From the 264 classes in 44 schools,1561 students were randomly selected as candidates of the study. After excluding 67
children with inadequate spirograms,1494 non-asthmatic children
satisfactorily completed the lung function studies and were entered for data analysis. Based on demographic data and lung function parameters (Table1), children who participated in the
lung function study were not different from the non-participants
in terms of age,height,and weight. The participants had a lower
prevalence of allergic rhinitis.