Food allergies and hypersensitivities among children in South Karelia:occurrence, inheritance and seasonality

The aim of the South Karelian Allergy Research Project (SKARP) was to quantify the occurrence of children’s food allergy and food-associated hypersensitivity symptoms and their associated factors. The study population comprised all children born between April 2001 and March 2006 and living in the province of South Karelia, in the south-eastern part of Finland. The questionnaire survey was conducted in co-operation with the child health clinics in the area in 2005–2006. Concurrently with but independently of the questionnaire study, the results of allergy tests regarding the same child population were collected from patient records. The participation rates in the questionnaire study were 54% (644/1194) among the newborn infants and 69% (3308/4779) among the children aged 1 to 4 years. The lifetime prevalence of parent-reported food allergies was 9% and that of parent-perceived food-associated hypersensitivity symptoms 21% by the age of 4 years. In addition, another 19% of children adhered to an elimination diet without previous symptoms associated with any food items. The prevalence of children with such diets decreased by age. Up to the age of 4 years, 19% of the participants had undergone a food allergy test and 8% of the participants had obtained a positive result in these tests. Physician-diagnosed food allergies and food allergies based on the tests were more common for milk, egg and cereals than for other food items. The tested children and those with a positive test result were only slightly overrepresented among the participants. Allergic manifestations in either biological parent doubled and in both biological parents tripled the incidence of a positive food allergy test. The spring season coinciding with the end of the first trimester of pregnancy predicted sensitisation to food items in the children. In early childhood, food allergies and food hypersensitivities were found to be common in a child population. New population-based knowledge regarding the inheritance of these conditions was ...