Diverse age-incidence patterns of atopic sensitization in an unselected Finnish population up to 12 years

• Main Authors: Pyrhönen, K. (Kaisa), Kulmala, P. (Petri), Näyhä, S. (Simo), Läärä, E. (Esa)
• Format: Article in Journal/Newspaper
• Language: English
• Published: Elsevier 2019
• Subjects: karelia*
• Online Access: http://urn.fi/urn:nbn:fi-fe2019051515578

Abstract Background: The temporal sequence in which allergic sensitization to different allergens emerges is not well characterized at the level of general population. Objective: We describe the incidence patterns of atopic sensitization to different allergens from birth up to 12 years of age in an unselected Finnish population. Methods: The study population comprised all children born between 2001 and 2006 identified from the nationwide population register as residents of the province of South Karelia, Finland (n = 5564). The results of allergy tests (22,380 results from skin prick tests, immunoglobulin E [IgE] antibodies, and open food challenges [OFCs], performed in 1827 children) were collected from patient records of all the health care units in the area. Results: The incidence rates of positive results for food and animal allergens as well as positive OFCs for cow’s milk showed prominent peaks at 5 months of age. Positive results for pollen allergens started to emerge after 1.5 years of age. The 12-year cumulative incidence of sensitization to food, animal, pollen, and any allergens was 12%, 8%, 10%, and 18%, respectively. The cumulative incidence of sensitization to house dust mites was 1% and to molds or latex less than 1%. Firstborn boys had the highest, and those who were not firstborn girls and children born in rural municipalities had the lowest early incidence of sensitization to inhalation allergens. Conclusion: In the unselected population, the atopic sensitization against food and animal allergens began before 6 months of age and was followed by sensitization to pollen allergens before 2 years of age. Primary prevention of sensitization to food and inhalation allergens should therefore occur in early infancy.