Lower economic status and inferior hygienic environment may protect against celiac disease.

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.

AIM: 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.