Asthma phenotypes in high and low income countries

Until the last fifteen years, asthma has generally been considered to be an allergic disease. However, there is an increasing awareness that not all asthma is caused by allergy; indeed, in some studies more than 50% of asthma has been shown to be due to mechanisms other than allergy. However, almost all previous work has been based in high-income/high-prevalence countries, meaning that it is unclear if these findings can be extrapolated to other settings. It is currently unclear whether asthma in different countries and socioeconomic settings involves a collection of different conditions, or is a single condition with multiple mechanisms and phenotypes, or what the underlying phenotypes may be.

The main aims of the study are to:

 (i) better understand and characterize asthma phenotypes (different types of asthma) in high income countries (such as UK and NZ) and low and middle income countries (Brazil, Ecuador and Uganda), and in centres with high and low prevalence;

 (ii) to compare their characteristics, including clinical severity;

 (iii) assess the risk factors for types of asthma in different countries; and

(iv) assess how the distributions of phenotypes differs between high prevalence and low prevalence centres.

The information provided by this study will enable us to more appropriately treat, manage, and understand the underlying causes of  asthma in different countries and settings.

RELATED PUBLICATIONS

Brooks C, van Dalen C, Zacharasiewicz A, Simpson J, Harper J, Le Gros G, Gibson P, Pearce N, Douwes J. Absence of airway inflammation in a large proportion of adolescents with asthma. Respirology, 2016; 21(3): 460-466.
Brooks C, van Dalen C, Hermans I, Gibson P, Simpson J, Douwes J. Sputum basophils are increased in eosinophilic asthma compared with non-eosinophilic asthma phenotypes. Allergy, 2017 (in press).