Association of insulin gene variable number of tandem repeats regulatory polymorphism with polycystic ovary syndrome

The present meta-analysis aimed to investigate the association between insulin gene variable number of tandem repeats (INS VNTR) and polycystic ovary syndrome (PCOS). Systematic searches of electronic databases, reference lists of included articles, and the abstracts presented at related scientific societies meetings were performed. Statistical analyses were conducted using software Stata 11.0. The pooled odds ratios (ORs) with 95% confidence intervals (95% CIs) were applied. Publication bias was tested by Begg's funnel plot and Egger's regression test. A total of 9 studies including 1075 PCOS patients and 2878 controls were included in the meta-analysis. There were evidence of statistical significant association between INS VNTR and PCOS in allelic model (OR=1.25, 95% CI=1.08-1.43, P=0.002) and dominant model (OR=1.34, 95% CI=1.11-1.63, P=0.003) but not in additive model (OR=1.38, 95% CI=0.93-2.04, P=0.11) and recessive model (OR=1.26, 95% CI=0.96-1.65, P=0.09). No significant publication bias was shown by funnel plots and Egger's regression tests. In conclusion, our meta-analysis suggests that the III allele of INS VNTR is associated with increased risk of PCOS.