Association of IRS-1 and IRS-2 genes polymorphisms with polycystic ovary syndrome: a meta-analysis

Insulin resistance (IR) plays an important role in the pathogenesis of polycystic ovary syndrome (PCOS) which is a common disorder in premenopausal women. The association between the single nucleotide polymorphisms (SNPs) of insulin receptor substrate (IRS) gene and PCOS in several populations has been studied, but the results are conflicting. The aim of this study was undertaken to investigate association of IRS-1 and IRS-2 genes polymorphisms with PCOS by conducting a meta-analysis. Literature search was conducted through PubMed and EMBASE databases (up to July 31, 2011). Fifteen articles with 1,358 cases and 1,561 controls were enrolled in the meta-analysis of the association between Gly972Arg variant and PCOS, and five articles with 519 cases and 883 controls were enrolled in the meta-analysis of Gly1057Asp variant. Summary odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using fixed and random-effects models. The Q-statistic test was used to assess heterogeneity, and Begg's test and Egger's test were used to evaluate publication bias. Sensitivity analysis was also performed. Our results indicated that A allele of Gly972Arg conferred a significantly increased risk of PCOS compared with G allele (OR = 1.91, 95% CI: 1.36-2.68). However, in Gly1057Asp polymorphism the OR of allele A vs. G is 0.92 (95% CI: 0.72, 1.18). Our meta-analysis suggested that IRS-1 Gly972Arg polymorphism might be considered a significant risk for PCOS. Otherwise, no significant associations were observed in IRS-2 Gly1057Asp polymorphism which needs to be further confirmed by further studies.