Asthma is the second most common cause of chronic respiratory deaths in the overall population of sub-Saharan Africa. The study led by researchers at Queen Mary and published today in The Lancet Child and Adolescent Health, is the first of its kind to determine the true prevalence and severity of asthma in undiagnosed, yet symptomatic young people in sub-Saharan Africa.
The researchers recruited 20,000 school students between the ages of 12 and 14 from schools in urban areas in Malawi, South Africa, Zimbabwe, Uganda, Ghana, and Nigeria. The first part of the trial screened for asthma symptoms – of the 20,000 students, 12% of the participants reported symptoms of asthma, but of that group, only 20% had received a formal diagnosis of the condition.
In the second part of the trial, the students who reported asthma symptoms were invited to complete a detailed questionnaire covering asthma control, current treatment, knowledge and perception of asthma, and barriers to achieving good control (including access to care and environmental factors). Researchers also carried out lung function tests, which are used as test to help asthma diagnosis. The study found that nearly half of undiagnosed participants with severe symptoms had positive diagnostic tests, making clinical asthma very likely.
Using International Study of Asthma and Allergies in Childhood (ISAAC) criteria, severe asthma symptoms were reported by two-thirds of adolescents, and 80% had not previously been diagnosed. Even where participants already had an asthma diagnosis, over 30% with severe symptoms were not using any asthma medication.
Concerningly, almost half of students with asthma symptoms were not able to access emergency medical care when it was needed. 45% of students with asthma symptoms had required emergency treatment within the previous year, with a similar proportion reporting that this had not been available to them.
Professor Jonathan Grigg, Professor of Paediatric Respiratory and Environmental Medicine at Queen Mary University of London, said: "The vast majority of children with asthma can be well controlled with inhaled medications. Our study done in six urban areas in sub-Saharan Africa shows that a large proportion of children with asthma symptoms have no formal diagnosis and are therefore untreated. Health professionals, policy makers, and the pharmaceutical industry must work together to address this unmet need that has been under recognised for far too long."
Dr Gioia Mosler, Head of Global Health Group and Community Engagement at Queen Mary University of London and the study's research manager, said: "If our data are generalisable, there are millions of adolescents with undiagnosed asthma symptoms in sub-Saharan Africa. To improve the poor state of asthma control in sub-Saharan Africa, potential solutions such as educational programmes, better diagnosis, and treatment and screening in schools should be considered."
The team who led the study, whose pioneering research on the impact of pollution on lung health was instrumental in introducing the Ultra Low-Emission Zone (ULEZ) in London, are calling for better access to asthma diagnosis and care in areas of rapid urbanisation and population growth.
