title: Perinatal risk factors increase the risk of being affected by both type 1 diabetes and coeliac disease.
abstract: OBJECTIVE
  This study investigated whether perinatal factors influenced the risk of a double diagnosis of type 1 diabetes and coeliac disease.
  
  
  METHODS
  We used multinomial logistic regression models to study the associations between perinatal factors, gender, mode of delivery, season of birth and the risk of type 1 diabetes, coeliac disease or both, in Swedish-born singleton children.
  
  
  RESULTS
  We found that 4327 of the 768 395 children (0.6%) had been diagnosed with type 1 diabetes, 3817 (0.5%) had been diagnosed with coeliac disease and 191 (0.02%) were affected by both diseases. If the children already had type 1 diabetes (n = 4518), the absolute risk of being affected by coeliac disease increased to 4.2% (n = 191). Children with both type 1 diabetes and coeliac disease were more likely to be female (OR = 1.48, 95% CI = 1.01-1.97), delivered by Caesarean section (OR = 1.60, 95% CI = 1.07-2.39), have native-born Swedish mothers (OR = 4.84, 95% CI = 1.96-11.97) or be born during the summer months (OR = 1.43, 95% CI = 1.07-1.92).
  
  
  CONCLUSIONS
  The increased risk of being affected by a double diagnosis of type 1 diabetes and coeliac disease was modulated by perinatal risk factors. This suggests that early life events are important when it comes to children with type 1 diabetes also developing coeliac disease.
authors.affiliation: Department of Paediatrics, Skåne University Hospital, Malmö, Sweden; Unit for Diabetes and Celiac Disease, Department of Clinical Sciences, Faculty of Medicine, Lund University, Malmö, Sweden.
authors.forename: Emma H
authors.initials: EH
authors.lastname: Adlercreutz
authors.forename: Carl Johan
authors.initials: CJ
authors.lastname: Wingren
authors.forename: Raquel P
authors.initials: RP
authors.lastname: Vincente
authors.forename: Juan
authors.initials: J
authors.lastname: Merlo
authors.forename: Daniel
authors.initials: D
authors.lastname: Agardh
mesh_terms: D000328:Adult; D002446:Celiac Disease / Q000150:complications / Q000453:epidemiology*; D002585:Cesarean Section / Q000009:adverse effects; D002675:Child, Preschool; D003922:Diabetes Mellitus, Type 1 / Q000150:complications / Q000453:epidemiology*; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D016015:Logistic Models; D008297:Male; D011247:Pregnancy; D012189:Retrospective Studies; D012307:Risk Factors; D012621:Seasons; D013548:Sweden / Q000453:epidemiology; D055815:Young Adult
keywords: Caesarean section; Coeliac disease; Epidemiology; Risk factors; Type 1 diabetes