title: Lack of association of INS VNTR polymorphism with polycystic ovary syndrome: a meta-analysis.
abstract: OBJECTIVE
  An association between the INS VNTR polymorphisms and polycystic ovary syndrome (PCOS) susceptibility has been reported in previous studies, but the results were inconsistent. This study was conducted to explore this association using meta-analysis.
  
  
  METHODS
  PubMed, Embase, and China National Knowledge Infrastructure (CNKI) were searched according to predefined criteria for all relevant studies published up to August 2013. Four genetic models, together with odds ratios (ORs) and 95 % confidence intervals (CI), were calculated. Subgroup analyses were performed by ethnicity, anovulatory PCOS, and Hardy-Weinberg equilibrium (HWE) in the controls.
  
  
  RESULTS
  In total, 13 case-control studies, including 1,767 cases and 4,108 controls, were included. No significant association was detected in overall population in all models (III/III vs. I/I: OR = 1.200, 95%CI = 0.866-1.664, P=0.277; I/III vs. I/I: OR = 1.041, 95%CI = 0.880-1.232, P=0.637; III/III + I/III vs. I/I: OR = 1.191, 95%CI = 0.912-1.554, P=0.199; III/III vs. I/III + I/I: OR = 1.100, 95%CI = 0.816-1.484, P=0.531), the same as in Caucasian and Asian populations. When the studies were limited to conform to HWE, the results remained persistent and robust. The anovulation subgroup showed significantly elevated risk in the I/III vs. I/I (OR = 1.460, 95%CI = 1.017-2.095, P=0.040).
  
  
  CONCLUSIONS
  This meta-analysis revealed no significant association between INS VNTR polymorphisms and the risk of PCOS in the overall population, while it supported that variance may be associated with susceptibility to PCOS with anovulation. Further confirmation is needed from more well-designed and larger studies.
authors.affiliation: Department of Clinical Laboratory, First Affiliated Hospital of Guangxi Medical University, Nanning, 530021, Guangxi, China.
authors.forename: Liu-ying
authors.initials: LY
authors.lastname: Song
authors.forename: Jing-rong
authors.initials: JR
authors.lastname: Luo
authors.forename: Qi-liu
authors.initials: QL
authors.lastname: Peng
authors.forename: Jian
authors.initials: J
authors.lastname: Wang
authors.forename: Li
authors.initials: L
authors.lastname: Xie
authors.forename: Yu
authors.initials: Y
authors.lastname: He
authors.forename: Shan
authors.initials: S
authors.lastname: Li
authors.forename: Xue
authors.initials: X
authors.lastname: Qin
mesh_terms: D000483:Alleles; D016022:Case-Control Studies; D002681:China; D005006:Ethnicity; D005260:Female; D056726:Genetic Association Studies; D020022:Genetic Predisposition to Disease; D006801:Humans; D007328:Insulin / Q000235:genetics*; D018598:Minisatellite Repeats / Q000235:genetics*; D011085:Polycystic Ovary Syndrome / Q000235:genetics* / Q000473:pathology; D020641:Polymorphism, Single Nucleotide; D044465:White People
chemical_list: D007328:Insulin