Abstract: The relative importance of atopy in the etiology of rhinitis is largely unknown. We investigated geographical variations in rhinitis in relation to atopy.The cross-sectional study involved 54,178 children (8-12 years) from 30 study centres in 22 countries worldwide. Symptoms of rhinoconjunctivitis and rhinitis without conjunctivitis in the last year were reported in parental questionnaires and children were skin prick tested.The prevalence of rhinoconjunctivitis and rhinitis without conjunctivitis varied widely (from 1.5% to 24.5% and from 1.4% to 45.2%, respectively). For rhinoconjunctivitis, the population attributable fraction (PAF) varied from 0 to 71% for a positive prick test to one or more seasonal allergens and from 0 to 41% for perennial allergens. The PAF for sensitization to seasonal and perennial allergens was higher for affluent countries (36% and 25%, respectively) than for non-affluent countries (1.3% and 12.6%, respectively). For rhinitis without conjunctivitis, the PAF for perennial allergens was 8% for affluent countries and 4% for non-affluent countries. No significant PAF was found for seasonal allergens.Overall, atopy explained only a limited proportion of rhinitis symptoms suggesting that the importance of other environmental factors have been underemphasized, particularly in less affluent countries. Atopy seems to be only marginally relevant for rhinitis without conjunctivitis, which seems mainly to reflect non-atopic rhinitis.
Eur Respir J 2008; 32: 12501261