Role of IL-17 gene polymorphisms in osteoarthritis: A meta-analysis based on observational studies

BACKGROUND Osteoarthritis (OA) is a chronic complex multifactorial joint disease, and a major degenerative form of arthritis. Existing studies on the association between polymorphisms of the IL-17 gene and the risk of OA in different populations have yielded conflicting findings. AIM To investigate the association between polymorphisms of the IL-17 gene and the risk of OA. METHODS We conducted a meta-analysis by systematically searching databases, including PubMed, EMBASE, MEDLINE, Cochrane Library, and Google Scholar to evaluate this association by calculating pooled odds ratios with 95% confidence intervals. Moreover, subgroup analyses stratified by ethnicity and OA type were also conducted. RESULTS In a total of 6 citations involving 8 studies (2131 cases and 2299 controls), 4 single nucleotide polymorphisms were identified. Of these 4 polymorphisms, 2 (rs2275913, rs763780) were common in five case-control studies. Together, the pooled results revealed that the A allele and genotype AA/GA of the rs2275913 polymorphism, and the C allele and genotype CC of the rs763780 polymorphism in the IL-17 gene increased the risk of OA. Furthermore, stratification analyses by ethnicity and OA type showed that the rs2275913 polymorphism increased the risk of OA among Asians and in knee/hip OA, respectively. In addition, stratification analyses also revealed that the rs763780 polymorphism increased OA risk among both Asians and Caucasians in knee/hip OA. CONCLUSION The rs763780 polymorphism of the IL-17F gene increased the risk of OA, whereas the rs2275913 polymorphism of the IL-17A gene increased the risk of OA only among Asians. Due to the limitations of this study, these findings should be validated in future studies.