Relationships of common polymorphisms in IL-6, IL-1A, and IL-1B genes with susceptibility to osteoarthritis: a meta-analysis

Observational and experimental studies have arrived at inconsistent conclusions about whether common polymorphisms in IL-6, IL-1A, and IL-1B genes are associated with an increased risk of osteoarthritis (OA). Therefore, we undertook a comprehensive meta-analysis to more systematically summarize the relationships of IL-6, IL-1A, and IL-1B genetic polymorphisms with susceptibility to OA. We screened the PubMed, Embase, Web of Science, Cochrane Library, CISCOM, CINAHL, Google Scholar, China BioMedicine (CBM), and China National Knowledge Infrastructure (CNKI) databases up to 31 March 2014. We used STATA software to analyze statistical data. Odds ratios (ORs) and their corresponding 95 % confidence intervals (95 % CIs) were calculated. Seventeen independent case-control studies were included in this meta-analysis with a total number of 7,491 subjects, comprised of 3,293 OA patients and 4,729 healthy controls. Our results indicate that IL-6, IL-1A, and IL-1B genetic polymorphisms are statistically correlated with an increased risk of OA under the allele and dominant models. According to a subgroup analysis based on disease, a higher frequency of IL-6 genetic polymorphisms was observed among knee OA and hand OA patients, but not among hip OA and DIP OA patients. A higher frequency of IL-1A genetic polymorphisms were found among hip OA patients, hand OA, hip OA and DIP OA patients. Furthermore, we observed a higher IL-1B polymorphism frequency among knee OA and hip OA patients, but not among hand OA patients. Our findings provide evidence that IL-6, IL-1A, and IL-1B genetic polymorphisms may be correlated with susceptibility to OA.