title: Lower economic status and inferior hygienic environment may protect against celiac disease.
abstract: BACKGROUND
  The populations in adjacent Russian Karelia and Finland are equally exposed to grain products and share partly the same ancestry, but live in completely different socioeconomic environments.
  
  
  OBJECTIVE
  This creates an ideal epidemiological setting to study gene-environmental interactions in pathogenesis of celiac disease.
  
  
  METHODS
  The prevalence of celiac disease and predisposing human leukocyte antigen (HLA) alleles was compared between Russian Karelia and Finland. Tissue transglutaminase antibodies and HLA-DQ alleles were screened from 1988 schoolchildren from Karelia and 3654 children from Finland. Children with transglutaminase antibodies were invited to small-bowel biopsy. Results. Transglutaminase antibodies were less frequent in Russian Karelia than in Finland (0.6% versus 1.4%, P = 0.005). Immunoglobulin class G (IgG) antigliadin antibodies were also less frequent in Russian Karelia (10.2% versus 28.3%, P<0.0001). Celiac disease was confirmed by duodenal biopsy in four of the eight transglutaminase antibody-positive Karelian children, giving a prevalence of 1 in 496 compared to 1 in 107 children in Finland. The same HLA-DQ alleles were associated with celiac disease and transglutaminase antibody positivity in both populations.
  
  
  CONCLUSIONS
  The prevalence of transglutaminase antibodies and celiac disease is lower in Russian Karelia than in Finland. This may be associated with a protective environment characterized by inferior prosperity and standard of hygiene in Karelia.
authors.affiliation: Department of Virology, University of Tampere, Medical School, Tampere, Finland.
authors.forename: Anita
authors.initials: A
authors.lastname: Kondrashova
authors.forename: Kirsi
authors.initials: K
authors.lastname: Mustalahti
authors.forename: Katri
authors.initials: K
authors.lastname: Kaukinen
authors.forename: Hanna
authors.initials: H
authors.lastname: Viskari
authors.forename: Vera
authors.initials: V
authors.lastname: Volodicheva
authors.forename: Anna-Maija
authors.initials: AM
authors.lastname: Haapala
authors.forename: Jorma
authors.initials: J
authors.lastname: Ilonen
authors.forename: Mikael
authors.initials: M
authors.lastname: Knip
authors.forename: Markku
authors.initials: M
authors.lastname: Mäki
authors.forename: Heikki
authors.initials: H
authors.lastname: Hyöty
mesh_terms: D000293:Adolescent; D000483:Alleles; D001323:Autoantibodies / Q000276:immunology; D001706:Biopsy; D002446:Celiac Disease / Q000175:diagnosis / Q000453:epidemiology* / Q000276:immunology; D002648:Child; D004032:Diet; D004386:Duodenum / Q000473:pathology; D005260:Female; D005387:Finland / Q000453:epidemiology; D005903:Gliadin / Q000276:immunology; D006683:HLA-DQ Antigens / Q000276:immunology*; D006801:Humans; D006920:Hygiene / Q000592:standards*; D007074:Immunoglobulin G / Q000276:immunology; D008297:Male; D015995:Prevalence; D012426:Russia / Q000453:epidemiology; D012959:Socioeconomic Factors; D011503:Transglutaminases / Q000276:immunology*
chemical_list: D001323:Autoantibodies; D006683:HLA-DQ Antigens; D007074:Immunoglobulin G; D005903:Gliadin; D011503:Transglutaminases