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Bisphenol A (BPA) has been shown to affect brain and behavior in rodents and nonhuman primates, but there are few studies focusing on its relationship to human neurobehavior. We aimed to investigate the relationship between environmental exposure to BPA and childhood neurobehavior. Methods: Urinary BPA concentrations and behavioral and learning characteristics were assessed in a general population of 1,089 children, aged 8-11 years. The main outcome measures were the Child Behavior Checklist (CBCL) and the Learning Disability Evaluation Scale (LDES). Results: Urinary levels of BPA were positively associated with the CBCL total problems score and negatively associated with the learning quotient from the LDES. The linear association with the CBCL anxiety/depression score and the quadratic association with the LDES listening score were significant after correction for multiple comparisons. Conclusions: Environmental exposure to BPA might be associated with childhood behavioral and learning development. The results suggest possible nonmonotonic relationships. (Contains 4 tables and 1 figure.)

Background: Subjective cognitive decline (SCD) is a risk factor for Alzheimer's disease (AD); however, the rates of cognitive decline are variable according to underlying pathologies and biomarker status. We conducted an observational study and aimed to investigate baseline characteristics and biomarkers related with cognitive declines in SCD. Our study also assessed whether SCD participants showed different cognitive and biomarker trajectories according to baseline amyloid deposition. Methods: This study is a part of a longitudinal cohort study conducted in multi-centers in South Korea between 2018 and 2021. Individuals (≥ 60 years old) with persistent cognitive complaint despite of normal cognitive functions were eligible for the study. All participants underwent neuropsychological tests, florbetaben PET scans, plasma amyloid markers, and brain MRI scans. Annual follow-up evaluations included neuropsychological tests and assessments for clinical progressions. Regional brain volumetry and amyloid burden represented by PET-based standardized uptake value ratio (SUVR) were measured. We compared cognitive and brain atrophic changes over 24 months between amyloid positive-SCD (Aβ + SCD) and amyloid negative-SCD (Aβ-SCD) groups. Baseline factors associated with cognitive outcomes were investigated. Results: A total of 120 participants with SCD were enrolled and 107 completed follow-up evaluations. Aβ + SCD participants (n = 20, 18.5%) were older and more frequently APOE4 carriers compared with Aβ-SCD participants (n = 87). Baseline cognitive scores were not different between the two groups, except the Seoul Verbal Learning Test (SVLT) scores showing lower scores in the Aβ + SCD group. After 24 months, plasma amyloid markers were higher, and regional volumes (entorhinal, hippocampal, and pallidum) were smaller in the Aβ + SCD participants compared with Aβ-SCD participants adjusted by age, sex, and baseline volumes. SVLT delayed recall and controlled oral word association test (COWAT) scores indicated more declines in Aβ + SCD participants. Baseline left entorhinal volumes were related to verbal memory decline, while baseline frontal volumes and global SUVR values were related to frontal functional decline. Conclusion: Aβ + SCD participants showed more cognitive decline and medial temporal atrophic changes during 24 months. Baseline neurodegeneration and amyloid burden were related with future cognitive trajectories in SCD. Trial registration: This study was registered at CRIS (KCT0003397). [ABSTRACT FROM AUTHOR]

Background: The present study assessed the association between blood lead and urinary cotinine levels and inattentive and hyperactive symptoms and neurocognitive performance in children. Methods: A total of 667 children (age range 8-11) were recruited from nine schools in five Korean cities. The teachers and parents completed the Korean version of the Attention-deficit/hyperactivity disorder Rating Scales (K-ARS), and the children performed neurocognitive tests. Blood lead and urinary cotinine levels were then measured. Results: The inattentive, hyperactive, and total scores of the teacher-rated K-ARS were positively associated with blood lead level, and the results of the continuous performance test (CPT), Stroop Color-Word Test, and Children's Color Trails Test were inversely associated with urinary cotinine level when controlled for age, gender, father's educational level, maternal IQ, child's IQ, residential area, birth weight, and cotinine (for lead) or lead (for cotinine). The association between blood lead level and commission errors score on the CPT disappeared when the effect of urinary cotinine level was controlled. Conclusions: These findings indicate that environmental exposure to tobacco smoke in children is associated with poor neurocognitive performance, and low levels of lead are associated with inattention and hyperactivity symptoms.

During the COVID-19 pandemic, working from home is associated with depressive symptoms, and anxiety symptoms in South Korea, and work-family conflict has a mediating role in the associations. These findings were more clearly observed among male, child-bearing, and precarious workers. Objective: We aimed to investigate the association between working from home (WFH), depression/anxiety, and work-family conflict (WFC) among Korean workers during the COVID-19 pandemic. Methods: We surveyed a total of 1074 workers online. Depression and anxiety were measured using the Centre for Epidemiologic Studies Depression Scale (CES-D) and Beck Anxiety Inventory (BAI). Mediating effects of WFC on the relationship between WFH and depression/anxiety were examined. Results: The WFH group had higher depression and anxiety scores than the daily commuting group. As WFC increased, the CES-D and BAI scores also increased. A possible mediating effect of WFC on the relationship between WFH and high CES-D and BAI scores was found. Conclusion: We observed a significant difference in depression/anxiety between WFH and daily commute workers, which was mediated by WFC, especially for young, child-growing, and precarious workers. [ABSTRACT FROM AUTHOR]

Background: Subjective cognitive decline (SCD) is a self-perceived cognitive worsening without objective cognitive impairment. Due to its heterogeneity and potential risk of Alzheimer's disease (AD), baseline biomarkers to predict progression are clinically important. In the present study, cognitive trajectories during a 24-month period were compared between amyloid-positive SCD (A+SCD) and amyloid-negative SCD (A−SCD) subjects, and biomarkers associated with memory decline were investigated. Methods: Data from a prospective cohort study in Korea between 2016 and 2019 were analyzed. SCD subjects ≥50 years of age were eligible. All participants underwent neuropsychological tests, brain magnetic resonance imaging, and florbetaben positron emission tomography scans. Amyloid burden and regional volumes were measured. Cognitive changes corrected for age were compared between A+SCD and A−SCD groups. Biomarkers associated with memory decline were assessed. Results: Forty-seven SCD subjects (69.9 ± 6.7 years, mini-mental state examination (MMSE) score 27.5) were enrolled, and 31 completed at least 1 annual follow-up (mean follow-up: 24.7 months). Baseline characteristics except age, hippocampal atrophy, and white matter hyperintensities were similar between A+SCDs (n = 12, 25.6%) and A−SCDs (n = 35). A+SCD subjects showed greater decline in the verbal memory function compared with the A−SCD subjects after adjustment for age. MMSE scores decreased more in the A+SCD (1.1 in the A+SCD; 0.55 in the A−SCD), although it was not statistically significant. Amyloid burden and baseline memory score were associated with memory decline. Conclusions: Within SCD, A+SCD subjects showed faster memory decline compared with the A−SCD subjects and amyloid burden might be associated with future memory decline in SCD. [ABSTRACT FROM AUTHOR]

Studies on the correlation of long-term PM2.5 exposure with childhood-onset asthma are limited to western countries. We aimed to study the association between long-term PM2.5 exposure and childhood-onset asthma in South Korea, which has higher ambient PM2.5 levels than western countries. We constructed a retrospective cohort of children aged 6–14 years living in seven metropolitan cities using the National Health Insurance service in South Korea from 2011 to 2016. Children who made a hospital visit with asthma from 2008 to 2010 were excluded. A child was diagnosed with asthma incidence if he or she visited the hospital three times or more with a primary diagnostic code of asthma. A time-varying Cox regression model was constructed to investigate the association of long-term district-level PM2.5 exposure with asthma incidence. Of the 1,425,638 children evaluated, 52,133 showed asthma incidence, with an incidence rate of 6.9 cases/1000 person-years. A 10 µg/m3 increase in the 48-month moving average PM2.5 exposure was associated with an elevated risk of asthma incidence, with a hazard ratio of 1.075 (95% confidence interval: 1.024–1.126), and this association was robust for different PM2.5 exposure levels (12-, 36-, and 60-month moving average). In this study, long-term exposure to PM2.5 was associated with asthma incidence in school-aged children in South Korea. Policies to reduce environmental PM2.5 levels and protect children from PM2.5 are necessary to prevent childhood-onset asthma. [ABSTRACT FROM AUTHOR]

Aim: There is no validated tool to predict persistent ovulatory dysfunction after medication with oral contraceptives in women with polycystic ovary syndrome (PCOS), which is the most severe subtype of PCOS. We aimed to build a model to predict persistent ovulatory dysfunction after medication of oral contraceptives in women with PCOS. Methods: A total of 286 patients with PCOS were treated with and without oral contraceptives at a tertiary academic medical center. Data were obtained from the electronic medical record system between January 2016 and March 2019. A risk prediction model was developed using multivariable logistic regression. Model 1 was based on age and chief complaints and Model 2 further included predictors evaluated during a clinic visit. Model 3 additionally included laboratory findings. Results: Of the study population, ovulatory dysfunction was persistent in 117 patients (40.9%). Compared with the simple model (Models 1 and 2), the full prediction model (Model 3) had better Akaike's information criterion (286, 244 vs. 225) and the area under the curve (AUC) increased from 0.74 and 0.79 to 0.84. The full model included 7 covariates measured during the evaluation of PCOS, and two covariates were significant predictors of persistent ovulatory dysfunction in PCOS: age (OR 0.91; 95% CI 0.84–0.97), and anti‐Müllerian hormone (OR 1.17; 95% CI 1.09–1.26). This model demonstrated good discrimination (AUC, 0.84) and calibration (Hosmer–Lemeshow goodness of fit test, p = 0.74). Conclusions: This prediction model was shown to be a useful method for predicting persistent ovulatory dysfunction after oral contraceptive medication in patients with PCOS. [ABSTRACT FROM AUTHOR]

Objectives: Attention-deficit hyperactivity disorder (ADHD) is a prevalent neurobehavioral disorder in children. There are limited studies for diet or dietary supplement effects on ADHD in preschool children in Asia. This study aimed to determine the association between dietary patterns in 4-year-old children and ADHD symptoms in 6-year-old children. Methods: We estimated dietary intake in 4-year-old children using a food frequency questionnaire. Using 33 food groups, major dietary patterns were identified in relation to the consumption of sweets, vegetables, meats, and carbohydrates. Parents of 6-year-old children used the Korean version of the ADHD Rating Scale for ADHD symptom assessment. Results: A sweet dietary pattern was associated with a higher risk of attention deficit (AD) (relative risk [RR], 1.34; confidence interval [CI], 1.17–1.55), hyperactivity (RR, 1.40; CI, 1.19–1.64), and ADHD symptoms (RR, 1.37; CI, 1.23–1.52). A vegetable dietary pattern was associated with a lower risk of ADHD symptoms (RR, 0.81; CI, 0.72–0.90). Food item analysis of the sweet dietary pattern showed that intake scores for chocolate, chips, and fruit jams positively correlated with AD, hyperactivity, and ADHD symptoms. Discussion: These findings can be useful to further understand the roles of dietary factors in ADHD. [ABSTRACT FROM AUTHOR]

Background: Sufficient sleep during childhood is important for cognitive functions such as learning and successful school performance. This study aimed to investigate the effects of sleep duration on the intelligence quotient (IQ) of 6-year-old children and aimed to analyze whether these effects differed by sex. Methods: The IQ of 538 6-year-old Korean participants from the cohort study, "The Environment and Development of Children," was measured during follow-up using the Korean Educational Developmental Institute's Wechsler Intelligence Scale for Children. The total, verbal, and performance IQ scores were evaluated. The relationship between sleep duration and IQ scores after adjusting for maternal age, maternal educational level, maternal occupation, maternal IQ, exposure to secondhand smoking, gestational age, and monthly age and birth season was also assessed. Results: Longer sleep duration was significantly associated with improved verbal IQ measures (β 0.55; p value 0.030). After stratifying participants by sex, a significant association was observed between sleep duration and total, verbal, and performance IQ scores in boys (total IQ 2.49, p value 0.012; verbal IQ 0.75, p value: 0.037; performance IQ 0.73, p value 0.048), but not in girls. Conclusions: The results indicated that only boys show a significant association between IQ scores and sleep duration. These findings support the hypothesis that sleep duration is associated with IQ, in a sex dependent manner. Future studies are needed for a thorough evaluation of the connection between sleep duration and health outcome in young children. [ABSTRACT FROM AUTHOR]

Several studies have suggested that estrogens have a protective function against lymphomagenesis. The treatment of breast cancer is driven by subtype classification, and the assessment of hormone receptor status is important for treatment selection. Thus, we evaluated the association between breast cancer and the incidence of NHL. We conducted a retrospective cohort study using a population-based nationwide registry in South Korea. We selected all women with newly diagnosed breast cancer between January 1st, 2002 and December 31st, 2016 who received curative treatment (N = 84,969) and a 1:10 sample of age-matched non-breast cancer controls (N = 1,057,674). Incident breast cancer (time-varying exposure) was the exposure and development of any type of NHL, including diffuse large B-cell lymphoma (DLBCL), follicular lymphoma (FL), mature T/NK-cell lymphomas, anaplastic large cell lymphoma (ALCL), and unspecified types of NHL, was the outcome. During follow-up, 1564 incident cases of NHL occurred. The fully adjusted Hazard Ratio (HR) for NHL associated with the development of breast cancer was 1.64 (95% CI = 1.34–2.00) after adjusting for body mass index, alcohol intake, physical activity, smoking, income, and comorbidity. The adjusted HR for NHL was much higher in participants who were aged <50 years and who received hormone therapy (either tamoxifen or aromatase inhibitors) than in those ≥50 years or who did not receive hormone therapy, respectively. The development of breast cancer was associated with a significantly increased risk of NHL, particularly follicular lymphoma and mature T/NK-cell lymphoma. In particular, the risk of NHL was higher in patients receiving hormone therapy and in younger patients. [ABSTRACT FROM AUTHOR]

Background: The association of physical activity with the development and progression of coronary artery calcium (CAC) scores has not been studied. This study aimed to evaluate the prospective association between physical activity and CAC scores in apparently healthy adults.Methods: Prospective cohort study of men and women free of overt cardiovascular disease who underwent comprehensive health screening examinations between 1 March 2011 and 31 December 2017. Baseline physical activity was measured using the International Physical Activity Questionnaire Short Form (IPAQ-SF) and categorised into three groups (inactive, moderately active and health-enhancing physically active (HEPA)). The primary outcome was the difference in the 5-year change in CAC scores by physical activity category at baseline.Results: We analysed 25 485 participants with at least two CAC score measurements. The proportions of participants who were inactive, moderately active and HEPA were 46.8%, 38.0% and 15.2%, respectively. The estimated adjusted average baseline CAC scores (95% confidence intervals) in participants who were inactive, moderately active and HEPA were 9.45 (8.76, 10.14), 10.20 (9.40, 11.00) and 12.04 (10.81, 13.26). Compared with participants who were inactive, the estimated adjusted 5-year average increases in CAC in moderately active and HEPA participants were 3.20 (0.72, 5.69) and 8.16 (4.80, 11.53). Higher physical activity was association with faster progression of CAC scores both in participants with CAC=0 at baseline and in those with prevalent CAC.Conclusion: We found a positive, graded association between physical activity and the prevalence and the progression of CAC, regardless of baseline CAC scores. [ABSTRACT FROM AUTHOR]

Purpose: We aimed to investigate the association between air pollution concentration levels and hospital admissions for heart failure (HF) among older adults in metropolitan cities in South Korea. Methods: We used hospital admission data of 1.8 million older adults in seven metropolitan cities from 2008 to 2016, derived from the National Health Insurance Service of South Korea. Daily HF admission data were linked to air pollutants concentrations for the respective dates, including particulate matter less than 2.5 μm in size (PM2.5), 10 μm (PM10), sulfur dioxide (SO2), nitrogen dioxide (NO2), carbon monoxide (CO), and ozone. We estimated the association between air pollutants and daily HF admissions using quasi-Poisson generalized additive models for each city. Results: During the study period, 142,490 hospital admissions for HF were noted. Increases of 10 μg/m3 of PM2.5 and PM10, and 10 ppb of SO2, NO2, and CO were associated with an increased risk of HF admission by 0.93% ([95% confidence intervals 0.51–1.36], 0.55% [0.31–0.80], 6.04% [2.15–10.08], 1.10% [0.38–1.82], and 0.05% [0.01–0.09]), respectively, on the same day. Increases in mean exposure to PM2.5, PM10, and SO2 for 8 days from the concurrent day were also significantly associated with HF admissions. During the warm season, the risk of HF admissions increased shortly after an increase in PM2.5, whereas prolonged effects were observed during the cold season. Conclusion: Our study suggests the adverse effects of air pollution on HF. Moreover, the evidence of seasonality may help tailor protection guidelines for older adults. [ABSTRACT FROM AUTHOR]

Background: Frailty is a multidimensional syndrome that leads to an increase in vulnerability. Previous studies have suggested that frailty is associated with poor health-related outcomes. For frailty screening, the Clinical Frailty Scale (CFS) is a simple tool that is widely used in various translated versions. We aimed to translate the CSF into Korean and evaluated its contents and concurrent validity.Methods: Translations and back-translations of the CFS were conducted independently. A multidisciplinary team decided the final CFS-K. Between August 2019 and April 2020, a total of 100 outpatient and inpatient participants aged ≥65 years were enrolled prospectively. The clinical characteristics were evaluated using the CFS-K. The CFS-K scores were compared with those of other frailty screening tools using Pearson's correlation coefficient and Spearman's rank correlation. The area under curve (AUC) for identifying the Eastern Cooperative Oncology Group Performance Status (ECOG PS) grade 3 or more was calculated for the CFS-K and other screening tools.Results: The mean age of the participants was 76.5 years (standard deviation [SD], 7.0), and 63 (63%) participants were male. The mean CFS-K was 4.8 (SD, 2.5). Low body mass index (p = 0.013) and low score on the Korean version of the Mini-Mental State Examination (p < 0.001) were significantly associated with high CFS-K scores, except for those assigned to scale 9 (terminally ill). The CFS-K showed a significant correlation with other frailty screening tools (R = 0.7742-0.9190; p < 0.01), except in the case of those assigned to scale 9 (terminally ill). In comparison with other scales, the CFS-K identified ECOG PS grade 3 or more with the best performance (AUC = 0.99). Patients assigned to scale 9 on the CFS-K (terminally ill) had similar frailty scores to those assigned to scale 4 (vulnerable) or 5 (mildly frail).Conclusions: In conclusion, the CFS-K is a valid scale for measuring frailty in older Korean patients. The CFS-K scores were significantly correlated with the scores of other scales. To evaluate the predictive and prognostic value of this scale, further larger-scale studies in various clinical settings are warranted. [ABSTRACT FROM AUTHOR]

Objectives: Although previous studies have investigated the correlation between fruit and vegetable consumption and depression, the results remain inconclusive. The present study aimed to investigate the association between weekly fruit and vegetable consumption and depressive symptoms in elderly Koreans.Methods: A multiple covariate linear regression analysis was performed using the data of 1,226 elderly individuals ≥ 60 years of age who participated in the Korean Elderly Environmental Panel II study from 2012 to 2014. Depressive symptoms were evaluated using the Korean version of the Short form Geriatric Depression Scale (SGDS-K). Generalized linear mixed-effects models were constructed to analyze the repeated measurements of 305 people who participated in the survey every year.Results: After adjusting for confounders, SGDS-K scores were negatively associated with the frequency of weekly fruit consumption as follows (β [95% confidence interval; CI]: -0.17 [-0.28 to -0.05], -0.17 [-0.27 to -0.07], -0.42 [-0.54 to 0.29], and -0.33 [-0.44 to -0.21]) for less than 1 time/wk, 1-3 times/wk, 4-6 times/wk, and daily, respectively, compared to no consumption. The SGDS-K scores were also negatively associated with the frequency of vegetable consumption (β [95% CI]: -0.86 [-1.18 to -0.55], -0.18 [-0.35 to -0.01], -0.36 [-0.53 to -0.18], and -0.15 [-0.29 to 0.00]) in the above order, respectively.Conclusions: Fruit consumption was inversely associated with depression levels in a dose-dependent manner. Although there was no dose-response relationship between vegetable consumption and the level of depression, it was negatively associated with SGDS-K scores. [ABSTRACT FROM AUTHOR]

Background: Long-term exposure to particulate matter <2.5 μm in size (PM2.5) is considered a risk factor for premature death. However, only a few studies have been conducted in areas with moderate PM2.5 concentrations. Moreover, an ageing society may be more susceptible to environmental exposure and future burden of mortality due to PM2.5.Methods: This study estimates hazard ratios (HRs) for all-cause and cause-specific mortality from long-term exposure to moderate PM2.5 concentrations in the elderly populations of seven cities in South Korea. We also projected nationwide elderly mortality caused by long-term exposure to PM2.5, accounting for population ageing until 2045. Mortality in 1 720 230 elderly adults aged ≥65 years in 2008 was monitored across 2009-16 and linked to modelled PM2.5 concentrations.Results: A total of 421 100 deaths occurred in 2009-16, and the mean of annual PM2.5 concentration ranged between 21.1 and 31.9 μg/m3 in most regions. The overall HR for a 10 μg/m3 increase in a 36-month PM2.5 moving average was 1.024 (95% confidence intervals: 1.009, 1.039). We estimated that 11 833 all-cause nationwide elderly deaths were attributable to PM2.5 exposure. Annual death tolls may increase to 17 948 by 2045. However, if PM2.5 is reduced to 5 μg/m3 by 2045, the tolls may show a lower increase to 3646.Conclusions: Long-term exposure to moderately high levels of PM2.5 was associated with increased mortality risk among the elderly. Thus, PM2.5 reduction in response to the projected ageing-associated mortality in South Korea is critical. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the prevalence of tinnitus among adolescents, and the factors known or hypothesized to be associated with tinnitus. Based on random sampling of school types and regions, a nationwide hearing survey of the first-year middle and high school students of South Korea was performed. The subjects underwent an otologic examination followed by pure tone audiometry up to 8 kHz. Questionnaires about the factors associated with hearing and tinnitus were completed by the students and their parents. Among the 1,593 subjects who completed the questionnaire and underwent pure tone audiometry, the prevalence of tinnitus was 46.0% and that of severe tinnitus was 9.1%. Tinnitus was associated with age, female gender, history of ear infection and sinusitis, leisure noise exposure due to karaoke and local-area-network gaming, alcohol consumption, and cigarette smoking. Noticeable hearing loss was not detected but participants with tinnitus complained of difficulty with sound localization, hearing in noise, and verbal working memory and were more susceptible to fatigue. The subjects with tinnitus also suffered more physical and mental health problems than did those without tinnitus. Thus, protection of the ears from noise and appropriate counseling should be considered for adolescents with tinnitus. [ABSTRACT FROM AUTHOR]

Background: Ambient fine particulate matter is a rising concern for global public health. It was recently suggested that exposure to fine particulate matter may contribute to the development of diabetes and dyslipidaemia. This study aims to examine the potential associations of ambient particulate matter exposure with changes in fasting glucose and lipid profiles in Koreans.Method: We used the data from the National Health Insurance Service-National Sample Cohort (NHIS-NSC), a nationwide database representative of the Korean population. A total of 85,869 individuals aged ≥20 years were included. Multiple regression analyses were conducted to assess the associations between exposure to particulate matter and changes in fasting glucose and lipid profiles at 2-year intervals after adjusting for confounders.Results: Significant associations were observed between an increase in interquartile range for particulate matter < 2.5 μm in diameter (PM2.5) and elevated levels of fasting glucose and low-density lipoprotein cholesterol (p for trend = 0.015 and 0.010, respectively), while no association for particulate matter sized 2.5-10 μm in diameter (PM10-2.5) was noted after adjusting for the other covariates. Sub-group analyses showed stronger associations in individuals who were older (≥60 years) or physically inactive.Conclusions: Fine particulate matter exposure affects worsening fasting glucose and low-density lipoprotein cholesterol levels, with no evidence of an association for coarse particulate matter. [ABSTRACT FROM AUTHOR]

In 2016, South Korea experienced extremely high temperatures and the Korea Centre for Disease Control and Prevention (KCDC) reported 17 heat-caused deaths during these heat waves, most due to heat stroke. Because the reported number of heat-caused deaths is only part of the total deaths associated with heat waves, we aimed to estimate attributable deaths during heat wave episodes. We linked mortality to meteorological data in 16 regions in South Korea and estimated relative risk at or above threshold of maximum temperature during summer using generalized linear regression models after controlling for confounders. We computed overall, age-, sex-, and cause-specific attributable deaths from 2006 to 2017. With a 1.5% increase in all-cause mortality per 1 °C increase in concurrent days' maximum temperature during summer, this study estimates a total of 1440 all-cause deaths associated with heat waves during the 2006–2017 study period in South Korea. We estimate that 343 deaths in 2016 can be ascribed to heat waves, which is approximately 20 times more than the number reported by the KCDC (17 heat-caused deaths). This study addresses attributable heat wave deaths in South Korea and illustrates that the reports of medically classified heat-caused deaths seriously underestimate the number of deaths attributable to heat waves. Our findings may enable the implementation and reinforcement of government- and individual-level management strategies for heat waves. [ABSTRACT FROM AUTHOR]

It is often difficult for standard blood banks in Korea to supply adequate amounts of blood for patients with rare phenotype. Moreover, the definition of a blood in need is ambiguous, and much remains to be learned. In this study, we determined the prevalence of various red blood cell (RBC) antigens from a donor viewpoint and estimated the demand for specific antigen-negative blood from a patient viewpoint. Our data will aid the establishment of a Rare Blood Program in Korea (KRBP). RBC genotyping of 419 blood donors was performed using a Lifecodes RBC/RBC-R typing kit (Immucor, Norcross, GA). A national recipient registry website has been established. Each hospital-based blood bank voluntarily enters data on antibodies detected and identified and the outcomes of specific antigen testing. We calculated the availabilities of specific antigen-negative blood components based on these registry data and predicted the prevalence of RBC antigens via RBC genotyping. The prevalences of various RBC antigens in the D-negative population were determined for the first time, and the Cartwright, Scianna, Dombrock, Colton, Landsteiner-Wiener, Cromer, and Knops blood group systems were identified. The availabilities of specific antigen-negative units differed when calculations were based on serotyping or genotyping, especially in the D-negative group. Data on the prevalences of various blood antigens are essential for estimating the availabilities of blood components that are appropriate for use by patients expressing relevant antibodies. Then, blood banks would be able to efficiently supply safe blood products. [ABSTRACT FROM AUTHOR]

Objectives: This study was conducted to establish the Korean national registry, to evaluate the distribution of unexpected antibodies, and to determine the frequencies of specific antigen-negative blood units.Methods: Data added to the Korean national registry between July 2013 and April 2016 were analyzed. The distribution of unexpected antibodies and frequencies of specific antigen-negative blood units were estimated.Results: In total, 3,513 cases from 22 institutes were registered. The most common single alloantibodies were anti-E, anti-Lea, and anti-M. The most common multiple alloantibodies were anti-E with anti-c, anti-C with anti-e, and anti-Lea with anti-Leb. The frequencies of E-, Lea-, and M-negative units were 42.3%, 56.9%, and 20.2%, respectively.Conclusions: The distribution of unexpected antibodies and frequencies of specific antigen-negative blood units were investigated using data from the Korean national registry. The results provide useful data to predict the number of blood units to be tested to obtain compatible blood units. [ABSTRACT FROM AUTHOR]

Background: While controversies on limitation of coverage by the national health insurance and relatively high direct or “out-of-pocket” household payments by the national health insurance in South Korea still remain, potential unfavorable influence of the insufficiency of the universal health coverage on depression has not yet been evaluated. Methods and findings: Baseline information were obtained from a community cohort (The Korean Genome and Epidemiology Study) of middle-aged subjects without depression at enrollment period (2001–2002). Subjects were followed-up biennially, and new onset depression was assessed using Becks Depression Inventory at 2nd round follow-up (2005–2006). Influence of direct medical expenditure on depression onset was investigated in all subjects and in stratified groups of different income level. Increasing risk of depression onset was observed for increased medical expenditure (OR [95% CI];1.44 [0.97–2.13], 1.90 [1.19–3.05], 1.71 [1.01–2.91] for spending <50000 KRW, 50000–100000 KRW, and ≥100000 KRW, respectively, vs. almost no expenditure per month; P for trend = 0.012), after adjusting for covariates such as monthly income and chronic disease history. Similar associations were observed in subjects less than or at average national income, but results were not significant in subgroup with monthly income above national average. Conclusions: Even with the universal coverage, high co-payments and uninsured services in the Korean health insurance system yet possibly make the insured pay much for medical service utilization. This might have led to onset of an unfavorable health condition such as depression. [ABSTRACT FROM AUTHOR]

Background: Prenatal and postnatal exposure to bisphenol A (BPA) may affect early brain development. Rodent studies suggest that prenatal and postnatal neurodevelopmental toxicity from BPA exposure may manifest as social deficits in offspring. We investigated the association between prenatal and postnatal exposure to BPA and social impairments in a sample of 4-year-old children.Methods: We recruited second-trimester pregnant women between 2008 and 2011, and measured their creatinine-adjusted prenatal urine BPA levels. In 2014-2015, a subset of 4-year-old children born to these women underwent neurobehavioral assessment and physical examination. We collected urine and blood from the children and assessed social impairments, including deficits in social interaction, social communication, and other behavior patterns using the Korean version of the Social Communication Questionnaire (K-SCQ) (n = 304). We examined social impairments associated with prenatal exposure at mid-term pregnancy and postnatal exposure to BPA at 4 years of age, using linear and piecewise linear regression models.Results: The relationship between prenatal BPA exposure and social communication was non-linear and statistically significant at or above the flexion point for BPA levels of 3.0 μg/g creatinine in girls (58.4%, 95% confidence interval [CI], 6.5% to 135.8%). Each 2-fold increase in postnatal BPA exposure was significantly associated with an 11.8% (95% CI, 0.6% to 24.3%) increase in impairment in social communication in 4-year old girls, as indicated by the linear regression model.Conclusion: Prenatal and postnatal BPA exposure is associated with social impairment at 4 years of age, particularly in girls. [ABSTRACT FROM AUTHOR]

Background: Mercury is a toxic heavy metal and is known to affect many diseases. However, few studies have examined the effects of mercury exposure on liver function in the general population. We examined the association between blood mercury concentrations and liver enzyme levels in the elderly.Methods: We included 560 elderly participants (60 years or older) who were recruited from 2008 to 2010 and followed up to 2014. Subjects visited a community welfare center and underwent a medical examination and measurement of mercury levels up to five times. Analyses using generalized estimating equations model were performed after adjusting for age, sex, education, overweight, alcohol consumption, smoking, regular exercise, high-density lipoproteins cholesterol, and total calorie intake. Additionally, we estimated interaction effects of alcohol consumption with mercury and mediation effect of oxidative stress in the relationship between mercury levels and liver function.Results: The geometric mean (95% confidence interval (CI)) of blood mercury concentrations was 2.81 μg/L (2.73, 2.89). Significant relationships were observed between blood mercury concentrations and the level of liver enzymes, including aspartate aminotransferase (AST), alanine aminotransferase (ALT), and gamma glutamyl transferase (GGT), after adjusting for potential confounders (P < 0.05). The odds ratios of having abnormal ALT levels were statistically significant in the highest mercury quartile compared to those with the lowest quartile. Particularly, regular alcohol drinkers showed greater effect estimates of mercury on the liver function than non-drinkers groups. There was no mediation effect of oxidative stress in the relationship between blood mercury concentrations and liver function.Conclusions: Our results suggest that blood mercury levels are associated with elevated liver enzymes and interact with alcohol consumption for the association in the elderly. [ABSTRACT FROM AUTHOR]

Background: To verify oxidative stress as a possible mechanism that establishes a relationship between exposure to bisphenol A (BPA) and adverse health outcomes in the elderly Korean population, we evaluated the relation between visit-to-visit variations in urinary BPA and oxidative stress biomarker.Methods: To assess the relation between BPA and urinary malondialdehyde (MDA) as an oxidative stress biomarker, we used a mixed effect model after controlling for age, sex, BMI, drinking status, exercise, urinary cotinine level, PM10 on lag day 2, and mean temperature and dew point on the day. The relation between exposure to BPA and MDA level by sex of participants and polymorphisms of oxidative stress-related genes (COX2, EPHX1, HSP70-hom, PON1, eNOS, CAT, DRD2, SOD2, and MPO) was also evaluated.Results: A significant association was found for BPA with MDA in both male and female elderly participants (male, β = 0.19 and p = 0.0003; female, β = 0.18 and p < .0001; and total, β = 0.18 and p < .0001). Furthermore, the association of BPA with MDA was found regardless of any genotype of the nine oxidative stress-related genes.Conclusions: The results of our study suggest a strong association of BPA with oxidative stress, not related with sex and oxidative stress-related gene polymorphisms. [ABSTRACT FROM AUTHOR]

Human papillomavirus (HPV) infection is an important etiologic factor in cervical carcinogenesis. Various HPV DNA detection methods have been evaluated for clinicopathological level. For the specimens with normal cytological finding, discrepancies among the detection methods were frequently found and adequate interpretation can be difficult. 6,322 clinical specimens were submitted and evaluated for real-time PCR and Hybrid Capture 2 (HC2). 573 positive or “Not Detected but Amplified” (NDBA) specimens by real-time PCR were additionally tested using genetic analyzer. For the reliability of real-time PCR, 325 retests were performed. Optimal cut-off cycle threshold (CT) value was evaluated also. 78.7% of submitted specimens showed normal or nonspecific cytological finding. The distributions of HPV types by real-time PCR were not different between positive and NDBA cases. For positive cases by fragment analysis, concordance rates with real-time PCR and HC2 were 94.2% and 84.2%. In NDBA cases, fragment analysis and real-time PCR showed identical results in 77.0% and HC2 revealed 27.6% of concordance with fragment analysis. Optimal cut-off CT value was different for HPV types. NDBA results in real-time PCR should be regarded as equivocal, not negative. The adjustment of cut-off CT value for HPV types will be helpful for the appropriate result interpretation. [ABSTRACT FROM AUTHOR]

Background: Although biologically plausible, few studies have linked cadmium exposure to depression or muscle strength. Herein, we hypothesized that blood cadmium concentrations are associated with depression and lower handgrip strength in a community-dwelling elderly population.Methods: Data from 983 elderly participants who completed up to 3 surveys between 2012 and 2015 were analyzed. At every survey, we assessed depressive status using the Korean version of the Geriatric Depression Scale-Short Form (SGDS-K) and measured handgrip strength and blood cadmium levels (mean, 1.24 μg/L). We evaluated the associations of cadmium with depression using generalized linear mixed models, and handgrip strength using linear mixed models. All models were adjusted for sociodemographic factors, lifestyle factors including active and passive smoking, weight, height, and comorbidity status.Results: Interquartile-range increase (0.645 μg/L) in blood cadmium levels was associated with depression defined as SGDS-K score ≥8 (odds ratio = 1.27, 95% confidence interval: 1.06, 1.52) and lower handgrip strength (right hand: β = -0.40, 95% confidence interval: -0.75, -0.09; left hand: β = -0.36, 95% confidence interval: -0.69, -0.04). The association between cadmium levels and handgrip strength was robust after further adjustment for depressive status, although it attenuated in size by 14.7%-18.0%.Conclusions: After adjusting for potential confounders, blood cadmium concentrations were associated with depression and lower handgrip strength in an elderly population. The participants' depressive status partially mediated the association between cadmium levels and handgrip strength. [ABSTRACT FROM AUTHOR]

Objective: Polycyclic aromatic hydrocarbons (PAH) are common dietary exposures that cross the human placenta and are classified as a probable human carcinogen. The aim of the present study was to investigate the potential impact of exposure to PAH-containing meat consumed during pregnancy on birth outcomes.Design: Prospective birth cohort study. Only non-smoking women with singleton pregnancies, who were free from chronic disease such as diabetes and hypertension, were included in the study. Maternal consumption of PAH-rich meat was estimated through FFQ. Multiple linear regression was used to assess factors related to higher intake and the association between dietary PAH and birth outcomes.Setting: Republic of Korea, 2006-2011.Subjects: Pregnant women (n 778) at 12-28 weeks of gestation enrolled in the Mothers and Children's Environmental Health (MOCEH) study.Results: The multivariable regression model showed a significant reduction in birth weight associated with higher consumption level of foods rich in PAH, such as grilled or roasted meat, during pregnancy (β=-17·48 g, P<0·05 for every 1 point higher in meat score). Further adjusting for biomarkers of airborne PAH did not alter this association. There was no evidence that higher consumption level of PAH-rich meat shortens the duration of gestation (P=0·561). Regression models performed for birth length and head circumference produced negative effects that were not statistically significant.Conclusions: Consumption of higher levels of barbecued, fried, roasted and smoked meats during pregnancy was associated with reduced birth weight. Dietary risk of PAH exposure in Korean women is of concern. [ABSTRACT FROM AUTHOR]

Background: Decreased muscle strength can lead to adverse health outcomes in the elderly. A potential association between phthalate exposure and muscle strength was suggested previously, but has not been investigated directly. We hypothesized that phthalate exposure is associated with lower handgrip strength and that the association is modified by the dietary omega-6 to omega-3 ratio.Methods: We analyzed 1,228 participants (≥60 years of age) recruited in Seoul and Asan, Republic of Korea. The study participants were surveyed up to three times between 2012 and 2015. At every survey, we collected urine samples and measured handgrip strength twice for each hand. The associations between urine phthalate metabolite concentrations and handgrip strength were evaluated using linear mixed models. Based on dietary information from 391 individuals who participated in the first survey in Seoul, we evaluated the heterogeneity of the association for those with high and low omega-6 to omega-3 ratios, using 8.81 (the 75th quantile) as a cutoff value.Results: Log-transformed creatinine-adjusted concentrations of mono-(2-ethyl-5-oxohexyl phthalate (MEOHP), mono-(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP), and mono-n-butyl phthalate (MnBP) were inversely associated with all measured handgrip strengths (β = -0.69 to -0.42, all p-values < 0.05). Associations between phthalate biomarkers and handgrip strength did not differ by sex. When the dietary subgroup was stratified by the omega-6 to omega-3 ratio, the associations were stronger among participants with high ratios.Conclusions: We found inverse associations between phthalate biomarkers and handgrip strength in the elderly; this association was modified by the dietary omega-6 to omega-3 ratio. [ABSTRACT FROM AUTHOR]

Background& Objective: Depression frequently combines with dementia, including early-onset Alzheimer's disease (EOAD). We investigated differences in prevalence and characteristics of depressive symptoms according to dementia severity in EOAD patients.Methods: The 15-item Korean version of the Geriatric Depression Scale (GDS-15) was administered to 412 EOAD patients. Factor analysis was used to assess GDS-15 factor structure. We subdivided participants into three groups by disease severity, then compared the frequencies and scores of individual GDS-15 items and performed logistic regression analysis to assess associations between depressive symptoms and EOAD stage.Results: Factor analysis yielded three factor categories: 1) "hopelessness and ominousness" (symptoms no. 6, 8, 12, 14, 15); 2) "unhappiness and dissatisfaction" (no. 1, 3, 5, 7, 11); and 3) "monotony and lack of energy" (no. 2, 4, 9, 10, 13). Factor 2 depressive symptoms (no. 1, 5, 11) were less common in moderate EOAD. The risk of Factor 1 symptoms: no. 12 (OR, 2.04; 95% CI, 1.19-3.50; p = 0.010) and 14 (OR, 1.84; 95% CI, 1.07-3.16; p = 0.028) was higher in mild than very mild EOAD. The risk of Factor 2 symptoms: no. 9 (OR, 2.69; 95% CI, 1.08-6.71; p = 0.033) and 13 (OR, 2.12; 95% CI, 1.02-4.40; p = 0.043) was higher in moderate than mild EOAD.Conclusion: We confirmed that depressive symptoms differ according to EOAD severity. When assessing depressive symptoms related to dementia progression, we recommend focusing on "hopelessness and ominousness" in very mild EOAD and "unhappiness and dissatisfaction" in mild EOAD. [ABSTRACT FROM AUTHOR]

Staphylococci are the leading cause of nosocomial blood stream infections. Fast and accurate identification of staphylococci and confirmation of their methicillin resistance are crucial for immediate treatment with effective antibiotics. A multiplex real-time PCR assay that targets mecA, femA specific for S. aureus, femA specific for S. epidermidis, 16S rRNA for universal bacteria, and 16S rRNA specific for staphylococci was developed and evaluated with 290 clinical blood culture samples containing Gram-positive cocci in clusters (GPCC). For the 262 blood cultures identified to the species level with the MicroScan WalkAway system (Siemens Healthcare Diagnostics, USA), the direct real-time PCR assay of positive blood cultures showed very good agreement for the categorization of staphylococci into methicillin-resistant S. aureus (MRSA), methicillin-susceptible S. aureus (MSSA), methicillin-resistant S. epidermidis (MRSE), methicillin-susceptible S. epidermidis (MSSE), methicillin-resistant non-S. epidermidis CoNS (MRCoNS), and methicillin-susceptible non-S. epidermidis CoNS (MSCoNS) (κ=0.9313). The direct multiplex real-time PCR assay of positive blood cultures containing GPCC can provide essential information at the critical point of infection with a turnaround time of no more than 4 h. Further studies should evaluate the clinical outcome of using this rapid real-time PCR assay in glycopeptide antibiotic therapy in clinical settings. [ABSTRACT FROM AUTHOR]

Purpose: There is limited evidence whether environmental exposure to perfluorinated compounds (PFCs) affects insulin resistance (IR) and whether vitamin C intake protects against the adverse effect of PFCs. This study was carried out to investigate the effect of PFCs on IR through oxidative stress, and the effects of a 4-week consumption of vitamin C supplement compared placebo on development of IR by PFCs. Methods: For a double-blind, community-based, randomized, placebo-controlled crossover intervention of vitamin C, we assigned 141 elderly subjects to both vitamin C and placebo treatments for 4 weeks. We measured serum levels of PFCs to estimate PFC exposures and urinary levels of malondialdehyde (MDA) and 8-hydroxy-2′-deoxyguanosine (8-OHdG) for oxidative stress. We also measured levels of fasting glucose and insulin and derived the homeostatic model assessment (HOMA) index to assess IR. Results: Perfluorooctane sulfonate (PFOS) and perfluorododecanoic acid (PFDoDA) levels were found to be positively associated with HOMA index at the baseline and after placebo treatment. Risks of IR for the top decile of PFOS and PFDoDA exposures were significantly elevated compared with those with lower PFOS and PFDoDA exposures (both, P < 0.0001). However, the effects of PFOS and PFDoDA on HOMA disappeared after vitamin C supplementation (both, P > 0.30). Furthermore, PFOS and PFDoDA levels were also significantly associated with MDA and 8-OHdG levels, and MDA levels were positively associated with HOMA index. Conclusion: PFOS and PFDoDA exposures were positively associated with IR and oxidative stress, and vitamin C supplementation protected against the adverse effects of PFOS and PFDoDA on IR. [ABSTRACT FROM AUTHOR]

Background: Birth defects are a leading cause of neonatal and infant mortality, and several studies have indicated an increase in the prevalence of birth defects; more recent investigations have suggested that the trends of some defects are increasing in rapidly industrialized areas. This study estimates the prevalence rate and types of birth defects in Korea.Methods: This study used medical insurance benefit data of 403,250 infants aged less than one year from the National Health Insurance Corporation from seven metropolitan areas in Korea for 2009 and 2010.Results: The prevalence rate of birth defects was 548.3 per 10,000 births (95% CI: 541.1-555.6), 306.8 among boys and 241.5 among girls. Anomalies of the circulatory system (particularly septal defects) were the most common (180.8 per 10,000), followed by defects of the genitourinary tract (130.1 per 10,000) (particularly obstructive genitourinary and undescended testis), musculoskeletal system (105.7 per 10,000), digestive system (24.7 per 10,000), and central nervous system (15.6 per 10,000).Conclusions: Relatively higher rates of some birth defects were found in the metropolitan areas. The high differences of birth prevalences for septal heart defects and undescended testis are probably due in part to progress in clinical management and more frequent prenatal diagnosis. Environmental exposure might play a critical role in the development of some birth defects. In attempting to describe the prevalence and spatio-temporal variations of birth defects in Korea, establishment of a registry system of birth defects and environmental surveillance are needed. [ABSTRACT FROM AUTHOR]

Oak tree death caused by symbiosis of an ambrosia beetle, Platypus koryoensis, and an ophiostomatoid filamentous fungus, Raffaelea quercus-mongolicae, has been a nationwide problem in Korea since 2004. In this study, we surveyed the yeast species associated with P. koryoensis to better understand the diversity of fungal associates of the beetle pest. In 2009, a total of 195 yeast isolates were sampled from larvae and adult beetles (female and male) of P. koryoensis in Cheonan, Coyang, and Paju; 8 species were identified by based on their morphological, biochemical and molecular analyses. Meyerozyma guilliermondii and Candida kashinagacola were found to be the two dominant species. Among the 8 species, Candida homilentoma was a newly recorded yeast species in Korea, and thus, its mycological characteristics were described. The P. koryoensis symbiont R. quercusmongolicae did not show extracelluar CM-cellulase, xylanase and avicelase activity that are responsible for degradation of wood structure; however, C. kashinagacola and M. guilliermondii did show the three extracellular enzymatic activities. Extracelluar CMcellulase activity was also found in Ambrosiozyma sp., C. homilentoma, C. kashinagacola, and Candida sp. Extracelluar pectinase activity was detected in Ambrosiozyma sp., C. homilentoma, Candida sp., and M. guilliermondii. All the 8 yeast species displayed compatible relationships with R. quercus-mongolicae when they were co-cultivated on yeast extract-malt extract plates. Overall, our results demonstrated that P. koryoensis carries the yeast species as a symbiotic fungal associate. This is first report of yeast diversity associated w ith P koryoensis. [ABSTRACT FROM AUTHOR]

Background: Spontaneous abortion (SA) affects 11.2% of recognized pregnancies in Korea. Many studies have focused on the increased risk of SA in obese populations, but there are few studies that have focused on underweight (Body mass index (BMI) <18.5 kg/m2) women, especially in relation to pre-pregnancy BMI. The aim of this study was to examine the role of pre-pregnancy BMI at age 18-20 in later SA.Methods: Among the women who were ever pregnant in the Health Examinees Study (HEXA), which was one of the cohorts studied in the KoGES (Korean Genome and Epidemiology Study) from 2004 to 2012 (N = 80,447), the likelihood of SA based on pre-pregnancy BMI, classified by the criteria for Asians (Underweight: <18.5 kg/m2; Normal range: 18.5-22.9 kg/m2; Overweight at risk: 23-24.9 kg/m2; Obese I: 25-29.9 kg/m2; Obese II: ≥30 kg/m2), was presented as odds ratios (ORs) and 95% confidence intervals (95% CIs) using logistic regression models.Results: Being underweight or obese relative to the normal weight range was associated with a higher likelihood of SA (OR = 1.10 [95% CI = 1.05-1.15] in underweight women and OR = 1.06 [95% CI = 0.96-1.16] in obese women), and this effect was much greater in women who experienced recurrent SAs (for three or more SAs: OR = 1.29 [95% CI 1.14-1.46] in underweight women and OR = 1.39 [95% CI 1.09-1.78] in obese women). Obesity was associated with an increased likelihood of SA at a younger age (≤25 years), whereas underweight was associated with an increased OR of SA at an older age (≥26 years).Discussion: As this study was conducted with baseline data of original cohort which focused on other chronic diseases, recall for previous pregnancy-related information might be less accurate. However, this study shows strength in its large size and prospective potential.Conclusions: Pre-pregnancy BMI at ages 18-20 years revealed a U-shaped association with SA, and underweight and obese women showed increased likelihood for SA during different age periods. [ABSTRACT FROM AUTHOR]

Background/Aims: The aims of this study were to determine baseline factors related to the progression of subjective memory impairment (SMI) in elderly subjects and to develop a new modeling scale to predict progression. Methods: Elderly subjects with SMI were recruited from the nationwide Clinical Research Centers for Dementia of South Korea (CREDOS) multicenter cohort and divided into two groups: (1) progressed to mild cognitive impairment or Alzheimer's disease or (2) stable without progression. Baseline clinical characteristics were compared between the groups, and the most relevant predictors of progression were assessed. A new modeling scale combining the predictors was developed. Results: In total, 129 subjects with SMI were analyzed. The follow-up duration was 0.5-4.7 years, and the median time to event was 3.64 years. The progressing group (n = 29) differed from the stable group (n = 100) in terms of baseline age, apolipoprotein E4 (APOE4) status, and some cognitive domains. Older age, a lower Mini-Mental State Examination recall score, APOE4 carrier, and a lower verbal delayed recall score were the most relevant predictors of progression, and a new modeling scale with these 4 predictors provided a better explanation of progression. Conclusion: SMI subjects with a higher risk of progression can be identified using a new modeling scale and might need further evaluations and more frequent follow-up. © 2015 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

BACKGROUND: Manganese is an essential trace element and common component of water, soil, and air. Prenatal manganese exposure may affect fetal and infantile neurodevelopment, but reports on in utero manganese exposure and infant neurodevelopment are rare. OBJECTIVE: This study was conducted to investigate a relationship between maternal blood manganese level and neurodevelopment of infants at 6 months of age. METHODS: Data were obtained from the Mothers and Children's Environmental Health (MOCEH) birth cohort study. The study population included 232 pairs of pregnant women and their infants at 6 months of age. Maternal blood manganese was measured at term, just before delivery. Mental and psychomotor development in infancy was assessed at 6 months of age using the Bayley Scales of Infant Development. The relationship between maternal blood manganese level and the mental and psychomotor development indexes (MDI and PDI) was estimated for manganese modeled as a linear and as a categorical variable and using penalized splines for nonlinear modeling. RESULTS: Mean ± SD maternal blood manganese concentration was 22.5 ± 6.5 µg/L. After adjustment for potential confounders, blood manganese was used as a continuous variable in a linear and nonlinear model. Associations between maternal blood manganese and MDI and PDI scores followed an inverted U-shape dose--response curve after adjustment for potential confounders, with lower scores associated with both low and high blood concentrations [MDI: likelihood-ratio test (LRT)p = 0.075, PDI: LRTp = 0.038]. Associations of both outcomes with increasing blood manganese shifted from positive to negative at concentrations of 24--28 µg/L in this cohort of term, normal birth weight children. CONCLUSION: Although no cut-off point has been established to define manganese toxicity, both high and low blood manganese levels may be associated with neurobehavioral function in infants. [ABSTRACT FROM AUTHOR]

Background: Low-level environmental exposure to lead has been associated with both reduced intelligence and symptoms of attention deficit/hyperactivity disorder (ADHD). However, few studies have estimated the association of lead and intelligence independent of ADHD, and it is not clear from previous studies whether lead is associated with both inattention and impulsivity ADHD symptoms. Objectives: We estimated mutually adjusted associations of environmental lead exposure with both intelligence and ADHD symptoms, and associations between lead and specific ADHD-related domains. Methods: Blood lead concentrations were measured in a general population of 1,001 children 8–11 years of age. We used multivariable linear regression models to estimate associations of blood lead concentrations with IQ scores, teacher and parent ratings of ADHD symptoms, and measures of inattention and impulsivity. Models were adjusted for demographic variables and other environmental exposures (blood levels of mercury and manganese, urinary concentrations of cotinine, phthalate metabolites, and bisphenol A). Results: Associations of blood lead with lower IQ and higher impulsivity were robust to adjustment for a variety of covariates. When adjusted for demographic characteristics, other environmental exposures, and ADHD symptoms or IQ, a 10-fold increase in blood lead concentration was associated with lower Full-Scale IQ (–7.23; 95% CI: –13.39, –1.07) and higher parent- and teacher-rated hyperactivity/impulsivity scores (ADHD Rating Scale, 1.99; 95% CI: 0.17, 3.81 and 3.66; 95% CI: 1.18, 6.13, respectively) and commission errors (Continuous Performance Test, 12.27; 95% CI: –0.08, 24.62). Blood lead was not significantly associated with inattention in adjusted models. Conclusions: Low-level lead exposure was adversely associated with intelligence in school-age children independent of ADHD, and environmental lead exposure was selectively associated with impulsivity among the clinical features of ADHD. [ABSTRACT FROM AUTHOR]

During the growing season of 2015, leaf specimens with yellow rust spots were collected from Salix koreensis Andersson, known as Korean willow, in riverine areas in Cheonan, Korea. The fungus on 5. koreensis was identified as the rust species, Melampsora yezoensis, based on the morphology of urediniospores observed by light and scanning electron microscopy, and the molecular properties of the internal transcribed spacer rDNA region. Pathogenicity tests confirmed that the urediniospores are the causal agent of the rust symptoms on the leaves and young stems of S. koreensis. Here, we report a new rust disease of 5. koreensis caused by the rust fungus, M. yezoensis, a previously unrecorded rust pathogen in Korea. [ABSTRACT FROM AUTHOR]

Objective To evaluate the association between long working hours and risk of coronary heart disease (CHD) estimated by Framingham risk score (FRS) in Korean adults. Methods This study evaluated adult participants in Korean National Health and Nutrition Examination Survey IV (2007-2009). After inclusion and exclusion criteria were applied, the final sample size for this study model was 8,350. Subjects were asked about working hours and health status. Participants also completed physical examinations and biochemical measurement necessary for estimation of FRS. Multiple logistic regression was conducted to investigate the association between working hours and 10-year risk for CHD estimated by FRS. Results Compared to those who work 31-40 hr, significantly higher 10-year risk was estimated among subjects working longer hours. As working hours increased, odds ratio (OR) for upper 10 percent of estimated 10-year risk for CHD was increased up to 1.94. Conclusions Long working hours are significantly related to risk of coronary heart disease. Am. J. Ind. Med. 57:1227-1234, 2014. © 2014 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Background: Although the effect of air pollution on various diseases has been extensively investigated, few studies have examined its effect on depression. Objectives: We investigated the effect of air pollution on symptoms of depression in an elderly population. Methods: We enrolled 537 participants in the study who regularly visited a community center for the elderly located in Seoul, Korea. The Korean version of the Geriatric Depression Scale-Short Form (SGDS-K) was used to evaluate depressive symptomatology during a 3-year follow-up study. We associated ambient air pollutants with SGDS-K results using generalized estimating equations (GEE). We also conducted a factor analysis with items on the SGDS-K to determine which symptoms were associated with air pollution. Results: SGDS-K scores were positively associated with interquartile range (IQR) increases in the 3-day moving average concentration of particulate matter with an aerodynamic diameter ≤10 µm (PM10) [17.0% increase in SGDS-K score, 95% confidence interval (CI): 4.9%, 30.5%], the 0-7 day moving average of nitrogen dioxide [NO2; 32.8% (95% CI: 12.6%, 56.6%)], and the 3-day moving average of ozone [O3; 43.7% (95% CI: 11.5%, 85.2%)]. For these three pollutants, factor analysis showed that air pollution was more strongly associated with emotional symptoms such as feeling happy and satisfied than with somatic or affective symptoms. Conclusions: Our study suggests that increases in PM10, NO2, and O3 may increase depressive symptoms among the elderly. Of the symptoms evaluated, ambient air pollution was most strongly associated with emotional symptoms. [ABSTRACT FROM AUTHOR]

A Mariannaea fungus was isolated during investigation of an elm tree infested with unidentified beetles. Based on morphological characteristics and molecular analysis of the internal transcribed spacer rDNA sequence, the fungus was identified as Mariannaea elegans var. elegans. Fungal growth was better on malt extract agar than on potato dextrose agar and oatmeal agar. Optimal temperature and pH for growth of the fungus were 30°C and pH 7.0, respectively. The fungus was found to have the ability to produce extracellular enzymes such as amylase, β-glucosidase, cellulase, and protease. This is first report on M. elegans var. elegans in Korea. [ABSTRACT FROM AUTHOR]

Background: Concern over phthalates has emerged because of their potential toxicity to humans. Objective: We investigated the relationship between the urinary concentrations of phthalate metabolites and children's intellectual functioning. Methods: This study enrolled 667 children at nine elementary schools in five South Korean cities. A cross-sectional examination of urine phthalate concentrations was performed, and scores on neuropsychological tests were obtained from both the children and their mothers. Results: We measured mono-2-ethylhexyl phthalate (MEHP) and mono(2-ethyl-5-oxohexyl) phthalate (MEOHP), both metabolites of di(2-ethylhexyl)phthalate (DEHP), and mono-nbutyl phthalate (MBP), a metabolite of dibutyl phthalate (DBP), in urine samples. The geometricmean (ln) concentrations of MEHP, MEOHP, and MBP were 21.3 μg/L [geometric SD (GSD) = 2.2 μg/L; range, 0.5-445.4], 18.0 μg/L (GSD = 2.4; range, 0.07-291.1), and 48.9 μg/L (GSD = 2.2; range, 2.1-1645.5), respectively. After adjusting for demographic and developmental covariates, the Full Scale IQ and Verbal IQ scores were negatively associated with DEHP metabolites but not with DBP metabolites. We also found a significant negative relationship between the urine concentrations of the metabolites of DEHP and DBP and children's vocabulary subscores. After controlling for maternal IQ, a significant inverse relationship between DEHP metabolites and vocabulary subscale score remained. Among boys, we found a negative association between increasing MEHP phthalate concentrations and the sum of DEHP metabolite concentrations and Wechsler Intelligence Scale for Children vocabulary score; however, among girls, we found no significant association between these variables. Conclusion: Controlling for maternal IQ and other covariates, the results show an inverse relationship between phthalate metabolites and IQ scores; however, given the limitations in crosssectional epidemiology, prospective studies are needed to fully explore these associations. [ABSTRACT FROM AUTHOR]

Genetic polymorphisms involved in the activation and detoxification of exogenous chemicals and in the production and scavenging of reactive oxygen species may modulate the levels of oxidative injury biomarker. We investigated 81 pregnant women in Inchon, Korea. In addition to a questionnaire survey, urinary concentrations of 8-hydroxydeoxyguanosine (8-OH-dG) and malondialdehyde (MDA) were measured as oxidative injury biomarkers. Cytochrome P-450(CYP)1A1, CYP2E1, glutathione S-transferase (GST)M1 and GSTT1 polymorphisms and myeloperoxidase (MPO) and manganese superoxide dismutase (MnSOD) polymorphisms were evaluated to determine the effect of genetic modification on urinary 8-OH-dG and MDA. The concentrations of urinary 8-OH-dG were significantly elevated in the presence of the MnSOD variant genotype (P=0.04) and in the case of GSTM1 null status (P=0.02) by multivariate regression. The concentrations of urinary MDA were not affected significantly by the genetic polymorphisms. This result shows that oxidative stress injury is modified by some heritable polymorphisms, including GSTM1 and MnSOD. [Copyright &y& Elsevier]

Describes the incongruous beginnings of modern philosophy in Korea initiated by philosopher Pak Chong-hong. Background on Pak Chong-hong; Important events in Pak's academic development; Specific characteristic of Pal's philosophy; Scientific effort to systematically construct philosophy and philosophical confrontation with reality; Pak's trial to connect himself to modernity.

Long-term air pollution exposure has been suggested to increase the risk of attention-deficit/hyperactivity disorder (ADHD). However, the association between short-term air pollution exposure and ADHD-related outcomes is still unknown. We investigated the associations between short-term exposure to particulate matter with an aerodynamic diameter ≤10 μm (PM 10), nitrogen oxide (NO 2), and sulfur dioxide (SO 2) and hospital admissions with a principal diagnosis of ADHD among adolescents (age 10–19 years) in 16 regions of the Republic of Korea from 2013 to 2015. We estimated the region-specific relative risks (RRs) and 95% confidence intervals (CIs) from quasi-Poisson regressions adjusted for potential confounders, considering single-day and moving average lag. Consequently, we performed meta-analyses to pool the region-specific estimates. The risks of ADHD-related hospital admissions were increased in the single-day and moving average lag models for PM 10 (largest association for lag 1 in the single-day lag model, RR = 1.12, 95% CI: 1.05, 1.20; lag 0–2 in the moving average lag model, RR = 1.17, 95% CI: 1.07, 1.27), NO 2 (lag 3, RR = 1.47, 95% CI: 1.25, 1.73; lag 1–3, RR = 1.68, 95% CI: 1.38, 2.04), and SO 2 (lag 1, RR = 1.27, 95% CI: 1.14, 1.41; lag 1–3, RR = 1.29, 95% CI: 1.12, 1.49). The associations were similar between boys and girls, but they were stronger among adolescents aged 15–19 years than those aged 10–14 years for NO 2 and SO 2. In conclusion, the results indicate that short-term exposure to PM 10 , NO 2 , and SO 2 may be a risk factor for the exacerbation of ADHD symptoms, leading to hospitalization. Image 1 • We performed time-series analyses using nationwide time-series data of adolescents. • Short-term air pollution exposure is associated with ADHD-related hospitalization. • The association is similar between boys and girls. • The association is stronger in those aged 15–19 years than those aged 10–14 years. • Short-term air pollution exposure may aggravate ADHD symptoms. [ABSTRACT FROM AUTHOR]

Background: Hormonal and menstrual factors are known to influence migraines in women. However, studies in the postmenopausal period are relatively insufficient for clinical translation. This study investigated the influence of endogenous and exogenous hormonal factors on migraines in spontaneous menopausal women. Methods: We obtained and analyzed the data related to hormonal factors from the Korean Health Examination database. A migraine diagnosis was identified using the Korean National Health Insurance Service database between 2009 and 2018. We observed migraine occurrence in spontaneous postmenopausal women. Study populations were divided into two groups depending on new diagnosis of migraine during the follow up periods. We investigated the association between endogenous and exogenous hormonal factors and migraine. Results: 1,114,742 spontaneous postmenopausal women were enrolled. Migraine risk tended to increase in the shorter lifetime number of years of menstruation group compared to the group with lifetime number of years of menstruation ≥40 years. All of the hormone replacement therapy (HRT) groups showed higher risk compared with the non-HRT group. Migraine risk tends to increase with greater postmenopausal years compared to the postmenopausal <5 years group. Conclusion: Our study suggests that female hormonal factors, including endogenous and exogenous estrogen exposure, may be associated with migraine occurrence in spontaneous menopausal women. [ABSTRACT FROM AUTHOR]

Introduction: Di(2-ethylhexyl) phthalate (DEHP) is a plasticizer commonly used in blood bags. Despite its protective effects on red blood cell (RBC) storage, concerns about its reproductive toxicity exist. This study investigated the in vitro quality of RBC concentrates stored in bags using di(isononyl) cyclohexane-1,2-dicarboxylate (DINCH) as an alternative plasticizer. Methods: Using a pool-and-split study design, we produced 20 matched homogenous quintets of RBC concentrates in two DINCH bags and three DEHP bags with citrate phosphate dextrose adenine (CPDA-1) anticoagulant. RBC storage quality was assessed weekly for 35 days. Results: On day 35, the median hemolysis levels in the DINCH bags (0.297–0.342%) were marginally higher (p < 0.05) than the DEHP bags (0.204–0.240%). All DINCH bags showed <0.8% hemolysis. RBCs in the DINCH bags showed increased mean corpuscular volume and decreased eosin 5′ maleimide binding than in the DEHP bags. Higher pO2 and lower pCO2 levels in the DINCH bags indicated better gas permeability than in DEHP bags. Other metabolic parameters were comparable in both bags. Compared to DEHP, DINCH exhibited considerably lower levels of plasticizer leaching into blood bags. Conclusion: The quality of RBC concentrates stored for 35 days in DINCH-plasticized blood bags with CDPA-1 is generally comparable to those in DEHP bags. Hence, DINCH can be a viable alternative to DEHP in blood bags for nonleukoreduced RBC storage even without the use of next-generation additive solutions to improve RBC preservation quality. Plain Language Summary: A plasticizer is a chemical substance added to plastic to increase its flexibility. DEHP is a plasticizer that has been widely used in many products including plastic tubing and bags of medical devices. However, concerns about DEHP-related toxicity have been debated for many years. DEHP has been replaced with other plasticizers in many products, but it is still being used in blood bags due to its protective effect on RBC preservation. DINCH is an alternative plasticizer with a low toxicology profile. This study investigated the quality of RBC concentrates stored in blood bags using DINCH. Twenty sets of five RBC concentrates were produced using two DINCH bags and three DEHP bags with CPDA-1 anticoagulant, and the storage quality was assessed weekly for 35 days. On day 35, the median hemolysis levels in the DINCH bags (0.297–0.342%) were slightly increased than the DEHP bags (0.204–0.240%). However, all DINCH bags showed hemolysis lower than the regulatory limit of 0.8%. DINCH bags exhibited better gas permeability than DEHP bags. Compared to DEHP, DINCH exhibited considerably lower levels of plasticizer leaching into blood bags. Most of the other metabolic parameters were comparable in both bags. The quality of nonleukocyte-reduced RBC concentrates stored for 35 days in DINCH-plasticized blood bags with CDPA-1 is generally comparable to those in DEHP bags. Hence, DINCH can be a viable alternative to DEHP in blood bags for RBC storage, even without the use of next-generation additive solutions to improve RBC preservation quality. [ABSTRACT FROM AUTHOR]

Background: Biological measurements have been employed as useful biomarkers for exposure. Because of its property of reflecting toxicokinetic differences, however, within-subject variability leads to biased results in epidemiologic studies.Method: We examined the variability of lead (Pb), mercury (Hg), and cadmium (Cd) levels in blood samples from 1429 participants among 1677 elderly individuals aged over 60 years who lived in an urban area from August 2008 to April 2015.Results: The geometric means of blood Pb, Hg, Cd were 1.92μg/dL, 2.48μg/L, and 1.33μg/L, and the intra-class correlations (ICCs) were 0.81, 0.71, and 0.83, respectively. The mean values of Pb and Hg levels in this study were lower than the results from single spot samples in other national biomonitoring surveys in Korea, with the exception of Cd was higher than those in other studies. Moreover, the predicted exceedances over the guidance levels for Pb, Hg, and Cd were 1.9%, 4.2%, and 0.3%, respectively.Conclusion: Korean elderly were exposed to high levels of Pb, Hg and Cd. Especially, those who had high levels of Cd were continuously exposed to Cd during study period with the 6 collection intervals. Therefore, factors affecting environmental Cd exposure should be further studied in the future. [ABSTRACT FROM AUTHOR]

Although an association of fine particulate matter (PM 2.5) with asthma incidence has been assumed, there is insufficient evidence regarding the effect of long-term exposure to PM 2.5 on incident asthma among elderly adults. This study aimed to investigate an association between long-term exposure to PM 2.5 and incident asthma among elderly adults in South Korea. Adults ≥65 years of age (n = 1,220,645) who did not visit hospitals for asthma during a washout period (between 2008 and 2010) were followed up until 2016 using data from the National Health Insurance System in South Korea. Incident asthma was defined as the number of patients with a primary diagnostic code of asthma who visited hospitals more than twice. We linked the health data with district-level PM 2.5 concentrations and estimated hazard ratios (HRs) and 95% confidence intervals (CIs) for incident asthma after adjusting for potential confounders in time-varying Cox proportional hazard models. Over 5,942,256 person-years, 54,522 patients developed asthma, with an incidence of 9.2 cases/1000 person-years. A 10 μg/m3 increase in the 36-month mean PM 2.5 concentration was significantly associated with a 9% increase in incident asthma (HR = 1.09, 95% CI: 1.04–1.14). This association was found to be robust for different definitions of incident asthma and washout periods. Long-term exposure to PM 2.5 was associated with the incidence of asthma in elderly adults. This finding provides evidence of an association between PM 2.5 and adult-onset asthma. • The association between PM 2.5 and incident asthma in elderly adults is understudied. • We constructed a retrospective cohort with 1,220,645 elderly adults. • Incidence of asthma in elderly adults is associated with long-term exposure to PM 2.5. • Implementing policies for improving ambient air quality is needed for healthy ageing. [ABSTRACT FROM AUTHOR]

• All the reported COVID-19 clusters were identified and categorized in South Korea. • COVID-19 clusters are categorized into large, medium, and small clusters. • Cluster distributions are correlated with the government's social distancing measures. The complete contact tracing of coronavirus disease-19 (COVID-19) cases in South Korea allows a unique opportunity to investigate cluster characteristics. This study aimed to investigate all reported COVID-19 clusters in the Seoul metropolitan area from January 23 to September 24, 2020. Publicly available COVID-19 data was collected from the Seoul Metropolitan City and Gyeonggi Province. Community clusters with ≥5 cases were characterized by size and duration, categorized using K-means clustering, and the correlation between the types of clusters and the level of social distancing investigated. A total of 134 clusters comprised of 4033 cases were identified. The clusters were categorized into small (type I and II), medium (type III), and large (type IV) clusters. A comparable number of daily reported cases in different time periods were composed of different types of clusters. Increased social distancing was related to a shift from large to small-sized clusters. Classification of clusters may provide opportunities to understand the pattern of COVID-19 outbreaks better and implement more effective suppression strategies. Social distancing administered by the government may effectively suppress large clusters but may not effectively control small and sporadic clusters. [ABSTRACT FROM AUTHOR]