Epidemiological Characteristics of COVID-19 Outbreak at Fitness Centers in Cheonan, Korea

Background@#In February 2020, a coronavirus disease 2019 (COVID-19) outbreak was reported in fitness centers in Cheonan, Korea. @*Methods@#From February 24 to March 13, an epidemiological investigation was conducted on the fitness center outbreak. All those who were screened were tested for severe acute respiratory syndrome coronavirus-2 (SARS CoV-2) using real-time reverse transcriptase polymerase chain reaction. Contacts were traced and self-isolated for 14 days. We determined the epidemiological characteristics of confirmed cases of SARS-CoV-2 infection, and estimated the time-dependent reproduction number to assess the transmission dynamics of the infection. @*Results@#A total of 116 cases were confirmed, and 1,687 contacts were traced. The source cases were 8 Zumba instructors who led aerobics classes in 10 fitness centers, and had the largest average number of contacts. A total of 57 Zumba class participants, 37 of their family members, and 14 other contacts were confirmed as cases. The attack rate was 7.3%. The contacts at Zumba classes and homes had a higher attack rate than other contacts. The mean serial interval (± standard deviation) were estimated to be 5.2 (± 3.8) days. The time-dependent reproduction number was estimated to be 6.1 at the beginning of the outbreak, but it dropped to less than 1, 2 days after the epidemiological investigation was launched. @*Conclusion@#The results suggest that the COVID-19 outbreak was effectively contained with rigorous contact tracing, isolating, and testing in combination with social distancing without a lock-down.

Environmental Health Studies in the Korean National Industrial Complexes (EHSNIC): Focus-Group Interviews

This study investigated the social outcomes of the Environmental Health Studies of National Industrial Complex (EHSNIC), which have been conducted by the National Institute of Environmental Research (NIER) in eight National Industrial Complex Areas (NICAs) since 2003. Eighteen sessions of focus-group interviews with 85 people were conducted from October 2016 to January 2017. Interviewees were stakeholders from eight NICAs and included resident representatives, environmental nongovernment organizations, local government officials, and environmental health and safety officers from companies. Interview results were divided into six categories: EHSNIC awareness, EHSNIC outcomes, EHSNIC limitations, EHSNIC continuation, EHSNIC improvement directions, and EHSNIC results use. They were then further indexed into 23 divisions. EHSNIC awareness varied across stakeholders. A major EHSNIC outcome is that a continued result database was established, which was used as a reference for environmental improvements. EHSNIC limitations included no proper healthcare actions taken during the EHSNIC study period, a lack of EHSNIC results disclosure, a failure to reflect local specificity, and a lack of validity in the results. Regarding EHSNIC continuation, all stakeholders said EHSNIC should be conducted continuously. EHSNIC improvement directions included conducting studies tailored to each NICA, identifying correlations between pollutant exposure and disease, increasing the sample size, and performing repeated studies. Regarding EHSNIC results use, respondents wanted to use the results as a reference to relocate residents, ensure distance between NICAs and residential areas, provide healthcare support, develop local government policies, and implement firms’ environmental controls. Since EHSNIC aims to identify the health effects of NICAs on residents and take appropriate actions, it should be continued in the future. Even during the study period, it is important to take steps to preventively protect residents’ health. EHSNIC also needs to reflect each NICA’s characteristics and conduct reliable research based on stakeholder participation and communication.

Environmental Health Studies in the Korean National Industrial Complexes (EHSNIC): Focus-Group Interviews

This study investigated the social outcomes of the Environmental Health Studies of National Industrial Complex (EHSNIC), which have been conducted by the National Institute of Environmental Research (NIER) in eight National Industrial Complex Areas (NICAs) since 2003. Eighteen sessions of focus-group interviews with 85 people were conducted from October 2016 to January 2017. Interviewees were stakeholders from eight NICAs and included resident representatives, environmental nongovernment organizations, local government officials, and environmental health and safety officers from companies. Interview results were divided into six categories: EHSNIC awareness, EHSNIC outcomes, EHSNIC limitations, EHSNIC continuation, EHSNIC improvement directions, and EHSNIC results use. They were then further indexed into 23 divisions. EHSNIC awareness varied across stakeholders. A major EHSNIC outcome is that a continued result database was established, which was used as a reference for environmental improvements. EHSNIC limitations included no proper healthcare actions taken during the EHSNIC study period, a lack of EHSNIC results disclosure, a failure to reflect local specificity, and a lack of validity in the results. Regarding EHSNIC continuation, all stakeholders said EHSNIC should be conducted continuously. EHSNIC improvement directions included conducting studies tailored to each NICA, identifying correlations between pollutant exposure and disease, increasing the sample size, and performing repeated studies. Regarding EHSNIC results use, respondents wanted to use the results as a reference to relocate residents, ensure distance between NICAs and residential areas, provide healthcare support, develop local government policies, and implement firms’ environmental controls. Since EHSNIC aims to identify the health effects of NICAs on residents and take appropriate actions, it should be continued in the future. Even during the study period, it is important to take steps to preventively protect residents’ health. EHSNIC also needs to reflect each NICA’s characteristics and conduct reliable research based on stakeholder participation and communication.

Health effects of environmental pollution in population living near industrial complex areas in Korea

Several epidemiological studies have reported an association between environmental pollution and various health conditions in individuals residing in industrial complexes. To evaluate the effects of pollution from industrial complex on human health, we performed a pooled analysis of environmental epidemiologic monitoring data for residents living near national industrial complexes in Korea. The respiratory and allergic symptoms and the prevalence of acute and chronic diseases, including cancer, were used as the outcome variables for health effects. Multiple logistic regression analysis was used to analyze the relationship between exposure to pollution from industrial complexes and health conditions. After adjusting for age, sex, smoking status, occupational exposure, level of education, and body mass index, the residents near the industrial complexes were found to have more respiratory symptoms, such as cough (odds ratio [OR], 1.18; 95% confidence interval [CI], 1.06 to 1.31) and sputum production (OR, 1.13; 95% CI, 1.03 to 1.24), and symptoms of atopic dermatitis (OR, 1.10; 95% CI, 1.01 to 1.20). Among residents of the industrial complexes, the prevalence of acute eye disorders was approximately 40% higher (OR, 1.39; 95% CI, 1.04 to 1.84) and the prevalence of lung and uterine cancer was 3.45 times and 1.88 times higher, respectively, than those among residents of the control area. This study showed that residents living in the vicinity of industrial complexes have a high risk of acute and chronic diseases including respiratory and allergic conditions. These results can be used as basic objective data for developing health management measures for individuals residing near industrial complexes.

Lead, Mercury, and Cadmium Exposure in the Korean General Population

BACKGROUND: Lead (Pb), mercury (Hg), and cadmium (Cd) are well-known environmental pollutants. They are unnecessary in the biological processes of humans. This study was performed to estimate the representative background exposure levels to the metals by measuring concentrations in whole blood of the Korean general population. METHODS: This population-based cross-sectional study included 4,000 subjects (1,886 males and 2,114 females) 0–83 years of age in 2010 and 2011. Adult subjects (≥ 19 years of age) were collected by sex- and age-stratified probability method, and preschool- and school-aged subjects were recruited by a cluster sampling method. Written consent was provided prior to blood sampling. Pb and Cd blood concentrations were determined by a flameless atomic absorption spectrophotometry, and blood Hg was analyzed by a direct Hg analyzer. RESULTS: The geometric mean, median and 95th percentile of blood Pb was 1.82 µg/dL, 1.83 µg/dL, and 3.78 µg/dL, respectively. The respective values were 2.92 µg/L, 2.87 µg/L, 9.12 µg/L for Hg, and 0.56 µg/L, 0.59 µg/L, 2.20 µg/L for Cd. Blood Pb and Hg were higher in males than in females, but no sex difference was observed, respectively, in subjects 0–4 years of age for Pb and in subjects less than 20 years for Hg. However, blood Cd was higher in females than in males and no sex difference was observed in subjects < 30 years of age. CONCLUSION: This study provides representative data of human exposure to Pb, Hg, and Cd covering whole age groups of the general population in Korea.

Health effects of environmental pollution in population living near industrial complex areas in Korea

Several epidemiological studies have reported an association between environmental pollution and various health conditions in individuals residing in industrial complexes. To evaluate the effects of pollution from industrial complex on human health, we performed a pooled analysis of environmental epidemiologic monitoring data for residents living near national industrial complexes in Korea. The respiratory and allergic symptoms and the prevalence of acute and chronic diseases, including cancer, were used as the outcome variables for health effects. Multiple logistic regression analysis was used to analyze the relationship between exposure to pollution from industrial complexes and health conditions. After adjusting for age, sex, smoking status, occupational exposure, level of education, and body mass index, the residents near the industrial complexes were found to have more respiratory symptoms, such as cough (odds ratio [OR], 1.18; 95% confidence interval [CI], 1.06 to 1.31) and sputum production (OR, 1.13; 95% CI, 1.03 to 1.24), and symptoms of atopic dermatitis (OR, 1.10; 95% CI, 1.01 to 1.20). Among residents of the industrial complexes, the prevalence of acute eye disorders was approximately 40% higher (OR, 1.39; 95% CI, 1.04 to 1.84) and the prevalence of lung and uterine cancer was 3.45 times and 1.88 times higher, respectively, than those among residents of the control area. This study showed that residents living in the vicinity of industrial complexes have a high risk of acute and chronic diseases including respiratory and allergic conditions. These results can be used as basic objective data for developing health management measures for individuals residing near industrial complexes.

Mercury Exposure in Association With Decrease of Liver Function in Adults: A Longitudinal Study / 예방의학회지

OBJECTIVES: Although mercury (Hg) exposure is known to be neurotoxic in humans, its effects on liver function have been less often reported. The aim of this study was to investigate whether total Hg exposure in Korean adults was associated with elevated serum levels of the liver enzymes aspartate aminotransferase (AST), alanine transaminase (ALT), and gamma-glutamyltransferase (GGT). METHODS: We repeatedly examined the levels of total Hg and liver enzymes in the blood of 508 adults during 2010-2011 and 2014-2015. Cross-sectional associations between levels of blood Hg and liver enzymes were analyzed using a generalized linear model, and nonlinear relationships were analyzed using a generalized additive mixed model. Generalized estimating equations were applied to examine longitudinal associations, considering the correlations of individuals measured repeatedly. RESULTS: GGT increased by 11.0% (95% confidence interval [CI], 4.5 to 18.0%) in women and 8.1% (95% CI, -0.5 to 17.4%) in men per doubling of Hg levels, but AST and ALT were not significantly associated with Hg in either men or women. In women who drank more than 2 or 3 times per week, AST, ALT, and GGT levels increased by 10.6% (95% CI, 4.2 to 17.5%), 7.7% (95% CI, 1.1 to 14.7%), and 37.5% (95% CI,15.2 to 64.3%) per doubling of Hg levels, respectively, showing an interaction between blood Hg levels and drinking. CONCLUSIONS: Hg exposure was associated with an elevated serum concentration of GGT. Especially in women who were frequent drinkers, AST, ALT, and GGT showed a significant increase, with a significant synergistic effect of Hg and alcohol consumption.

Antigenic characterization of classical swine fever virus YC11WB isolates from wild boar

Classical swine fever (CSF), a highly contagious disease that affects domestic pigs and wild boar, has serious economic implications. The present study examined the virulence and transmission of CSF virus strain YC11WB (isolated from a wild boar in 2011) in breeding wild boar. Virulence of strain YC11WB in domestic pigs was also examined. Based on the severe clinical signs and high mortality observed among breeding wild boar, the pathogenicity of strain YC11WB resembled that of typical acute CSF. Surprisingly, in contrast to strain SW03 (isolated from breeding pigs in 2003), strain YC11WB showed both acute and strong virulence in breeding pigs. None of three specific monoclonal antibodies (7F2, 7F83, and 6F65) raised against the B/C domain of the SW03 E2 protein bound to the B/C domain of strain YC11WB due to amino acid mutations (⁷²⁰K→R and ⁷²³N→S) in the YC11WB E2 protein. Although strains YC11WB and SW03 belong to subgroup 2.1b, they had different mortality rates in breeding pigs. Thus, if breeding pigs have not developed protective immunity against CSF virus, they may be susceptible to strain YC11WB transmitted by wild boar, resulting in severe economic losses for the pig industry.

Short-term Effect of Fine Particulate Matter on Children's Hospital Admissions and Emergency Department Visits for Asthma: A Systematic Review and Meta-analysis / 예방의학회지

OBJECTIVES: No children-specified review and meta-analysis paper about the short-term effect of fine particulate matter (PM2.5) on hospital admissions and emergency department visits for asthma has been published. We calculated more precise pooled effect estimates on this topic and evaluated the variation in effect size according to the differences in study characteristics not considered in previous studies. METHODS: Two authors each independently searched PubMed and EMBASE for relevant studies in March, 2016. We conducted random effect meta-analyses and mixed-effect meta-regression analyses using retrieved summary effect estimates and 95% confidence intervals (CIs) and some characteristics of selected studies. The Egger's test and funnel plot were used to check publication bias. All analyses were done using R version 3.1.3. RESULTS: We ultimately retrieved 26 time-series and case-crossover design studies about the short-term effect of PM2.5 on children's hospital admissions and emergency department visits for asthma. In the primary meta-analysis, children's hospital admissions and emergency department visits for asthma were positively associated with a short-term 10 μg/m3 increase in PM2.5 (relative risk, 1.048; 95% CI, 1.028 to 1.067; I2=95.7%). We also found different effect coefficients by region; the value in Asia was estimated to be lower than in North America or Europe. CONCLUSIONS: We strengthened the evidence on the short-term effect of PM2.5 on children's hospital admissions and emergency department visits for asthma. Further studies from other regions outside North America and Europe regions are needed for more generalizable evidence.

Korean research project on the integrated exposure assessment of hazardous substances for food safety

OBJECTIVES: This survey was designed to conduct the first nationwide dietary exposure assessment on hazardous substances including the intakes of functional food and herbal medicine. In this paper, we introduced the survey design and the results of the dietary exposure status and internal exposure levels of lead (Pb), cadmium (Cd), and mercury (Hg). METHODS: We selected 4867 subjects of all ages throughout Korea. We conducted a food survey, dietary survey, biomonitoring, and health survey. RESULTS: Pb and Cd were the highest (median value) in the seaweed (94.2 mug/kg for Pb; 594 mug/kg for Cd), and Hg was the highest in the fish (46.4 mug/kg). The dietary exposure level (median value) of Pb was 0.14 mug/kg body weight (bw)/d, 0.18 mug/kg bw/d for Cd, and 0.07 mug/kg bw/d for Hg. Those with a blood Pb level of less than 5.00 mug/dL (US Centers for Disease Control and Prevention, reference value for those 1 to 5 years of age) were 99.0% of all the subjects. Those with a blood Cd level with less than 0.30 mug/L (German Federal Environmental Agency, reference value for non-smoking children) were 24.5%. For those with a blood Hg level with less than 5.00 mug/L (human biomonitoring I, references value for children and adults, German Federal Environmental Agency) was 81.0 % of all the subjects. CONCLUSIONS: The main dietary exposure of heavy metals occurs through food consumed in a large quantity and high frequency. The blood Hg level and dietary exposure level of Hg were both higher than those in the European Union.

Korean research project on the integrated exposure assessment of hazardous substances for food safety

OBJECTIVES: This survey was designed to conduct the first nationwide dietary exposure assessment on hazardous substances including the intakes of functional food and herbal medicine. In this paper, we introduced the survey design and the results of the dietary exposure status and internal exposure levels of lead (Pb), cadmium (Cd), and mercury (Hg). METHODS: We selected 4867 subjects of all ages throughout Korea. We conducted a food survey, dietary survey, biomonitoring, and health survey. RESULTS: Pb and Cd were the highest (median value) in the seaweed (94.2 mug/kg for Pb; 594 mug/kg for Cd), and Hg was the highest in the fish (46.4 mug/kg). The dietary exposure level (median value) of Pb was 0.14 mug/kg body weight (bw)/d, 0.18 mug/kg bw/d for Cd, and 0.07 mug/kg bw/d for Hg. Those with a blood Pb level of less than 5.00 mug/dL (US Centers for Disease Control and Prevention, reference value for those 1 to 5 years of age) were 99.0% of all the subjects. Those with a blood Cd level with less than 0.30 mug/L (German Federal Environmental Agency, reference value for non-smoking children) were 24.5%. For those with a blood Hg level with less than 5.00 mug/L (human biomonitoring I, references value for children and adults, German Federal Environmental Agency) was 81.0 % of all the subjects. CONCLUSIONS: The main dietary exposure of heavy metals occurs through food consumed in a large quantity and high frequency. The blood Hg level and dietary exposure level of Hg were both higher than those in the European Union.

International Symposia on Integrated Exposure Assessment for Hazardous Materials

OBJECTIVES: On September 2, 2010 and November 25, 2011, the Korean Research Project on Integrated Exposure Assessment to Hazardous Materials for Food Safety (KRIEFS) organized two international symposia in Seoul, Korea. KRIEFS, established by the Korean Food and Drug Administration in March 2010, envisioned these international symposia as means to obtain advanced experiences from other countries and to reflect on and refine the KRIEFS's survey design and methods. METHODS: For the first symposium KRIEFS invited human biomonitoring (HBM) experts from Germany, the US, and Canada. The visiting HBM experts shared the details of their national studies while the KRIEFS discussed study design, as well as the methods, results and policymaking processes of the KRIEFS project. The second symposium was organized to share the survey design and results on endocrine disruptors from Taiwan. RESULTS: The Speaker from Germany introduced the German Environmental Survey and shared their experiences in HBM design, such as the process of developing reference values, and discussed the new HBM plan in Germany and the European Union. The Representative from Canada shared insights from national HBM approach. In the case of the US, the speaker focused on risk communication with subjects in epidemiological studies. In the second international symposium, the speaker shared the experience of endocrine disruptors'studies from Taiwan. CONCLUSIONS: KRIEFS was able to better understand previous nationwide HBM research designs, policy making process, and risk communication with research subjects.

Relationship of Serum Homocysteine with Brachial-Ankle Pulse Wave Velocity in Middle Aged Women / 가정의학회지

BACKGROUND: Several studies showed the relationship between serum homocysteine and pulse wave velocity, but their subjects were confined to high risk group for cardiovascular diseases and recent study revealed no relationship in young healthy adults. We hypothesized that time interval would be needed for serum homocysteine to infl uence pulse wave velocity after exposure to vascular endothelium. The purpose of this study was to determine the relationship between serum homocysteine and pulse wave velocity in middle aged women on the basis of that hypothesis and necessity for further study in general population. METHODS: The study subjects were 110 middle aged women who visited a health promotion center of a general hospital. We collected medical history by means of self-reported questionnaire and measured height, weight, blood pressure and brachial-ankle pulse wave velocity (baPWV). Blood sampling was performed after overnight fasting. We analyzed the relationship between several cardiovascular risk factors and baPWV and performed multiple regression analysis. RESULTS: BaPWV velocity was correlated significantly with age, mean blood pressure, serum homocysteine, total cholesterol and diabetes mellitus, but not with body mass index, high-density lipoprotein cholesterol, triglyceride, creatinine clearance, alcohol intake, hypertension and smoking. In multiple regression, there was a significant association between age (P = 0.04), moderate hyperhomocysteinemia (P = 0.02), mean blood pressure (P < 0.001) and baPWV. CONCLUSION: In middle aged women, there was an independently positive association between serum homocysteine and baPWV

The Relationship between Serum Ferritin and High Sensitivity C-reactive Protein among Adults in a Health Promotion Center

BACKGROUND: More attention is given to oxidative hypothesis which causes atherosclerosis to be recognized as inflammatory response. The relationship between serum ferritin which catalyzes lipid peroxidation and high sensitivity C-reactive protein which reflects vascular inflammation was investigated among adults in a health promotion center. METHODS: The study group consisted of 297 men and women (men 86, women 211) who visited the health promotion center of a hospital in Seoul to have a health checkup from October 1, 2004 to April 1, 2005. These subjects answered the questionnares and were measured in the following; blood tests, brachial-ankle pulse wave velocity and several anthropometric measurements. Statistical analysis was performed on 111 subjects after exclusion of those subjects who were taking antihypertensive agents or antidiabetic agents, and who had acute inflammatory diseases, acute liver diseases, anemia, and who had a WBC > or =11,000x10(3)/mm3 or a serum ferritin > or =200 ug/L or a ABI (Ankle Brachial Index) <0.9. RESULTS: The average serum ferritin concentration of men against women was 132.57+/-43.12 ng/ml to 78.23+/-38.10 ng/ml which means that men have about 1.7 times as high concentration than women (P<0.001). Serum ferritin was significantly correlated with high sensitivity C-reactive protein (r=0.332). Even in multiple stepwise regression analysis, there was a independent relationship between serum ferritin and high sensitivity C-reactive protein (beta=0.138, P=0.010). When we analyzed with distinction of sex, this relationship in women was constant (beta=0.131, P=0.031), but serum ferritin in men just showed the trend of correlation with BMI (beta=9.510, P=0.059). CONCLUSION: There is a significant relationship between the increase of serum ferritin and high sensitivity C-reactive protein in healthy women; furthermore, studies in men need to be confirmed.

Relationship of Serum Ferritin with Cardiovascular Risk Factors

BACKGROUND: Sullivan has suggested that higher incidence of coronary heart disease in men and postmenopausal women is due to higher levels of stored iron in these two groups. A few epidemiologic studies in humans have reported the association between iron stores and increased risk of cardiovascular diseases. But there is conflicting evidence regarding the relationship between iron and cardiovascular diseases. The present study evaluated the relationship between ferritin and well established cardiovascular risk factors. METHODS: There were 288 healthy subjects who visited a health promotion center of a general hospital. We collected data by means of self-reported questionnare and measured height, weight and blood pressure. Serum ferritin, fasting blood glucose, lipid profiles, and C-reactive protein were measured at a fasting state. RESULTS: Mean serum ferritin values were 150.1+/-82.2 ng/mL in men and 61.7+/-38.2 ng/mL in women (P<0.001). Serum ferritin level in current smoker was higher than in non-smoker (157.6+/-111.8 ng/mL versus 100.5+/-64.2 ng/mL, P=0.006). Serum ferritin was significantly and positively correlated with body mass index, systolic blood pressure, diastolic blood pressure, fasting blood glucose, total cholesterol and triglyceride. There was no statistical significance in age, C-reactive protein, high-density lipoprotein cholesterol and low-density lipoprotein cholesterol. In multiple regression analysis, there was association between ferritin and sex (beta=-80.333, P<0.001) and triglycerides (beta=0.182, P=0.030). CONCLUSION: The serum ferritin level in men is higher than in women in healthy adults. Serum ferritin is positively associated with triglycerides.