Data sources
Symptoms, medication, doctor’s diagnoses of allergic diseases and environmental exposures were assessed using interviewer-administered questionnaires. Information on sleep disturbance, impairment of daily activities, leisure and/or sport, impairment of school or work and presence of troublesome symptoms was collected to define the severity of AR. Data regarding tonsillectomy and adenoidectomy were collected from the medical records.
All children underwent skin prick testing (SPT) to common aeroallergens for our region(16), including house dust mites (Dermatophagoides pteronyssinus and Dermatophagoides farinae ), grass pollen mix (Phleum pratense, Poa pratensis, Dactylis glomerata, Lolium perenne, Festuca pratensis, and Avena eliator) weed pollen mix (Artemisia, Urtica, Taraxacum, Plantago) tree pollen mix (Alnus glutinosa, Corylus avellane, Populus alba, Ulmus minor, Betula alba) molds (Alternaria, Cladosporium, Penicillium, and Aspergillus) and animal dander (cat and dog). Histamine (10 mg/ml of histamine phosphate) and 0.9% saline were used as positive and negative controls, respectively. Total serum IgE level was measured using ImmunoCAP (Phadia AB, Uppsala, Sweden).
Blood eosinophil counts were determined from Coulter Counter (Beckman Coulter, Fullerton, CA, USA) leucocyte measurements.
Pulmonary function tests were performed using Zan 100 spirometer (Nspire Health, Oberthulba, Germany) according to recommendations by the European Respiratory Society(17). Three best efforts were recorded, and the highest value (presented as percent predicted according to age, gender, weight, and height(18)) was used in the analysis.