Objective: We carried out three consecutive projects in our region over the last 15 years in order to assess changes in the prevalence of asthma and allergic diseases and to investigate the relationship between the allergic diseases and possible risk factors. In the last survey, we compared two different questionnaire techniques - the direct parent-reported and the doctor guided-parent reported questi onnaires-in determining the risk factors for allergic diseases among school-age children.

Materials and Methods: ISAAC questionnaires were given to 5150 school-age children (6-14 years) and 3470 (67.3%) of these were returned. The parents completed a simple two-page written questionnaire about asthma, allergic rhinoconjunctivitis and atopic eczema and a one-page questionnaire about the risk factors. According to the questionnaire results, we constituted an atopic group of 100 children, and 100 children with no allergic symptoms were chosen randomly as the control group. Skin prick test, pulmonary function tests and specific IgE levels were evaluated in those 200 children.

Results: 11.6-41.8% of the parents denied their answers in the second questionnaire, even though they were living under the same conditions. 17.8- 52.8% of the parents accepted some of the questions regarding the risk factors in the second questionnaire after denial in the first. There were differences between the two questionnaires regarding the risk factors for asthma and other allergic diseases. History of varicella and history of recurrent lower respiratory tract infection were found as major risk factors both in the first and second questionnaire. Family history of allergic rhinitis was the major risk factor for the development of allergic rhinitis in both questionnaires.

Conclusion: In order to obtain a reliable cause-result relationship between the risk factors and the prevalence of allergic diseases, we suggest that detailed serologic and immunologic laboratory tests should be performed in addition to the questionnaire studies, especially in populations with lower socioeconomic status.