Associations of MMP-7 and OPN gene polymorphisms with risk of coal workers' pneumoconiosis in a Chinese population: a case-control study

Background: The matrix metalloproteinase-7 (MMP-7) and osteopontin (OPN) are both multifunctional proteins with roles in inflammation, cell proliferation, tissue remodeling and so on, implicated in the pathogenesis of numerous conditions including pulmonary fibrosis. In this study, we investigated the associations between the potential functional polymorphisms in MMP-7 and OPN and the risk of coal workers' pneumoconiosis (CWP) in a Chinese population.Methods: Four polymorphisms (rs10502001 in MMP-7, rs1126772, rs11728697 and rs9138 in OPN) were genotyped and analyzed in a case-control study of 697 CWP and 694 control subjects.Results: Our results revealed that three single nucleotide polymorphisms (SNPs, MMP-7 rs10502001, OPN rs1126772 and OPN rs11728697) were associated with increased risk of CWP under a recessive model (adjusted odds ratio [OR]=1.80, 95% confidence interval [CI]=1.01-3.20, p=0.045 for MMP-7 rs10502001; adjusted OR=2.09, 95% CI=1.17-3.72, p=0.013 for OPN rs1126772; adjusted OR=2.48, 95% CI=1.37-4.51, p=0.003 for OPN rs11728697). Additionally, a combined effect was observed in a dose-dependent manner with increasing numbers of risk variant alleles (P-trend=0.003). Furthermore, logistic regression analysis revealed no significant interaction between SNPs and smoking status on CWP risk.Conclusions: Our results indicate that three functional SNPs (MMP-7 rs10502001, OPN rs11728697 and OPN rs1126772) are associated with an increased risk of CWP in a Chinese population.