BACKGROUND:Recent studies have reported the burden of attention deficit hyperactivity disorder [ADHD], autism spectrum disorder [ASD], and depressive disorder. Also, there is mounting evidence on the effects of environmental factors, such as ambient air pollution, on these disorders among children and adolescents. However, few studies have evaluated the burden of mental disorders attributable to air pollution exposure in children and adolescents. METHODS:We estimated the risk ratios of major mental disorders (ADHD, ASD, and depressive disorder) associated with air pollutants among children and adolescents using time-series data (2011-2019) obtained from a nationwide air pollution monitoring network and healthcare utilization claims data in the Republic of Korea. Based on the estimated risk ratios, we determined the population attributable fraction (PAF) and calculated the medical costs of major mental disorders attributable to air pollution. RESULTS:A total of 33,598 patients were diagnosed with major mental disorders during 9 years. The PAFs for all the major mental disorders were estimated at 6.9% (particulate matter < 10 μm [PM10]), 3.7% (PM2.5), and 2.2% (sulfur dioxide [SO2]). The PAF of PM10 was highest for depressive disorder (9.2%), followed by ASD (8.4%) and ADHD (5.2%). The direct medical costs of all major mental disorders attributable to PM10 and SO2 decreased during the study period. CONCLUSION:This study assessed the burden of major mental disorders attributable to air pollution exposure in children and adolescents. We found that PM10, PM2.5, and SO2 attributed 7%, 4%, and 2% respectively, to the risk of major mental disorders among children and adolescents.

FeNO (fractional exhaled nitric oxide) is a crucial marker to understand children's respiratory diseases such as asthma, and severity may vary depending on PM diameter and respiratory tract region. This study investigates the relationship between size-segregated respiratory deposited PM dose and FeNO for children. Size-segregated PM (PM1.0, PM1.0-2.5, and PM2.5-10.0) and FeNO were measured for eighty children based on individual exposure assessment in five consecutive days. Individual physical activity was measured by an accelerometer device. Accordingly, a dosimetry model estimated the respiratory deposited dose by PM diameter in the extrathoracic (ET), tracheobronchial (TB), and pulmonary (PUL) regions. A linear mixed model (LMM) with distributed lag non-linear model (DLNM) was used for analysis. The effects of home environment and traffic-related factors were also examined for sensitivity analysis. We found that IQR increases of PM2.5-10.0 and PM1.0 were associated with 15.1 % (95 % CI: 3.5, 28.1) and 15.9 % (95 % CI: 2.7, 30.9) FeNO increase in respiratory Total region in 0-12 h lag. In cumulative lag 0-24 h, PM1.0 was only associated with FeNO increase: 16.6 % (95 % CI: 1.5, 34.1) in total region. No association was observed in lag 12-24 h. PM2.5-10.0 was related to short-term airway inflammation in the upper respiratory tract whereas PM1.0 has a cumulative effect on both the upper and lower respiratory tract. In sensitivity analysis, PM2.5-10.0 was associated with a 0-12 h lag, whereas both PM2.5-10.0 and PM1.0 were associated with a cumulative lag of 0-24 h. Both home environment and traffic-related factors showed a synergetic effect with PM1.0 in short-term exposure and an antagonistic effect with PM2.5-10.0 in long-term exposure. This study highlights that airway inflammation depends on PM sizes, exposure durations, and respiratory tract regions.

BACKGROUND AND AIM: Short-term exposure of particulate matter mass and count could be related to airway inflammation for children. This research is to find different risk level of airway inflammation by size-segregated PM from 0.25 um to 10.0 um. METHOD: Based on individual exposure assessment, PM mass and count were monitored for 5 consecutive days against 51 children. Baseline information including exposure factors related airway inflammation was surveyed. Real-time portable monitoring device able to detect both mass and count over size from 0.25 um to 10 um was utilized. The PM sizes were classified into six categories: PM0.25-10.0, PM0.25-4.0, PM0.25-2.5, PM0.25-1.0, PM0.25-0.5, PM0.25-0.25. FeNO was measured two times day (early morning and late evening) under the standardized procedures by the American Thoracic Society. All participants were adjusted accelerometer device in order to consider physical activity level. Deposition fraction of particle in each respiratory region (ET: Extrathoracic, TB: Tracheobronchial, AV: Alveolor) was calculated by using dosimetry model (MPPD v3.04 by ARA. US). Dose was calculated with concentration of PM mass and count by size, inhalation rate from accelerometer, and deposition fraction from dosimetry model. We applied distributed non-linear lag model and linear mixed-model to evaluate the FeNO and PM mass-count association. RESULTS: Different relative risk level and dose-response relations was observed in different PM mass-count sizes. Risk was higher when PM size was smaller. Different dose-response between PM mass and count in same respiratory regions was detected. Also different dose-response over PM sizes in same respiratory regions was detected. Risk patterns were different in different respiratory region for same PM size CONCLUSIONS: Our study showed clear risk pattern of FeNO by PM mass and count over sizes and by respiratory tract. Small size of PM is more vulnerable than Big size of PM. Particle count shows more risk than PM mass.

Background: Although influenza poses substantial mortality burden, most studies have estimated excess mortality using time-aggregated data. Here, we estimated mortality risk and population attributable fraction (PAF) attributed to seasonal influenza using individual-level data from a nationwide matched cohort. Methods: Individuals with influenza during four consecutive influenza seasons (2013-2017) (n = 5,497,812) and 1:4 age-and sex-matched individuals without influenza (n = 20,990,683) were identified from a national health insurance database. The endpoint was mortality within 30 days after influenza diagnosis. All-cause and cause-specific mortality risk ratios (RRs) attributed to influenza were estimated. Excess mortality, mortality RR, and PAF of mortality were determined, including for underlying disease subgroups. Results: Excess mortality rate, mortality RR, and PAF of all-cause mortality were 49.5 per 100,000, 4.03 (95% confidence interval [CI], 3.63-4.48), and 5.6% (95% CI, 4.5-6.7%). Cause-specific mortality RR (12.85; 95% CI, 9.40-17.55) and PAF (20.7%; 95% CI, 13.2- 27.0%) were highest for respiratory diseases. In subgroup analysis according to underlying disorders, PAF of all-cause mortality was 5.9% (95% CI, 0.6-10.7%) for liver disease, 5.8% (95% CI, 2.9-8.5%) for respiratory disease, and 3.8% (95% CI, 1.4-6.1%) for cancer. Conclusion: Individuals with influenza had a 4-fold higher mortality risk than individuals without influenza. Preventing seasonal influenza may lead to 5.6% and 20.7% reductions in all-cause and respiratory mortality, respectively. Individuals with respiratory disease, liver disease, and cancer may benefit from prioritization when establishing influenza prevention strategies.

In this study, 16 children's products with the highest detection potential of phthalates were selected, and a phthalate assay and transdermal delivery analysis (NIER, US EPA Wipe [stress condition], US EPA Wipe [physiological condition], and US EPA Hand Wipe) were conducted with these products. The content of 6 controlled phthalates (DBP, BBP, DEHP, DNOP, DINP, and DIDP) was measured and most products contained more phthalates than the regulated guidelines (a total content of 6 phthalates to be ≤0.1%). For transdermal delivery, all items were found to be lower in the NIER transdermal delivery test method compared to the US EPA Hand Wipe (stress condition and physiological condition) transdermal delivery test method. For the US EPA Hand Wipe (stress condition and physiological condition) transdermal delivery test method, a similar result was observed, except for DINP. The average daily dose (ADD) estimated by determining the exposure algorithm for each transdermal delivery test method was highest in mats with a large contacting surface area and a long exposure time in the respective test methods. Conclusively, there was a difference between the NIER transdermal delivery test method and the US EPA Wipe transdermal delivery test method.

Preschool children aged 3–6 years are vulnerable to exposed to particulate matter (“PM10” and “PM2.5”). It is required in evaluating the risk based on dose of preschool children. Microenvironments which preschool children mainly visited were classified. Inhalation type was adapted in each microenvironment in consideration of intensity of activity. The exposure scenario was described as preschool children had been living in Seoul, South Korea, and dose was calculated by considering time-activity-pattern with major microenvironments and inhalation type of preschool children for 24 h. Monte-Carlo simulation technique is used to estimate dose of particulate matter in probabilistic distribution by age and sex. The contribution of exposure by microenvironments and inhalation type was calculated. Risk assessment was performed based on WHO interim target-3 24-h concentration in order to estimate. Sensitivity analysis was performed to determine the effective variable of dose. As a result of the study, the dose of PM was higher for boys than girls and tended to decrease with age. The overall contributions of PM doses by microenvironments were daycare center, home, other facilities, transit, and outdoors, respectively, although differed between daycare center and home priority by age and sex. Especially, the contribution of daycare center and home was very high, accounting over 85% of the total. The overall contributions of PM doses by inhalation type were “run,” “stable,” “sleep,” and “walk inhalation,” respectively. The results of hazard quotient showed that “PM10” exceeded the WHO interim target-3 24-h concentration standard by about 10% and “PM2.5” exceeded about half. Through sensitivity analysis, PM concentration was confirmed as a major influence variable for doses. This study was able to affirm the overall exposure status of “PM10” and “PM2.5” for preschool children, and this is expected to be used in regulation and public health.

Estimating the lung cancer disease burden can provide evidence for public health practitioners, researchers, and policymakers. This study uses claim data from lung cancer patients for 2006–2015 from the Korean National Health Insurance Service to estimate the lung cancer burdens attributable to residential radon in Korea using disability-adjusted life years (DALY) and patients' annual economic burden with societal perspectives using the cost-of-illness (COI) method. The number of patients increased during our study period (from 35,866 to 59,168). The disease burden and that attributable to residential radon, respectively, increased from 517.57 to 695.74 and 64.62 (95%; CIs 61.33–67.69) to 86.99 (95%; CIs 82.7–91.1) DALYs per 100,000 patients. The percentage of years lost due to disability among the DALY doubled from 8% to 17%. The cost for all the patients was US$2.33 billion, with US$292 (95%; CIs 278–306) million attributable to residential radon. During the last decade, the lung cancer disease burden increased by 1.34 times, with a doubled percentage of non-fatal burden and average annual growth rate of 9.5% of the total cost. Hence, the burden and cost of lung cancer in Korean provinces have been steadily increasing. The findings could be used as input data for future cost-effectiveness analysis of policies regarding radon reduction.

Background: The weather has well-documented effects on infectious disease and reports suggest that summer peaks in the incidences of gram-negative bacterial infections among hospitalized patients. We evaluated how season and temperature changes affect bloodstream infection (BSI) incidences of major pathogens to understand BSI trends with an emphasis on acquisition sites. Methods: Incidence rates of BSIs by Staphylococcus aureus, Enterococcus spp., Escherichia coli, Klebsiella pneumoniae, Acinetobacter spp., and Pseudomonas aeruginosa were retrospectively analyzed from blood cultures during 2008–2016 at a university hospital in Seoul, Korea according to the acquisition sites. Warm months (June–September) had an average temperature of ≥20 °C and cold months (December–February) had an average temperature of ≤5 °C. Results: We analyzed 18,047 cases, where 43% were with community-onset BSI. E. coli (N = 5,365) was the most common pathogen, followed by Enterococcus spp. (N = 3,980), S. aureus (N = 3,075), K. pneumoniae (N = 3,043), Acinetobacter spp. (N = 1,657), and P. aeruginosa (N = 927). The incidence of hospital-acquired BSI by Enterococcus spp. was weakly correlated with temperature, and the median incidence was higher during cold months. The incidence of community-onset BSI by E. coli was higher in warm months and was weakly correlated with temperature. Conclusion: We found seasonal or temperature-associated variation in some species-associated BSIs. This could be a useful information for enhancing infection control and public health policies by taking season or climate into consideration.

BACKGROUND:Epidemiological studies have revealed associations between the fine particle (PM2.5; aerodynamic diameter <2.5 μm) exposure and cardiovascular disease. Researchers have also recently begun investigating the association between PM2.5 exposure and hemorrhagic stroke (HS) and identifying subpopulations vulnerable to PM2.5 exposure. Long-term cumulative average PM2.5 exposure may affect the risk of HS, and these effects may be modified by risk factors. METHODS:This retrospective study evaluated the effects of PM2.5 on the time-to-first-diagnosis of HS among 62,676 Seoul metropolitan city residents with 670,431 total person-years of follow-up; this cohort is a subset from a nationally representative cohort of 1,025,340 individuals from the Korean National Health Insurance Service database (2002-2013). A time-dependent Cox proportional hazards model was used to adjust for age, sex, household income, insurance type, body mass index, smoking status, medical history, and family history. The annual mean PM2.5 concentrations for 25 districts were used as the time-dependent variable. Subgroup analyses of the traditional risk factors of HS were performed to evaluate potential effect modifications. RESULTS:Each 10-μg/m increment in cumulative average PM2.5 exposure was noticeably associated with HS (hazard ratio [HR] = 1.43; 95% confidence interval [CI]: 1.09-1.88). The adverse effects of PM2.5 exposure were modified by ≥65 years of age (HR = 2.00; 95% CI = 1.32, 3.02) and obesity (body mass index ≥25 kg/m; HR = 1.91; 95% CI = 1.28, 2.84). CONCLUSIONS:Cumulative average PM2.5 exposure might increase the risk of HS. Elderly (≥65 years) and obese individuals may be more vulnerable to the effects of PM2.5 exposure.

The Korean Medical Association (KMA) has been requested to respond proactively and effectively to local agendas reflecting global perspectives in order to lead our society through the dynamic and fast-changing health care environment, which faces issues such as big data, artificial intelligence, and the increasing health-related impacts of climate change and fine particulate matter. Since the KMA joined the World Medical Association (WMA) in 1949 and the Confederation of Medical Associations in Asia and Oceania (CMAAO) in 1956, the KMA has made continuous progress in international affairs. Based on these achievements, the KMA has recently played important roles, such as the chair of the WMA Finance and Planning Committee, a council member in the WMA, and a council chair in the CMAAO. For the next several decades, the WMA and CMAAO are still expected to be the basic channels for sharing trends and visions, discussing health challenges across borders, and developing powerful initiatives that improve people's health. Maintaining current partnerships with the WMA and CMAAO and strengthening strategic collaboration with promising national medical associations are required to extend the KMA's influence. Training next-generation representatives to build capacity for international relations might also be necessary for the sustainability of international collaboration. Through the KMA's advancements in international affairs, incorporating harmonious perspectives on local, regional, and global agendas, the KMA is fully expected to contribute to addressing health challenges by demonstrating its leadership.

PURPOSE:Inconsistent findings have been reported regarding the effect of ambient temperature on ischemic stroke. Furthermore, little is known about how underlying disease and low socioeconomic status influence the association. We, therefore, investigated the relationship between ambient temperature and emergency department (ED) visits for ischemic stroke, and aimed to identify susceptible populations. MATERIALS AND METHODS:Using medical claims data, we identified ED visits for ischemic stroke during 2005-2009 in Seoul, Korea. We conducted piecewise linear regression analyses to find optimum ambient temperature thresholds in summer and winter, and estimated the relative risks (RR) and 95% confidence intervals (CI) per a 1°C increase in temperature above/below the thresholds, adjusting for relative humidity, holidays, day of the week, and air pollutant levels. RESULTS:There were 63564 ED visits for ischemic stroke. In summer, the risk of ED visits for ischemic stroke was not significant, with the threshold at 26.8°C. However, the RRs were 1.055 (95% CI, 1.006-1.106) above 25.0°C in medical aid beneficiaries and 1.044 (1.007-1.082) above 25.8°C in patients with diabetes. In winter, the risk of ED visits for ischemic stroke significantly increased as the temperature decreased above the threshold at 7.2°C. This inverse association was significant also in patients with hypertension and diabetes mellitus above threshold temperatures. CONCLUSION:Ambient temperature increases above a threshold were positively associated with ED visits for ischemic stroke in patients with diabetes and medical aid beneficiaries in summer. In winter, temperature, to a point, and ischemic stroke visits were inversely associated.

Phthalate is an endocrine disruptor that interferes with homeostasis and developmental regulation.It is highly toxic to the environment and is associated with various diseases of the human body.Using biological samples from 140 adult subjects, to evaluate the influencing factors which are related to contaminant concentration levels, we used correlation analysis and multiple regression analysis.Lastly, in order to analyze the health effects related to exposure to phthalates, we conducted a risk assessment by estimating acceptable daily intake exposure according to the influential factors.When we compared the concentration level according to influential factors, in general, the subjects who had engaged in home remodeling work had higher urinary phthalate metabolite concentrations levels than the subjects who had not engaged in home remodeling work.We can confirm statistically significant differences in DBP metabolites.In addition, we can confirm the concentration appeared higher in the categories such as using air freshener, sofa and foods.Through conducting a risk assessment of DEHP, BBzP, DiBP, and DnBP by using data on phthalate metabolite concentration in urine, it was found that the average concentration of all metabolites did not exceed TDI.

The atmosphere is the first medium containing hazardous compounds entering the living environment. Metropolitan areas contain many industrial complex areas with high emissions of volatile organic compounds (VOCs), and consequently also large-scale exposure groups. As respiration is the most important part of the human exposure pathway, the atmosphere should be treated with greater importance than other media. It is therefore very important to monitor the emission of hazardous air pollutants (HAPs) and measure the concentration of VOCs in the atmosphere of such areas. It is essential to establish basic measures in order to protect public health as part of overall national safety management. This study utilized the national air pollution monitoring network data from Seoul, Incheon, and Gyeonggi, and investigated the differences in risk levels for humans considering various factors of the receptors, including gender and age. A total of 13 VOCs were categorized into carcinogens and noncarcinogens for risk assessment. The carcinogens 1,3-butadiene and benzene demonstrated a high level of cancer risk, ranging between 10(-4) and 10(-6), respectively. Noncarcinogens did not exceed Hazard Quotient (HQ) 1 in any area. The results will serve as important references for managing urban air environments and setting air quality standards.

Traffic-related pollutants have been reported to increase the morbidity of respiratory diseases. In order to apply management policies related to motor vehicles, studies of the floating population living in cities are important. The rate of metro rail transit system use by passengers residing in Seoul is about 54% of total public transportation use. Through the rate of metro use, the people-flow ratios in each administrative area were calculated. By applying a people-flow ratio based on the official census count, the floating population in 25 regions was calculated. The reduced level of deaths among the floating population in 14 regions having the roadside monitoring station was calculated as assuming a 20% reduction of mobile emission based on the policy. The hourly floating population size was calculated by applying the hourly population ratio to the regional population size as specified in the official census count. The number of people moving from 5 a.m. to next day 1 a.m. could not be precisely calculated when the population size was applied, but no issue was observed that would trigger a sizable shift in the rate of population change. The three patterns of increase, decrease, and no change of population in work hours were analyzed. When the concentration of particulate matter less than 10 μm in aerodynamic diameter was reduced by 20%, the number of excess deaths varied according to the difference of the floating population. The effective establishment of directions to manage the pollutants in cities should be carried out by considering the floating population. Although the number of people using the metro system is only an estimate, this disadvantage was supplemented by calculating inflow and outflow ratio of metro users per time in the total floating population in each region. Especially, 54% of metro usage in public transport causes high reliability in application.

Carbon monoxide (CO) is one of the primary components of emissions from light-duty vehicles, and reportedly comprises 77% of all pollutants emitted in terms of concentration. Exposure to CO aggravates cardiovascular disease and causes other health disorders. The study was aimed to assess the negative effects by injecting different amounts of CO concentration directly to human volunteers boarding in the car.

From 2002 through 2015, hundreds of people died of fatal lung injuries associated with the use of humidifier disinfectants (HDs) in Korea. Several chemical disinfectants used for household humidifiers were later clinically confirmed to cause HD-associated lung injury (HDLI). The aim of this study is to evaluate the registered lung disease cases and to compare the distribution of HDLI patients, including deaths, by HD use characteristics including types of HD and HD brands categorized by age group. A total of 530 registered were clinically examined through two rounds of investigations conducted from July 2013 until April 2015. Information on HD use was obtained from a structured questionnaire and home investigations. Approximately one-half of the patients (n=221) were clinically confirmed to be associated with the use of HDs. Pregnant women (n=35, 16%) and pre-school children≤6years old (n=128, 58%) accounted for most of the HD-associated lung injury patients (n=163, 74%). Sixty-seven percent of HDLI patients developed HDLI after less than one year of HD use. HD products containing polyhexamethylene guanidine phosphate (PHMG) were the most frequently used among confirmed HDLI patients (n=123, 55.7%), followed by oligo (2-(2-ethoxy) ethoxyethyl guanidinium (PGH) (n=24, 10.9%) and a mixture of chloromethylisothiazolinone (CMIT) and methylisothiazolinone (MIT) (n=3, 1.4%). Other HDs did not appear to be linked to HDLI. The majority of the HDLI patients (n=85, 38.5%) was found to use only Oxy Saksak® products containing PHMG. The development of HDLI was clinically found to be associated with the use of several HD products containing PHMG and PGH, and to lesser extent, CMIT/MIT.

Introduction: Epidemiological studies have revealed adverse associations between ambient fine particulate matter (PM 2.5 ; aerodynamic diameter < 2.5 μm) and cardiovascular diseases. Recently, there has been increased interest in investigating the association between long-term PM 2.5 exposure and hemorrhagic stroke (HS) and identifying the most susceptible subpopulations to the PM 2.5 exposure, if any. Hypothesis: We assessed the hypothesis that long-term cumulative averages of PM 2.5 exposure affect HS and its effect might be modified by risk factors. Methods: This study was based on a nationwide representative cohort of 1,025,340 participants, or 2% of the National Health Insurance Service enrollees in Korea (2002-2013). We analyzed the effects of PM 2.5 on time to first hospital diagnosis for HS for participants living in Seoul. A time-dependent Cox proportional hazards model was used with adjustments for age, sex, household income, insurance type, body mass index, smoking status, exercise, medical history, and family history. Annual cumulative mean PM 2.5 concentrations for 25 districts were used as the time-dependent variables. Subgroup analyses were performed to evaluate potential effect modification. Results: Cumulative PM 2.5 exposure was associated with HS events with a hazard ratio of 1.04 (95% confidence interval [CI]: 1.01-1.07) per 1 μg/m 3 elevation in PM 2.5 . Its adverse effects were modified by risk factors with greater effects observed among women (1.05 [1.01-1.09]) and subgroups with hypertension (1.06 [1.03-1.10]), without diabetes (1.05 [1.02-1.09]), or without family history of stroke (1.04 [1.01-1.07]). Conclusions: To our best knowledge, this is the first study to investigate the effect of cumulative averages of PM 2.5 exposure on time to first hospital diagnosis for HS. Cumulative PM 2.5 exposure might increase the risk of HS. Participants with hypertension, without diabetes or family history of stroke, or women were more susceptible to PM 2.5 exposure. Our findings show the first time that long-term cumulative PM 2.5 exposure could be crucial to cerebrovascular event and have public health implications.

Objectives The goal of this study was to investigate the short-term effect of ambient air pollution on emergency department (ED) visits in Seoul for asthma according to patients’ prior history of allergic diseases. Methods Data on ED visits from 2005 to 2009 were obtained from the Health Insurance Review and Assessment Service. To evaluate the risk of ED visits for asthma related to ambient air pollutants (carbon monoxide [CO], nitrogen dioxide [NO2], ozone [O3], sulfur dioxide [SO2], and particulate matter with an aerodynamic diameter <10 μm [PM10]), a generalized additive model with a Poisson distribution was used; a single-lag model and a cumulative-effect model (average concentration over the previous 1-7 days) were also explored. The percent increase and 95% confidence interval (CI) were calculated for each interquartile range (IQR) increment in the concentration of each air pollutant. Subgroup analyses were done by age, gender, the presence of allergic disease, and season. Results A total of 33 751 asthma attack cases were observed during the study period. The strongest association was a 9.6% increase (95% CI, 6.9% to 12.3%) in the risk of ED visits for asthma per IQR increase in O3 concentration. IQR changes in NO2 and PM10 concentrations were also significantly associated with ED visits in the cumulative lag 7 model. Among patients with a prior history of allergic rhinitis or atopic dermatitis, the risk of ED visits for asthma per IQR increase in PM10 concentration was higher (3.9%; 95% CI, 1.2% to 6.7%) than in patients with no such history. Conclusions Ambient air pollutants were positively associated with ED visits for asthma, especially among subjects with a prior history of allergic rhinitis or atopic dermatitis.

Lung cancer was the second highest absolute cancer incidence globally and the first cause of cancer mortality in 2014. Indoor radon is the second leading risk factor of lung cancer after cigarette smoking among ever smokers and the first among non-smokers. Environmental burden of disease (EBD) attributable to residential radon among non-smokers is critical for identifying threats to population health and planning health policy.