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OBJECTIVES@#The aim of this study was to estimate the age-specific effects of 8-hour maximum ozone levels on pneumonia in children and adolescents. @*METHODS@#We performed quasi-Poisson regression analyses for individuals of 0-4 years, 5-9 years, 10-14 years, and 15-19 years of age using nationwide time-series data from the Korea (2011-2015). We constructed distributed lag linear models employing a generalized difference-in-differences method and controlling for other air pollutants. @*RESULTS@#A 10.0-parts per billion increase in 8-hour maximum ozone levels was associated with a higher risk of hospital admissions due to pneumonia at 0-4 (relative risk [RR], 1.02; 95% confidence interval [CI], 1.01 to 1.03) and 5-9 years of age (RR, 1.06; 95% CI, 1.04 to 1.08), but not at 10-14 (RR, 1.01; 95% CI, 0.98 to 1.04) or 15-19 years of age (RR, 1.01; 95% CI, 0.97 to 1.06). The association between ozone and hospital admissions due to pneumonia was stronger in cool seasons (from November to April) than in warm seasons (from May to October), but was similar between boys and girls. @*CONCLUSIONS@#Short-term exposure to ozone was associated with a higher risk of pneumonia at 0-4 years and 5-9 years of age, but not at 10-14 years or 15-19 years of age. Our findings can help identify vulnerable periods, determine the target populations for public health interventions, and establish air pollution standards.
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Background@#In 2017, Korea implemented nationwide latent tuberculosis infection (LTBI) project targeting healthcare workers (HCWs). We aimed to assess its performance using the cascade of care model. @*Methods@#We included 45,503 employees of medical institutions with positive interferongamma release assay result who participated between March 2017 and December 2018. We described percentages of LTBI participants completing each step in the cascade of care.Poisson regression model was conducted to assess individual characteristics and factors associated with not-visiting clinics for further care, not-initiating LTBI treatment, and notcompleting treatment. @*Results@#Proportions of visiting clinics and initiating and completing treatment in HCWs were 54.9%, 38.5%, and 32.0%, respectively. Despite of less likelihood of visiting clinics and initiating LTBI treatment, older age ≥ 65 years were more likely to complete treatment (adjusted relative risk [aRR], 0.80; 95% confidence interval [CI], 0.64–0.99), compared to young age < 35 years. Compared to nurses, doctors were less likely to visit clinic; however, were more likely to initiate treatment (aRR, 0.88; 95% CI, 0.81–0.96). Those who visited public health centers were associated with not-initiating treatment (aRR, 1.34; 95% CI, 1.29–1.40). When treated at private hospitals, 9-month isoniazid monotherapy was less likely to complete treatment, compared to 3-month isoniazid and rifampicin combination therapy (aRR, 1.33; 95% CI, 1.16–1.53). @*Conclusion@#Among employees of medical institutions with LTBI, only one third completed treatment. Age, occupation, treatment center, and initial regimen were significantly related to LTBI treatment performance indicators. Rifampicin-based short treatment regimens were effective under standard of care.
ABSTRACT
In 2017, the Korean government launched an unprecedentedly large-scaled latent tuberculosis infection (LTBI) screening project which covered more than a million individuals in congregate settings. A total of 1,047,689 participants of source population (n = 2,336,157) underwent LTBI testing from 2017 to 2018. The overall LTBI test uptake rate during this project was 44.8%. Workers in daycare centers (83.5%) and kindergartens (78.9%) showed high participation rate. A total of 1,012,206 individuals with valid results of interferongamma release assay (IGRA) were selected to constitute the IGRA cohort. Most of the enrolled participants in the IGRA cohort were in their working age. Approximately, threequarters of total enrolled population were female. Investigating the LTBI prevalence, stages of LTBI care cascade, natural history of LTBI, efficacy of LTBI treatment and cost-effectiveness of LTBI screening are feasible within this IGRA cohort.
ABSTRACT
In 2017, the Korean government launched an unprecedentedly large-scaled latent tuberculosis infection (LTBI) screening project which covered more than a million individuals in congregate settings. A total of 1,047,689 participants of source population (n = 2,336,157) underwent LTBI testing from 2017 to 2018. The overall LTBI test uptake rate during this project was 44.8%. Workers in daycare centers (83.5%) and kindergartens (78.9%) showed high participation rate. A total of 1,012,206 individuals with valid results of interferongamma release assay (IGRA) were selected to constitute the IGRA cohort. Most of the enrolled participants in the IGRA cohort were in their working age. Approximately, threequarters of total enrolled population were female. Investigating the LTBI prevalence, stages of LTBI care cascade, natural history of LTBI, efficacy of LTBI treatment and cost-effectiveness of LTBI screening are feasible within this IGRA cohort.
ABSTRACT
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.
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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.
ABSTRACT
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.
Subject(s)
Epidemiology , Exercise , Reproduction , World Health OrganizationABSTRACT
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.
ABSTRACT
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.
Subject(s)
Air Pollutants , Air Pollution , Carbon Monoxide , Cohort Studies , Environmental Medicine , Epidemiologic Studies , Korea , Mortality , Nitrogen Dioxide , Ozone , Particulate Matter , Sulfur DioxideABSTRACT
The Environmental Health Study in the Korean National Industrial Complexes (EHSNIC) is a project that aims to monitor the exposure and health effects of environmental pollution among residents of national industrial complexes, as well as propose appropriate environmental health measures. Since its launch in 2003, this project has been initiated in eight national industrial complexes. Currently, it is necessary to review the accomplishments and limitations of the phases 1 and 2 of this project, and establish the direction of the upcoming the phase 3. Thus, the present study has developed principles and goals for the phase 3, considering the rationale and justification of the EHSNIC, and presented specific research contents accordingly. In the phase 3, it is important to improve the methods for exposure assessment and evaluation of health effects, in order to identify clearly the association between the pollutants released from industrial complexes and their health impacts, to develop and to reinforce communication strategies to promote participation of residents of communities near industrial complexes. Nonetheless, it is also important to maintain the basic goal of continuously monitoring the level of exposure to and health effects of environmental pollutants.
Subject(s)
Environmental Health , Environmental Pollutants , Environmental PollutionABSTRACT
Particulate matter is an air pollutant emitted from both natural and anthropogenic sources, and its adverse health effects have been well documented in time-series analyses and cohort studies. The effect size of particulate matter exposure—a roughly 0.5% increase in mortality for each 10 µg/m³ increment of short-term exposure to particulate matter with aerodynamic diameter ≤10 µm and approximately a 10% increase for each 10 µg/m³ increment of long-term exposure to particulate matter with aerodynamic diameter ≤2.5 µm—is small compared to other risk factors, but the exposure is involuntary and affects the entire population, which makes particulate matter pollution an important public health issue. The World Health Organization and Korean government have both established guidelines for particulate matter concentrations, but the Korean guideline is less stringent than that of the World Health Organization. The annual mean concentration of particulate matter in Korea is decreasing, but the trend seems to be slowing. In addition to policy efforts to reduce particulate matter emission, personal approaches such as the use of face masks and air purifiers have been recommended. Personal approaches may not solve the fundamental problem, but can provide temporary mitigation until efforts to reduce emission make progress.
ABSTRACT
Particulate matter is an air pollutant emitted from both natural and anthropogenic sources, and its adverse health effects have been well documented in time-series analyses and cohort studies. The effect size of particulate matter exposure—a roughly 0.5% increase in mortality for each 10 µg/m³ increment of short-term exposure to particulate matter with aerodynamic diameter ≤10 µm and approximately a 10% increase for each 10 µg/m³ increment of long-term exposure to particulate matter with aerodynamic diameter ≤2.5 µm—is small compared to other risk factors, but the exposure is involuntary and affects the entire population, which makes particulate matter pollution an important public health issue. The World Health Organization and Korean government have both established guidelines for particulate matter concentrations, but the Korean guideline is less stringent than that of the World Health Organization. The annual mean concentration of particulate matter in Korea is decreasing, but the trend seems to be slowing. In addition to policy efforts to reduce particulate matter emission, personal approaches such as the use of face masks and air purifiers have been recommended. Personal approaches may not solve the fundamental problem, but can provide temporary mitigation until efforts to reduce emission make progress.
Subject(s)
Humans , Air Filters , Cohort Studies , Environmental Medicine , Epidemiology , Korea , Masks , Mortality , Particulate Matter , Public Health , Risk Factors , World Health OrganizationABSTRACT
The Environmental Health Study in the Korean National Industrial Complexes (EHSNIC) is a project that aims to monitor the exposure and health effects of environmental pollution among residents of national industrial complexes, as well as propose appropriate environmental health measures. Since its launch in 2003, this project has been initiated in eight national industrial complexes. Currently, it is necessary to review the accomplishments and limitations of the phases 1 and 2 of this project, and establish the direction of the upcoming the phase 3. Thus, the present study has developed principles and goals for the phase 3, considering the rationale and justification of the EHSNIC, and presented specific research contents accordingly. In the phase 3, it is important to improve the methods for exposure assessment and evaluation of health effects, in order to identify clearly the association between the pollutants released from industrial complexes and their health impacts, to develop and to reinforce communication strategies to promote participation of residents of communities near industrial complexes. Nonetheless, it is also important to maintain the basic goal of continuously monitoring the level of exposure to and health effects of environmental pollutants.
Subject(s)
Environmental Health , Environmental Pollutants , Environmental PollutionABSTRACT
The industrial complexes built during the course of economic development in South Korea played a pivotal role in the country's rapid economic growth. However, this growth was accompanied by health problems due to the pollutants released from the industrial complexes inevitably located near residential areas, given the limited land area available in South Korea. This study was conducted to evaluate the exposure to each pollutant emanating from industrial complexes for residents living in nearby areas, and to determine the substances requiring priority attention in future surveys. Pollutants were comprehensively categorized according to their emission and exposure levels based on data previously collected from the study areas. The emission, ambient concentration, and biomarker concentration levels of major pollutants emitted from eight national industrial complexes (Ulsan, Pohang, Gwangyang, Yeosu, Chungju, Daesan, Sihwa, and Banwol) were determined and tabulated. Each of the values was compared with the national/local average values, reference values, or control area concentrations depending on availability. Substances with completed exposure pathways and with high values for emissions, ambient concentrations, and biomarker concentrations were considered the substances posing exposure risks to the residents living near the corresponding industrial complex. The substances requiring continuous monitoring or supplementary exposure investigation were also categorized and presented. Lead and benzene had higher values for emissions, ambient concentrations, and biomarker concentrations in the Ulsan Industrial Complex area; thus, they were most likely to pose exposure risks to residents living in the area's neighborhoods. In other areas, styrene, xylene, cadmium, nitrogen oxide, trichloroethylene, nickel, manganese, and chromium required continuous monitoring, and arsenic, nickel, manganese, and chromium required biomarker measurements. In conclusion, the substances identified and categorized in this study need to be given appropriate attention in future surveys on exposure risks and health effects related to industrial complexes.
Subject(s)
Arsenic , Benzene , Cadmium , Chromium , Economic Development , Environmental Pollutants , Korea , Manganese , Nickel , Nitrogen , Reference Values , Residence Characteristics , Styrene , Trichloroethylene , XylenesABSTRACT
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.
Subject(s)
Humans , Body Mass Index , Chronic Disease , Cough , Dermatitis, Atopic , Education , Employment , Environmental Pollution , Epidemiologic Studies , Epidemiological Monitoring , Korea , Logistic Models , Lung , Prevalence , Smoke , Smoking , Sputum , Uterine NeoplasmsABSTRACT
The industrial complexes built during the course of economic development in South Korea played a pivotal role in the country's rapid economic growth. However, this growth was accompanied by health problems due to the pollutants released from the industrial complexes inevitably located near residential areas, given the limited land area available in South Korea. This study was conducted to evaluate the exposure to each pollutant emanating from industrial complexes for residents living in nearby areas, and to determine the substances requiring priority attention in future surveys. Pollutants were comprehensively categorized according to their emission and exposure levels based on data previously collected from the study areas. The emission, ambient concentration, and biomarker concentration levels of major pollutants emitted from eight national industrial complexes (Ulsan, Pohang, Gwangyang, Yeosu, Chungju, Daesan, Sihwa, and Banwol) were determined and tabulated. Each of the values was compared with the national/local average values, reference values, or control area concentrations depending on availability. Substances with completed exposure pathways and with high values for emissions, ambient concentrations, and biomarker concentrations were considered the substances posing exposure risks to the residents living near the corresponding industrial complex. The substances requiring continuous monitoring or supplementary exposure investigation were also categorized and presented. Lead and benzene had higher values for emissions, ambient concentrations, and biomarker concentrations in the Ulsan Industrial Complex area; thus, they were most likely to pose exposure risks to residents living in the area's neighborhoods. In other areas, styrene, xylene, cadmium, nitrogen oxide, trichloroethylene, nickel, manganese, and chromium required continuous monitoring, and arsenic, nickel, manganese, and chromium required biomarker measurements. In conclusion, the substances identified and categorized in this study need to be given appropriate attention in future surveys on exposure risks and health effects related to industrial complexes.
Subject(s)
Arsenic , Benzene , Cadmium , Chromium , Economic Development , Environmental Pollutants , Korea , Manganese , Nickel , Nitrogen , Reference Values , Residence Characteristics , Styrene , Trichloroethylene , XylenesABSTRACT
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.
Subject(s)
Adolescent , Child , Humans , Checklist , Child Behavior , Education , Environmental Health , Korea , Parents , Problem Behavior , Smoke , TobaccoABSTRACT
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.
Subject(s)
Humans , Body Mass Index , Chronic Disease , Cough , Dermatitis, Atopic , Education , Employment , Environmental Pollution , Epidemiologic Studies , Epidemiological Monitoring , Korea , Logistic Models , Lung , Prevalence , Smoke , Smoking , Sputum , Uterine NeoplasmsABSTRACT
Inferring causality is necessary to achieve the goal of epidemiology, which is to elucidate the cause of disease. Causal inference is conducted in three steps: evaluation of validity of the study, inference of general causality, and inference of individual causality. To evaluate validity of the study, we propose a checklist that focuses on biases and generalizability. For general causal inference, we recommend utilizing Hill’s 9 viewpoints. Lastly, individual causality can be inferred based on the general causality and evidence of exposure. Additional considerations may be needed for social or legal purposes; however, these additional considerations should be based on the scientific truth elucidated by the causal inference described in the present article.
Subject(s)
Bias , Checklist , Environmental Exposure , EpidemiologyABSTRACT
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.