title: Effect of age on bronchial reactivity in children with asthma.
abstract: In contrast to an abundance of data concerning age-related changes of bronchial sensitivity, the relationship between age and rapidity of bronchoconstriction (bronchial reactivity) remains unclear. We studied age and bronchial reactivity in children with asthma. Enrolled in this study were 511 asthmatic subjects and 115 age-matched control subjects 1 to 16 years of age. Bronchial reactivity was represented by the slope of the methacholine transcutaneous oxygen pressure dose-response curve (SPO(2)) in younger children and the slope of the respiratory resistance dose-response curve (SRrs) in older children. Overall, SPO(2) and SRrs were higher in asthmatic than control subjects. SPO(2) increased significantly from 1 to 6 years in asthmatic subjects, reaching a plateau after age 7. This age-related change in SPO(2) also was seen in controls. SRrs in asthmatic subjects decreased after age 13, while SRrs in controls showed no significant change between age 7 and 16. Age-related change in bronchial reactivity occurs during childhood, possibly reflecting early changes in airway smooth muscle maturity and later changes in airway wall rigidity.
authors.affiliation: Gunma University, Graduate School of Medicine, Department of Pediatrics and Developmental Medicine, Gunma, Japan. mochihi@med.gunma-u.ac.jp
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Mochizuki
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Arakawa
authors.forename: Kenichi
authors.initials: K
authors.lastname: Tokuyama
authors.forename: Akihiro
authors.initials: A
authors.lastname: Morikawa
mesh_terms: D000293:Adolescent; D000367:Age Factors; D000403:Airway Resistance / Q000187:drug effects / Q000502:physiology; D001249:Asthma / Q000503:physiopathology*; D001785:Blood Gas Monitoring, Transcutaneous; D001985:Bronchial Provocation Tests; D002648:Child; D002675:Child, Preschool; D005260:Female; D005541:Forced Expiratory Volume / Q000187:drug effects / Q000502:physiology; D006801:Humans; D007223:Infant; D008297:Male; D016210:Methacholine Chloride / Q000494:pharmacology; D010100:Oxygen / Q000097:blood; D010313:Partial Pressure; D012123:Pulmonary Ventilation / Q000187:drug effects / Q000502:physiology*; D012737:Sex Factors
chemical_list: D016210:Methacholine Chloride; D010100:Oxygen