International Study of Asthma and Allergies in Childhood, 1992-2005

Worldwide epidemiological research programme established in 1991 to investigate asthma, rhinoconjunctivitis and eczema in children, due to considerable concern that these conditions were increasing in many countries, and that the causes of this increase were unknown. ISAAC Phase One was an international multi-centre cross-sectional study involving two age groups of school children, 13-14 year olds (adolescents) and 6-7 year olds (children). Schools were randomly selected from a defined geographical area. Written questionnaires on asthma, rhinitis and eczema symptoms (translated from English) were completed by the adolescents at school, and at home by the parents of the children. An asthma symptoms video questionnaire for the adolescents was optional. ISAAC Phase Two involved more intensive studies in a smaller number of selected centres. Children aged 8-12 years were examined for flexural dermatitis, underwent skin prick tests for atopy, bronchial responsiveness to hypertonic saline, blood sampling and storage for serum IgE and genetic analyses, and additional questionnaires were completed by their parents. ISAAC Phase Three, a repeat of Phase One after at least five years, examined variations in time trends of childhood asthma, rhinoconjunctivitis and eczema around the world, and expanded the world maps of these conditions. Additional questions on risk factors were included in Phase Three. The ISAAC programme grew to involve nearly 2 million children from 306 study centres in 105 countries, before it formally closed in December 2012.  Further information about the study can be found on the ISAAC study website. To obtain a free account please register with the UKDA.