Sex influences on lung function and medication in childhood asthma

Aim: To evaluate possible sex differences in prevalence, diagnosis and treatment of asthma, and influence on lung function associated with asthma severity in a population-based birth cohort ( BAMSE) of 4089 children. Methods: At 4-y follow-up, 92% responded to a questionnaire on symptoms of asthma, current medication and doctor's diagnosis of asthma. A total of 2965 children participated in clinical testing, including measurements of peak expiratory flow ( PEF), and were assigned to groups of asthma or no asthma by reported airway symptoms. Results: Children in asthma groups had lower PEF readings compared to healthy children. This effect was most pronounced for both sexes in the persistent group ( boys p < 0.05, girls p < 0.001) and for girls in the transient group ( p < 0.01). A doctor's diagnosis of asthma did not significantly differ between boys and girls, but significantly more boys than girls had inhaled corticosteroids, even when stratifying by frequency of symptoms. Conclusion: These results suggest that when 4-y-old children are stratified according to common diagnostic criteria, girls have a larger effect on PEF of asthma symptoms and are less frequently treated compared to boys.