Clinical Features and Risk Factors of Post-COVID-19 Condition in Korea / 예방의학회지

Objectives@#Numerous studies have explored the causes and spread of outbreaks, yet there is a lack of research on post-coronavirus disease 2019 condition (PCC) in Korea. The goal of this study was to identify the various types of PCC and associated factors in discharged patients and to provide directions for the ongoing health management of confirmed patients. @*Methods@#A telephone survey was conducted among 680 coronavirus disease 2019 (COVID-19) patients diagnosed between July 7, 2021 and August 26, 2021, in Dangjin, Chungnam, Korea. A descriptive analysis of characteristics, univariate analysis, and regression were performed using data from basic epidemiological surveys conducted at the time of diagnosis and post-discharge questionnaires. @*Results@#Of the 585 patients who responded, 159 (27.2%) developed PCC. Of the 211 patients with no initial symptoms, 27 (12.8%) developed PCC, versus 132 (35.3%) of the 374 patients with initial symptoms. Among the initial symptoms, fever or chills, cough or sputum, loss of smell, and sore throat were associated with PCC. Compared to patients with less than 10 days of hospitalization, those with a hospitalization period of 21 days to 30 days (odds ratio [OR], 2.3; 95% confidence interval [CI], 1.0 to 5.2) and 31 days or more (OR, 5.8; 95% CI, 1.9 to 18.1) had a higher risk of PCC. @*Conclusions@#More than a quarter of COVID-19 patients, including those who had no initial symptoms, experienced PCC in Korea. People with the initial symptoms of fever, chills, and respiratory symptoms and those who had prolonged hospital stays had a high risk of PCC.

Exposure to Hazardous Substances and Their Health Effects Among Residents Living Near Three Industrial Waste Incinerators in Korea

Background@#This study aimed to evaluate exposure to various hazardous substances emitted by incineration facilities and their likely effect on the health for residents of Bugi-myeon, Cheongju, Korea, which has three incineration facilities. @*Methods@#Heavy metals, polycyclic aromatic hydrocarbons (PAHs), and dioxin concentrations in the air and soil of exposed and control areas were measured. Moreover, the exposure levels to harmful substances and its effects on health were investigated in 1,124 exposed and 232 control adults. @*Results@#PAHs and dioxin concentrations in the air in the exposed area were significantly higher than in the control area. Urinary cadmium and PAHs metabolite concentrations were significantly higher in the exposed group than in the control group. The exposure group also had a higher prevalence of depression and self-reported allergic symptoms than the control group. @*Conclusion@#The possibility of residents in Bugi-myeon being exposed to hazardous substances at incineration facilities cannot be ruled out. To prevent them from further exposure to hazardous substances, it is necessary to prohibit the expansion of additional incineration facilities in this area and to implement continuous monitoring projects for residents

Associations between Exposure to Bisphenol A and Behavioral and Cognitive Function in Children with Attention-deficit/Hyperactivity Disorder: A Case-control Study

Objective@#Bisphenol A (BPA) is a widely produced synthetic chemical used to manufacture polycarbonate plastics and epoxy resins. We aimed to investigate the association between exposure to BPA and behavioral and cognitive function in children with attention-deficit/hyperactivity disorder (ADHD) and healthy controls. @*Methods@#The study included 444 children aged from 6 to 10 years. The ADHD and control groups included 195 and 249 children, respectively. BPA levels were assessed via urinalysis, while behavior was assessed using the Korean version of the ADHD Rating Scale (K-ARS) and the Behavior Assessment System for Children (BASC-2). Cognitive function was assessed using the Continuous Performance Test (i.e., ADHD Diagnostic System [ADS]). Participants were categorized into tertile groups based on urinary BPA concentration. @*Results@#Scores on the K-ARS and the hyperactivity, aggression, anxiety, and depression subscales of the BASC-2 were significantly different among tertile groups for urinary BPA levels. Scores on visual omission error, commission error, response time variability, and auditory commission error of the ADS were significantly different among three BPA groups. Subgroup analysis revealed that these differences of behavior and cognition among three BPA groups were observed in only boys and normal controls. @*Conclusion@#Exposure to BPA was associated with unfavorable behavioral and cognitive outcomes. Our study extends the findings of previous studies regarding the association between BPA exposure and behavior/cognitive function by including children with ADHD. Further studies are required to determine the mechanisms underlying sex- and group-based differences in these associations.

Association Between Air Conditioning Use and Self-reported Symptoms During the 2018 Heat Wave in Korea / 예방의학회지

Objectives@#The purpose of this study was to investigate the health effects of air conditioning use during the 2018 heat wave in Korea, included the highest temperature ever recorded in the nation. @*Methods@#The participants in this study were 1000 adults aged 19 years and older recruited from across Korea. The participants were asked about their experience of symptoms of various diseases, disruptions of their daily lives, and use of air conditioning during the heat wave. The associations between air conditioning use during the heat wave and health outcomes were analyzed using the chi-square test and multiple logistic regression models. @*Results@#Among participants who lacked air conditioning in the main space where they spent time outside the home, 33.9%, 8.1%, 43.5%, and 19.4% experienced symptoms of heat-related, cardiovascular, nervous system diseases, and air-conditioningitis, respectively. In comparison, participants who did have air conditioning outside the home experienced the same symptoms at proportions of 21.0%, 1.9%, 26.8%, and 34.2%, respectively (p=0.027, 0.007, 0.007, and 0.023, respectively). Among participants who had no air conditioner at home, 10.0% were absent from school or work due to the heat wave. In contrast, among participants who had an air conditioner at home, only 3.7% were absent as a result of the heat wave (p=0.007). @*Conclusions@#When air conditioning was not used at home or in the main space where participants spent time outside the home during the 2018 heat wave, adverse health effects were more prevalent, but the risk of air-conditioningitis was reduced.

Associations among High Risk for Sleep-disordered Breathing, Related Risk Factors, and Attention Deficit/Hyperactivity Symptoms in Elementary School Children

Objective@#Habitual snoring is a common problem in children. We evaluated the association between a high risk for sleep-disordered breathing and attention deficit/hyperactivity symptoms. @*Methods@#Parents of 13,560 children aged 6 to 12 years responded to questionnaires including items on habitual snoring and the Korean attention deficit/hyperactivity disorder rating scale. The snoring score comprised the number of “yes” responses to habitual-snoring items, and a high risk for sleep-disordered breathing was defined as a snoring score ≥ 2. @*Results@#The odds ratio (OR) of a high risk for sleep-disordered breathing was significantly higher in boys (OR = 1.47; p ＜ 0.001), overweight children (OR = 2.20; p ＜ 0.001), and children with current secondhand-smoking exposure (OR = 1.38; p ＜ 0.001). The Korean attention deficit/hyperactivity disorder rating scale score increased significantly with the snoring score (0 vs. 1, B = 1.56, p ＜ 0.001; 0 vs. 2, B = 2.44, p＜ 0.001; 0 vs. 3, B = 2.48, p＜ 0.001; 0 vs. 4, B = 3.95; p ＜ 0.001). @*Conclusion@#Our study confirms several risk factors of sleep-disordered breathing, namely male sex, overweight, and exposure to tobacco smoking, and found a positive association between habitual snoring and attention deficit/hyperactivity symptoms.

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.

Current State of Research on the Risk of Morbidity and Mortality Associated with Air Pollution in Korea

PURPOSE: The effects of air pollution on health can vary regionally. Our goal was to comprehensively review previous epidemiological studies on air pollution and health conducted in Korea to identify future areas of potential study. MATERIALS AND METHODS: We systematically searched all published epidemiologic studies examining the association between air pollution and occurrence of death, diseases, or symptoms in Korea. After classifying health outcomes into mortality, morbidity, and health impact, we summarized the relationship between individual air pollutants and health outcomes. RESULTS: We analyzed a total of 27 studies that provided 104 estimates of the quantitative association between risk of mortality and exposure to air pollutants, including particulate matter with aerodynamic diameter less than 10 µm, particulate matter with aerodynamic diameter less than 2.5 µm, sulfur dioxide, nitrogen dioxide, ozone, and carbon monoxide in Korea between January 1999 and July 2018. Regarding the association with morbidity, there were 38 studies, with 98 estimates, conducted during the same period. Most studies examined the short-term effects of air pollution using a time series or case-crossover study design; only three cohort studies that examined long-term effects were found. There were four health impact studies that calculated the attributable number of deaths or disability-adjusted life years due to air pollution. CONCLUSION: There have been many epidemiologic studies in Korea regarding air pollution and health. However, the present review shows that additional studies, especially cohort and experimental studies, are needed to provide more robust and accurate evidence that can be used to promote evidence-based policymaking.

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.

Attention-Deficit/Hyperactivity Disorder Symptom Characteristics in Korean Elementary School Children: Comparison with US Population

OBJECTIVE: Attention-deficit/hyperactivity disorder (ADHD) is a common neurodevelopmental disorder in elementary school children. The present study investigated the characteristics of ADHD in Korean elementary school children using the Korean version of the ADHD Rating Scale (K-ARS). The data was compared with those obtained from a comparable American population. METHODS: Participants included 29,914 elementary school children, aged 6–12 years, from a medium-sized city. The parents completed the home version of the K-ARS. The total and subscale-specific normative data and sex- and age-related mean score differences were analyzed. These data were compared with those obtained from the American population using independent t-tests. RESULTS: Mean total and subscale K-ARS scores were significantly higher among boys (vs. girls) and younger children aged equal to or less than 8 years old (vs. older children). Mean scores on the hyperactivity-impulsivity subscale were lower than those of American children, but similar to another Korean sample. CONCLUSION: Our data characterized ADHD symptoms in Korean children. However, further studies are needed to identify the cultural differences underlying ratings of ADHD symptom severity.

Health Indicators Related to Disease, Death, and Reproduction / 예방의학회지

One of the primary goals of epidemiology is to quantify various aspects of a population’s health, illness, and death status and the determinants (or risk factors) thereof by calculating health indicators that measure the magnitudes of various conditions. There has been some confusion regarding health indicators, with discrepancies in usage among organizations such as the World Health Organization the, Centers for Disease Control and Prevention (CDC), and the CDC of other countries, and the usage of the relevant terminology may vary across papers. Therefore, in this review, we would like to propose appropriate terminological definitions for health indicators based on the most commonly used meanings and/or the terms used by official agencies, in order to bring clarity to this area of confusion. We have used appropriate examples to make each health indicator easy for the reader to understand. We have included practical exercises for some health indicators to help readers understand the underlying concepts.

Health Indicators Related to Disease, Death, and Reproduction / 예방의학회지

One of the primary goals of epidemiology is to quantify various aspects of a population’s health, illness, and death status and the determinants (or risk factors) thereof by calculating health indicators that measure the magnitudes of various conditions. There has been some confusion regarding health indicators, with discrepancies in usage among organizations such as the World Health Organization the, Centers for Disease Control and Prevention (CDC), and the CDC of other countries, and the usage of the relevant terminology may vary across papers. Therefore, in this review, we would like to propose appropriate terminological definitions for health indicators based on the most commonly used meanings and/or the terms used by official agencies, in order to bring clarity to this area of confusion. We have used appropriate examples to make each health indicator easy for the reader to understand. We have included practical exercises for some health indicators to help readers understand the underlying concepts.

Environmental Tobacco Smoke Exposure at Home and Attributable Problem Behaviors in Korean Children and Adolescents for 2012–2014 in a Nationally Representative Survey

BACKGROUND: This study aimed to examine the environmental tobacco smoke (ETS) exposure at home and associated problem behaviors in Korean children and adolescents. METHODS: Approximately 2,167 children aged 3–18 years were included in the study after excluding 163 active smokers from the Korean Environmental Health Survey in Children and Adolescents (2012–2014). ETS data were obtained using a questionnaire; problem behaviors were measured using the Child Behavior Checklist administered to parents. The relationship between ETS exposure and problem behavior was evaluated using a survey regression model adjusted for region, age, sex, income, and father's education. The population-attributable fraction (PAF%) was calculated based on problem behaviors related to ETS exposure at home. RESULTS: The rates of ETS exposure at home were 20%, 28%, and 39% in children aged 3–5, 6–11, and 12–18 years, respectively; ETS exposure at home was associated with behavioral problems: the exposed group having higher total behavioral problem score (95% confidence interval [CI]) than the non-exposed by 2.46 (0.60–4.32) and 2.74 (0.74–4.74) in children aged 6–11 and 12–18 years, respectively, with no significant association in those aged 3–5 years. The PAF% (95% CI) of total problem behaviors for ETS exposure at home were 2.68 (−10.11–17.78), 10.66 (3.25–17.55), and 11.62 (3.03–18.96) in children aged 3–5, 6–11, and 12–18 years, respectively. Children with externalizing problems had higher PAF% than those with internalizing problems. CONCLUSION: In Korea, ETS exposure at home is associated with problem behaviors in children and adolescents with about more than 10% population attributable fraction.

The Symptom Trajectory of Attention-Deficit Hyperactivity Disorder in Korean School-Age Children

OBJECTIVE: We aimed to investigate symptom trajectory of attention-deficit hyperactivity disorder (ADHD) in Korean school-age children. METHODS: Four hundred fifty six elementary school children were enrolled when they were in 1st grade and assessed once per year until 4th grade. Symptom severity was assessed by parents using the Korean version of the ADHD rating scale (K-ARS). High-risk was defined as a K-ARS score >18; 377, 325, and 284 children participated in the subsequent assessments. Symptom trajectory was analyzed using a mixed-model approach consistent with the longitudinal nature of the present study including missing data. RESULTS: K-ARS scores demonstrated significant main effects of time (F=35.33; p < 0.001), sex (F=20.77; p < 0.001), and first-year high-risk group (F=240.90; p<0.001). It also demonstrated a significant time×first-year high-risk group interaction effect (F=38.14; p < 0.001), but not a time×sex interaction effect. CONCLUSION: K-ARS scores demonstrated a tendency to decline with aging. Individuals in the high-risk group demonstrated earlier declining tendency than those in the non-high risk group. Although total K-ARS scores differed significantly between the sexes at all assessments, the declining pattern between both sexes did not differ significantly. Further studies including larger sample sizes, diagnostic interviews, and complete data sets are needed to confirm findings of the present study.

Dietary Factors Associated with Attention Deficit Hyperactivity Disorder (ADHD) in School-aged Children / 대한지역사회영양학회지

OBJECTIVES: An association between dietary patterns and mental health in children has been suggested in a series of studies, yet detailed analyses of dietary patterns and their effects on ADHD (attention deficit hyperactivity disorder) are limited. METHODS: We included 4569 children who had dietary intake data as part of the CHEER (Children's Health and Environmental Research) study conducted nationwide from 2005 to 2010. We assessed ADHD (Attention Deficit Hyperactivity Disorder) by the DuPaul's ADHD Rating Scales and dietary intake by a semi-quantitative food frequency questionnaire. Using intake data, we constructed five dietary patterns: “Plant foods & fish,” “Sweets,” “Meat & fish,” “Fruits & dairy products,” and “Wheat based.” RESULTS: The overall proportion of ADHD was 12.3%. Boys (17.8%) showed a higher rate of ADHD than girls (6.5%). The total intake of calories (85 kcal) and plant fat (2g) in the ADHD group was significantly higher than that of the normal group. ADHD was significantly negatively associated with dietary habits such as having breakfast and meal frequency, and positively associated with eating speed, unbalanced diet, overeating, and rice consumption. Regarding dietary patterns, the “Sweets” category was relevant to high ADHD risk (OR 1.59, 95% CI: 1.18, 2.15 for Q5 vs. Q1) in a linear relationship. An inverse, non-linear association was found between “Fruits & dairy products” and ADHD (OR 0.55, 95% CI: 0.39, 0.76 for Q4 vs. Q1). CONCLUSIONS: Our study confirms both positive and negative associations between diet and ADHD in elementary school age children. Moreover, linear or nonlinear associations between diet and ADHD draw attention to the possible threshold role of nutrients. Further studies may consider characteristics of diet in more detail to develop better intervention or management in terms of diet and health.

Dietary Factors Associated with Attention Deficit Hyperactivity Disorder (ADHD) in School-aged Children / 대한지역사회영양학회지

OBJECTIVES: An association between dietary patterns and mental health in children has been suggested in a series of studies, yet detailed analyses of dietary patterns and their effects on ADHD (attention deficit hyperactivity disorder) are limited. METHODS: We included 4569 children who had dietary intake data as part of the CHEER (Children's Health and Environmental Research) study conducted nationwide from 2005 to 2010. We assessed ADHD (Attention Deficit Hyperactivity Disorder) by the DuPaul's ADHD Rating Scales and dietary intake by a semi-quantitative food frequency questionnaire. Using intake data, we constructed five dietary patterns: “Plant foods & fish,” “Sweets,” “Meat & fish,” “Fruits & dairy products,” and “Wheat based.” RESULTS: The overall proportion of ADHD was 12.3%. Boys (17.8%) showed a higher rate of ADHD than girls (6.5%). The total intake of calories (85 kcal) and plant fat (2g) in the ADHD group was significantly higher than that of the normal group. ADHD was significantly negatively associated with dietary habits such as having breakfast and meal frequency, and positively associated with eating speed, unbalanced diet, overeating, and rice consumption. Regarding dietary patterns, the “Sweets” category was relevant to high ADHD risk (OR 1.59, 95% CI: 1.18, 2.15 for Q5 vs. Q1) in a linear relationship. An inverse, non-linear association was found between “Fruits & dairy products” and ADHD (OR 0.55, 95% CI: 0.39, 0.76 for Q4 vs. Q1). CONCLUSIONS: Our study confirms both positive and negative associations between diet and ADHD in elementary school age children. Moreover, linear or nonlinear associations between diet and ADHD draw attention to the possible threshold role of nutrients. Further studies may consider characteristics of diet in more detail to develop better intervention or management in terms of diet and health.

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.

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.

Association between GABA3 Gene Polymorphisms and Attention Deficit Hyperactivity Disorder in Korean Children

OBJECTIVE: Attention deficit hyperactivity disorder (ADHD) is common disorder of the school-age population. ADHD is familial and genetic studies estimate heritability at 80–90%. The aim of the present study was to investigate the association between the genetic type and alleles for gamma-aminobutyric acid receptor subunit beta-3 (GABA3) gene in Korean children with ADHD. METHODS: The sample consisted of 180 ADHD children and 159 control children. We diagnosed ADHD according to DSM-IV. ADHD symptoms were evaluated with Conners' Parent Rating Scales and Dupaul Parent ADHD Rating Scales. Blood samples were taken from the 339 subjects, DNA was extracted from blood lymphocytes, and PCR was performed for GABA3 rs2081648, rs1426217 and rs981778 Polymorphism. Alleles and genotype frequencies were compared using the chi-square test. We compared the allele and genotype frequencies of GABA3 gene polymorphism in the ADHD and control groups. RESULTS: This study showed that there was a significant correlation among the frequencies of the rs2081648 (OR=0.71, 95% CI=0.51–0.98, p=0.040) of alleles of MAO, but the final conclusions are not definite. Follow up studies with larger patient or pure subgroups are expected. CONCLUSION: These results suggested that GABA3 might be related to ADHD symptoms.