Profiles and characteristics of bronchial responsiveness in general 7‐year‐old children

Abstract

Background Although bronchial responsiveness (BR) is usually categorized as normal or hyperresponsive to aid the diagnosis of asthma, it exists on a continuous spectrum, not in a dichotomous manner. We aimed to evaluate the distribution profile of BR in a general population of 7‐year‐olds. Methods In 2015, 7‐year‐old Korean children from a nationwide birth cohort study visited regional study hospitals for skin prick test, standard spirometry, and bronchial provocation to establish reference values for the general population. Their BR degrees were categorized into five ordered groups: hyperresponsive BRs were classified into group 1 (provocative concentration (PC) of methacholine causing a 20% fall in forced expiratory volume in 1 second [FEV1], PC20 of <4 mg/mL) and group 2 (PC20 of ≥4 mg/mL and <16 mg/mL), and nonresponsive BRs were categorized into group 3 (final FEV1 percentage fall after inhaling 16 mg/mL of methacholine [FEV1%fall] of >15% and ≤20%), group 4 (FEV1%fall of >10% and ≤15%), and group 5 (FEV1%fall of ≤10%). Results In total, 559 subjects finished all tests reliably. Groups 1 and 2 comprised 10.0% and 15.7% of the total population, respectively. Groups 3, 4, and 5 comprised 14.7%, 18.4%, and 41.1%, respectively. As the group number increased, the proportion of those with recent wheezing and those with indoor allergen sensitization decreased (P for trend = 0.001 and P for trend < 0.001, respectively), and the baseline FEV1/FVC increased (P for trend < 0.001) Conclusion BR of the 7‐year‐olds in the general population, while showing a wide distribution across phenotypes, is associated with allergic symptoms, negatively correlated with baseline lung function and positively correlated with indoor allergen sensitization.

Pulmonary function of healthy Korean children from three independent birth cohorts: Validation of the Global Lung Function Initiative 2012 equation

“…Data were obtained from the 7th or 8th year follow‐up of three independent population‐based birth cohorts in Korea: (i) the Panel Study on Korean Children (PSKC), (ii) the Cohort for Childhood Origin of Asthma and Allergic Diseases (COCOA) study, and (iii) the Environment and Development of Children (EDC) study 16–20 . The PSKC cohort is a nationwide cohort based in 17 regional centers, and the EDC cohort is a nationwide cohort based in one center.…”

Predictors of Airway Hyperresponsiveness in Symptomatic Children with Normal Spirometry and Suspicious of Possible Asthma

“…Several studies have identified a personal history of having an allergy to various antigens as a risk factor for AHR [4,[17][18][19]. Tree pollen, especially, has been described as an important allergen in this context [20], while no association could be verified in relation to mold sensitization [20,21].…”

Novel predictors of airway hyperresponsiveness in children with respiratory symptoms without obstructive pattern

“…Several studies have identified a personal history of having an allergy to various antigens as a risk factor for AHR (3,(12)(13)(14). Tree pollen, especially, has been described as an important allergen in this context (15), while no association could be verified in relation to mold sensitization (15,16).…”

“…Wheezing was identified in several studies as the most sensitive single symptom for asthma (12,20) and was also included in many scores developed for the prediction of asthma (24). An interrelation between wheezing associated with colds, AHR and asthma has been reported (19,25).…”

“…FEV 1 reflects mainly the functioning of the large and medium airways (30), whereas FEF represents the functioning of the medium-sized and small airways (30)(31)(32). There are several studies observing the important role of FEV 1 in predicting AHR (12,14,33). After excluding children with an obstructive pattern, FEF becomes more important, and FEV 1 has been reported to lose its significance (7,32).…”