Impacts of long-term ragweed pollen load and other potential risk factors on ragweed pollen allergy among schoolchildren in Hungary.

Introduction and objective. Hungary is one of the areas in Europe most infected with ragweed (Ambrosia artemisiifolia L.) and its pollen, and is the most important cause of seasonal allergic rhinoconjunctivitis in the country. The aim of the study was to investigate the association between ragweed pollen allergy and long-term ragweed pollen load, as well as analysis of the the impacts of additional potential risk factors on health outcomes. Materials and method. A modified version of standardized questionnaires, based on the International Study of Asthma and Allergy in Childhood, were completed by the parents of schoolchildren aged 8 - 9 attending 3rd grade classes throughout the country. Pollen load was calculated for each settlement from daily ragweed pollen concentrations monitored by 19 monitoring stations in the country. Descriptive and analytical statistical methods were applied. Results. At national level there was a significant inverse association between prevalence of ragweed allergy and its pollen load, but significance was lost after excluding data from Budapest, the capital city, due to the impact of urbanization. In the adjusted model, parental atopic disease was the strongest risk factor (either parent had atopic disease aOR=2.60; 95% CI=2.31-2.93 or both parents had atopic disease aOR=4.56; 95% CI=3.71-5.60). Further significant risk factors were male gender (aOR=1.52; 95% CI=1.36-1.71), lower respiratory infection in the first two years of life (aOR=1.91; 95% CI=1.70-2.16), and unshared children's room (aOR=1.22; 95% CI=1.09-1.37). Allergy was significantly less common among children whose parents received social aid (aOR=0.83; 95% CI=0.72-0.97) and whose mother smoked during pregnancy (aOR=0.80; 95% CI=0.64-0.99). Conclusions. Higher ragweed pollen exposure was not found to be associated with higher risk of ragweed allergy.