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Background and Objective: Preterm birth or fetal growth has been associated with reduced lung function and asthma during childhood in the general population. We aimed to elucidate whether prematurity or fetal growth has a significant influence on lung function or symptoms in children with stable asthma. Methods: We included children with stable asthma who participated in the Korean childhood Asthma Study cohort. Asthma symptoms were determined by asthma control test (ACT). Percent predicted values of pre‐ and post‐bronchodilator (BD) lung function including forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC), and forced expiratory flow at 25%–75% of FVC (FEF25%–75%) were measured. Lung function and symptoms were compared according to the history of preterm birth and birth weight (BW) for gestational age (GA). Results: The study population consisted of 566 children (age range: 5–18 years). There were no significant differences in lung function and ACT between preterm and term subjects. We observed no significant difference in ACT but significant differences were observed in pre‐ and post‐BD FEV1, pre‐ and post‐BD FVC, and post‐BD FEF25%–75% according to BW for GA in total subjects. Two‐way ANOVA revealed that BW for GA rather than prematurity was a significant determining factor for pre‐ and post‐BD lung function. After regression analysis, BW for GA was still a significant determining factor of pre‐ and post‐BD FEV1 and pre‐ and post‐BD FEF25%–75%. Conclusion: Fetal growth rather than prematurity appears to have a significant effect on lung function in children with stable asthma. [ABSTRACT FROM AUTHOR]

Background: Asthma exacerbation (AE) leads to social and economic costs and long‐term adverse outcomes. We aimed to predict exacerbation‐prone asthma (EPA) in children. Methods: The Korean childhood Asthma Study (KAS) is a prospective nationwide pediatric asthma cohort of children aged 5–15 years followed every 6 months. Patients with AE during the 6 months prior to all three visits, with AE prior to one or two visits, and without AE prior to any visit were defined as having EPA, exacerbation‐intermittent asthma (EIA), and exacerbation‐resistant asthma (ERA), respectively. Risk factors and prediction models of EPA were explored. Results: Of the 497 patients who completed three visits, 42%, 18%, and 15% had exacerbations prior to visits 1, 2, and 3 and 5%, 47%, and 48% had EPA, EIA, and ERA, respectively. Univariate and multivariable logistic regression revealed forced expiratory volume in 1 s (FEV1) z‐score, forced vital capacity (FVC) z‐score, white blood cell (WBC) count, and asthma control test (ACT) score as relevant EPA risk factors. The EPA prediction model comprised FVC z‐score, WBC count, ACT score, sex, and parental education level (area under the receiver operating characteristic curve [AUROC] 0.841 [95% confidence interval (CI): 0.728–0.954]). Conclusion: With appropriate management, AE decreases over time, but persistent AEs may occur. Apart from asthma control level, baseline lung function and WBC count predicted EPA. [ABSTRACT FROM AUTHOR]