Worldwide trends in the burden of asthma symptoms in school-aged children: Global Asthma Network Phase I cross-sectional study
Authors: M Innes Asher, Charlotte E Rutter, Karen Bissell, Chen-Yuan Chiang, Asma El Sony, Eamon Ellwood, Philippa Ellwood, Luis García-Marcos, Guy B Marks, Eva Morales, Kevin Mortimer, Virginia Pérez-Fernández, Steven Robertson, Richard J Silverwood, David P Strachan, Neil Pearce, Karen Bissell, Chen-Yuan Chiang, Eamon Ellwood, Philippa Ellwood, Guy B Marks, Refiloe Masekela, Eva Morales, Kevin Mortimer, Neil Pearce, David Strachan, Philippa Ellwood, Eamon Ellwood, Antonela Martinez-Torres, Eva Morales, Virginia Pérez-Fernández, Neil Pearce, Stephen Robertson, Charlotte Rutter, Richard Silverwood, David Strachan, Javier Mallol, Manuel Soto-Martínez, Angelita Cabrera Aguilar, Konstantinos Douros, Mohammed Sabir, Meenu Singh, Virendra Singh, Thevaruparambil Unny Sukumaran, Shally Awasthi, Sushil Kumar Kabra, Sundeep Salvi, Roberto García-Almaráz, J. Valente Mérida-Palacio, Blanca E Del Río Navarro, Sandra Nora González-Díaz, Elsy Maureen Navarrete-Rodriguez, José Félix Sánchez, Adegoke G Falade, Heather J Zar, Angel López-Silvarrey Varela, Carlos González Díaz, Magde Nour, Gazal Dib, Yousser Mohammad, Jing-Long Huang, Sasawan Chinratanapisit, Manuel E Soto-Quirós, Pakit Vichyanond, Pedro Aguilar, Sergio Barba, Lata Kumar, S K Sharma, Francisco J Linares-Zapién, Babatunde O Onadeko, Omer Abdel Aziz Musa, Viviana Aguirre, Manuel Baeza-Bacab, Samira Mohammad, Eliana Cortez, Christina H Gratziou, Kamlesh Chopra, Neeta Milind Hanumante, Hugo Nelson, Alfonso Delgado Rubio, Kue-Hsiung Hsieh, Jayant Shah
Journal: The Lancet (2021)

BackgroundAsthma is the most common chronic disease in children globally. The Global Asthma Network (GAN) Phase I study aimed to determine if the worldwide burden of asthma symptoms is changing.MethodsThis updated cross-sectional study used the same methods as the International study of Asthma and Allergies in Childhood (ISAAC) Phase III. Asthma symptoms were assessed from centres that completed GAN Phase I and ISAAC Phase I (1993–95), ISAAC Phase III (2001–03), or both. We included individuals from two age groups (children aged 6–7 years and adolescents aged 13–14 years) who self-completed written questionnaires at school. We estimated the 10-year rate of change in prevalence of current wheeze, severe asthma symptoms, ever having asthma, exercise wheeze, and night cough (defined by core questions in the questionnaire) for each centre, and we estimated trends across world regions and income levels using mixed-effects linear regression models with region and country income level as confounders.FindingsOverall, 119 795 participants from 27 centres in 14 countries were included: 74 361 adolescents (response rate 90%) and 45 434 children (response rate 79%). About one in ten individuals of both age groups had wheeze in the preceding year, of whom almost half had severe symptoms. Most centres showed a change in prevalence of 2 SE or more between ISAAC Phase III to GAN Phase I. Over the 27-year period (1993–2020), adolescents showed a significant decrease in percentage point prevalence per decade in severe asthma symptoms (–0·37, 95% CI –0·69 to –0·04) and an increase in ever having asthma (1·25, 0·67 to 1·83) and night cough (4·25, 3·06 to 5·44), which was also found in children (3·21, 1·80 to 4·62). The prevalence of current wheeze decreased in low-income countries (–1·37, –2·47 to –0·27], in children and –1·67, –2·70 to –0·64, in adolescents) and increased in lower-middle-income countries (1·99, 0·33 to 3·66, in children and 1·69, 0·13 to 3·25, in adolescents), but it was stable in upper-middle-income and high-income countries.InterpretationTrends in prevalence and severity of asthma symptoms over the past three decades varied by age group, country income, region, and centre. The high worldwide burden of severe asthma symptoms would be mitigated by enabling access to effective therapies for asthma.FundingInternational Union Against Tuberculosis and Lung Disease, Boehringer Ingelheim New Zealand, AstraZeneca Educational Grant, National Institute for Health Research, UK Medical Research Council, European Research Council, and Instituto de Salud Carlos III.