title: Number and sex ratio of children and impact of parental diabetes in individuals with Type 1 diabetes.
abstract: OBJECTIVE
  To assess the number and sex ratio of children in individuals with Type 1 diabetes mellitus and the influence of parental diabetes on age at onset of Type 1 diabetes in our cohort.
  
  
  METHODS
  In a cross-sectional study in a German region comprising 350,000 inhabitants, 697 subjects with Type 1 diabetes (364 women, 333 men) underwent a standardized assessment regarding the number and sex of their children and the family history of diabetes.
  
  
  RESULTS
  Compared with 1.36 children per woman in the German background population, the total fertility rate in the calendar year of 2010 in our female cohort with Type 1 diabetes (age 18-49 years) was 0.88. Men with Type 1 diabetes had a fertility rate of 0.65. More men (51.1%) than women (35.7%; P < 0.0001) were childless. Twenty per cent of all women aged 41-45 years in the background population were childless compared with 36.2% of all women and 52% of all men in this specific age group from our cohort. The sex ratio of female vs. male offspring of individuals with Type 1 diabetes did not differ significantly from the expected 1:1 ratio. Maternal Type 1 or Type 2 diabetes increased the age at onset of Type 1 diabetes from 22.9 ± 13.7 (no maternal diabetes) to 28.6 ± 16.8 and 30.1 ± 15.1 years (p < 0.0001), respectively.
  
  
  CONCLUSIONS
  Compared with the German reference population, individuals with Type 1 diabetes had significantly fewer children and were more often childless. The sex ratio female vs. male offspring of women and men with Type 1 diabetes was unaffected. Maternal history of Type 1 and Type 2 diabetes was associated with a significant later onset of Type 1 diabetes.
authors.affiliation: Lippe-Detmold Hospital, First Department of Medicine, Detmold, Germany. andreas.holstein@t-online.de
authors.forename: A
authors.initials: A
authors.lastname: Holstein
authors.forename: O
authors.initials: O
authors.lastname: Patzer
authors.forename: T
authors.initials: T
authors.lastname: Tiemann
authors.forename: J
authors.initials: J
authors.lastname: Vortherms
authors.forename: P
authors.initials: P
authors.lastname: Kovacs
mesh_terms: D000293:Adolescent; D000328:Adult; D017668:Age of Onset; D000704:Analysis of Variance; D001723:Birth Rate; D016241:Child of Impaired Parents; D003430:Cross-Sectional Studies; D003922:Diabetes Mellitus, Type 1 / Q000453:epidemiology*; D016640:Diabetes, Gestational / Q000453:epidemiology*; D005260:Female; D005858:Germany / Q000453:epidemiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D010290:Parents; D011247:Pregnancy; D012307:Risk Factors; D017678:Sex Distribution; D012959:Socioeconomic Factors; D055815:Young Adult