Worldwide variations in the prevalence of symptoms of atopic eczema in theinternational study of asthma and allergies in childhood

Background: Little is known about the prevalence of atopic eczema outside N orthern Europe. Objectives: We sought to describe the magnitude and variation in the preval ence of atopic eczema symptoms throughout the world. Methods: A cross-secti onal questionnaire survey was conducted on random samples of schoolchildren aged 6 to 7 years and 13 to 14 years from centers in 56 countries througho ut the world. Those children with a positive response to being questioned a bout the presence of an itchy relapsing skin rash in the last 12 months tha t had affected their skin creases mere considered to have atopic eczema. Ch ildren whose atopic eczema symptoms resulted in sleep disturbance for 1 or more nights per week were considered to have severe atopic eczema. Results: Complete data was available for 256,410 children aged 6 to 7 years in 90 centers and 458,623 children aged 13 to 14 gears in 153 centers. The prevalence range for symptoms of atopic eczema was from less than 2% in Ir an to over 16% in Japan and Sweden in the 6 to 7 year age range and less th an 1% in Albania to over 17% in Nigeria for the 13 to 14 year age range. Hi gher prevalences of atopic eczema symptoms were reported in Australasia and Northern Europe, and lower prevalences were reported in Eastern and Centra l Europe and Asia. Similar patterns were seen for symptoms of severe atopic eczema. Conclusions: Atopic eczema is a common health problem for children and adol escents throughout the world. Symptoms of atopic eczema exhibit wide variat ions in prevalence both within and between countries inhabited by similar e thnic groups, suggesting that environmental factors may be critical in dete rmining disease expression. Studies that include objective skin examination s are required to confirm these findings.