title: Association of parity with risk of type 2 diabetes and related metabolic disorders.
abstract: OBJECTIVE
  The relationship between parity and risk of diabetes is controversial, and little information is available regarding associations between parity and measures of insulin resistance and beta-cell function. The objective of this study was to investigate the association between parity and risk of glucose intolerance and related metabolic disorders using data from a population-based study in a Native Canadian community.
  
  
  METHODS
  Female participants (n = 383, aged 12-79 years) provided fasting blood samples for the determination of glucose, insulin, C-peptide, and proinsulin concentrations. A 75-g oral glucose tolerance test was administered, and diabetes and impaired glucose tolerance were diagnosed according to World Health Organization criteria. Waist circumference and percent body fat were determined. Information regarding occurrence of live births and previously diagnosed diabetes was obtained from interviewer-administered questionnaires.
  
  
  RESULTS
  Parity was associated with a significantly reduced risk of diabetes (nulliparous vs. >or=1 birth, odds ratio 0.43, 95% CI 0.19- 0.94, P < 0.05) after adjustment for age and waist circumference. In addition, nondiabetic nulliparous women had significantly elevated concentrations of fasting insulin and proinsulin relative to nondiabetic parous women (all P < 0.05) in analyses adjusted for age and waist circumference.
  
  
  CONCLUSIONS
  Our results are consistent with those from other populations experiencing high rates of diabetes and suggest the presence of a diabetes-prone phenotype within the nulliparous subcohort of this population, which may contribute to infertility.
authors.affiliation: Department of Public Health Sciences, University of Toronto, Toronto, Canada. hanley@mshri.on.ca
authors.forename: Anthony J G
authors.initials: AJ
authors.lastname: Hanley
authors.forename: Gail
authors.initials: G
authors.lastname: McKeown-Eyssen
authors.forename: Stewart B
authors.initials: SB
authors.lastname: Harris
authors.forename: Robert A
authors.initials: RA
authors.lastname: Hegele
authors.forename: Thomas M S
authors.initials: TM
authors.lastname: Wolever
authors.forename: Jeremy
authors.initials: J
authors.lastname: Kwan
authors.forename: Bernard
authors.initials: B
authors.lastname: Zinman
mesh_terms: D000273:Adipose Tissue / Q000033:anatomy & histology; D000293:Adolescent; D000328:Adult; D000368:Aged; D001786:Blood Glucose / Q000032:analysis / Q000378:metabolism; D002096:C-Peptide / Q000097:blood; D002648:Child; D003924:Diabetes Mellitus, Type 2 / Q000453:epidemiology*; D005260:Female; D005951:Glucose Tolerance Test; D006706:Homeostasis; D006801:Humans; D007328:Insulin / Q000097:blood; D008659:Metabolic Diseases / Q000453:epidemiology*; D008875:Middle Aged; D010298:Parity / Q000502:physiology*; D015995:Prevalence; D011384:Proinsulin / Q000097:blood; D012307:Risk Factors
chemical_list: D001786:Blood Glucose; D002096:C-Peptide; D007328:Insulin; D011384:Proinsulin