The increased incidence of allergic diseases in “westernized societies” may be due to increased hygiene. To evaluate the impact of prenatal and postnatal environment on the development of allergic disease, we compared children born in different conditions, but subsequently raised in similar environments: Icelandic adoptees born in Calcutta, India (Group I) and native Icelandic children (Group II).

Atopic status of Group I and II was compared using a standardized questionnaire (ISAAC), skin prick testing (SPT) for 8 aeroallergens and 5 food allergens and total IgE (CAP). Children in Group I were less than 2 years of age at time of adoption and had all lived in Iceland for over a year. Age matched controls were recruited during same time period from relatives or friends.

46 and 26 children were recruited to Group I and II, respectively, mean age 8 and 7,4 years. No differences were between the groups with regards to frequency of positive SPT: 18 (39%) vs. 7 (27%) (OR: 1,5; p=0,6); history of wheezing 13 (28%) vs. 8 (30%), (OR: 0,9; p=1,0); pollen allergy 8 (17%) vs. 4 (15%) or eczema 12 (27%) vs. 9 (35%), for Group I and II, respectively. The geometric mean total IgE was 65,4 vs. 19,1 kU/L (P=0,024; T-test) in group I and II, respectively.

No significant difference was found in SPT reactivity or history of atopic disease in children who were born in India and adopted to Iceland, compared with native Icelandic children of the same age. However, total IgE was higher in the adopted children.