The global study outcomes are based on a large, multi-centre cross-sectional study of 8- to 12-year-old children who participated in the International Study of Asthma and Allergy in Childhood (ISAAC).

“Atopic sensitisation has long been known to be related to childhood asthma,” wrote Gudrun Weinmayr, M.D., M.P.H., of the Institute of Epidemiology of Ulm University in Germany, and lead investigator of the study. She noted that the strongest relationships have been found in studies in affluent western countries. “Thus, it may be that the link between asthma and atopic sensitisation differs between countries.”

Weinmayr and colleagues evaluated parents’ answers about their children’s respiratory symptoms from over 54,000 standardized questionnaires; assessed the results of more than 31,000 skin-prick tests; and analysed the serum levels of allergen-specific IgE in nearly 9,000 children from 22 countries, from rural African to urban Europe.

They then determined the degree to which allergic sensitisations and asthma symptoms varied with the gross national income per capita (GNI) of the country from which they were collected. Children living in affluent countries with allergic sensitisations were four times as likely to have asthma than their non-sensitised counterparts; in non-affluent countries, children with allergic responses were only 2.2 times as likely to have asthma.

“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 “centre level correlation with GNI does not imply a similar relation at the individual level with personal wealth.”; Source: American Thoracic Society (ATS)