Exercise-induced wheezing among Japanese pre-school children and pupils.
BACKGROUND
Exercise-induced wheezing (EIW) may be a symptom of asthma and is a predictor of exercise-induced bronchoconstriction, transient narrowing of the lower airway following exercise in the presence or absence of diagnosed asthma. Population-based studies with a large sample of EIW in relation to age, sex, current asthma severity and medication usage have been sparse.


METHODS
International Study of Asthma and Allergies in Childhood questionnaires were distributed at 885 nurseries, 535 primary schools, 321 junior high schools and 190 high schools, respectively, across Japan, and the corresponding data on 46,597, 41,216, 45,960 and 51,104 children were analyzed.


RESULTS
Prevalence of EIW was 4.8, 4.7, 17.9 and 15.4% for each of the four educational facility types, respectively. Among 24,103 current asthmatics, 20.9, 28.7, 76.1 and 73.6% of subjects for the 4 educational facility groups reported to have experienced EIW, respectively. Severity of current asthma was associated with the risk of EIW; odds ratio (95% confidence interval) of children with asthma attack every day for having EIW once a week or more, using intermittent asthmatics as reference group, were 24.48 (19.33 to 31.01) adjusted for other covariates. Among current asthmatic kindergartners, increase in risk for EIW due to ascending severity of current asthma was mitigated by daily use of leukotriene receptor antagonist (p for interaction = 0.071).


CONCLUSIONS
EIW was not rare among current asthmatic children. An increased risk for EIW was in accordance with increasing severity of current asthma and this relation was mitigated with leukotriene receptor antagonist daily use among kindergartners.
Department of Paediatrics, National Hospital Organization Fukuoka National Hospital, Fukuoka, Japan.
Yoko
Y
Murakami
Department of Paediatrics, National Hospital Organization Fukuoka National Hospital, Fukuoka, Japan.
Satoshi
S
Honjo
Department of Paediatrics, National Hospital Organization Fukuoka National Hospital, Fukuoka, Japan.
Hiroshi
H
Odajima
Department of Paediatrics, Faculty of Medicine, Graduate School of Medicine and Pharmaceutical Science for Education, Toyama University, Toyama, Japan.
Yuichi
Y
Adachi
Division of Allergy, Tokyo Metropolitan Children's Medical Centre, Tokyo, Japan.
Koichi
K
Yoshida
Division of Allergy, National Centre for Child Health and Development, Tokyo, Japan.
Yukihiro
Y
Ohya
Division of Allergy, Tokyo Metropolitan Children's Medical Centre, Tokyo, Japan.
Akira
A
Akasawa
D000293:Adolescent; D018927:Anti-Asthmatic Agents / Q000008:administration & dosage / Q000627:therapeutic use; D001250:Asthma, Exercise-Induced / Q000175:diagnosis / Q000188:drug therapy / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D015444:Exercise; D005260:Female; D006801:Humans; D007564:Japan / Q000453:epidemiology; D020024:Leukotriene Antagonists / Q000008:administration & dosage / Q000627:therapeutic use; D008297:Male; D016017:Odds Ratio; D011159:Population Surveillance; D012135:Respiratory Sounds / Q000175:diagnosis / Q000187:drug effects / Q000209:etiology*; D012720:Severity of Illness Index; D013334:Students
D018927:Anti-Asthmatic Agents; D020024:Leukotriene Antagonists