Scoping the challenge
Asthma is a chronic disease of the airways that is estimated to affect about 300 million people globally. It is the most common chronic disease among children, whose prevalence is increasing in low- and middle-income countries (LMICs). The primary causes of asthma are not known, but the so-called “Hygiene Hypothesis” and “Old Friends Hypothesis”, suggest that the increase may be due, at least in part, to the impact on the immune system of a relative absence of exposure to infectious organisms with which humans have co-evolved.

According to the Global Asthma Report 2018 urbanization is a key factor driving the increase in Asthma prevalence in LMICs. The report states that in many LMICs, prevalence in urban children can be as high as 20-30%, compared to 5-10% in rural children. A study published in the Journal of Asthma also found that the prevalence of asthma in urban areas of sub-Saharan Africa has increased by over 50% in the past decade, driven by rapid urbanization and environmental changes.

A Human Face
Kameruka,[1] an 18-year-old Hotel Management student in Entebbe, an urban area in central Uganda, struggles with daily activities due to asthma. "I often get chest pain and difficulty breathing when walking uphill, especially in the mornings and on rainy days," she says. Mary relies on her inhaler and Cetirizine tablets to manage her symptoms, frequently visiting Entebbe Grade A Hospital for treatment.

Pamela[2], a mother of three, also shared her experiences. Two of her children were diagnosed with asthma during the study. "Having lost a brother to acute asthma in the early 90s, I feared the worst for my children," Pamela recounts. Fortunately, her children have medical insurance through her husband's workplace, ensuring they receive necessary treatments.

Lynn [3], a 17-year-old awaiting university admission, discovered she had asthma during the study. Initially suffering from dust allergies, Lynn experienced breathing difficulties during cold weather and physical activities. With medical advice and treatment, she now manages her asthma effectively through sports, a balanced diet, and medication.

Reinforcing community health structures
Throughout the study period, the establishment of on-site asthma clinics in participating schools significantly improved the diagnosis and management of asthma among children. Of the 561 children enrolled with asthma, 252 (45%) were newly diagnosed and subsequently enrolled in treatment programs. This increased focus on asthma testing and control highlighted the necessity for enhancing the capacity of healthcare providers to effectively manage asthma.

Partnering with Mulago National Specialised Referral Hospital and Kisubi Hospital, the study facilitated staff training at Kisubi and Entebbe hospitals to improve asthma care. As a result, Kisubi Hospital now hosts a dedicated asthma clinic, providing ongoing care to affected children. According to Dr. Rogers Ssendijja, the lead pediatrician who supported the establishment of Kisubi hospital’s asthma clinic, “While Kisubi Hospital sees an average of 10-15 asthmatic children monthly, we suspect a much larger number of children suffer from undiagnosed asthma due to limited awareness and knowledge of available treatment facilities.”

Regular asthma awareness events at major health care provision facilities such as Kisubi Hospital and Entebbe Grade A Hospital provided opportunities for regular public engagement and education on asthma prevention and management.

Rose, a parent of a child with Asthma, noted, “Participating in the study enabled me to know with certainty my children’s condition. This has helped me to manage their Asthma well and keep them stable, unlike before when we thought it was allergies.”

Expanding Research and Support
The study led to the establishment of an open data archive at the London School of Hygiene and Tropical Medicine (LSHTM Data Compass) and archived samples, available on request and following local approvals.This has significantly enhanced data accessibility for scientists aiming to deepen their understanding of asthma in Africa and foster the development of further related studies.

One such follow-on study at the Unit, funded by the European Research Council, was the World Asthma Phenotypes (WASP) study. Led by Professor Neil Pearce at LSHTM, WASP aimed to better understand and characterise different asthma sub-types (phenotypes) in five countries: Uganda, Brazil, Ecuador, New Zealand, and United Kingdom. This international collaborative study was built on prior asthma research conducted in Uganda and made direct comparisons of asthma sub-types across four continents.

Key findings from WASP revealed that only a third of asthma cases in children from low- and middle-income countries (LMICS) such as Uganda, Brazil, and Ecuador were of the ‘allergy sub-type’, compared to half of the cases in children and young adults in New Zealand and the United Kingdom. These results raise important questions for future research and asthma management, as current asthma medications primarily target the ‘allergy sub-type’ and do not adequately manage the two thirds of children with the ‘non-allergy asthma sub-type.’

Building on insights from WASP, further funding from the European Research Council supported the Causes and Mechanisms for Non-Atopic Asthma in children (CAMERA) Study. CAMERA aims to shed more light on the causes and mechanisms of the non-allergic (non-atopic) asthma sub-type, which remain largely unknown. Additionally, a study to establish the objective measure of psychological stress, by measuring cortisol levels (the stress hormone) in hair, was launched with support from LSHTM and the Wellcome. Recognising psychological stress as a trigger for asthma symptoms, this study successfully established the Hair Cortisol Concentration assay in the Unit’s immunology laboratory, which will be used in the CAMERA study.

According to Dr. Harriet Mpairwe, a Clinician and Asthma researcher (the study PI)

“This study not only provided valuable insights into asthma risk factors but also spurred initiatives that improved care and management for children with asthma in Entebbe and Wakiso in Uganda. However, there’s need for continued efforts to improve asthma diagnosis and management across the country, and further research to identify the exact causes of asthma to combat the growing asthma prevalence in urban areas of LMICs.”

[1] All names are pseudonyms