Worldwide time trends in prevalence of symptoms of rhinoconjunctivitis in children: Global Asthma Network Phase I

Background The Global Asthma Network (GAN), by using the International Study of Asthma and Allergies in Childhood (ISAAC) methodology, has updated trends in prevalence of symptoms of childhood allergic diseases, including non‐infective rhinitis and conjunctivitis (‘rhinoconjunctivitis’), which is reported here. Methods Prevalence and severity of rhinoconjunctivitis were assessed by questionnaire among schoolchildren in GAN Phase I and ISAAC Phase I and III surveys 15–23 years apart. Absolute rates of change in prevalence were estimated for each centre and modelled by multi‐level linear regression to compare trends by age group, time period and per capita national income. Results Twenty‐seven GAN centres in 14 countries surveyed 74,361 13‐ to 14‐year‐olds (‘adolescents’) and 45,434 6‐ to 7‐year‐olds (‘children’), with average response proportions of 90% and 79%, respectively. Many centres showed highly significant (p