Atopic sensitization among children in an arctic environment

BACKGROUND: Asthma has been reported to be rare among Inuits, but so far total and specific IgE levels have never been determined in arctic populations.

OBJECTIVE: To determine the prevalence of atopy in children living in an arctic environment, and to examine whether atopy and total IgE levels were associated with parental place of birth, as a measure of ethnicity, and travel history.

MATERIAL AND METHODS: All schoolchildren in Sisimiut, a community on the West coast of Greenland, were screened for atopy. Blood samples were analysed for total IgE and for specific IgE against inhalant and food allergens. Information on place of birth of children and their parents was obtained from national registries. Information on travel history was obtained from self-administered questionnaires.

RESULTS: A total of 1031 schoolchildren aged 5 to 18 years had a blood sample drawn (85% of available children for the study). Of these, 151 (14.6%) children were sensitized to at least one inhalant allergen and 42 (4.1%) to at least one food allergen. Sensitization to grass was most common, whereas sensitization to mugwort, birch, animal-dander and house-dust mite was infrequent. Children whose parents were both born abroad had a higher risk of sensitization to inhalant allergens compared with children born of Greenlandic parents (OR = 8.6, 95% CI 2.8-27.1). Furthermore, children who had been abroad had a higher risk of sensitization towards pollen (OR = 1.6, 95% CI 1.0-2.5) and animal-dander (OR = 2.1, 95% CI 1.0-4.6) after adjustment for confounders. Both atopic and non-atopic children demonstrated high levels of total IgE (medians of 251 and 58 kU/L).

CONCLUSIONS: Compared with European findings Greenlandic children have high levels of total IgE but a low prevalence of allergic sensitization towards inhalant allergens. This may be due to a low genetic susceptibility to atopy and less allergen exposure, as well as to living conditions in an arctic environment.