Heredity of food allergies in an unselected child population: an epidemiological survey from Finland.

The heredity of food allergies (FA) has not previously been addressed in a large unselected child population. Our target population comprised all children born from April 2001 to March 2006 resident in one province of South-East Finland (n c. 6000), as identified from the national population register. In a questionnaire survey conducted in 2005-2006, data were obtained on allergic manifestations (FA symptoms, atopic rash, allergic asthma, hay fever/pollen allergy, or animal allergy) in the biologic parents of 3800 children (64% of the total). Concurrently with the survey but independently of it, results of specific immunoglobulin E antibodies (sIgE), skin prick tests (SPT), and open food challenges (OFC) in the offspring were collected from patient records throughout the province. Up to the age of 4 yr, the incidences of any positive FA test, a positive SPT or sIgE for food items, and a positive OFC in these children were threefold higher if both parents reported having an allergic manifestation and twofold higher if either mother or father had such a manifestation when compared with children whose parents did not report any of these conditions. The estimated risk of any positive FA test increased by a factor of 1.3 (95% CI 1.2-1.4) for each additional allergic manifestation in the parents. Positive FA tests in the offspring were relatively strongly associated with the reports of allergic phenotypes and the number of these phenotypes in their biologic parents.