title: Insulin resistance, polycystic ovary syndrome, and type 2 diabetes mellitus.
abstract: OBJECTIVE
  To review the definition and prevalence of two insulin resistance (IR)-associated phenotypes, polycystic ovary syndrome (PCOS) and type 2 diabetes mellitus, as well as the risk and nature of their simultaneous presentation.
  
  
  METHODS
  Review of published literature.
  
  
  RESULTS
  Insulin resistance affects between 10% and 25% of the general population. Two common disorders frequently associated with IR are PCOS, affecting 4% to 6% of reproductive-aged women, and type 2 diabetes mellitus, which is observed in about 2% to 6% of similarly aged women. Overall, about 50% to 70% of women with PCOS and 80% to 100% of patients with type 2 diabetes mellitus have variable degrees of IR. Insulin resistance and its secondary hyperinsulinemia appear to underlie many of the endocrine features of PCOS in a large proportion of such patients. The risk of type 2 diabetes mellitus among PCOS patients is 5- to 10-fold higher than normal. In turn, the risk of PCOS among reproductive-aged type 2 diabetes mellitus patients appears to be similarly increased.
  
  
  CONCLUSIONS
  It remains to be determined whether PCOS and type 2 diabetes mellitus represent no more than different clinical manifestations of the same IR syndrome, with their phenotypic differences due to the presence or absence of a coincidental genetic defect at the level of the ovary or pancreas, respectively, or representing the result of etiologically different subtypes of IR syndromes.
authors.affiliation: Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA.
authors.forename: Fernando
authors.initials: F
authors.lastname: Ovalle
authors.forename: Ricardo
authors.initials: R
authors.lastname: Azziz
mesh_terms: D003924:Diabetes Mellitus, Type 2 / Q000150:complications / Q000453:epidemiology / Q000209:etiology / Q000503:physiopathology*; D005060:Europe; D005260:Female; D006801:Humans; D007333:Insulin Resistance / Q000502:physiology*; D011085:Polycystic Ovary Syndrome / Q000150:complications / Q000453:epidemiology / Q000209:etiology / Q000503:physiopathology*; D015995:Prevalence; D012307:Risk Factors; D009626:Terminology as Topic; D014481:United States