Some years ago, Faniran et compared the prevalence of asthma and atopy in children between an affluent versus a non-affluent country, having a smaller prevalence of wheeze and persistent cough in Nigeria when compared to Australia (10.2% and 5.1% compared to 21.9% and 9.6%, respectively).
Anyway, a recent report from Aït-Khaled evidenced a wide range of atopic disorders prevalent all over Africa, not only with the highest presence of current asthma in urban areas with higher standard of living (concordant with the hygiene hypothesis) but also with a representative prevalence in endemic parasite and tuberculosis zones (opposed to the hygiene hypothesis).
In Latin America, protective factors to avoid having asthma seem not to play a role, and the non-allergic factors like pollution are not conditioning a higher prevalence of respiratory symptoms. However, this prevalence is similar to industrialized countries. In a recent survey of rural Asian children, 16.1% of wheezing prevalence in the past 12 months was found, not different from other developing regions of the planet.
The former reports, the International Study of Allergy and Asthma in Children (ISAAC), utilized the same methodology of evaluation, having strength enough to make conclusions and to compare different cultures and latitudes.
However, scarce tendency data are available from LMIC since the possibility of having these tools for evaluation has become recently available. An example is the ISAAC Phases I and III in comparison with Brazil, where nocturnal cough and wheezing slightly but significantly diminished; however, the generalization of these results is improbable when considering previous references.
Taken all together, we could conclude that globally, the prevalence of asthma is high and still demonstrates a slight increasing tendency, even though there is a lessening of differences.