Background: Asthma diagnosed in children shows wide geographical variations. Large scale surveys identify children with diagnosed asthma, but neglect the group of youngsters with multiple asthmatic complaints.
Methods: A short validated asthma questionnaire was included in six national surveys of the Health Behaviour in School-Aged Children Study. Prevalence rates are presented by country, gender and age. Gender and age differences are analysed using binary and multinomial logistic regressions controlling for age and smoking.
Results: Large country differences are observed in the prevalence rates of diagnosed asthma (8.6%-20.9% in boys, 6.9%-18.5% in girls) and young people with "asthma-like symptoms" (9.6%-20.2% in boys, 9.2%-23.1% in girls). When controlling for age and smoking, significant gender differences are observed (more diagnosed asthma in boys, more asthmatic symptoms in girls). Age differences were observed in adolescents with "asthma-like symptoms", but not in diagnosed asthma.
Conclusions: Using a short asthma questionnaire, large differences in diagnosed asthma and wheezing symptoms are observed between the countries. A considerable group of youngsters with "asthma-like symptoms" is detected in all countries, and may be an unrecognised risk group in health promotion.