Relationship between duration of disease and bronchial responsiveness in 6-8 years old children with asthma

• Published in: Allergy asthma & respiratory disease Vol. 2; no. 1; pp. 23 - 29
• Main Authors: Shim, Eunhee, Yu, Jinho
• Format: Journal Article
• Language: English
• Published: 대한 소아알레르기 호흡기학회 01.03.2014
• Subjects: 소아과학
• ISSN: 2288-0402; 2288-0410
• DOI: 10.4168/aard.2014.2.1.23

Purpose: Bronchial hyperresponsiveness is considered as a hallmark of asthma. The duration of asthma was demonstrated to be associated with bronchial responsiveness, expressed as methacholine PC20. We investigated the relationship between duration of asthma and percentage fall in forced vital capacity (FVC) at PC20 (ΔFVC), another index of bronchial responsiveness, which reflects excessive bronchoconstriction. Methods: Six- to 8-year-old children with asthma underwent methacholine inhalation test. The PC20 and ΔFVC were calculated for each individual. The subjects were classified into those with wheezing onset in the first three years of life (early-onset asthma [EA], n=63) and those with wheezing onset from three years onwards (late-onset asthma [LA], n=99). Results: From the time of wheezing onset, duration of asthma ranged from 0.2 to 8.3 years. The mean duration of asthma in patients with EA was 5.6 years (standard deviation [SD], 1.2 years), compared with 2.2 years (SD, 1.3 years) in the patients with LA. Patients with EA had a significantly lower forced expiratory volume in 1 second/FVC than did those with LA (84.6%±5.9% vs. 86.8%±5.1%, P<0.05). The ΔFVC was significantly higher in patients with EA than in those with LA (19.4%±5.1% vs. 17.0%±4.5%, P<0.01), but PC20 was not different between the two groups. In total subjects, asthma duration correlated significantly with ΔFVC (r=0.222, P<0.01), but not with PC20. Conclusion: These data suggest that prolonged asthma is associated with worsened bronchial responsiveness during childhood, and such an association may be reflected primarily by ΔFVC rather than PC20 KCI Citation Count: 3