The Burden of Asthma, Hay Fever and Eczema in Children in 25 Countries: GAN Phase I Study

To provide an updated analysis of prevalence and severity of asthma, rhinoconjunctivitis, and eczema from centers around the world.

This study included 157 784 adolescents (ages 13–14 years old) from 25 countries and 101 777 children (ages 6–7 years old) from 16 countries.

This is a cross-sectional study utilizing a previously validated questionnaire (from the International Study of Asthma and Allergies in Childhood Phase 1 Study) to collect information about asthma, rhinoconjunctivitis, and eczema. Three indicators were assessed for each of the 3 conditions, including (1) “Ever having” the condition(s), (2) “Current symptoms within last 12 months” of the condition(s), and (3) “Severe symptoms” of the condition(s). Investigators also calculated income categories for each country.

The overall prevalence of ever having asthma, hay fever, and eczema for adolescents was 10.5%, 15.2%, and 10.6% respectively. In children, the rates were 7.6%, 11.1%, and 13.4%, respectively. In terms of severity in adolescents, girls had a higher prevalence of severe asthma, hay fever, and eczema symptoms. In contrast, boys 6 to 7 years old had more severe asthma and rhinoconjunctivitis indicators. There was a high variability between centers and countries.

Overall, the global burden of atopic conditions such as asthma, rhinoconjunctivitis, and eczema is substantial. In both age groups, the prevalence of asthma, severe rhinoconjunctivitis (but not “hay fever ever”), and eczema was lower in countries classified as low or low-middle income countries. Severity of disease, especially in asthma and rhinoconjunctivitis, did seem to differ among sexes and shift between childhood to adolescence, which could be explained by hormonal effects in these disease states.

Limitations of this study include the manner in which diagnosis of the 3 conditions were obtained and the subjective nature of self-assessment questions, which could be interpreted differently within various languages. However, this study does a nice job providing a global assessment of prevalence rates for the common atopic diseases in childhood. Although there was a lack of representation of several countries, including northern Europe, North America, and Australia, the number of participants and large number of centers sampled was robust. The differences in prevalence, which was higher between countries than within countries, support that environmental factors play a role in these disease states.