Altogether, children living in affluent countries with allergic sensitizations were 4 times as likely to have asthma than their non-sensitized counterparts; in non-affluent countries, children with allergic responses were only 2.2 times as likely to have asthma.
This means that local environmental factors may affect asthma and allergy in different ways, said Renato T. Stein, M.D., Ph.D., of the Pontificia Universidade Catolica do Rio Grande do Sul, in Brazil, another researcher involved in the study.
Another way to interpret these findings is that asthma in [more affluent] cities is predominantly atopic asthma, while in socially less developed areas asthma may be more of the non-atopic phenotype, said Dr. Stein.
The researchers speculated that a possible explanation could be that some factors that protect children with allergic sensitization from developing asthma are less present in affluent settings, or that acquired commensal bacteria (gut flora), which may also differ with GNI, play a role in development of tolerance and immune function.
A wide range of different factors, including nutrition, microbial and allergen exposure, housing conditions, and exposure to pollutants, and so forth may have played a role, they wrote, remarking that a center level correlation with GNI does not imply a similar relation at the individual level with personal wealth.
The research will continue with further investigations in other risk factors in asthma development, including diet, the presence of rhinitis, and eczema. Data to study the impact of genetics in asthma and allergies has been collected and is a central part in the next steps of this study, said Dr. Stein.
|Contact: Suzy Martin|
American Thoracic Society