• Clinical and Experimental Pediatrics
• /
• v.53 no.11
• /
• pp.951-956
• /
• 2010

Purpose: To compare the profiles of the bronchodilator response (BDR) among children with asthma and/or allergic rhinitis (AR) and to determine whether BDR in these children is reduced by treatment with inhaled and/or nasal corticosteroid. Methods: Sixty-eight children with asthma (mean age, 10.9 years), 45 children with comorbid asthma and AR (mean age, 10.5 years), and 44 children with AR alone (mean age, 10.2 years) were investigated. After a 2-week baseline period, all children were treated with inhaled fluticasone propionate (either 100 or $250{\mu}g$ b.i.d., tailored to asthma severity) or nasal fluticasone propionate (one spray b.i.d. in each nostril) or both, according to the condition. Before and 2 weeks after starting treatment, all children were evaluated with spirometry and bronchodilator testing. BDR was calculated as a percent change from the forced expiratory volume in 1 second ($FEV_1$) at baseline. Results: The mean BDR was 10.3% [95% confidence interval (CI) 8.3-12.4%] in children with asthma, 9.0% (95% CI 7.3-10.9%) in subjects with asthma and AR, and 5.0% (95% CI 4.1-5.9%) in children with AR alone ($P$<0.001). After treatment, the mean BDR was reduced to 5.2% (95% CI 4.2-6.3%) ($P$<0.001) in children with asthma and to 4.5% (95% CI 3.5-5.5%) ($P$<0.001) in children with asthma and AR. However, children with rhinitis showed no significant change in BDR after treatment, with the mean value being 4.7% (95% CI 3.7-5.8%) ($P$=0.597). Conclusion: The findings of this study imply that an elevated BDR in children with AR cannot be attributed to nasal inflammation alone and highlights the close relationship between the upper and lower airways.

• Clinical and Experimental Pediatrics
• /
• v.63 no.3
• /
• pp.104-109
• /
• 2020

Background: It is challenging to diagnose asthma in preschool children. The asthma predictive index (API) has been used to predict asthma and decide whether to initiate treatment in preschool children. Purpose: This study aimed to investigate the association between questionnaire-based current asthma with API, pulmonary function, airway hyperreactivity (AHR), fractional expiratory nitric oxide (FeNO), and atopic sensitization in preschool children. Methods: We performed a population-based cross-sectional study in 916 preschool children aged 4-6 years. We defined current asthma as the presence of both physician-diagnosed asthma and at least one wheezing episode within the previous 12 months using a modified International Study of Asthma and Allergies in Childhood questionnaire. Clinical and laboratory parameters were compared between groups according to the presence of current asthma. Results: The prevalence of current asthma was 3.9% in the study population. Children with current asthma showed a higher rate of positive bronchodilator response and loose and stringent API scores than children without current asthma. The stringent API was associated with current asthma with 72.2% sensitivity and 82.0% specificity. The diagnostic accuracy of the stringent API for current asthma was 0.771. However, no intergroup differences in spirometry results, methacholine provocation test results, FeNO level, or atopic sensitization rate were observed. Conclusion: The questionnaire-based diagnosis of current asthma is associated with API, but not with spirometry, AHR, FeNO, or atopic sensitization in preschool children.

• Clinical and Experimental Pediatrics
• /
• v.51 no.4
• /
• pp.343-350
• /
• 2008

Asthma and allergic diseases are one of the most common disorders in children. Due to its increased prevalence, as well as the increased morbidity and mortality from these diseases, asthma and allergic diseases have come to be recognized as a major worldwide public health issue. In addition, socioeconomic burden of asthma and allergic diseases has increased in Korea also. The International Study of Asthma and Allergies in Childhood (ISAAC) investigated the worldwide prevalence of asthma and other allergic diseases using simple standardized methods because of the comparison of asthma and allergic diseases between the countries. In Korea, several epidemiologic studies have been conducted to determine the prevalence of asthma in children. Although these studies showed increased prevalence of asthma among Korean children (from 3.4% in 1964 to 10.1% in 1989), these findings were based on data from small numbers of subjects. The first Nationwide Study of Asthma and Allergies in Korean Children, which utilized the Korean version of ISAAC written and video questionnaire, was conducted in 1995 and the second Nationwide Study of Asthma and Allergies in Korean Children was conducted in 2000, directed by the Korean Academy of Pediatric Allergy and Respiratory Diseases. We report here the prevalence of asthma and other allergic diseases in Korean children and adolescents, and show the changes that occurred over this 5 year period. We also describe the risk factors for development of these diseases in Korean children. We developed Korean versions of the ISAAC written (WQ) and video (AVQ) questionnaires for allergic diseases. In 1995, the enrolled population consisted of 25,117 children selected from 34 elementary school and 14,946 children selected from 34 middle school across the nation, the response rate was 94.8%. In 2000, 27,831 children selected from 34 elementary school and 15,214 children selected from 34 middle school, and the response rate was 96.4%. From these studies, we can confirm that increase of the prevalences of asthma, allergic rhinitis, and atopic dermatitis in Korea, except the prevalence of food allergy. Especially, the video questionnaire showed increases in the lifetime and 12 month prevalence rates of wheeze at rest, exercise-induced wheeze, nocturnal wheeze, nocturnal cough, and severe wheeze over this period of time in middle school children. In addition, the increase of prevalences of symptoms, diagnosis and treatment of atopic dermatitis was noted significantly. Risk factor analysis showed that body mass index (BMI), passive smoking and living with a dog or cat were associated with higher risk of wheeze. Also the occurrence of fever during infancy and the frequent use of antibiotics were associated with the risk of wheeze. In conclusion, during the 5 year period from 1995 to 2000, the prevalences of asthma, allergic rhinitis, and atopic dermatitis has increased in Korean children. BMI, passive smoking, living with a dog or cat, the fever episodes in infancy, and the frequent use of antibiotics in infancy are important risk factors to development of asthma and atopic dermatitis. In the near future, the birth cohort study will be needed to investigate the causes of this increase and the natural course of allergic diseases, then we develop the methods to control asthma and allergic diseases.

• Clinical and Experimental Pediatrics
• /
• v.57 no.6
• /
• pp.271-277
• /
• 2014

Purpose: A nationwide outbreak of Mycoplasma pneumoniae pneumonia (MP) refractory to macrolide antibiotics occurred in Korea during 2011. Steroid therapy has been reported to be both efficacious and well tolerated in pediatric patients with refractory MP. We compared clinical features and laboratory characteristics between children with refractory MP requiring steroid treatment and those with macrolide-responsive MP and evaluated the risk factors associated with refractory MP. Methods: We investigated 203 children who were admitted to our institution with MP from June to November 2011. Refractory MP was defined by persistent fever over $38.3^{\circ}C$ with progressive pulmonary consolidation or pleural effusion despite administration of appropriate macrolide antibiotics for 5 days or longer after admission. Steroid therapy was initiated on the fifth day after admission for refractory cases. Results: There were 26 patients with refractory MP requiring steroid therapy. The mean duration of steroid therapy was 5.4 days and most of the patients were afebrile within 24 hours after initiation of steroid therapy. The prevalence of refractory MP was higher in patients with pleural effusion, lobar pneumonia affecting more than 2 lobes, higher levels of serum lactate dehydrogenase, increased oxygen requirements, and longer duration of hospitalization. Atopic sensitization and history of asthma were also associated with refractory MP after adjusting for age and gender. Conclusion: Children with refractory MP had more severe pneumonia. Atopic sensitization and history of asthma may be risk factors for refractory MP requiring steroid therapy in Korean children.

• Clinical and Experimental Pediatrics
• /
• v.60 no.9
• /
• pp.290-295
• /
• 2017

Purpose: Airway pathology in children with atopic asthma can be reflected by the concave shape of the maximal expiratory flow-volume (MEFV) curve and high fractional exhaled nitric oxide (FeNO) values. We evaluated the capacity of the curvilinearity of the MEFV curve, FeNO, and their combination to distinguish subjects with atopic asthma from healthy individuals. Methods: FeNO and angle ${\beta}$, which characterizes the general configuration of the MEFV curve, were determined in 119 steroid-naïve individuals with atopic asthma aged 8 to 16 years, and in 92 age-matched healthy controls. Receiver operating characteristic (ROC) curve analyses were performed to determine the cutoff points of FeNO and angle ${\beta}$ that provided the best combination of sensitivity and specificity for asthma detection. Results: Asthmatic patients had a significantly smaller angle ${\beta}$ and higher FeNO compared with healthy controls (both, P<0.001). For asthma detection, the best cutoff values of angle ${\beta}$ and FeNO were observed at $189.3^{\circ}$ and 22 parts per billion, respectively. The area under the ROC curve for the combination of angle ${\beta}$ and FeNO improved to 0.91 (95% confidence interval [CI], 0.87-0.95) from 0.80 (95% CI, 0.75-0.86; P<0.001) for angle ${\beta}$ alone and 0.86 (95% CI, 0.82-0.91; P=0.002) for FeNO alone. In addition, the combination enhanced sensitivity with no significant decrease in specificity. Conclusion: These data suggest that the combined use of the curvilinearity of the MEFV curve and FeNO is a useful tool to differentiate between children with and without atopic asthma.

• Clinical and Experimental Pediatrics
• /
• v.64 no.5
• /
• pp.229-238
• /
• 2021

Background: Bronchial hyperresponsiveness (BHR), an important physiological feature of asthma, is a prognostic marker of childhood asthma. Purpose: We aimed to investigate the factors associated with BHR in adolescents with childhood asthma. Methods: Two hundred and fifteen adolescents (≥13 years of age; 149 males, 66 females) who were diagnosed with asthma during childhood were enrolled, underwent methacholine challenge tests, and were divided into the BHR group (<25 mg/mL of provocation concentration causing a 20% fall in forced expiratory volume in 1 second [FEV₁] [PC₂₀], n=113) or non-BHR group (≥25 mg/mL of PC₂₀, n=102). We examined longitudinal changes in BHR and the risk factors for its persistence in the 108 adolescents for whom baseline data, including methacholine PC₂₀ at age 6 years, were available. Multivariate logistic regression analyses were performed to assess the factors associated with BHR in adolescents. Results: Mold sensitization (adjusted odds ratio [aOR], 5.569; P=0.005) and increased blood eosinophil count (aOR, 1.002; P=0.026) were independently associated with BHR in boys but not girls. The odds of BHR decreased by 32% with each 1-year increase in age in boys (aOR, 0.683; P=0.010) but not girls. A reduced FEV₁/forced vital capacity ratio (<90%) was independently related with BHR in female patients only (aOR, 7.500; P=0.007). BHR decreased with age throughout childhood. A low methacholine PC₂₀ at age 6 years was independently associated with persistent BHR throughout childhood in male and female patients, whereas early mold sensitization was a risk factor for persistent BHR in male patients only (aOR, 7.718; P=0.028). Conclusion: Our study revealed sex-specific differences in the factors associated with BHR in adolescents with childhood asthma. Our findings suggest the risk factors that might affect asthma transition from childhood to adolescence and adulthood.

• Clinical and Experimental Pediatrics
• /
• v.62 no.1
• /
• pp.22-29
• /
• 2019

Particulate matter (PM) is a ubiquitous air pollutant that is a growing public health concern. Previous studies have suggested that PM is associated with asthma development and exacerbation of asthma symptoms. Although several studies have suggested increased risks of atopic dermatitis, allergic rhinitis, and allergic sensitization in relation to PM exposure, the evidence remains inconsistent. The plausible mechanisms underlying these effects are related to oxidative stress, enhancement of sensitization to allergens, inflammatory and immunological responses, and epigenetics. This review discusses the effect of PM on childhood allergic diseases, along with plausible mechanisms. Further studies are required to understand the role of PM exposure on childhood allergic diseases, to reduce these diseases in children.

• Pediatric Gastroenterology, Hepatology & Nutrition
• /
• v.24 no.4
• /
• pp.337-345
• /
• 2021

The immune system is not fully developed in human neonates and infants; breastfeeding is important in this stage as the bioactive components of human breast milk are known to have anti-microbial, anti-inflammatory, and immunomodulatory effects, and can therefore contribute to an infant's immunity against allergies, asthma, autoimmune diseases, and inflammatory bowel disease. Herein, the positive effect on the immune system by human colostrum and milk are reviewed.

• Clinical and Experimental Pediatrics
• /
• v.54 no.11
• /
• pp.456-462
• /
• 2011

Purpose: Synthesis of regulated on activation, normal T-cells expressed and secreted (RANTES) in the airway has previously been shown to be elevated after respiratory syncytial virus (RSV) infection. However, since few studies have examined whether RSV-infected asthma patients express a higher level of RANTES than do normal individuals, we used a murine model of asthma to address this question. Methods: We prepared Dermatophagoides farinae-sensitized mice as an asthma model, and then infected them with RSV and analyzed the changes in airway responsiveness and the cell populations and cytokine levels of bronchoalveolar lavage fluid. Results: RANTES synthesis increased in response to RSV infection in both control mice and in asthma model (D. farinae) mice. However, there was no significant difference in the amount of RANTES produced following RSV infection between control and D. farinae mice. RSV infection affected neither interferon-${\gamma}$ synthesis nor airway responsiveness in either control or D. farinae mice. Conclusion: RSV infection did not induce more RANTES in a murine model of asthma than in control mice.

• Clinical and Experimental Pediatrics
• /
• v.48 no.6
• /
• pp.580-587
• /
• 2005

New evidence is emerging that airway smooth muscle(ASM) may act as an immunomodulatory cell by providing pro-inflammatory cytokines and chemokines, polypeptide growth factors, extracellular matrix proteins, cell adhesion receptors and co-stimulatory molecules. ASM can promote the formation of the interstitial extracellular matrix, and potentially contribute to the alterations within the extracellular matrix in asthma. In addition, extracellular matrix components can alter the proliferative, survival, and cytoskeletal synthetic function of ASM cells through integrin-directed signaling. Increased ASM mass is one of the most important features of the airway wall remodeling process in asthma. Three different mechanisms may contribute to the increased ASM mass : cell proliferation, increased migration and decreased rate of apoptosis. The major signaling pathways of cell proliferation activated by ASM mitogens are those dependent on extracellular signal-regulated kinase and phosphoinositide 3'-kinase. The key signaling mechanisms of cell migration have been identified as the p38 mitogen-activated protein kinase and the p21-activated kinase 1 pathways. ASM cells contain ${\beta}2$-adrenergic receptors and glucocorticoid receptors. They may represent a key target for ${\beta}2$-adrenergic receptor agonist/corticosteroid interactions which have antiproliferative activity against a broad spectrum of mitogens.