Bronchial reactivity and asthma over adolescence
Background: Bronchial reactivity decreases over the adolescent period, but how that relates to persistent asthma is unknown. We describe the association of persistent bronchial reactivity to asthma groups over adolescence.
Methods: The Isle of Wight Birth Cohort (N = 1456) was reviewed at 1, 2, 4, 10 and 18-years. Questionnaires on physician diagnosis of asthma, wheeze and asthma treatment were collected alongside methacholine bronchial challenges in 784 and 585 subjects at 10 and 18 years respectively. Asthma and bronchial hyper-reactivity reactivity groups were defined as “no asthma/no BHR” (no asthma or no BHR at 10 and 18 years), “persistent asthma / persistent BHR” (asthma or BHR at age 10 and 18), “remission asthma / BHR” (asthma or BHR at age 10 but not at 18) and “adolescent-onset asthma/ adolescent-onset BHR” (asthma or BHR at age 18 but not at age 10).
Results: Bronchial reactivity was found in 30% (236/784) and 7.5% (44/585) of the cohort at 10 and 18 years respectively. Data on asthma and BHR were available for 406 subjects at 10 and 18 years. BHR over adolescence comprised of 7% (n=30) persistent BHR, 68% (274) no BHR, 24% (97) remission BHR and 1% (5) adolescent onset BHR. Most persistent BHR 63% (19/30) was observed in persistent asthma, with 10% (3/30) remission asthma and 20% (6/30) adolescent-onset asthma and 7% (2/30) in no asthma group. Among asthma groups 56% (15/27) of remission, 34% (21/62) of persistent, 53% (20/38) adolescent-onset asthma demonstrated no BHR over 10 to 18 year period.
Conclusion: We confirm earlier diminishing airway reactivity over the adolescent period. Persistent BHR was mostly seen with persistence of asthma while over half of remission asthma lacked BHR over adolescence.