title: Parity and type 2 diabetes mellitus: a study of insulin resistance and β-cell function in women with multiple pregnancies.
abstract: OBJECTIVE
  Increasing parity may be a risk factor for the development of type 2 diabetes mellitus and the metabolic alterations during a normal pregnancy induces a prediabetic state; thus, multiple pregnancies may act as a risk factor for development of type 2 diabetes if these physiological alterations in glucose homeostasis are not reversed postpartum. We hypothesize that multiple pregnancies may lead to β-cell exhaustion and that the insulin resistance that occurs during pregnancy may persist after multiple births.
  A total of 28 healthy premenopausal women were recruited: 15 high parity women (≥4 children) and 13 body mass index (BMI)-matched and age-matched low parity women (1 and 2 children). The study consisted of an intravenous glucose tolerance test for assessment of β-cell function followed by a hyperinsulinemic euglycemic clamp for assessment of insulin sensitivity. Dual-energy X-ray absorptiometry was performed to assess body composition.
  
  
  RESULTS
  All anthropometric measures, measures of body composition and baseline blood samples were comparable between the 2 groups. Neither first phase insulin release (0-10 min, p=0.92) nor second phase insulin release (10-60 min, p=0.62), both measured as area under the curve, differed between the 2 groups. The M-value, calculated as the mean glucose infusion rate during the last 30 min of the clamp period, was 8.66 (7.70 to 9.63) mg/kg/min in the high parity group compared with 8.41 (7.43 to 9.39) mg/kg/min in the low parity group (p=0.69).
  
  
  CONCLUSIONS
  We did not detect any effects of increasing parity on insulin sensitivity or β-cell function.
authors.affiliation: Department of Obstetrics and Gynecology , Aarhus University Hospital , Aarhus , Denmark.
authors.forename: Ditte Smed
authors.initials: DS
authors.lastname: Iversen
authors.affiliation: Department of Endocrinology and Internal Medicine , Aarhus University Hospital , Aarhus , Denmark.
authors.forename: Julie
authors.initials: J
authors.lastname: Støy
authors.affiliation: Department of Endocrinology and Internal Medicine , Aarhus University Hospital , Aarhus , Denmark.
authors.forename: Ulla
authors.initials: U
authors.lastname: Kampmann
authors.affiliation: Department of Endocrinology and Internal Medicine , Aarhus University Hospital , Aarhus , Denmark.
authors.forename: Thomas Schmidt
authors.initials: TS
authors.lastname: Voss
authors.affiliation: Department of Endocrinology and Internal Medicine , Aarhus University Hospital , Aarhus , Denmark.
authors.forename: Lene Ring
authors.initials: LR
authors.lastname: Madsen
authors.affiliation: Department of Endocrinology and Internal Medicine , Aarhus University Hospital , Aarhus , Denmark.
authors.forename: Niels
authors.initials: N
authors.lastname: Møller
authors.affiliation: Department of Obstetrics and Gynecology , Aarhus University Hospital , Aarhus , Denmark.
authors.forename: Per Glud
authors.initials: PG
authors.lastname: Ovesen
keywords: Beta Cell Function; Insulin Sensitivity; Parity; Type 2 Diabetes