Association between urinary arsenic concentration and genetic polymorphisms in Korean adults.

Arsenic (As) is a human carcinogen widely distributed in the environment. This study evaluated the association between the urinary As concentration and single nucleotide polymorphisms (SNPs) in Korean adults to determine the genetic factors related to As concentration. The study included 496 participants for the genome-wide association study (GWAS) and 1483 participants for the candidate gene approach study. Participants were 19 years and older. The concentrations of total As (Tot As) and total As metabolites (Tmet As, the sum of inorganic As and their metabolites; arsenite, arsenate, monomethylarsonic, and dimethylarsinic acid) in the urine were analyzed. The GWAS identified four SNPs (rs1432523, rs3776006, rs11171747, and rs807573) associated with urinary Tot As and four SNPs (rs117605537, rs3776006, rs11171747, and rs148103384) significantly associated with urinary Tmet As concentration (P < 1 × 10-4). The candidate gene study identified two SNPs (PRDX2 rs10427027 and GLRX rs3822751) in genes related to the reduction reaction associated with urinary Tot As and Tmet As. This study suggests that genetic factors may play a role in regulating As metabolism in the human body, affecting both exposure levels and its potential health risks in the general Korean population, even at low exposure levels. Supplementary Information: The online version contains supplementary material available at 10.1007/s43188-023-00216-x.

Impact of Radiofrequency Exposure From Mobile Phones on the Risk of Developing Brain Tumors in Korean and Japanese Adolescents: A MOBI-Kids Case-control Study.

BACKGROUND: This study aimed to examine the association between risk of brain tumors and radiofrequency (RF) exposure from mobile phones among young people in Korea and Japan. METHODS: This case-control study of brain tumors in young people was conducted in Korea and Japan under the framework of the international MOBI-Kids study. We included 118 patients diagnosed with brain tumors between 2011 and 2015 and 236 matched appendicitis controls aged 10-24 years. Information on mobile phone use was collected through face-to-face interviews. A detailed RF exposure algorithm, based on the MOBI-Kids algorithm and modified to account for the specificities of Japanese and Korean phones and networks, was used to calculate the odds ratios (ORs) for total cumulative specific energy using conditional logistic regression. RESULTS: The adjusted ORs in the highest tertile of cumulative call time at 1 year before the reference date were 1.61 (95% confidence interval [CI], 0.72-3.60) for all brain tumors and 0.70 (95% CI, 0.16-3.03) for gliomas, with no indication of a trend with exposure. The ORs for glioma specifically, were below 1 in the lowest exposure category. CONCLUSION: This study provided no evidence of a causal association between mobile phone use and risk of brain tumors as a whole or of glioma specifically. Further research will be required to evaluate the impact of newer technologies of communication in the future.

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

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

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

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

Mediation of daily ambient ozone concentration on association between daily mean temperature and mortality in 7 metropolitan cities of Korea.

BACKGROUND: Climate change is suspected to cause adverse health effects, and increased ozone concentration is one of the proposed pathways. We examined the mediation of ozone on the association between temperature and daily mortality and estimated excess mortality due to climate change. METHODS: Daily mean temperature, 8-hour maximum ozone concentration, and daily number of non-accidental deaths from 7 metropolitan cities in Korea (Seoul, Busan, Daegu, Incheon, Daejeon, Gwangju, and Ulsan) between January 1, 2006 and December 31, 2019 were analyzed. A mediation analysis using a linear regression model for temperature and ozone and a Poisson regression model for temperature and mortality adjusting for ozone was conducted on days with temperature higher than or lower than city specific minimum mortality temperature. We calculated excess mortality due to direct and indirect effects of daily temperature exceeding average daily temperature from 1960 to 1990. RESULTS: The daily mean temperature from 2006 to the end of 2019 was 1.15 ± 2.94 °C higher than the average daily temperature from 1960 to 1990. The pooled relative risk (for a 1 °C increment) of indirect effects through increased ozone were 1.0002 [95% confidence interval (CI): 0.9999, 1.0004] and 1.0003 (95% CI: 1.0002, 1.0005) in days with higher than or lower than minimum mortality temperature, respectively. The numbers of excess deaths during the study period were 2072.5 (95% CI: 1957.1, 2186.5) due to direct effects in days with higher than minimal mortality temperature, and 94.6 (95% CI: 84.3, 101.7) and 268.5 (95% CI: 258.4, 289.1) due to indirect effects in days with higher than and lower than minimal mortality temperature, respectively. CONCLUSION: We observed a mediating effect of ozone between temperature and daily mortality. There has been excess deaths due direct effect of temperature and indirect effects through ozone.

Effects of Environmental Cadmium Exposure on the Liver in Korean Adults: Cross-Sectional and Longitudinal Studies.

Cadmium (Cd) is a ubiquitous environmental pollutant with an exceptionally long biological half-life. The liver is a major organ for Cd metabolism, but the toxicity of Cd is unclear. This study sought to determine whether blood Cd (BCd) level (representing recent exposure [months] to Cd) was associated with liver function in Korean adults, both cross-sectionally and longitudinally. The baseline cross-sectional study involved 2,086 adults (male: 908, female: 1,178) in 2010 - 2011, and 503 of them (male: 207, female: 296) were followed up in 2014 - 2015. BCd was measured by graphite-furnace atomic absorption spectrometry, and liver function indices (aspartate aminotransferase [AST], alanine aminotransferase [ALT], and γ-glutamyltransferase [GGT]) were determined. Liver damage was defined as an abnormal elevation of more than one liver function index. The geometric mean of BCd (1.07 µg/L) was higher in females than in males (1.16 vs. 0.96 µg/L). Liver function indices increased significantly in a dose-dependent manner according to the BCd levels, except for ALT in males, and were higher in males than in females. BCd level was also associated with the risk of liver damage in both sexes. No significant changes in BCd were observed between baseline and follow-up. The liver function indices in 2014 - 2015 were comparable to those in 2010 - 2011 in males, while ALT and GGT were significantly increased in 2014 - 2015 compared to 2010 - 2011 in females with relatively high BCd. These findings suggest that even a low level of environmental Cd exposure, short- and long-term, may affect liver function, and females appear more susceptible than males.

Associations of cold exposure with hospital admission and mortality due to acute kidney injury: A nationwide time-series study in Korea.

BACKGROUND: Emerging evidence supports an association between heat exposure and acute kidney injury (AKI). However, there is a paucity of studies on the association between cold exposure and AKI. OBJECTIVE: We aimed to investigate the associations of cold exposure with hospital admission and mortality due to AKI and to explore whether these associations were influenced by age and sex. METHODS: Information on daily counts of hospital admission and mortality due to AKI in 16 regions of Korea during the cold seasons (2010-2019) was obtained from the National Health Insurance Service (a single national insurer providing universal health coverage) and Statistics Korea. Daily mean temperature and relative humidity were calculated from hourly data obtained from 94 monitoring systems operated by the Korean Meteorological Administration. Associations of low temperatures (<10th percentile of daily mean temperature) and cold spells (≥2 consecutive days with <5th percentile of daily mean temperature) up to 21 days with AKI were estimated using quasi-Poisson regression models adjusted for potential confounders (e.g., relative humidity and air pollutants) with distributed lag models and univariate meta-regression models. RESULTS: Low temperatures were associated with hospital admission due to AKI [relative risk (RR) = 1.12, 95 % confidence interval (CI): 1.09, 1.16]. Cold spells were associated with hospital admission (RR = 1.87, 95 % CI: 1.46, 2.39) and mortality due to AKI (RR = 4.84, 95 % CI: 1.30, 17.98). These associations were stronger among individuals aged ≥65 years than among those aged <65 years. CONCLUSION: Our results underscore the need for the general population, particularly the elderly, physicians, and other healthcare providers to be more vigilant to cold exposure, given the risk of AKI. Government agencies need to develop specific strategies for the prevention and early detection of cold exposure-related AKI.

Associations between Dietary Intake and Attention Deficit Hyperactivity Disorder (ADHD) Scores by Repeated Measurements in School-Age Children.

Attention deficit hyperactivity disorder (ADHD) is a common psychiatric disorder in school-age children and adolescents. However, the reported associations between ADHD and single nutrient intake are inconsistent. The aim of the study was to investigate the relationships between dietary intake changes and the prevalence of ADHD over time with repeat measurements using data from the Children Health and Environment Research (CHEER). To assess changes over time, we used data obtained in 2006 and 2008 (Phases 1 and 2). In this study, there were 2899 children aged 8 years or older in Phase 1 and 2120 children aged 9 years or older in Phase 2 from Korea, and the ADHD scores and dietary intake of 1733 children in Phases 1 and 2 were used in the final analysis. The YN group refers to children whose disease had improved in Phase 2, and the NY group refers to children diagnosed with ADHD in Phase 2. A notable within-group result was the increase in vegetable protein (p = 0.03) in the YN group. A between-group comparison showed that significant changes in nutrient intake could be confirmed most in the NY group, and the YN group tended to have a lower nutrient intake than the NY group. In the correlation of changes in nutrient intake and three subtypes (combined, AD, and HD), the total fat (p = 0.048) and animal protein (p = 0.099) showed a positive correlation with the prevalence of AD. Vegetable iron (p = 0.061 and p = 0.044, respectively), zinc (p = 0.022 and p = 0.007, respectively), vegetable protein (p = 0.074), and calcium (p = 0.057) had inhibitory effects on ADHD and its subtype. In conclusion, management of dietary and nutritional status should be considered to ameliorate ADHD and its subtypes in school-age children, and these relationships require further exploration in other settings.

Associations between cold spells and hospital admission and mortality due to diabetes: A nationwide multi-region time-series study in Korea.

BACKGROUND: Climate change is predicted to increase the frequency, intensity, and duration of extreme cold events in the mid-latitudes. However, although diabetes is one of the most critical metabolic diseases due to its high and increasing prevalence worldwide, few studies have investigated the short-term association between cold exposure and diabetes-related outcomes. OBJECTIVE: The aim of this study was to investigate the associations between cold spells and their characteristics (intensity, duration, and seasonal timing) and hospital admission and mortality due to diabetes. METHODS: This study used claims data from the National Health Insurance Service and cause-specific mortality data from Statistics Korea (2010-2019). Cold spells were defined as ≥2 consecutive days with a daily mean temperature lower than the region-specific 5th percentile during the cold season (November-March). Quasi-Poisson regressions combined with distributed lag models were used to assess the associations between exposures and outcomes in 16 regions across the Republic of Korea. Meta-analyses were conducted to pool the region-specific estimates. RESULTS: Exposure to cold spells was associated with an increased risk of hospital admission [relative risk (RR) = 1.45, 95% confidence interval (CI): 1.26, 1.66] and mortality (RR = 2.02, 95% CI: 1.37, 2.99) due to diabetes. The association between cold spells and hospital admission due to diabetes was stronger for cold spells that were more intense, longer, and occurred later during the cold season. The association between cold spells and diabetes-related mortality was stronger for more intense and longer cold spells. CONCLUSION: This study emphasizes the importance of developing effective interventions against cold spells, including education on the dangers of cold spells and early alarm systems. Further studies are needed to create real-world interventions and evaluate their effectiveness in improving diabetes-related outcomes.

Effect modification of consecutive high concentration days on the association between fine particulate matter and mortality: a multi-city study in Korea.

OBJECTIVES: Although there is substantial evidence for the short-term effect of fine particulate matter (PM2.5) on daily mortality, few epidemiological studies have explored the effect of prolonged continuous exposure to high concentrations of PM2.5. This study investigated how the magnitude of the mortality effect of PM2.5 exposure is modified by persistent exposure to high PM2.5 concentrations. METHODS: We analyzed data on the daily mortality count, simulated daily PM2.5 level, mean daily temperature, and relative humidity level from 7 metropolitan cities from 2006 to 2019. Generalized additive models (GAMs) with quasi-Poisson distribution and random-effects meta-analyses were used to pool city-specific effects. To investigate the effect modification of continuous exposure to prolonged high concentrations, we applied categorical consecutive-day variables to the GAMs as effect modification terms for PM2.5. RESULTS: The mortality risk increased by 0.33% (95% confidence interval [CI], 0.16 to 0.50), 0.47% (95% CI, -0.09 to 1.04), and 0.26% (95% CI, -0.08 to 0.60) for all-cause, respiratory, and cardiovascular diseases, respectively, with a 10 µg/m3 increase in PM2.5 concentration. The risk of all-cause mortality per 10 µg/m3 increase in PM2.5 on the first and fourth consecutive days significantly increased by 0.63% (95% CI, 0.20 to 1.06) and 0.36% (95% CI, 0.01 to 0.70), respectively. CONCLUSIONS: We found increased risks of all-cause, respiratory, and cardiovascular mortality related to daily PM2.5 exposure on the day when exposure to high PM2.5 concentrations began and when exposure persisted for more than 4 days with concentrations of ≥35 µg/m3. Persistently high PM2.5 exposure had a stronger effect on seniors.

Cancer risk in the residents of a town near three industrial waste incinerators in Korea: a retrospective cohort study.

BACKGROUND: Three industrial waste incinerators (IWIs) were built in 1999, 2001, and 2010, within a 3 km radius of a town with a population of around 5000 in Korea. This study evaluated whether residents near these three IWIs had increased cancer incidence than those from other areas in Korea using regional health data. METHODS: Standardized incidence ratios (SIR) were calculated using the frequency of cancer cases in the National Cancer Registry of the exposed area (Buki-myeon), Chungcheongbuk-do (Chungbuk, state including Buki-myeon), and whole Korea from 1999 to 2017. A retrospective cohort was created using National Health Insurance System data from 2002 to 2018. The exposed group was defined as those having a residential history in the exposed area. The control group was defined as those having a residential history in nearby towns or counties in Chungbuk, excluding counties having living and cultural areas in other provinces and cities. Hazard ratio (HR) and 95% confidence intervals (CI) were estimated using the Cox proportional hazard model adjusted for age, level of health insurance fee, and smoking history. RESULTS: In the ecological study using National Cancer Registry data, the risk of all cancers, all cancers excluding thyroid, esophageal, stomach, and lung cancers in the exposed area were 1.13 (95% CI 1.03-1.24), 1.15 (95% CI 1.04-1.26), 1.91 (95% CI 1.13-2.89), 1.39 (95% CI 1.14-1.66), and 1.29 (95% CI 1.03-1.57) times higher than in whole Korea among exposed males, respectively. In the retrospective cohort, 4300 males (26,821 person-years) and 3796 females (24,746 person-years) in exposed group, 150,964 males (1,212,010 person-years) and 134,535 females (1,104,025 person-years) in control group were analyzed. After adjusting for several confounding factors, the risks for gallbladder cancer among males and kidney cancer among females were 2.65 (95% CI 1.38-5.06) and 2.82 (95% CI 1.13-7.03) times higher in the exposed group versus the control group, respectively. CONCLUSIONS: Cancer risk was higher in Koreans having residential history living near IWIs compared to the other areas. Further study warrants nationwide effects and longer follow-up of WIs for cancers in Korea.

Association of indoor and outdoor short-term PM2.5 exposure with blood pressure among school children.

The association between particulate matter and children's increased blood pressure is inconsistent, and few studies have evaluated indoor exposure, accounting for time-activity. The present study aimed to examine the association between personal short-term exposure to PM2.5 and blood pressure in children. We conducted a panel study with up to three physical examinations during different seasons of 2018 (spring, summer, and fall) among 52 children. The indoor PM2.5 concentration was continuously measured at home and classroom of each child using indoor air quality monitors. The outdoor PM2.5 concentration was measured from the nearest monitoring station. We constructed a mixed effect model to analyze the association of short-term indoor and outdoor PM2.5 exposure accounting for time-activity of each participant with blood pressure. The average PM2.5 concentration was 34.3 ± 9.2 µg/m3 and it was highest in the spring. The concentration measured at homes was generally higher than that measured at outdoor monitoring station. A 10-µg/m3 increment of the up to previous 3-day mean (lag0-3) PM2.5 concentration was associated with 2.7 mmHg (95%CI = 0.8, 4.0) and 2.1 mmHg (95%CI = 0.3, 4.0) increases in systolic and diastolic blood pressure, respectively. In a panel study comprehensively evaluating both indoor and outdoor exposures, which enabled more accurate exposure assessment, we observed a statistically significant association between blood pressure and PM2.5 exposure in children.

Exposure Levels and Contributing Factors of Various Arsenic Species and Their Health Effects on Korean Adults.

Arsenic is a human carcinogen. Data on urinary arsenic species analyses of Koreans are limited. This study evaluated the arsenic exposure level, contributing factors, and health effects in Korean adults. Dietary intake information and urine samples were obtained from 2044 participants. Arsenic exposure was assessed based on urinary concentrations of arsenic species, such as inorganic arsenic, As(III) and As(V), monomethylarsonic acid (MMA), dimethylarsinic acid (DMA), and arsenobetaine (AsB), using high-performance liquid chromatography with inductively coupled plasma mass spectrometry, followed by determination of biomarkers, malondialdehyde and c-peptide. The geometric mean concentrations were 30.9 µg/L for the sum of inorganic arsenic and their metabolites, and 84.7 µg/L for the total sum of arsenic measured. Urinary concentrations of arsenic species were influenced by age, inhabitant area (inland or coastal), and seafood intake, which was positively correlated with inorganic arsenic, DMA, and AsB. Rice intake was positively correlated with inorganic arsenic and its metabolites but not with AsB. Additionally, malondialdehyde and c-peptide levels were significantly associated with urinary concentrations of various arsenic species. Seafood and rice are major sources of organic/inorganic arsenic exposure in Korean adults; however, it is necessary to evaluate whether their overconsumption could have a potentially detrimental effect on human health.

Pathogen-specific response of infectious gastroenteritis to ambient temperature: National surveillance data in the Republic of Korea, 2015-2019.

OBJECTIVE: The objective of this study was to investigate the relationship between ambient temperature and common viral and bacterial gastroenteritis in the Republic of Korea, which has a high-income and temperate climate, considering the different lagged effects of each causative pathogen. METHODS: We obtained the number of weekly reported cases of infectious gastroenteritis caused by norovirus, group A rotavirus, enteric adenovirus, Clostridium perfringens, non-typhoidal Salmonella, and Campylobacter between 2015 and 2019 from the Korean Infectious Diseases Sentinel Surveillance System. We obtained weather data from the Korea Meteorological Administration for the same period. Generalized linear models with quasi-Poisson distributions and distributed lag non-linear models were utilized after adjusting for relative humidity, precipitation, long-term trends, and seasonality. We investigated the associations between weekly mean temperature and the weekly number of reported cases of each type of infectious gastroenteritis by applying different maximum lags for each type. RESULTS: Compared with the 50th percentile temperature, the lag-cumulative relative risks (RRs) with 95% confidence intervals (CIs) at the 5th percentile temperature for norovirus gastroenteritis, rotavirus gastroenteritis, adenovirus gastroenteritis were 11.0 (4.7-25.7), 2.7 (1.4-5.2), and 4.7 (1.4-15.8) by applying the maximum lag of 6, 4, and 3 weeks, respectively. Compared with the 50th percentile temperature, the lag-cumulative RRs with 95% CIs at the 95th percentile temperature for C. perfringens gastroenteritis, Salmonella gastroenteritis, and Campylobacter gastroenteritis were 1.2 (0.8-1.9), 3.0 (1.5-6.2), and 2.0 (1.1-3.6), by applying the maximum lag of 2, 3, and 2 weeks, respectively. CONCLUSIONS: Cold temperature increased the risk of viral gastroenteritis and showed relatively long lagged effects. Hot temperature increased the risk of bacterial gastroenteritis and showed relatively short lagged effects.

Associations Between Sleep-Disordered Breathing and Behavioral and Cognitive Functions in Children With and Without Attention-Deficit/Hyperactivity Disorder.

BACKGROUND: Sleep-related problems are highly prevalent comorbidities in Attention-Deficit/Hyperactivity Disorder (ADHD). OBJECTIVE: This study aimed to investigate the associations between sleep-disordered breathing (SDB) and behavioral and cognitive functions in children with and without ADHD. METHODS: A total of 341 children were included (ADHD group: 155, control group: 186; age: 6-10 years). The participants' sleep-related symptoms were assessed using a parent-rated questionnaire, and they were categorized into low- and high-risk SDB groups based on their scores. Behavioral symptoms were assessed using the Behavioral Assessment System for Children, Second Edition (BASC-2), and cognitive sustained attention and inhibitory control were assessed using a computer-based continuous performance test. RESULTS: In the ADHD group, the high-risk SDB children showed significantly higher scores than the low-risk SDB group in externalizing problems (F = 4.22; P = 0.042), including hyperactivity (F = 4.65; P = 0.033) and attention problems (F = 8.19; P = 0.005), but not internalizing problems. Meanwhile, in the control group, the high-risk SDB children showed significantly higher scores than the low-risk SDB group in internalizing problems (F = 9.89; P = 0.002), depression (F = 9.45; P = 0.002), and somatization (F = 7.83; P = 0.006), as well as in externalizing problems (F = 7.72; P = 0.006), including hyperactivity (F = 6.23; P = 0.013), aggression (F = 5.00; P = 0.027), and conduct problems (F = 6.79; P = 0.010). Contrary to the behavioral outcomes, none of the attention performance subscale scores showed significant differences between the high- and low-risk SDB groups in either the ADHD or control group. CONCLUSIONS: The present findings suggest that SDB is associated with behavioral problems in children with ADHD and controls, with stronger associations in control children. On the contrary, SDB has no association with cognitive attention performance. This study extends our understanding of the associations of SDB with behavioral symptoms and cognitive functions in children.

Parent-Reported Suicidal Ideation in Three Population-Based Samples of School-Aged Korean Children With Autism Spectrum Disorder and Autism Spectrum Screening Questionnaire Screen Positivity.

OBJECTIVES: Higher prevalence of suicidality has been reported in individuals with ASD. This study aimed to (1) Estimate the prevalence of suicidal ideation (SI) in epidemiologically-ascertained, population-based, samples of children with ASD or Autism Spectrum Screening Questionnaire (ASSQ) Screen Positivity (ASP); (2) Determine whether ASD/ASP is an independent risk factor for SI, controlling for known SI risk factors; and, (3) Develop an explanatory model for SI in children with ASD/ASP. METHODS: Participants came from three epidemiologically-ascertained samples of school-aged Korean children (n = 14,423; 3,702; 4,837). ASSQ ≥ 14 was the cutoff for ASP. A subsample (n = 86) was confirmed to have ASD. SI was based on parents' endorsement of items on the Behavioral Assessment System for Children-2-Parent Report Scale-Children. Logistic regressions were used to assess associations between SI and ASD/ASP, controlling for demographics, peer victimization, behavior problems, and depression. To develop an explanatory model for SI within ASD/ASP, the associations between SI and child characteristics (comorbid conditions, ASD symptoms, IQ, adaptive function) were tested. RESULTS: SI was higher in children with ASD (14%) and ASP (16.6-27.4%) than ASSQ Screen Negative (ASN) peers (3.4-6.9%). ASD/ASP was strongly predictive of SI (ORs: 2.87-5.67), after controlling for known SI risk factors compared to ASN. Within the ASD and ASP groups, anxiety was the strongest predictor of SI. CONCLUSIONS: SI prevalence was higher in non-clinical samples of children with ASD and ASP, relative to ASN peers. These results underscore the need for routine screening for SI in children with ASD and social difficulties, particularly those with high anxiety. HighlightsPopulation-based, epidemiologically-ascertained, school-aged childrenASD and ASP are independent risk factors for SI in school-aged childrenAnxiety is an independent risk factor for SI in children with ASD or ASP.

Mobile Phone Use and Time Trend of Brain Cancer Incidence Rate in Korea.

This study evaluated the time trends in mobile phone subscriber number by mobile network generation (G) and brain cancer incidence by type in Korea. We obtained data from the Information Technology Statistics of Korea (1984-2017) and Korea Central Cancer Registry (1999-2017). The average annual percent change was estimated using Joinpoint regression analysis. We evaluated 29,721 brain cancer cases with an age-standardized incidence rate (ASR) of 2.89/100,000 persons. The glioma and glioblastoma annual ASR significantly increased in 2.6% and 3.9% of males and 3.0% and 3.8% of females, respectively. The ASR for frontal lobe involvement was the highest. The ASR of gliomas of unspecified grade annually increased by 7.8%; those for unspecified topology and histology decreased. The incidence of glioma, glioblastoma, frontal, temporal, and high-grade glioma increased among those aged ≥60 years. No association was observed between the mobile phone subscriber number and brain cancer incidence in Korea. Furthermore, long-term research is warranted because of the latency period of brain cancer. © 2021 Bioelectromagnetics Society.

Prenatal exposure to paternal smoking and likelihood for autism spectrum disorder.

LAY ABSTRACT: What is Already Known about This Subject: Genetics, (including de novo mutations), environmental factors (including toxic exposures), and their interactions impact autism spectrum disorder etiology. Paternal smoking is a candidate risk for autism spectrum disorder due to biological plausibility, high prevalence, and potential intervention.What This Study Adds: This original study and its replication confirms that paternal factors can substantially contribute to autism spectrum disorder risk for their offspring. It specifically indicates that paternal smoking both before and during pregnancy contributes significantly to autism spectrum disorder risk.Implications for practice, research, or policy: Smoking prevention, especially in pregnancy planning, may decrease autism spectrum disorder risk in offspring.

Cancer cluster among small village residents near the fertilizer plant in Korea.

OBJECTIVES: In Jang-jeom, a small village in Hamra-myeon, Iksan-si, Jeollabuk-do, South Korea, residents raised concerns about a suspected cancer cluster that they attributed to a fertilizer plant near the village. We aimed to investigate whether the cancer incidence in the village was higher than that in the general Korean population when the factory was in operation (2001-2017) and whether living in the village was associated with a higher risk of cancer. METHODS: Using national population data and cancer registration data of South Korea, we estimated the standardized incidence ratios (SIRs) in the village to investigate whether more cancer cases occurred in the village compared to other regions. The SIRs were standardized by age groups of 5 years and sex. In order to investigate whether residence in the village increased the risk of cancer, a retrospective cohort was constructed using National Health Insurance Service (NHIS) databases. We estimated the cancer hazard ratios (HRs) using the Cox proportional hazard model, and defined the exposed area as the village of Jang-jeom, and the unexposed or control area as the village neighborhood in Hamra-myeon. We considered potential confounding variables such as age, sex, and income index in the models. Additionally, we measured polycyclic aromatic hydrocarbons (PAHs) and tobacco-specific nitrosamines (TSNAs), suspected carcinogens that may have caused the cancer cluster, in samples collected from the plant and the village. RESULTS: Twenty-three cancer cases occurred in Jang-jeom from 2001 to 2017. Between 2010 and 2016, the incidence rates of all cancers (SIR: 2.05, except thyroid cancer: 2.22), non-melanoma skin cancer (SIR: 21.14, female: 25.41), and gallbladder (GB) and biliary tract cancer in men (SIR: 16.01) in the village were higher than those in the national population in a way that was statistically significant. In our cohort analysis that included only Hamra-myeon residents who have lived there for more than 7 years, we found a statistically significant increase in the risk of all cancers (HR: 1.99, except thyroid cancer: 2.20), non-melanoma skin cancer (HR: 11.60), GB and biliary tract cancer (HR: 15.24), liver cancer (HR: 6.63), and gastric cancer (HR: 3.29) for Jang-jeom residents compared to other Hamra area residents. We identified PAHs and TSNAs in samples of deposited dust and residual fertilizer from the plant and TSNAs in dust samples from village houses. CONCLUSIONS: The results of the SIR calculation and cancer risk analyses of Jang-jeom village residents from the retrospective cohort design showed consistency in the effect size and direction, suggesting that there was a cancer cluster in Jang-jeom. This study would be a good precedent for cancer cluster investigation.

Network analysis for the symptom of depression with Children's Depression Inventory in a large sample of school-aged children.

BACKGROUND: Depressive disorders have various symptom presentations, which may have complex and dynamic interactions. This study aimed to investigate the network structures underlying the symptoms and to identify the central symptoms of depression in school-aged children. METHODS: Participants were a large community sample of elementary school children aged 6 to 12 years (N = 10,233). To assess the depressive symptoms, we utilized the Children's Depression Inventory (CDI). We binarized the scores on the CDI to generate a symptom network using the eLasso method, based on the Ising model. We evaluated the centralities in individual symptoms using the network centrality indices and the associations between symptoms. RESULTS: Of the symptoms, loneliness, self-hatred, school dislike, and low self-esteem were the most central symptoms in the network of depressive symptoms. School work difficulty-school performance decrement, sadness-crying, self-hatred-negative body image, low self-esteem-fight, anhedonia-school dislike, sadness-loneliness, self-deprecation-school work difficulty, and school dislike-lack of friendship had significantly higher edge weight than most edges. The estimated network between the symptoms was robust to stability and accuracy tests. LIMITATIONS: Participants were not clinical but community samples, who show lower level of symptoms. CONCLUSION: The present symptom network analysis provided important insights on various interconnectivities between individual symptoms in childhood depression and on the central symptoms. In addition, our findings presented both similarities and differences with a previous Western study, thus, warranting future cross-cultural studies.