title: Prevalence of celiac disease autoimmunity in children with type 1 diabetes: regional variations across the Øresund strait between Denmark and southernmost Sweden.
abstract: OBJECTIVE
  The aim was to determine the prevalence of celiac disease autoimmunity in children with type 1 diabetes (T1D) diagnosed in Denmark and Sweden.
  
  
  METHODS
  A total of 662 Swedish children with T1D were matched with 1080 Danish children with T1D and 309 healthy children from Sweden and 283 from Denmark served as controls. Sera were analyzed for the presence of IgA and IgG (IgAG) autoantibodies against deamidated gliadin peptide (DGP) and tissue transglutaminase (tTG) with enzyme-linked immunosorbent assay (ELISA) and IgG-tTG separately in a radioligand binding assay (RBA). Human leukocyte antigen (HLA)-DQB1 and DQA1 genotyping were determined in the T1D cohorts.
  
  
  RESULTS
  In the Swedish T1D cohort, 17.2% (114/662) were IgAG-DGP/tTG positive compared with 11.7% (126/1080) in the Danish T1D cohort (p = 0.001) and with 9.4% (29/309) Swedish (p = 0.001) and 5.7% (16/283) Danish (p = 0.003) controls. In the Swedish T1D cohort, both levels of IgAG-DGP/tTG and IgG-tTG were higher compared with the levels in the Danish T1D (p < 0.001). In the control group, 2.8% of the Danish children were positive for both IgAG-DGP/tTG and IgG-tTG, compared to 0.3% of the Swedish. Presence of HLA-DQ2 was equally distributed among 89 children with T1D positive for both IgAG-DGP/tTG and IgG-tTG.
  
  
  CONCLUSIONS
  The discrepancy in levels of IgAG-DGP/tTG and IgG-tTG between Swedish and Danish T1D cohorts was independent of HLA and suggests that regional variations in comorbidity of celiac disease in T1D is caused by difference in exposure to environmental factors.
authors.affiliation: Department of Clinical Sciences, Skåne University Hospital SUS, Lund University/CRC, Malmö, Sweden.
authors.forename: Emma H
authors.initials: EH
authors.lastname: Adlercreutz
authors.affiliation: Department of Paediatrics, Herlev Hospital, Herlev, Denmark.|Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Jannet
authors.initials: J
authors.lastname: Svensson
authors.affiliation: Department of Paediatrics, Odense University Hospital, Odense, Denmark.
authors.forename: Dorthe
authors.initials: D
authors.lastname: Hansen
authors.affiliation: The Bartholin Institute, Rigshospitalet, Copenhagen, Denmark.
authors.forename: Karsten
authors.initials: K
authors.lastname: Buschard
authors.affiliation: Department of Clinical Sciences, Skåne University Hospital SUS, Lund University/CRC, Malmö, Sweden.
authors.forename: Åke
authors.initials: Å
authors.lastname: Lernmark
authors.affiliation: Department of Paediatrics, Herlev Hospital, Herlev, Denmark.|Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Henrik Bindesbøl
authors.initials: HB
authors.lastname: Mortensen
authors.affiliation: Department of Clinical Sciences, Skåne University Hospital SUS, Lund University/CRC, Malmö, Sweden.
authors.forename: Daniel
authors.initials: D
authors.lastname: Agardh
mesh_terms: D000293:Adolescent; D001323:Autoantibodies / Q000032:analysis*; D015551:Autoimmunity; D002446:Celiac Disease / Q000097:blood / Q000150:complications / Q000453:epidemiology / Q000276:immunology*; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D003718:Denmark / Q000453:epidemiology; D003922:Diabetes Mellitus, Type 1 / Q000097:blood / Q000150:complications / Q000276:immunology*; D005260:Female; D019204:GTP-Binding Proteins / Q000037:antagonists & inhibitors*; D005903:Gliadin / Q000037:antagonists & inhibitors* / Q000737:chemistry; D006801:Humans; D007070:Immunoglobulin A / Q000032:analysis; D007074:Immunoglobulin G / Q000032:analysis; D007223:Infant; D008297:Male; D010446:Peptide Fragments / Q000037:antagonists & inhibitors / Q000378:metabolism; D015995:Prevalence; D000091345:Protein Glutamine gamma Glutamyltransferase 2; D012189:Retrospective Studies; D012306:Risk; D013548:Sweden / Q000453:epidemiology; D011503:Transglutaminases / Q000037:antagonists & inhibitors*
chemical_list: D001323:Autoantibodies; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D010446:Peptide Fragments; D005903:Gliadin; D000091345:Protein Glutamine gamma Glutamyltransferase 2; D011503:Transglutaminases; D019204:GTP-Binding Proteins
keywords: T1D; celiac disease