while TNFAIP3 rs5029939, CD226 rs763361, CD247 rs2056626, and IRF5 rs10488631 polymorphisms are not.
On the other hand, IRAK1 rs1059702 was consistently associated with presence of pulmonary fibrosis (PF), because statistical significance was observed when comparing SSc patients PF+ versus controls (PFDR=0.039, OR=1.30, 95% CI 1.07 to 1.58) and SSc patients PF+ versus SSc patients PF- (p=0.025, OR=1.26, 95% CI 1.03 to 1.55).