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Worldwide time trends for symptoms of rhinitis and conjunctivitis: Phase III of the International Study of Asthma and Allergies in Childhood
Author(s) -
Björkstén Bengt,
Clayton Tadd,
Ellwood Philippa,
Stewart Alistair,
Strachan David,
Phase III Study Group The ISAAC
Publication year - 2008
Publication title -
pediatric allergy and immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.269
H-Index - 89
eISSN - 1399-3038
pISSN - 0905-6157
DOI - 10.1111/j.1399-3038.2007.00601.x
Subject(s) - medicine , asthma , allergy , allergic conjunctivitis , dermatology , pediatrics , immunology
In Phase III of the International Study of Asthma and Allergies in Childhood (ISAAC) time trends in the prevalence of rhinoconjunctivitis symptoms were analysed. Cross‐sectional questionnaire surveys with identical protocols and questionnaires were completed a mean of 7 yr apart in two age groups comprising 498,083 children. In the 13‐ to 14‐yr age group 106 centres in 56 countries participated, and in the 6‐ to 7‐yr age group 66 centres in 37 countries participated. A slight worldwide increase in rhinoconjunctivitis prevalence was observed, but the variations were large among the centres and there was no consistent regional pattern. Prevalence increases in the older children exceeding 1% per year were recorded in 13 centres, including 3 of 9 centres in Africa, 2 of 15 in Asia‐Pacific, 1 of 8 in India, 3 of 15 in Latin America, 3 of 9 in Eastern Europe and 1 of 34 in Western and Northern Europe. Decreasing rhinoconjunctivititis prevalence of similar magnitude was only seen in four centres. The changes were less pronounced in the 6‐ to 7‐yr‐old children and only in one centre did any change exceed 1% per year. The decrease in highest prevalence rates in ISAAC Phase I suggests that the prevalence has peaked in those regions. An increase was recorded in several centres, mostly in low and mid‐income countries. The increases were more pronounced in the older age group, suggesting that environmental influences on the development of allergy may not be limited to early childhood.