Characteristics in Pediatric Patients with Coronavirus Disease 2019 in Korea.

BACKGROUND: Based on the reports of low prevalence and severity of pediatric severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections, the Korean government has released new SARS-CoV-2 infection response and treatment guidelines for children under the age of 12 years. The government has further directed school reopening under strict preventive measures. However, there is still considerable concern on the impact of school reopening on community transmission of Coronavirus disease 2019 (COVID-19). In the present study, we aimed to evaluate the appropriateness of these directives and the severity of SARS-CoV-2 infections in children as compared to adults using sufficient national sample data. METHODS: In the present study, we evaluated the severity of SARS-CoV-2 infection in pediatric patients as compared to adults by analyzing the length of hospital stays (LOS), medical expenses, and hospital and intensive care unit (ICU) admission rates. A multivariate linear regression analysis was carried out to examine the effects of COVID-19 patients that the characteristics on the LOS and medical expenses, and multivariate logistic regression analysis were performed to identify COVID-19 characteristics that affect hospital and ICU admission rates and to prove the low SARS-CoV-2 infection severity in pediatric patients. RESULTS: The hospitalization period for children aged 0-9 was 37% shorter and that of patients aged 10-19 years was 31% shorter than those of older age groups (P < 0.001). The analysis of the medical expenses by age showed that on average, medical expenses for children were approximately 4,900 USD lower for children than for patients over 80 years of age. The linear regression analysis also showed that patients who were 0-9 years old spent 87% and those aged 10-19 118% less on medical expenses than those aged 70 and over, even after the correction of other variables (P < 0.001). The probability of hospitalization was the lowest at 10-19 years old (odds ratio [OR], 0.05; 95% confidence interval [CI], 0.03-0.09), and their ICU admission rate was also the lowest at 0.14 (OR, 0.14; 95% CI, 0.08-0.24). On the other hand, the likelihood of hospitalization and ICU admission was the highest in children aged 0-9 years, and among patients under the age of 50 years in general. CONCLUSION: This study demonstrated the low severity of SARS-CoV-2 infection in younger patients (0-19 years) by analyzing the LOS, medical expenses, hospital, and intensive care unit admission rates as outcome variables. As the possibility to develop severe infection of coronavirus at the age of 10-19 was the lowest, a mitigation policy is also required for middle and high school students. In addition, children with underlying diseases need to be protected from high-risk infection environments.

Stop Discussing New Medical Specialty Boards.

The Korean society is rapidly aging and the health care needs for aged people are increasing. In this context, some physicians claim to establish new medical specialty board (MSB) for geriatric medical experts but also MSB for primary medical care specialists, clinical pharmacologists, and public health experts. In Korea, basic concept for the specialty board system is still under debates and the legal support for the system is poor. At present, doctors with MSBs in private sectors supply 92.4% of primary medical care but the National Health Care System requires more primary care physicians than specialists in Korea. Therefore, the government must invest in the education of doctors more to improve the public health care system. The proposal of the new MSB for geriatric medicine must be gradually developed according to the national long-term health plan, social needs, and national budget for the public benefit. Please stop discussing unprepared new MSBs.

What Factors Impact Consumer Perception of the Effectiveness of Health Information Sites? An Investigation of the Korean National Health Information Portal.

Lay public's concerns around health and health information are increasing. In response, governments and government agencies are establishing websites to address such concerns and improve health literacy by providing better access to validated health information. Since 2011, the Korean government has constructed the National Health Information Portal (NHIP) website run in collaboration with the Korean Academy of Medical Sciences (KAMS). This study therefore aimed to 1) examine consumer use of NHIP, with respect to the usage patterns, evaluation on health information provided, and perceived effectiveness of the site; and 2) identify factors that may impact perceived effectiveness of the site. An online survey was conducted with 164 NHIP users, recruited through a popup window on the main screen of the portal website from October to November 2015. The significant predicting factors supported by the data include the relevance of health information on the site, the usefulness of information in making health decisions, and the effective visualization of information. These factors can inform future efforts to design more effective health information websites, possibly based on metadata systems, to further advance the lay public's information seeking and health literacy.

Macrolide Resistance and Its Impacts on M. Pneumoniae Pneumonia in Children: Comparison of Two Recent Epidemics in Korea.

PURPOSE: The aim of this study was to investigate the change in macrolide resistance rate in pediatric Mycoplasma pneumoniae pneumonia and to evaluate the influence of macrolide-resistant M. pneumoniae (MRMP) on the clinical course of disease, by comparing 2 recent, consecutive epidemics in Korea. METHODS: A total of 250 patients with M. pneumoniae pneumonia admitted to a single tertiary hospital were enrolled in this study. Detection of MRMP was based on specific point mutations in domain V of the 23S rRNA gene. The medical records of enrolled patients were reviewed retrospectively, and the clinical courses and laboratory data were compared. RESULTS: The macrolide resistance rate of M. pneumoniae was 51.1% (48/94) in the 2011 epidemic, and 87.2% (136/156) in the 2015 epidemic. All MRMP isolates had the A2063G point mutation. In comparison of 2 epidemics, the mean age of patients with M. pneumoniae pneumonia was increased, and the total febrile days and febrile days after initiation of macrolides were prolonged in the 2015 epidemic. Overall severity of MRMP or macrolide-susceptible M. pneumoniae (MSMP) pneumonia over 2 epidemics was not significantly changed. However, the proportion of patients who had a fever lasting more than 72 hours after initiation of macrolides and who received corticosteroid treatment were higher in MRMP pneumonia during 2 epidemics. CONCLUSIONS: The macrolide resistance rate of M. pneumoniae has risen rapidly over 2 recent, consecutive epidemics, and this has been associated with a prolonged clinical course and increased use of corticosteroids to treat pediatric M. pneumoniae pneumonia.

CCR3 Monoclonal Antibody Inhibits Eosinophilic Inflammation and Mucosal Injury in a Mouse Model of Eosinophilic Gastroenteritis.

PURPOSE: Although the role of eosinophils in eosinophilic gastroenteritis (EGE) is not fully understood, they are believed to be a principal effector cell. Previous studies have demonstrated that eotaxin and its specific receptor, cysteine-cysteine chemokine receptor-3 (CCR3), play a central role in eosinophil trafficking into the gastrointestinal (GI) tract. Thus, we examined the targeting of CCR3 as a potential therapeutic intervention for EGE in a mouse model. METHODS: Eight- to 10-week-old BALB/c mice were intraperitoneally sensitized and intragastrically challenged with ovalbumin (OVA). Different groups of mice were administered either an anti-CCR3 antibody or a control IgG by intraperitoneal injection 1 hour before each OVA challenge. Eosinophilic inflammation in the intestinal mucosa, mucosal injury, and severity of diarrhea were compared between different groups at 1 hour after final OVA challenge. RESULTS: Anti-CCR3 antibody reduced the number of eosinophils in peripheral blood and intestinal mucosa, but not in bone marrow. This reduction was associated with restoration of reduced villous crypt ratio, increased intestinal epithelial cell proliferation, and weight loss induced by OVA challenge. However, Anti-CCR3 antibody had no effect on the level of OVA specific immunoglobulin E (IgE) and the expression of critical chemokines or cytokines in eosinophil trafficking into the GI tract, such as eotaxin-1, interleukin (IL)-5, and IL-13. CONCLUSIONS: Anti-CCR3 antibody significantly reduced the severity of eosinophilic inflammation, mucosal injury, and diarrhea in a mouse model of food allergen-induced GI eosinophilic inflammation. CCR3 may be a novel therapeutic target for treatment of EGE and other GI eosinophil-mediated diseases.

Are children with asthma in South Korea also associated with vitamin D deficiency?

Recently, epidemiologic studies have shown that the lack of serum vitamin D levels may be associated with high asthma prevalence, but its effect is still controversial, depending on season, area, and food consumption. We aimed to examine the association of serum vitamin D levels with the prevalence of pediatric asthma in Korea. A total of 80 children (50 asthmatic children and 30 healthy controls) aged 6-14 years were participated in this study. Serum vitamin D levels were measured and compared between the two groups. Moreover, the relationship of serum vitamin D levels with results of pulmonary function test and environmental factors (lifestyle habits and residential factors) collected by a questionnaire survey were examined in asthmatic patients. Serum vitamin D levels in asthmatic children (16.63±4.20 ng/mL) were significantly lower than that in healthy controls (24.24±6.76 ng/mL) (p<0.05). Also, we found that the prevalence of asthma increase to 0.79-fold (odds ratio, 0.79; 95% confidence interval, 0.71 to 0.88; p<0.001) as serum vitamin D level is 1 ng/mL decreases. The increased time spent in outdoor could affect the increases of serum vitamin D levels significantly. However, no associations of serum vitamin D with pulmonary function and residential environmental factors (i.e., housing type, living floor, and indoor activity time) were observed. Our findings suggest that serum vitamin D levels were also associated with pediatric asthma in Korea. Moreover, management of serum vitamin D level in asthmatic children would be a promising approach for preventing exaggeration of their severity.

Effect of the prenatal maternal environments and diets on cord blood interleukin-4 and interferon -gamma: A pilot study.

BACKGROUND AND OBJECTIVE: TThe environment of a pregnant woman can affect not only fetal growth and development, but also diseases in childhood. Neonatal cord blood cytokines are commonly used to evaluate the immune development of neonates. The purpose of this study was to evaluate the effects of the environment and diet during pregnancy on IL-4 and IFN-γ in neonatal cord blood. METHOD: A total of 111 pregnant women participated in this study from April to November 2010. Allergy history, sensitization assessed by the skin prick test, dietary intake and indoor environment were evaluated. IL-4 and IFN-γ levels were measured in the complete cord blood of neonates using real-time PCR. RESULTS: There were 54 pregnant women with allergic disease. Both IL-4 and IFN-γ levels in neonatal cord blood were higher in samples from allergic mothers than in non-allergic mothers (p<0.05). The indoor environment and nutrient intake were not different between allergic and non-allergic mothers, except regarding carpet use. When the cytokine levels were divided into quartiles, lower folate and vitamin B6 intake was associated with the highest levels of IL-4 in neonatal cord blood (p<0.05), and higher folate and vitamin B6 intake was associated with highest levels of IFN-γ in neonatal cord blood. CONCLUSIONS: In this study, a strong association between IL-4 and IFN-γ levels in cord blood and the intake of folate and vitamin B6 was found, which indicates that food intake during pregnancy might have a strong influence on IL-4 and IFN-γ levels in cord blood, to a greater extent than environmental factors.

Congenital miliary tuberculosis in an 18-day-old boy.

Congenital tuberculosis (TB) is a rare disease that is associated with high mortality. Mycobacterium tuberculosis, the causative agent, may be transmitted from the infected mother to the fetus by the transplacental route or by aspiration of infected amniotic fluid. Clinical symptoms and signs are not specific. Miliary patterns are the most common findings in the chest X-rays of many infants with congenital TB. In this case, an 18-day-old boy had jaundice on the fifth day of birth, and fever and respiratory distress appeared on the 18th day. Chest X-ray showed diffuse fine bilateral infiltration. Clinically, pneumonia or sepsis was suspected. Respiratory symptoms and chest X-ray findings worsened despite empirical antibiotic therapy. The lungs showed miliary infiltration suggestive of TB. Gastric aspirates were positive for M. tuberculosis. Respiratory distress and fever were gradually improved after anti-TB medication. Congenital TB is difficult to detect because of minimal or no symptoms during pregnancy and nonspecific symptoms in neonates. Hence, clinicians should suspect the possibility of TB infection even if neonates have non-specific symptoms. Early diagnosis and meticulous treatment are required for the survival of neonates with TB.

Leptin and Atopic Dermatitis in Korean Elementary School Children.

The prevalence of atopic dermatitis (AD) and obesity have been increasing considerably in Korean school-children. AD is a chronic pruritic recurrent inflammatory skin disorder. Leptin is secreted by adipocytes which has been suggested to be immunologically active; however, their role in AD has not yet been well understood. A total of 227 subjects out of 2,109 elementary school children were defined as having AD based on the ISAAC questionnaire survey. Ninety subjects with AD, aged between 6 and 12 years, completed scoring of severity of AD (SCORAD), skin prick testing, blood tests for total IgE, eosinophil counts, eosinophil cationic protein (ECP) and lipid profiles. Serum leptin levels were also measured. A subject with atopic AD was defined as an AD patient showing at least 1 positive reaction to allergens in skin prick testing. There were no significant differences in age, body mass index, percentage of breast milk feeding, mode of delivery, prevalence of atopy, and lipid profiles between atopic AD and non-atopic AD subjects. The serum leptin levels (log mean±SD) were significantly higher in non-atopic AD group than in the atopic AD group (0.86±0.57 ng/mL vs 0.53±0.72 ng/mL, p=0.045). Subjects with mild-to-moderate AD showed significantly higher serum leptin levels than those with severe AD (0.77±0.67 ng/mL vs 0.33±0.69 ng/mL, p=0.028). There was a marginal inverse correlation between the SCORAD index and the serum leptin concentration in total AD subjects (r=-0.216, p=0.053). The serum leptin levels were significantly higher in non-atopic AD subjects or mild-to-moderate AD subjects. Leptin did not seem to be associated with IgE-mediated inflammation in AD. Obesity-associated high leptin differed between non-atopic AD and atopic AD subjects.

GIS-based Association Between PM10 and Allergic Diseases in Seoul: Implications for Health and Environmental Policy.

PURPOSE: The role of PM10 in the development of allergic diseases remains controversial among epidemiological studies, partly due to the inability to control for spatial variations in large-scale risk factors. This study aims to investigate spatial correspondence between the level of PM10 and allergic diseases at the sub-district level in Seoul, Korea, in order to evaluate whether the impact of PM10 is observable and spatially varies across the subdistricts. METHODS: PM10 measurements at 25 monitoring stations in the city were interpolated to 424 sub-districts where annual inpatient and outpatient count data for 3 types of allergic diseases (atopic dermatitis, asthma, and allergic rhinitis) were collected. We estimated multiple ordinary least square regression models to examine the association of the PM10 level with each of the allergic diseases, controlling for various sub-district level covariates. Geographically weighted regression (GWR) models were conducted to evaluate how the impact of PM10 varies across the sub-districts. RESULTS: PM10 was found to be a significant predictor of atopic dermatitis patient count (P<0.01), with greater association when spatially interpolated at the sub-district level. No significant effect of PM10 was observed on allergic rhinitis and asthma when socioeconomic factors were controlled for. GWR models revealed spatial variation of PM10 effects on atopic dermatitis across the sub-districts in Seoul. The relationship of PM10 levels to atopic dermatitis patient counts is found to be significant only in the Gangbuk region (P<0.01), along with other covariates including average land value, poverty rate, level of education and apartment rate (P<0.01). CONCLUSIONS: Our findings imply that PM10 effects on allergic diseases might not be consistent throughout Seoul. GIS-based spatial modeling techniques could play a role in evaluating spatial variation of air pollution impacts on allergic diseases at the sub-district level, which could provide valuable guidelines for environmental and public health policymakers.

Submicron fungal fragments as another indoor biocontaminant in elementary schools.

There has been great concern about mold in school environments, but few comprehensive assessments of mold have been performed in such settings. Even spore counts or microscopic enumeration only may not be sufficient for evaluating fungal exposure. We explored the levels of submicron fungal fragments with potential heath impact due to their small size in elementary schools and investigated the variation in the concentrations of such particles before and after the rainy season. The concentrations of (1,3)-ß-D-glucan in submicron fungal fragments, airborne mold and bacteria, and PM10 were measured both indoors and outdoors in 70 classrooms at 8 elementary schools from May (before the rainy season) to July (after the rainy season) in 2012. Temperature and relative humidity were also monitored. We compared the levels of submicron fungal fragments among schools before and after the rainy season. The associations of the levels of submicron fungal fragments with other variables were analyzed. Overall, the concentrations of (1,3)-ß-D-glucan ranged from 10 to 347 pg m(-3), and the indoor/outdoor ratios were greater than 1 in every school. After the rainy season, the (1,3)-ß-D-glucan concentrations decreased by about 35%, and similar significant decreases in the concentrations of airborne mold and bacteria and PM10 were observed. This difference was prominent for PM10 (P < 0.001). Only relative humidity was negatively associated with the concentration of submicron fungal fragments (P = 0.007). Our findings confirmed the comparable amounts of submicron fungal fragments in school environments. More comprehensive exposure assessments for smaller-sized fungal particles should be performed for better understanding of their health impact, particularly with regard to seasonal changes.

The association between asthma and invasive pneumococcal disease: a nationwide study in Korea.

The purpose of this study was to investigate the association between asthma and invasive pneumococcal disease (IPD) in Korea. A retrospective population-based cohort study was conducted using the Korean Health Insurance Review and Assessment database 2010-2011. The subjects included 935,106 (2010) and 952,295 (2011), of whom 398 (2010) and 428 (2011) patients with IPD were identified. There was significant difference in the prevalence of IPD in patients with and without asthma (0.07% vs. 0.02% in 2010 and 0.08% vs. 0.01% in 2011; P<0.001). After adjusting for age and gender, patients with asthma showed over a three-fold increased risk of IPD compared with patients without asthma (adjusted odds ratio [aOR] 3.90, 95% confidence interval [CI] 3.02-5.03 in 2010 / aOR, 5.44; 95% CI, 4.10-7.22 in 2011; P<0.001). These findings were also significant in children (aOR, 2.08; 95% CI, 1.25-3.45 in 2010; P=0.005 / aOR, 3.26; 95% CI, 1.74-6.11 in 2011; P<0.001). Although diabetes mellitus was also significantly associated with IPD, relatively low ORs compared with those of asthma were noted (aOR, 1.85; 95% CI, 1.35-2.54 in 2010 / aOR, 2.40; 95% CI, 1.78-3.24 in 2011; P<0.001). Both children and adults with asthma are at increased risk of developing IPD.

Clinical and immunological effects of a forest trip in children with asthma and atopic dermatitis.

Asthma and atopic dermatitis are common allergic diseases, and their prevalence has increased in urban children. Recently, it is becoming understood that forest environment has favorable health effects in patients with chronic diseases. To investigate favorable clinical and immunologic effects of forest, we examined changes in clinical symptoms, indirect airway inflammatory marker, and serum chemokines before and after a short-term forest trip. The forest trips were performed with 21 children with asthma and 27 children with atopic dermatitis. All participating children were living in air polluted urban inner-city. We measured spirometry and fractional exhaled nitric oxide (FeNO) in children with asthma and measured scoring atopic dermatitis (SCORAD) index and Thymus and Activation-Regulated Chemokine (TARC)/CCL17 and Macrophage-Derived Chemokine (MDC)/CCL22 levels in children with atopic dermatitis before and after the forest trip. Indoor air pollutants such as indoor mold, particulate matter 10 (PM10) and total volatile organic compounds (TVOCs) of each child's home and the accommodations within forest were measured. A significant increase in forced vital capacity (FVC) and a significant decrease in FeNO were observed after the forest trip in children with asthma. SCORAD indices and MDC/CCL22 levels were significantly decreased after the forest trip in children with atopic dermatitis. Airborne mold and PM10 levels in indoor were significantly lower in the forest accommodations than those of children's homes; however, TVOC levels were not different between the two measured sites. Short-term exposure to forest environment may have clinical and immunological effects in children with allergic diseases who were living in the urban community.

Infrared camera-proven water-damaged homes are associated with the severity of atopic dermatitis in children.

BACKGROUND: Moisture problems in dwellings have been linked to respiratory symptoms, but little is known about their association with symptoms of atopic dermatitis (AD). Moreover, the questionnaire-based survey or visual inspection for water damage does not use a standardized approach for assessing dampness. OBJECTIVE: To determine water damage in the houses of children with AD by assessing variations in surface temperature with an infrared camera, an interview-led questionnaire, and evaluation of the relation between the presence of water damage and the severity of AD. METHODS: Fifty-two homes of patients with AD were visited, and air samples were obtained from the living room and a child's bedroom. Water damage was determined by thermal assessments using an infrared camera and by the presence of visible mold or water stains. The effect of water damage on the severity of AD was analyzed by comparing the presence or absence of water damage and other aggravating factors between water-damaged and undamaged homes. RESULTS: Water damage was observed in 31 of 52 homes (59.6%), and the concentrations of airborne mold were significantly higher in water-damaged homes than in undamaged homes (P = .0013). However, there was no difference in airborne mold levels between homes with and those without visible mold or water stains. Logistic regression analyses showed that water-damaged homes were significantly related to moderate to severe AD (adjusted odds ratio 14.52, 95% confidence interval 1.75-121.13, P = .0025). CONCLUSION: Water-damaged homes affect the severity of AD in children. Infrared camera-driven assessment is a promising tool for determining moisture problems in buildings.

Exploring Household-level Risk Factors for Self-reported Prevalence of Allergic Diseases Among Low-income Households in Seoul, Korea.

PURPOSE: Indoor risk factors for allergic diseases in low-income households in Korea have been characterized only partially. We evaluated the prevalences of atopic dermatitis, asthma, and allergic rhinitis in Seoul, Korea, to identify key housing and behavioral risk factors of low-income households. METHODS: Statistical analysis of the prevalence of these diseases and various risk factors was conducted using data from a 2010 Ministry of Environment household survey. Logistic regression models were generated using data from 511 low-income household apartments in districts of Seoul. RESULTS: In general, housing factors such as renovation history (P<0.1) and crowding status (P<0.01) were associated with allergic rhinitis, whereas behavioral factors such as frequency of indoor ventilation (P<0.05) and cleaning (P<0.1) were inversely correlated with atopic dermatitis. Indoor smoking was a major trigger of asthma and atopic dermatitis in low-income households (P<0.05). The presence of mold and water leakage in houses were the most important risk factors for all three diseases (P<0.05). CONCLUSIONS: Various risk factors play a role in triggering allergic diseases among low-income households in Seoul, and health or environmental programs mitigating allergic diseases should be tailored to address appropriate housing or behavioral factors in target populations.

Predictive value of C-reactive protein in response to macrolides in children with macrolide-resistant Mycoplasma pneumoniae pneumonia.

PURPOSE: The prevalence of macrolide-resistant Mycoplasma pneumoniae (MRMP) has increased worldwide. The aim of this study was to estimate the proportion of MRMP in a tertiary hospital in Korea, and to find potential laboratory markers that could be used to predict the efficacy of macrolides in children with MRMP pneumonia. METHODS: A total of 95 patients with M. pneumoniae pneumonia were enrolled in this study. Detection of MRMP was based on the results of specific point mutations in domain V of the 23S rRNA gene. The medical records of these patients were reviewed retrospectively and the clinical course and laboratory data were compared. RESULTS: The proportion of patients with MRMP was 51.6% and all MRMP isolates had the A2063G point mutation. The MRMP group had longer hospital stay and febrile period after initiation of macrolides. The levels of serum C-reactive protein (CRP) and interleukin-18 in nasopharyngeal aspirate were significantly higher in patients who did not respond to macrolide treatment. CRP was the only significant factor in predicting the efficacy of macrolides in patients with MRMP pneumonia. The area under the curve for CRP was 0.69 in receiver operating characteristic curve analysis, indicating reasonable discriminative power, and the optimal cutoff value was 40.7 mg/L. CONCLUSION: The proportion of patients with MRMP was high, suggesting that the prevalence of MRMP is rising rapidly in Korea. Serum CRP could be a useful marker for predicting the efficacy of macrolides and helping clinicians make better clinical decisions in children with MRMP pneumonia.

The level of submicron fungal fragments in homes with asthmatic children.

OBJECTIVES: Much scientific evidence indicates a positive association between moldy environments and respiratory illnesses and/or symptoms (e.g., asthma). Recently, submicron fungal fragments (<1.0 µm) have been suggested as a potential contributor to adverse health effects due to their biological composition (e.g., antigens, mycotoxins, and (1,3)-ß-D-glucan) as well as their small size. However, the contribution of exposure to fine fungal particles on adverse health outcomes has been poorly characterized, particularly in homes with asthmatic children. We characterized the airborne level of smaller-sized fungal particles between homes with and without asthmatic children. METHODS: We visited 29 homes with (n=15) and without (n=14) an asthmatic child and sampled submicron fungal fragments in a living room and child׳s bedroom, along with outdoor sampling, using the NIOSH two-stage sampler. (1,3)-ß-D-glucan of fungal fragments analyzed by Limulus Amebocyte lysate assay (LAL) was used for quantifying their exposure. RESULTS: Overall, the geometric mean (GM) concentration of (1,3)-ß-D-glucan in submicron fungal fragments in indoor air was two-fold higher in homes with asthmatic children (50.9 pg/m(3)) compared to homes with non-asthmatic children (26.7 pg/m(3)) (P<0.001). The GM concentration of these particles in child׳s bedroom in homes with an asthmatic child (66.1 pg/m(3)) was about three times higher than that in homes with non-asthmatic children (23.0 pg/m(3)) (P<0.001). The relative humidity had a negative correlation with the concentration of (1,3)-ß-D-glucan in submicron fungal fragments (Pearson coefficient=-0.257, P=0.046). CONCLUSIONS: Our findings indicate that homes with asthmatic children have a higher concentration of submicron fungal fragments compared to homes with non-asthmatic children. A greater exposure to smaller-sized fungal particles may occur in homes with an asthmatic child as relative humidity decreases. The very careful control of relative humidity in indoor air is necessary for reducing exposure to fine fungal particles and inhibiting the growth of microorganisms in homes with allergic diseases.

Asthma and allergic diseases in preschool children in Korea: findings from the pilot study of the Korean Surveillance System for Childhood Asthma.

OBJECTIVE: This article was intended to introduce the Korean Surveillance System for Childhood Asthma (KSSCA) and also to determine the factors that increase the risk for the development of asthma and allergic diseases in preschool children in Korea based on the study results. METHODS: The KSSCA pilot study was a web-based, cross-sectional survey that sampled 1002 parents with a biological child aged 2-6 years that visited the website and participated in the survey. This website consisted of a questionnaire designed to measure the history and prevalence of asthma and allergic diseases, the characteristics of dwelling, lifestyle, and the socioeconomic status of the subjects. Using logistic regression analysis, odds ratios (ORs) and 95% confidence intervals (CIs) between each risk factor and disease development were calculated. RESULTS: The rate of a family where a child had asthma was 7.4%, while 34.7% and 35.9% for allergic rhinitis and atopic dermatitis, respectively. The OR (95% CI) that a child whose parents had an allergic disease and was also diagnosed with an allergic disease was 2.86 (2.20-3.72). Children who lived in the first floor or basement of apartments had a higher risk of atopic dermatitis, as well as children from socioeconomically vulnerable families. Upon analysis of allergic reaction tests and disease development, it was found that asthma was associated with the positive reaction of cockroaches and food, allergic rhinitis with mites, and atopic dermatitis with mold and food. CONCLUSION: The study indicated that genetic and some environmental or socioeconomic factors might be important in the development of asthma and allergic diseases among preschool children in Korea through the web-survey.

Humidifier disinfectant-associated children's interstitial lung disease.

RATIONALE: Beginning in 2006, epidemics of a fatal lung injury of unknown cause in children were observed in Korea every spring. A recent study demonstrated that this type of children's interstitial lung disease (chILD) is associated with humidifier disinfectant use. OBJECTIVES: To determine the clinical characteristics of this type of chILD and to assess whether the nationwide suspension of humidifier disinfectant sales in the autumn of 2011 affected its incidence. METHODS: The clinical characteristics of suspected cases between 2006 and 2011 were determined by a nationwide retrospective study. The potential causal relationship with humidifier disinfectants was examined by a prospective surveillance study after humidifier disinfectant sales were suspended. MEASUREMENTS AND MAIN RESULTS: In total, 138 children were diagnosed with this type of chILD, which was characterized by rapid progression, high mortality, predominance in the spring season, and a familial tendency. The annual incidence increased in 2011 and then dropped to zero in 2012. The children were on average 30.4 months old. The most frequent symptoms at admission were cough and dyspnea. As the disease progressed, the typical complication was spontaneous air leak. Eighty children (58%) died. Two years after humidifier disinfectant-sale suspension, no more new cases were found. CONCLUSIONS: This study suggests that humidifier disinfectant inhalation causes an idiopathic type of chILD that is characterized by spontaneous air leak, rapid progression, lack of response to treatment, and high mortality. Further safety studies must be performed on common environmental compounds, particularly those that enter the human body by an unusual route.

Relationships between exhaled nitric oxide and atopy profiles in children with asthma.

PURPOSE: We examined whether fractional exhaled nitric oxide (FeNO) levels are associated with atopy profiles in terms of mono-sensitization and poly-sensitization in asthmatic children. METHODS: A total of 119 children underwent an assessment that included FeNO measurements, spirometry, methacholine challenge, and measurement of blood eosinophil count, serum total IgE, and serum eosinophil cationic protein (ECP). We also examined sensitization to five classes of aeroallergens (house dust mites, animal danders, pollens, molds, and cockroach) using skin prick testing. The children were divided into three groups according to their sensitization profiles to these aeroallergens (non-sensitized, mono-sensitized, and poly-sensitized). RESULTS: The geometric means (range of 1 SD) of FeNO were significantly different between the three groups (non-sensitized, 18.6 ppb [10.0-34.7 ppb]; mono-sensitized, 28.8 ppb [16.6-50.1 ppb]; and poly-sensitized, 44.7 ppb [24.5-81.3 ppb], P=0.001). FeNO levels were correlated with serum total IgE concentrations, peripheral blood eosinophilia, and serum ECP levels to different degrees. CONCLUSIONS: FeNO levels vary according to the profile of atopy, as determined by positive skin prick test results to various classes of aeroallergens. FeNO is also moderately correlated with serum total IgE, blood eosinophilia, and serum ECP. These results suggest that poly-sensitized asthmatic children may have the highest risk of airway inflammation.