[Occurrence of asthma in schoolchildren. Is the disease underdiagnosed?].

A cross sectional study of 1064 unselected school children aged 6-17 years obtained the following for 851 of them (80%): complete data from a questionnaire on current asthma diagnosed by a physician, information on previous recurrent wheezing and present exposure to tobacco smoking combined with measurement of peak expiratory flow rate (PEFR) before and after six minutes running. Seventy-five (8.8%) had had previous periods of recurrent wheezing, and 535 (62.7%) were exposed to tobacco smoking at home. A correlation was found between passive smoking and previous recurrent wheezing. Thirty-four (4.0%) suffered from current asthma. Thirty-one children (3.6%) without an earlier diagnosis of asthma showed a significant exercise-induced fall in PEFR) (at least 15%). Thirty of these 31 children were followed up, and at reinvestigation, 27 (95%) were confirmed to suffer from hyperreactive airways based on significant exercise-induced fall in PEFR and/or a significantly increased variability of PEFR of at least 15% as measured by home recordings of PEFR. In conclusion the point prevalence of asthma diagnosed by a physician was 4.0%. In addition at least 3.2% had reproducible significant bronchial hyperreactivity indicating a point prevalence of asthma/clinically significant bronchial hyperreactivity of at least 7.2%. Asthma seems to be underdiagnosed in school children. Furthermore, our results indicate an association between passive smoking and recurrent wheezing.