The Global Asthma Network (GAN), established in 2012, followed the International Study of Asthma and Allergies in Childhood (ISAAC). ISAAC Phase One involved over 700 000 adolescents and children from 156 centres in 56 countries; it found marked worldwide variation in symptom prevalence of asthma, rhinitis and eczema that was not explained by the current understanding of these diseases; ISAAC Phase Three involved over 1 187 496 adolescents and children (237 centres in 98 countries). It found that asthma symptom prevalence was increasing in many locations especially in low- and middle-income countries where severity was also high, and identified several environmental factors that required further investigation.GAN Phase I, described in this article, builds on the ISAAC findings by collecting further information on asthma, rhinitis and eczema prevalence, severity, diagnoses, asthma emergency room visits, hospital admissions, management and use of asthma essential medicines. The subjects will be the same age groups as ISAAC, and their parents. In this first global monitoring of asthma in children and adults since 2003, further evidence will be obtained to understand asthma, management practices and risk factors, leading to further recognition that asthma is an important non-communicable disease and to reduce its global burden.
There have been no worldwide standardised surveys of prevalence and severity of asthma, rhinoconjunctivitis and eczema in school children for 15 years. The present study aims to provide this information.Following the exact International Study of Asthma and Allergies in Childhood (ISAAC) methodology (cross-sectional questionnaire-based survey) the Global Asthma Network (GAN) Phase I was carried out between 2015 and 2020 in many centres worldwide.The study included 157 784 adolescents (13–14 years of age) in 63 centres, in 25 countries; and 101 777 children (6–7 years of age) in 44 centres, in 16 countries. The current prevalence of symptoms, respectively, was: 11.0% and 9.1% for asthma; 13.3% and 7.7% for rhinoconjunctivitis; and 6.4% and 5.9% for eczema. For asthma ever, hay fever ever and eczema ever prevalence was 10.5% and 7.6%; 15.2% and 11.1%; and 10.6% and 13.4%. Centres in countries with low- or lower-middle- gross national income (LICs or L-MICs) had significantly lower prevalence of the three disease symptoms and diagnoses (except for hay fever). In children, the prevalence of asthma and rhinoconjunctivitis symptoms were higher in males, while the reverse occurred among adolescents. For eczema, while the prevalence among female adolescents was double that of males, there was no sex difference among children. Centre accounted for a non-negligible variability of all disease symptoms (10% to 20%).The burden of asthma, rhinoconjunctivitis and eczema vary widely among the limited number of countries studied. Although symptom prevalence is lower in LICs and L-MICs, it represents a considerable burden everywhere studied.
Background—The Global Asthma Network (GAN) Phase I is surveying school pupils in high-income and low- or middle-income countries using the International Study of Asthma and Allergies in Childhood (ISAAC) methodology. Methods—Cross-sectional surveys of participants in two age groups in randomly selected schools within each centre (2015–2020). The compulsory age group is 13–14 years (adolescents), optionally including parents or guardians. Six to seven years (children) and their parents are also optional. Adolescents completed questionnaires at school, and took home adult questionnaires for parent/guardian completion. Children took home questionnaires for parent/guardian completion about the child and also adult questionnaires. Questions related to symptoms and risk factors for asthma and allergy, asthma management, school/work absence and hospitalisation. Results—53 centres in 20 countries completed quality checks by 31 May 2020. These included 21 centres that previously participated in ISAAC. There were 132,748 adolescents (average response rate 88.8%), 91,802 children (average response rate 79.1%), and 177,622 adults, with >97% answering risk factor questions and >98% answering questions on asthma management, school/work absence and hospitalisation. Conclusion—The high response rates achieved in ISAAC have generally been maintained in GAN. GAN Phase I surveys, partially overlapping with ISAAC centres, will allow within-centre analyses of time-trends in prevalence.
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