Objective: To better understand the effects of corticosteroid inhalation on asthma and asymptomatic bronchial hyperresponsiveness (BHR).
Methods: A double blind, randomized study was conducted to compare the effects of beclomethasone dry powder (BDP, 600 micrograms/day) inhalation with placebo on BHR and asthmatic symptoms in 59 students (12-18 yrs) for one year.
Results: After one year of treatment, lgPD20-FEV1 increased significantly in asthmatics in the BDP group (0.385 +/- 0.424 vs 1.187 +/- 0.603 mumol histamine). Thirty percent of asthmatics in BDP group and 86% in the control group developed symptoms in this year (P = 0.076). There was no significant difference in lgPD20-FEV1 between the BDP and the control group in asymptomatic BHR students. However, none in the BDP group of asymptomatic BHR students developed asthmatic symptoms compared with 3 cases (15%) in control group. The accumulative symptom score showed significant difference between the BDP group and the control group in asymptomatic BHR students (1.50 +/- 2.54 vs 5.58 +/- 6.22, P < 0.01).
Conclusion: The results suggested that BDP could significantly relieve the severity of BHR and symptoms in asthmatics, and could have some prophylactic effects on the development of asthma in those with asymptomatic BHR.