Severe Asthma Symptoms Reported by Two-Thirds of Sub-Saharan African Adolescents

Research findings published in The Lancet Child & Adolescent Health show that a large proportion of adolescents in sub-Saharan Africa with symptoms of severe asthma are not receiving formal diagnoses and appropriate subsequent therapy. Rapid urbanization and population growth are factors of increased incidence of asthma; however, the condition remains undiagnosed.^1,2

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According to the investigators, asthma is the second most common cause of chronic respiratory deaths in sub-Saharan Africa’s overall population. For this 2-phase, multi-country, school-based, cross-sectional study, the researchers assessed asthma symptom prevalence and severity in sub-Saharan African adolescents aged 12 to 14 years by screening them for symptoms using the International Study of Asthma and Allergies in Children (ISAAC) questionnaire. In phase 1, the enrolled participants were screened with the survey, and in the second phase, symptomatic adolescents were invited to complete a detailed survey on asthma severity, treatment, and exposure to environmental risk factors. Between November 1, 2018, and November 1, 2021, participants were recruited from 149 schools across 6 regions in 6 sub-Saharan countries to participate in the study.²

Additionally, adolescents performed diagnostic tests for childhood asthma. Positive tests were classified as a forced expiratory volume in 1 sec (FEV1) predicted under 80%, a FEV1 under lower “normal” limits, or FEV1 divided by forced vital capacity under the lower limits of normal, among other factors. The authors note that their study is the first of its kind to determine an accurate prevalence and severity of asthma in undiagnosed and symptomatic young people in sub-Saharan Africa.²

“The vast majority of children with asthma can be well controlled with inhaled medications. Our study done in 6 urban areas in sub-Saharan Africa shows that a large proportion of children with asthma symptoms have no formal diagnosis and are therefore untreated,” said Jonathan Grigg, BSc, MBBS. MD, MRCP, FRCPCH, professor of pediatric respiratory and environmental medicine at Queen Mary University of London, in a news release. “Health [care] professionals, policy makers, and the pharmaceutical industry must work together to address this unmet need that has been under recognized for far too long.”¹

The investigators administered phase 1 asthma questionnaires from January 20, 2019 to November 11, 2021, and data were obtained from 27,272 participants. Approximately 57.4% of adolescents (n = 14,918) were female the mean age was 13 years (IQR 12–13). Nearly all recruited adolescents were of Black African ethnicity (n = 26,821; 98.3%). In the first phase, a total of 3236 (11.9%) adolescents reported wheeze in the past 12 months, and among this group, 644 (19.9%) had a formal clinical diagnosis of asthma. The prevalence of adolescents with asthma symptoms ranged from 23.8% (Durban, South Africa) to 4.2% (Blantyre, Malawi). Based on ISAAC criteria, approximately 66.3% of adolescents (n = 2146) reported severe asthma symptoms, the majority of which had no diagnosis of asthma by a health care professional (n = 1672; 77.9%).²

Between July 16, 2019, and November 26, 2021, the phase 2 questionnaire was administered to the 1654 adolescents who had asthma symptoms in phase 1 and consented to enroll in the second phase. In the phase 2 cohort, approximately 58.0% of participants (n = 959) were female and the mean age was 13 years (IQR 12–14). One or more diagnostic tests for asthma were obtained in about 93.5% (n = 1546) of participants. One or more positive asthma tests were found in about 48.8% (n = 374) undiagnosed adolescents with severe symptoms, and 42.4% (n = 176) of 415 of undiagnosed adolescents with symptoms that were mild to moderate in severity. Among the 392 adolescents in phase 2 who were diagnosed with asthma by a health care professional, approximately 75.0% (n = 294) reported severe asthma symptoms, with 32.0% (n = 94) of those with severe symptoms not using any asthma medication.²

The investigators suggest that educational programs, better diagnoses, and treatment and screening within schools should be considered as intervention methods to improve overall asthma control. Additionally, they note that if the findings are generalizable, millions of sub-Saharan African adolescents could be affected with undiagnosed asthma.^1,2

“Undiagnosed and poorly controlled asthma greatly impacts on the physical and psychosocial well-being of the affected children and their caregivers. The high burden of severe undiagnosed asthma revealed by the ACACIA study requires urgent attention, including access to medicines and diagnostics,” said Rebecca Nantanda, PhD, pediatrician and senior research scientist, College of Health Sciences, Makerere University Lung Institute, Makerere University, Kampala, in the news release.¹

REFERENCES

1. Queen Mary University of London. Study uncovers the true burden of asthma in African pupils, highlighting need for better access to asthma diagnosis and care. News release. October 21, 2024. Accessed October 31, 2024. https://www.eurekalert.org/news-releases/1061823

2. Oyenuga VO, Mosler G, Addo-Yobo E, et al. Asthma symptoms, severity, and control with and without a clinical diagnosis of asthma in early adolescence in sub-Saharan Africa: a multi-country, school-based, cross-sectional study. The Lancet Child Adolesc Health. 2024. doi:10.1016/S2352-4642(24)00232-3