Atmospheric environment and persistence of pediatric asthma: A population-based cohort study.

BACKGROUND: Asthma is a heterogeneous disease with different outcomes. For children with asthma at the age of 7 years, 67-75% are symptom-free as adults. Data on the important link between childhood and adult asthma are sparse. OBJECTIVE: We aimed to investigate factors associated with persistence of childhood asthma over three years of follow-up by linking data between Korea childhood Asthma Study (KAS) and their matched claims data from Health Insurance Review and Assessment Service (HIRA). METHODS: We analyzed data from 450 preadolescent children aged 7 to 10 years and classified them into remission or persistence groups. Baseline clinical characteristics and exposure to air pollution materials including PM2.5 and PM10 during three years of follow-up were compared. The main outcome was asthma persistence which was defined as the presence of asthma episodes with healthcare utilization and prescription of asthma medications within three years after KAS enrollment. RESULTS: At the third year of follow-up, after stepwise regression analysis, lower age at enrollment (adjusted odds ratio (aOR): 0.79; 95% confidence interval (CI): 0.64-0.96), male sex (aOR: 1.66; 95%CI: 1.05-2.63), proximity from an air-polluting facility (aOR: 2.4; 95%CI: 1.34-4.29), higher level outdoor PM2.5 (aOR: 1.1; 95%CI: 1.02-1.20), and higher rate of doctor-diagnosed food allergy (FA) (aOR: 2.33; 95%CI: 1.06-5.12) were significantly associated with persistence. CONCLUSION: We discovered various independent risk factors for the persistence of childhood asthma. By linking HIRA claims data, we could clarify risk factors for persistence in a well-defined study population.

Frequency of exacerbation and degree of required asthma medication can characterize childhood longitudinal asthma trajectories.

BACKGROUND: To the best of our knowledge, there have been no investigations of longitudinal asthma trajectories based on asthma exacerbation frequency and medications required for asthma control in children. OBJECTIVE: To investigate longitudinal asthma trajectories based on the exacerbation frequency throughout childhood and asthma medication ranks. METHODS: A total of 531 children aged 7 to 10 years were enrolled from the Korean childhood Asthma Study. Required asthma medications for control of asthma from 6 to 12 years of age and asthma exacerbation frequency from birth to 12 years of age were obtained from the Korean National Health Insurance System database. Longitudinal asthma trajectories were identified on the basis of asthma exacerbation frequency and asthma medication ranks. RESULTS: Four asthma clusters were identified: lesser exacerbation with low-step treatment (8.1%), lesser exacerbations with middle-step treatment (30.7%), highly frequent exacerbations in early childhood with small-airway dysfunction (5.7%), and frequent exacerbations with high-step treatment (55.6%). The frequent exacerbations with high-step treatment cluster were characterized by a high prevalence of male sex, increased blood eosinophil (counts) with fractional exhaled nitric oxide, and high prevalence of comorbidities. The highly frequent exacerbation in early childhood with small-airway dysfunction cluster was characterized by recurrent wheeze in preschool age, with high prevalence of acute bronchiolitis in infancy and a greater number of family members with small-airway dysfunction at school age. CONCLUSION: The present study identified 4 longitudinal asthma trajectories on the basis of the frequency of asthma exacerbation and asthma medication ranks. These results would help clarify the heterogeneities and pathophysiologies of childhood asthma.

Fetal growth rather than prematurity determines lung function in children with asthma.

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.

Longitudinal asthma exacerbation phenotypes in the Korean childhood asthma study cohort.

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.

Eosinophil-derived neurotoxin: An asthma exacerbation biomarker in children.

Background: Asthma is a heterogeneous disease, characterized by chronic airway inflammation. Asthma exacerbations (AE) are episodes characterized by a progressive increase in symptoms of shortness of breath, cough, wheezing, or chest tightness with a decrease in lung function. There have been previous studies that examined the role of eosinophil-derived neurotoxin (EDN) in asthma, but there have been no studies of the role of EDN in children experiencing AE. Objective: In this study, we aimed to examine the association of EDN with lung function and prognosis in children admitted for severe AE. Methods: We enrolled 82 children who were admitted for severe AE at two different university hospitals in South Korea between January 2018 and December 2019. Blood tests, including white blood cell count, myeloperoxidase (MPO), total eosinophil count, EDN, C-reactive protein (CRP) level, and interleukin (IL) 4, IL-5, IL-10 values, and lung function were measured on admission and at discharge in each patient. Results: We observed significant decreases in the levels of MPO, EDN, CRP, and IL-4, with significant improvement in lung function after treatment. We then classified the subjects into two groups of different clinical phenotypes: eosinophilic asthma exacerbation (EAE) group and non-EAE group. EDN levels were higher and lung functions were lower in the EAE group. Also, we found that the EDN level was a significant biomarker useful for predicting the number of days for hospital stay. Conclusion: We found that EDN can act as a biomarker that reflects lung function, and that EDN could act as a prognostic biomarker, which demonstrated the complex role of EDN in children experiencing AE.

Annual and seasonal patterns in etiologies of pediatric community-acquired pneumonia due to respiratory viruses and Mycoplasma pneumoniae requiring hospitalization in South Korea.

BACKGROUND: Community-acquired pneumonia (CAP) is one of the leading worldwide causes of childhood morbidity and mortality. Its disease burden varies by age and etiology and is time dependent. We aimed to investigate the annual and seasonal patterns in etiologies of pediatric CAP requiring hospitalization. METHODS: We conducted a retrospective study in 30,994 children (aged 0-18 years) with CAP between 2010 and 2015 at 23 nationwide hospitals in South Korea. Mycoplasma pneumoniae (MP) pneumonia was clinically classified as macrolide-sensitive MP, macrolide-less effective MP (MLEP), and macrolide-refractory MP (MRMP) based on fever duration after initiation of macrolide treatment, regardless of the results of in vitro macrolide sensitivity tests. RESULTS: MP and respiratory syncytial virus (RSV) were the two most commonly identified pathogens of CAP. With the two epidemics of MP pneumonia (2011 and 2015), the rates of clinical MLEP and MRMP pneumonia showed increasing trends of 36.4% of the total MP pneumonia. In children < 2 years of age, RSV (34.0%) was the most common cause of CAP, followed by MP (9.4%); however, MP was the most common cause of CAP in children aged 2-18 years of age (45.3%). Systemic corticosteroid was most commonly administered for MP pneumonia. The rate of hospitalization in intensive care units was the highest for RSV pneumonia, and ventilator care was most commonly needed in cases of adenovirus pneumonia. CONCLUSIONS: The present study provides fundamental data to establish public health policies to decrease the disease burden due to CAP and improve pediatric health.

Asthma control test reflects not only lung function but also airway inflammation in children with stable asthma.

Objective: Various numerical asthma control tools have been developed to distinguish different levels of symptom control. We aimed to examine whether the asthma control test (ACT) is reflective of objective findings such as lung function, fractional exhaled nitric oxide (FeNO) and laboratory data in patients with stable asthma.Methods: We included patients who were enrolled in the Korean Childhood Asthma Study. ACT, spirometry, blood tests and FeNO were performed in patients after stabilization of their asthma. We examined differences among spirometry parameters, blood tests and FeNO according to control status as determined by ACT and investigated for any significant correlations.Results: The study population consisted of 441 subjects. Spirometry showed that forced expiratory volume in one second (FEV1), forced expiratory flow between 25% and 75% of forced vital capacity and FEV1/forced vital capacity were all significantly higher in the controlled asthma group. Likewise, FeNO and percent-change in FEV1 were both significantly lower in the controlled asthma group. In blood tests, the eosinophil fraction was significantly lower in the controlled asthma group while white blood cell count was significantly higher in the controlled asthma group. Lastly, among the various factors analyzed, only provocative concentration of methacholine causing a 20% fall in FEV1 significantly correlated with ACT score.Conclusion: ACT is useful as part of the routine evaluation of asthmatic children and should be used as a complement to existing tools such as spirometry and FeNO measurement.

Rhinovirus Infection of ORMDL3 Transgenic Mice Is Associated with Reduced Rhinovirus Viral Load and Airway Inflammation.

Orosomucoid like 3 (ORMDL3), a gene localized to chromosome 17q21, has been linked in epidemiologic studies to childhood asthma and rhinovirus (RV) infections. As the single nucleotide polymorphisms linking ORMDL3 to asthma are associated with increased expression of ORMDL3, we have used hORMDL3zp3-Cre mice (which have universal increased expression of human ORMDL3) to determine whether infection of these transgenic mice with RV influences levels of airway inflammation or RV viral load. RV infection of hORMDL3zp3-Cre mice resulted in reduced RV viral load assessed by quantitative real-time PCR (lung and airway epithelium), as well as reduced airway inflammation (total bronchoalveolar lavage cells, neutrophils, macrophages, and lymphocytes) compared with RV-infected wild-type mice. Levels of the antiviral pathways including IFNs (IFN-α, IFN-ß, IFN-λ) and RNAse L were significantly increased in the lungs of RV-infected hORMDL3zp3-Cre mice. Levels of the antiviral mouse oligoadenylate synthetase (mOas)1g pathway and RNAse L were upregulated in the lungs of unchallenged hORMDL3zp3-Cre mice. In addition, levels of mOas2, but not mOas1 (mOas1a, mOas1b, mOas1g), or mOas3 pathways were significantly more upregulated by IFNs (IFN-α, IFN-ß, IFN-λ) in epithelial cells from hORMDL3zp3-Cre mice compared with RV-infected wild-type mouse epithelial cells. RNAse L-deficient mice infected with RV had increased RV viral load. Overall, these studies suggest that increased levels of ORMDL3 contribute to antiviral defense to RV infection in mice through pathways that may include IFNs (IFN-α, IFN-ß, IFN-λ), OAS, and RNAse L.

Korean childhood asthma study (KAS): a prospective, observational cohort of Korean asthmatic children.

BACKGROUND: Asthma is a syndrome composed of heterogeneous disease entities. Although it is agreed that proper asthma endo-typing and appropriate type-specific interventions are crucial in the management of asthma, little data are available regarding pediatric asthma. METHODS: We designed a cluster-based, prospective, observational cohort study of asthmatic children in Korea (Korean childhood Asthma Study [KAS]). A total of 1000 Korean asthmatic children, aged from 5 to 15 years, will be enrolled at the allergy clinics of the 19 regional tertiary hospitals from August 2016 to December 2018. Physicians will verify the relevant histories of asthma and comorbid diseases, as well as airway lability from the results of spirometry and bronchial provocation tests. Questionnaires regarding subjects' baseline characteristics and their environment, self-rating of asthma control, and laboratory tests for allergy and airway inflammation will be collected at the time of enrollment. Follow-up data regarding asthma control, lung function, and environmental questionnaires will be collected at least every 6 months to assess outcome and exacerbation-related aggravating factors. In a subgroup of subjects, peak expiratory flow rate will be monitored by communication through a mobile application during the overall study period. Cluster analysis of the initial data will be used to classify Korean pediatric asthma patients into several clusters; the exacerbation and progression of asthma will be assessed and compared among these clusters. In a subgroup of patients, big data-based deep learning analysis will be applied to predict asthma exacerbation. DISCUSSION: Based on the assumption that asthma is heterogeneous and each subject exhibits a different subset of risk factors for asthma exacerbation, as well as a different disease progression, the KAS aims to identify several asthma clusters and their essential determinants, which are more suitable for Korean asthmatic children. Thereafter we may suggest cluster-specific strategies by focusing on subjects' personalized aggravating factors during each exacerbation episode and by focusing on disease progression. The KAS will provide a good academic background with respect to each interventional strategy to achieve better asthma control and prognosis.

Fstl1 Promotes Asthmatic Airway Remodeling by Inducing Oncostatin M.

Chronic asthma is associated with airway remodeling and decline in lung function. In this article, we show that follistatin-like 1 (Fstl1), a mediator not previously associated with asthma, is highly expressed by macrophages in the lungs of humans with severe asthma. Chronic allergen-challenged Lys-Cre(tg) /Fstl1(Δ/Δ) mice in whom Fstl1 is inactivated in macrophages/myeloid cells had significantly reduced airway remodeling and reduced levels of oncostatin M (OSM), a cytokine previously not known to be regulated by Fstl1. The importance of the Fstl1 induction of OSM to airway remodeling was demonstrated in murine studies in which administration of Fstl1 induced airway remodeling and increased OSM, whereas administration of an anti-OSM Ab blocked the effect of Fstl1 on inducing airway remodeling, eosinophilic airway inflammation, and airway hyperresponsiveness, all cardinal features of asthma. Overall, these studies demonstrate that the Fstl1/OSM pathway may be a novel pathway to inhibit airway remodeling in severe human asthma.

My child cannot breathe while sleeping: a report of three cases and review.

BACKGROUND: Sudden breath-holding episodes during sleep in young children are potentially related to sudden infant death syndrome and other life-threatening events. Additionally, these episodes can negatively affect child's growth and development. CASE PRESENTATION: Here, we present 3 cases of preschool children with similar paroxysmal nocturnal waking events associated with choking that had different etiologies (nocturnal frontal lobe epilepsy, nocturnal gastroesophageal reflux disease, and parasomnia, respectively). CONCLUSIONS: It is important to take into consideration the fact that breath spells during sleep can occur as a rare manifestation of parasomnia due to gastroesophageal reflux or as a symptom of nocturnal frontal lobe epilepsy. Full video electroencephalography, polysomnography, and simultaneous gastric pH monitoring should be used for the differential diagnosis of sleep-related disorders, such as breath spells, in children.

Exhaled nitric oxide as a better diagnostic indicator for evaluating wheeze and airway hyperresponsiveness in preschool children.

OBJECTIVE: Fractional concentration of exhaled nitric oxide (FeNO) is a known marker of airway inflammation. The aims of this study were to evaluate FeNO, impulse oscillometry (IOS), and spirometry in preschool children and to investigate their relationship with wheeze and airway hyperresponsiveness (AHR). METHODS: We performed a population-based, cross-sectional study with 561 children aged 5-6 years. A total of 544 children completed a modified International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire and eligible for the study. We measured FeNO, spirometry, methacholine bronchial provocation, and IOS. AHR was defined as the induction of a 20% decrease in FEV(1)(PC(20)) by a methacholine concentration ≤8.0 mg/dL. RESULTS: Children who had wheeze or AHR had higher FeNO levels than children without these symptoms. However, neither IOS nor spirometry parameters showed significant differences between children with wheeze or AHR and those without. FeNO was associated with AHR, whereas IOS or spirometry parameters showed no association. Mean FeNO levels were positively correlated with a dose-response slope for methacholine, but neither IOS nor spirometry parameters showed significant correlations. CONCLUSIONS: FeNO is a more sensitive measurement of AHR and wheeze than spirometry or IOS in preschool children.

Epidemiologic differences of four major respiratory viruses between children, adolescents, and adults in Korea.

The purpose of this study was to investigate the epidemiology of four major respiratory viruses among the Korean population. This retrospective study was conducted over four years, from January 2005 to December 2008. Among a total of 23,806 specimens, 5512 virus isolates underwent culture for influenza A and B viruses (IFA/B), parainfluenza virus (PIV), respiratory syncytial virus (RSV), and adenovirus (ADV). Patients were divided into two groups: children/adolescents and adults. The viruses detected in specimens from children/adolescents included PIV (7.8%), RSV (7.3%), ADV (4.0%), IFA (2.9%), and IFB (2.2%). In adults, IFB (5.6%), IFA (4.4%), RSV (1.1%), PIV (0.5%), and ADV (0.2%) were detected, thus demonstrating two distinct patterns of virus infection. Influenza viruses had similar seasonal patterns and periods of infection among children/adolescents and adults; however, the isolation rate in adults was slightly higher than that in children and adolescents. Correlation coefficient analysis based on weekly seasonal patterns indicated that influenza viruses were detected a week earlier in children than in adults. RSV, PIV, and ADV did not show similar trends between the two age groups due to low detection rates and sporadic isolations among adult patients. Of note, different respiratory viruses should be considered depending on patient age when a clinical respiratory viral infection is suspected. Furthermore, in the case of influenza, a preceding epidemic among a pediatric population could be useful to predict a subsequent epidemic among adults.

Effect of Air Pollutants on Allergic Inflammation in Structural Cells of the Nasal Mucosa.

OBJECTIVES: Air pollution is an increasing global concern, and its effect on allergic inflammation has attracted the attention of many researchers. Particulate matter (PM) is a major component of ambient air pollution, and heavy metals are the primary toxic constituents of PM. As previous studies on the impact of air pollutants on allergic inflammation did not adequately mimic real-world atmospheric exposure, we developed an experimental model to investigate the effects of aerosolized air pollutants on nasal epithelial cells and fibroblasts. METHODS: We collected particulate matter 2.5 (PM2.5) samples from ambient 24-hour air samples obtained in Seoul from August 2020 to August 2022, and then conducted component analysis for metallic constituents. Primary nasal epithelial cells and nasal fibroblasts, obtained and cultured from the turbinate tissues of human participants, were treated with PM2.5. The associations of heavy metals identified from the component analysis with cytokine expression were investigated. A three-dimensional (3D)-hybrid culture model, consisting of co-culture of an air-liquid interface and nasal fibroblast spheroids, was constructed to observe the impact of aerosolized air pollutants. RESULTS: Among the heavy metals, Si was the predominant component of PM2.5, and Zn showed the highest correlation with the concentration of PM2.5 in Seoul. PM2.5, Zn, and Si increased the production of epithelial cell-derived cytokines, and PM2.5 and Zn exhibited similar trends with one another. Exposure of the 3D-hybrid model to aerosolized PM2.5 and Zn resulted in elevated periostin, alpha-smooth muscle actin, and fibronectin expression in fibroblast spheroids, and those without an epithelial barrier exhibited a similar increase in periostin expression. CONCLUSION: Ambient air pollutants in the form of aerosols increase the expression of allergic inflammatory cytokines in both nasal epithelial cells and fibroblasts. Regulations on air pollution will help reduce the global burden of allergic diseases in the future.

Particulate matter-induced gene expression patterns in human-derived cells based on 11 public gene expression datasets.

BACKGROUND: Exposure to particulate matter (PM) and house dust mite (HDM) can change the expression patterns of inflammation-, oxidative stress-, and cell death-related genes. We investigated the changes in gene expression patterns owing to PM exposure. OBJECTIVE: This study examined the changes in gene expression patterns following PM exposure. METHODS: We searched for differentially expressed genes (DEGs) following PM exposure using five cell line-based RNA-seq or microarray datasets and six human-derived datasets. The enrichment terms of the DEGs were assessed. RESULTS: DEG analysis yielded two gene sets. Thus, enrichment analysis was performed for each gene set, and the enrichment terms related to respiratory diseases were presented. The intersection of six human-derived datasets and two gene sets was obtained, and the expression patterns following PM exposure were observed. CONCLUSIONS: Two gene sets were obtained for cells treated with PM and their expression patterns were presented following verification in human-derived cells. Our findings suggest that exposure to PM2.5 and HDM may reveal changes in genes that are associated with diseases, such as allergies, highlighting the importance of mitigating PM2.5 and HDM exposure for disease prevention.

Evaluation of the Simplexa Flu A/B and RSV test for the rapid detection of influenza viruses.

Recently, various molecular systems have been introduced for the detection of influenza viruses. Among these, the Simplexa Flu A/B and respiratory syncytial virus (RSV) test can provide results in approximately 2 hr. Nasopharyngeal swabs from 241 patients (influenza A, n = 81; influenza B, n = 80; influenza A and influenza B mixed, n = 1; influenza A and RSV A mixed, n = 2; and influenza and RSV negative, n = 77) were analyzed using the Simplexa Flu A/B and RSV test, a conventional reverse-transcription polymerase chain reaction (RT-PCR) assay, and a real-time RT-PCR assay. Compared to conventional RT-PCR, the Simplexa test had respective sensitivities and specificities of 100% and 100% for influenza A and 100% and 99.4% for influenza B with extracted RNA samples, and 91.7% and 99.4% for influenza A, and 97.5% and 98.1% for influenza B with unprocessed patient specimens. All RSV A specimens were successfully detected by the Simplexa test using both extracted RNA samples and unprocessed patient specimens. The real-time RT-PCR assay had respective sensitivities and specificities of 96.4% and 99.4% for influenza A, and 98.8% and 99.4% for influenza B. The Simplexa test was effective at detecting influenza viruses from extracted RNA samples as well as from unprocessed patient specimens. The assay was not only simple and rapid for influenza detection, but the performance was also comparable to that of other conventional molecular methods.

Effect of paracetamol use on the modification of the development of asthma by reactive oxygen species genes.

BACKGROUND: Recent studies have identified an increase in the prevalence of asthma associated with paracetamol use. OBJECTIVE: To identify the relationship among asthma, biomarkers, genes, and paracetamol use in preschool children. METHODS: We undertook a population-based, cross-sectional survey of 933 preschool children. Asthma status was classified according to medical history and asthmatic symptoms. History of paracetamol use in infancy was recorded. Impulse oscillometry, blood tests for eosinophils and total IgE, and genotyping of NAT2, Nrf2, and GSTP1 polymorphisms by TaqMan assay were conducted. RESULT: Paracetamol use in infancy was associated with an increased risk of treatment for asthma within the previous 12 months. Paracetamol use together with a family history of asthma increased the risk of asthma diagnosis ever, current asthma, and treatment for asthma within the previous 12 months. Gene polymorphisms in NAT2 (rs4271002), Nrf2 (rd6726395), and GSTP1 (rd1695) increased the risk of treatment for asthma within the last 12 months. Eosinophils were significantly elevated in the group with paracetamol use and a family history of asthma; however, the serum total IgE level and IOS did not show any significant difference. CONCLUSION: Paracetamol use in infancy was significantly associated with increased risk of asthma. The association is more significant in genetically susceptible children, related to antioxidant genes, and the effect may be mediated by eosinophilic inflammation.

Association between maternal characteristics and neonatal birth weight in a Korean population living in the Seoul metropolitan area, Korea: a birth cohort study (COCOA).

Previous studies suggest that maternal characteristics may be associated with neonatal outcomes. However, the influence of maternal characteristics on birth weight (BW) has not been adequately determined in Korean populations. We investigated associations between maternal characteristics and BW in a sample of 813 Korean women living in the Seoul metropolitan area, Korea recruited using data from the prospective hospital-based COhort for Childhood Origin of Asthma and allergic diseases (COCOA) between 2007 and 2011. The mean maternal age at delivery was 32.3 ± 3.5 yr and prepregnancy maternal body mass index (BMI) was 20.7 ± 2.5 kg/m(2). The mean BW of infant was 3,196 ± 406 g. The overall prevalence of a maternal history of allergic disease was 32.9% and the overall prevalence of allergic symptoms was 65.1%. In multivariate regression models, prepregnancy maternal BMI and gestational age at delivery were positively and a maternal history of allergic disease and nulliparity were negatively associated with BW (all P < 0.05). Presence of allergic symptoms in the mother was not associated with BW. In conclusion, prepregnancy maternal BMI, gestational age at delivery, a maternal history of allergic disease, and nulliparity may be associated with BW, respectively.

Epidemiology of patients with asthma in Korea: Analysis of the NHISS database 2006-2015.

Background: There has been a concerning increase in the prevalence and socioeconomic burden of asthma in Korea. Korea's National Health Insurance System (NHIS) covers insurance payment and claims management for all Koreans. Using National Health Insurance Sharing Service (NHISS) claims data. This study aimed to investigate patterns of healthcare utilization and direct cost in patients with asthma over a 10-year period. Methods: In this retrospective population-based study, we examined NHISS claims records between July 2005 and June 2016 and investigated healthcare utilization among patients with asthma based on age group and severity of disease (non-severe asthma [NSA] and severe asthma [SA]). Results: From 2006 to 2015, the total number of patients with asthma in Korea steadily increased from 743 968 to 2 286 309, with a corresponding increase in prevalence from 1.62% to 4.74%. The proportion of patients with SA decreased from 3.16% in 2006 to 1.56% in 2015; the proportion was consistently higher in men than in women. In addition, patients with SA had a higher cost per outpatient visit than patients with NSA, and the number of outpatient visits per year increased. The inhaled corticosteroid (ICS) prescription rate among patients with asthma decreased from 22.9% in 2006 to 15.7% in 2015. Furthermore, for a period of 10 years, more than 40% of patients with SA have been prescribed short-acting ß-2 agonists (SABAs). Conclusions: Although patients with SA comprised a small proportion of patients with asthma, they incurred greater medical costs per person. The pharmaceutical prescription pattern indicated a lack of ICS-based prescriptions and frequent SABA prescriptions.