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Increases in human mobility have been linked to rises in novel coronavirus disease 2019 (COVID-19) transmission. The pandemic era in Japan has been characterized by changes in inter-prefectural mobility across state of emergency (SOE) declarations and travel campaigns, but they have yet to be characterized.Using Yahoo Japan mobility data extracted from the smartphones of more than 10 million Japanese residents, we calculated the monthly number of inter-prefectural travel instances, stratified by residential prefecture and destination prefecture. We then used this adjacency matrix to calculate two network connectedness metrics, closeness centrality and effective distance, that reliably predict disease transmission.Inter-prefectural mobility and network connectedness decreased most considerably during the first SOE, but this decrease dampened with each successive SOE. Mobility and network connectedness increased during the Go To Travel campaign. Travel volume between distant prefectures decreased more than travel between prefectures with geographic proximity. Closeness centrality was found to be negatively correlated with the rate of COVID-19 infection across prefectures, with the strength of this association increasing in tandem with the infection rate. Changes in effective distance were more visible among geographically isolated prefectures (Hokkaido and Okinawa) than among metropolitan, central prefectures (Tokyo, Aichi, Osaka, and Fukuoka).The magnitude of reductions in human mobility decreased with each subsequent state of emergency, consistent with pandemic fatigue. The association between network connectedness and rates of COVID-19 infection remained visible throughout the entirety of the pandemic period, suggesting that inter-prefectural mobility may have contributed to disease spread.

Objectives The Japanese prime minister declared a state of emergency on April 7 2020 to combat the outbreak of coronavirus disease 2019 (COVID-19). This declaration was unique in the sense that it was essentially driven by the voluntary restraint of the residents. We examined the change of the infection route by investigating contact experiences with COVID-19–positive cases. Study design This study is a population-level questionnaire-based study using a social networking service (SNS). Methods To assess the impact of the declaration, this study used population-level questionnaire data collected from an SNS with 121,375 respondents (between March 27 and May 5) to assess the change in transmission routes over the study period, which was measured by investigating the association between COVID-19–related symptoms and (self-reported) contact with COVID-19–infected individuals. Results The results of this study show that the declaration prevented infections in the workplace, but increased domestic infections as people stayed at home. However, after April 24, workplace infections started to increase again, driven by the increase in community-acquired infections. Conclusions While careful interpretation is necessary because our data are self-reported from voluntary SNS users, these findings indicate the impact of the declaration on the change in transmission routes of COVID-19 over time in Japan., Highlights • After a weak lockdown, the transmission route of coronavirus disease 2019 (COVID-19)–related symptoms changed. • COVID-19 monitoring responses from more than 120,000 social networking service users in Japan were used for analysis. • The emergency declaration prevented infections in the workplace and increased domestic infections. • Even lockdown with limited enforcement may prevent the spread of infection.

Background The World Health Organization declared the novel coronavirus outbreak (COVID-19) to be a pandemic on March 11, 2020. Large-scale monitoring for capturing the current epidemiological situation of COVID-19 in Japan would improve preparation for and prevention of a massive outbreak. Methods A chatbot-based healthcare system named COOPERA (COvid-19: Operation for Personalized Empowerment to Render smart prevention And care seeking) was developed using the LINE app to evaluate the current Japanese epidemiological situation. LINE users could participate in the system either though a QR code page in the prefectures' websites or a banner at the top of the LINE app screen. COOPERA asked participants questions regarding personal information, preventive actions, and non-specific symptoms related to COVID-19 and their duration. We calculated daily cross correlation functions between the reported number of infected cases confirmed using polymerase chain reaction and the symptom-positive group captured by COOPERA. Results We analyzed 206,218 participants from three prefectures reported between March 5 and 30, 2020. The mean age of participants was 44.2 (standard deviation, 13.2) years. No symptoms were reported by 96.93% of participants, but there was a significantly positive correlation between the reported number of COVID-19 cases and self-reported fevers, suggesting that massive monitoring of fever might help to estimate the scale of the COVID-19 epidemic in real time. Conclusions COOPERA is the first real-time system being used to monitor trends in COVID-19 in Japan and provides useful insights to assist political decisions to tackle the epidemic.

Acute lung injury (ALI) is an acute inflammatory disorder. However, the precise mechanisms underlying the pathology of ALI remain elusive. An increasing evidence suggests the role of the gut-microbiota axis in the pathology of lung injury. This study aimed to investigate whether antibiotic-induced microbiome depletion could affect ALI in mice after lipopolysaccharide (LPS) administration.The effects of antibiotic cocktail (ABX) on ALI in the mice after intratracheally administration of LPS (5 mg/kg) were examined. Furthermore, 16s rRNA analysis and measurement of short-chain fatty acids in feces samples and metabolomics analysis of blood samples were performed.LPS significantly increased the interleukin-6 (IL-6) levels in the bronchoalveolar lavage fluid (BALF) of water-treated mice. Interestingly, an ABX significantly attenuated the LPS-induced increase in IL-6 in BALF and lung injury scores. Furthermore, ABX and/or LPS treatment markedly altered the α- and β-diversity of the gut microbiota. There were significant differences in the α- and β-diversity of the water + LPS group and ABX + LPS group. LEfSe analysis identified Enterococusfaecalis, Clostriumtertium, and Bacteroidescaecimyris as potential microbial markers for ABX + LPS group. Untargeted metabolomics analysis identified several plasma metabolites responsible for discriminating water + LPS group from ABX + LPS group. There were correlations between the relative abundance of the microbiome and plasma metabolites. Integrative network analysis showed correlations between IL-6 levels in BALF and several gut microbes (or plasma metabolites).These data suggest that ABX-induced microbiome depletion could protect against LPS-induced ALI via the gut-microbiota-lung axis.

BackgroundThe Tokyo 2020 Summer Olympic Games (23 July–8 August 2021) were held in the middle of Japan’s fifth wave of COVID-19, when the number of cases was on the rise, and coincided with the fourth state of emergency implemented by the host city, Tokyo.AimThis study aimed to assess whether the hosting of the Games was associated with a change in the number of COVID-19 cases in Japan using a synthetic control method.MethodsA weighted average of control countries with a variety of predictors was used to estimate the counterfactual trajectory of daily COVID-19 cases per 1 000 000 population in the absence of the Games in Japan. Outcome and predictor data were extracted using official and open sources spanning several countries. The predictors comprise the most recent country-level annual or daily data accessible during the Games, including the stringency of the government’s COVID-19 response, testing capacity and vaccination capacity; human mobility index; electoral democracy index and demographic, socioeconomic, health and weather information. After excluding countries with missing data, 42 countries were ultimately used as control countries.ResultsThe number of observed cases per 1 000 000 population on the last day of the Games was 109.2 (7-day average), which was 115.7% higher than the counterfactual trajectory comprising 51.0 confirmed cases per 1 000 000 population. During the Olympic period (since 23 July), the observed cumulative number of cases was 61.0% higher than the counterfactual trajectory, comprising 143 072 and 89 210 confirmed cases (p=0.023), respectively. The counterfactual trajectory lagged 10 days behind the observed trends.ConclusionsGiven the increasing likelihood that new emerging infectious diseases will be reported in the future, we believe that the results of this study should serve as a sentinel warning for upcoming mega-events during COVID-19 and future pandemics.

Environmental exposure to persistent organic pollutants during pregnancy has potential adverse health effects on the fetus. One of the environmental pollutants is polychlorinated biphenyl (PCB). Earlier, we reported the presence of PCBs in fetal tissues such as the umbilical cord. Telomere length (TL) is a biomarker of aging because it shortens with each cell division. According to the Developmental Origins of Health and Disease hypothesis, fetal exposure to environmental pollutants during pregnancy affects the occurrence of non-communicable diseases in later life. In the current study, we investigated the association between cord tissue TL and serum levels of PCBs. The subjects were 114 mother-child pairs participating in a birth cohort study, the Chiba Study of Mother and Child Health (C-MACH). Maternal serum was collected during pregnancy, and cord serum and tissue were obtained at birth. TL was assessed by qPCR using genomic DNA extracted from the cord tissue. Maternal and cord serum PCB congener levels were assessed using gas chromatography and negative ion chemical ionization qMS. In male fetuses, serum levels of PCB74 in the cord blood were significantly associated with TL following covariate adjustment, but no significant association was found in female fetuses. These data suggest that the TL of the umbilical cord is affected by fetal exposure to PCBs.

ObjectiveOn 7 April 2020, the Japanese government declared a state of emergency in response to the novel coronavirus outbreak. To estimate the impact of the declaration on regional cities with low numbers of COVID-19 cases, large-scale surveillance to capture the current epidemiological situation of COVID-19 was urgently conducted in this study.DesignCohort study.SettingSocial networking service (SNS)-based online survey conducted in five prefectures of Japan: Tottori, Kagawa, Shimane, Tokushima and Okayama.Participants127 121 participants from the five prefectures surveyed between 24 March and 5 May 2020.InterventionsAn SNS-based healthcare system named COOPERA (COvid-19: Operation for Personalized Empowerment to Render smart prevention And care seeking) was launched. It asks questions regarding postcode, personal information, preventive actions, and current and past symptoms related to COVID-19.Primary and secondary outcome measuresEmpirical Bayes estimates of age-sex-standardised incidence rate (EBSIR) of symptoms and the spatial correlation between the number of those who reported having symptoms and the number of COVID-19 cases were examined to identify the geographical distribution of symptoms in the five prefectures.Results97.8% of participants had no subjective symptoms. We identified several geographical clusters of fever with significant spatial correlation (r=0.67) with the number of confirmed COVID-19 cases, especially in the urban centres of prefectural capital cities.ConclusionsGiven that there are still several high-risk areas measured by EBSIR, careful discussion on which areas should be reopened at the end of the state of emergency is urgently required using real-time SNS system to monitor the nationwide epidemic.

Short-chain chlorinated paraffins (SCCPs) are listed in Annex A (elimination) of the Stockholm Convention on persistent organic pollutants, and products containing SCCPs require detoxification. In the present study, the metal sodium (Na) dispersion method was applied to a wax sample containing SCCPs (58%, C10–C13 and Cl5–Cl9) to assess the dechlorination effect. Effective dechlorination of SCCPs was confirmed using 2-L and 20-L reaction systems. The initial concentrations of the wax (5, 10, 20, 30%), reaction time (10, 30, 60, 120, 180 min), and the ratios of the amount of Na dispersion and the initial amount of the wax containing SCCPs (Na/wax ratios; 3.9, 4.4, 5.2) were tested. The destruction efficiency of SCCPs was over 99.999% after 10 min of reaction at 90 °C under several conditions. The initial concentrations of the wax and the Na/wax ratios did not affect the results. The ultralow SCCP contents in exhaust gas from the reaction tank demonstrated a destruction removal efficiency of over 99.999999%. Trace levels of polychlorinated dibenzo-p-dioxins and furans, dioxin-like polychlorinated biphenyls, hexachlorobenzene, and pentachlorobenzene in the wax sample and treated materials (oil, water, and gas) met various regulatory values or exhibited the same levels as the environmental background. After dechlorination of the SCCPs, the main reaction products in the reaction liquid and final oil phase were identified as aliphatic compounds. The metal Na dispersion method was found to be an effective and decontaminated destruction technique for application to SCCPs in liquid-like samples with no formation of hazardous organic byproducts.

Background In Japan, the latest estimates of excess all-cause deaths through January to July 2020 showed that the overall (direct and indirect) mortality burden from the Coronavirus Disease 2019 (COVID-19) in Japan was relatively low compared to Europe and the United States. However, consistency between the reported number of COVID-19 deaths and excess all-cause deaths was limited across prefectures, suggesting the necessity of distinguishing the direct and indirect consequences of COVID-19 by cause-specific analysis. To examine whether deaths from road injuries decreased during the COVID-19 pandemic in Japan, consistent with a possible reduction of road transport activity connected to Japan’s state of emergency declaration, we estimated the exiguous deaths from road injuries in each week from January to September 2020 by 47 prefectures. Methods To estimate the expected weekly number of deaths from road injuries, a quasi-Poisson regression was applied to daily traffic fatalities data obtained from Traffic Accident Research and Data Analysis, Japan. We set two thresholds, point estimate and lower bound of the two-sided 95% prediction interval, for exiguous deaths, and report the range of differences between the observed number of deaths and each of these thresholds as exiguous deaths. Results Since January 2020, in a few weeks the observed deaths from road injuries fell below the 95% lower bound, such as April 6–12 (exiguous deaths 5–21, percent deficit 2.82–38.14), May 4–10 (8–23, 21.05–43.01), July 20–26 (12–29, 30.77–51.53), and August 3–9 (3–20, 7.32–34.41). However, those less than the 95% lower bound were also observed in weeks in the previous years. Conclusions The number of road traffic fatalities during the COVID-19 pandemic in Japan has decreased slightly, but not significantly, in several weeks compared with the average year. This suggests that the relatively small changes in excess all-cause mortality observed in Japan during the COVID-19 pandemic could not be explained simply by an offsetting reduction in traffic deaths. Considering a variety of other indirect effects, evaluating an independent, unbiased measure of COVID-19-related mortality burden could provide insight into the design of future broad-based infectious disease counter-measures and offer lessons to other countries.

Lead poisoning is considered a public health threat, particularly in developing countries. Health problems from Pb exposure occur in many parts of the world, especially near Pb mines, Pb smelters, and used lead-acid battery (ULAB) recycling plants. In this study, we analyzed the urine metabolome of residents in a village located near a ULAB recycling facility to investigate the biological effects of Pb exposure (ULAB: n = 44, Reference: n = 51). Lasso linear regression models were moderately predictive of blood Pb levels, as evaluated by a training set (R2 = 0.813) and against an external test set (R2EXT = 0.647). In lasso logistic regression models, areas under receiver operating characteristic curves, as measured by 5-fold cross-validation (AUCCV = 0.871) and against an external test set (AUCEXT = 0.917), indicated accurate classification of urine samples from the affected village and from a reference site. Ten candidate biomarkers identified at false discovery rates of

Aims/Introduction We aimed to explore novel predictive markers for gestational diabetes mellitus using metabolomic analysis in pregnant Japanese women. Materials and Methods We carried out a case–control study with a cohort of participants enrolled during the first or early second trimester in the Center of Chiba Unit of the Japan Environment and Children's Study. Participants were classified as either gestational diabetes mellitus cases or matched controls based on age, body mass index and parity. Metabolite levels of their serum and urine obtained randomly before the diagnosis of gestational diabetes mellitus were analyzed using hydrophilic interaction chromatography tandem mass spectrometry. Orthogonal projections to latent structures discriminant analysis was carried out to investigate metabolome profiles for the different groups. Metabolites with a variable importance in projection value of >1.5 were identified as potential markers. Results In total, 242 participants were enrolled in the study, of which 121 were cases. The R2X, R2Y and Q2 parameters for the discrimination ability of the resulting models were 0.388, 0.492 and 0.45 for serum, and 0.454, 0.674 and 0.483 for urine, respectively. We finally identified three metabolites in serum and 20 in urine as potential biomarkers. Glutamine in serum and ethanolamine and 1,3‐diphosphoglycerate in urine showed >0.8 area under the receiver operating characteristic curves. Conclusions The present study identified serum and urine metabolites that are possible predictive markers of subsequent gestational diabetes mellitus in Japanese women. Further studies are required to elucidate their efficacy.

Although the suicide rate in Japan increased during the COVID-19 pandemic, the reasons for suicide have yet to be comprehensively investigated.To assess which reasons for suicide had rates that exceeded the expected number of suicide deaths for that reason during the COVID-19 pandemic.This national, population-based cross-sectional study of data on suicides gathered by the Ministry of Health, Labor, and Welfare from January 2020 to May 2021 used a times-series analysis on the numbers of reason-identified suicides. Data of decedents were recorded by the National Police Agency and compiled by the Ministry of Health, Labor, and Welfare.For category analysis, we compared data from January 2020 to May 2021 with data from December 2014 to June 2020. For subcategory analysis, data from January 2020 to May 2021 were compared with data from January 2019 to June 2020.The main outcome was the monthly excess suicide rate, ie, the difference between the observed number of monthly suicide deaths and the upper bound of the 1-sided 95% CI for the expected number of suicide deaths in that month. Reasons for suicide were categorized into family, health, economy, work, relationships, school, and others, which were further divided into 52 subcategories. A quasi-Poisson regression model was used to estimate the expected number of monthly suicides. Individual regression models were used for each of the 7 categories, 52 subcategories, men, women, and both genders.From the 29 938 suicides (9984 [33.3%] women; 1093 [3.7%] aged20 years; 3147 [10.5%] aged80 years), there were 21 027 reason-identified suicides (7415 [35.3%] women). For both genders, all categories indicated monthly excess suicide rates, except for school in men. October 2020 had the highest excess suicide rates for all cases (observed, 1577; upper bound of 95% CI for expected number of suicides, 1254; 25.8% greater). In men, the highest monthly excess suicide rate was 24.3% for the other category in August 2020 (observed, 87; upper bound of 95% CI for expected number, 70); in women, it was 85.7% for school in August 2020 (observed, 26; upper bound of 95% CI for expected number, 14).In this study, observed suicides corresponding to all 7 categories of reasons exceeded the monthly estimates (based on data from before or during the COVID-19 pandemic), except for school-related reasons in men. This study can be used as a basis for developing intervention programs for suicide prevention.

Fetal exposure to polychlorinated biphenyls (PCBs), polychlorinated-p-dibenzodioxins (PCDDs), and polychlorinated dibenzofurans (PCDFs) have been associated with a number of adverse health outcomes. Although the placenta acts as a barrier between the mother and the fetus, these contaminants transfer through the placenta exposing the fetus. Several studies have investigated placental transfer, but few have assessed the co-variation among these contaminants. Maternal blood, cord blood, and cord tissue were collected from 41 Japanese mother-infant pairs and analyzed for dioxin-like PCBs and PCDD/Fs. Hierarchical cluster analysis followed by principal component analysis were used to assess the co-variation. Two stable clusters of dioxin-like PCBs were found in maternal and cord blood. One cluster of low/medium chlorinated dioxin-like PCBs was present in all three matrices with 2,3’,4,4’,5-PeCB(#118) and 3,3’,4,4’,5-PeCB(#126) explaining the majority of the clusters’ variances. Medium/high chlorinated dioxin-like PCBs clustered in maternal blood and cord blood but not in cord tissue. 2,3,4,4’,5-PeCB(#114) and 2,3,3’,4,4’,5,5’-HpCB(#189) explained the majority of the clusters’ variances. There was a substantial correlation between the sum of dioxin-like PCBs and total PCDD/F in all three matrices. The sum of the four suggested PCBs plus 3,3’,4,4’-TeCB(#77) correlated well with total PCDD/F in all three matrices. Apart from the dioxin-like PCBs, little co-variation existed among the studied contaminants. The five PCBs can be used as fetal exposure markers for dioxin and dioxin-like PCBs in maternal and cord blood respectively. In cord tissue, more higher chlorinated dioxin-like PCBs need to be measured as well. Electronic supplementary material The online version of this article (10.1007/s11356-018-1447-y) contains supplementary material, which is available to authorized users.

Aims/Introduction Impaired glucose tolerance (IGT) is a subtype of prediabetes, a condition having high risk for development to diabetes mellitus, but its pathophysiology is not fully understood. In the present study, we examined metabolic changes in IGT by using two types (D‐glucose [Glc] and partial hydrolysate of starch [PHS]) of oral glucose tolerance tests (OGTTs), with emphasis on serum incretins and metabolites. Materials and Methods We carried out the two types of OGTT (Glc/OGTT and PHS/OGTT) in 99 young Japanese individuals who had tested either positive (GU +; n = 48) or negative (GU −; n = 51) for glycosuria. After OGTT, they were sub‐grouped into five categories: normal glucose tolerance (NGT) in the GU − group (GU −/NGT; n = 49), NGT in the GU + group (GU +/NGT; n = 28), IGT (n = 12), diabetes mellitus (n = 1) and renal glycosuria (n = 9). Serum incretin and metabolites of GU −/NGT and IGT were then measured. Results When the serum insulin level at each time‐point during PHS/OGTT was expressed as its ratio relative to Glc/OGTT, it was increased time‐dependently in GU −/NGT, but not in IGT. Such an increase in the ratio was also detected of serum incretin levels in GU −/NGT, but not in IGT, suggesting a lack of deceleration of oligosaccharide absorption in IGT. Metabolome analysis showed a difference in the serum levels of two metabolites of unknown function in mammals, methylcysteine and sedoheptulose 1,7‐bisphosphate, between GU −/NGT and IGT. Conclusions Comparison of PHS/OGTT and Glc/OGTT showed that oligosaccharide absorption was accelerated in IGT. Methylcysteine and sedoheptulose 1,7‐bisphosphate could be novel markers for dysregulated glucose metabolism.

Aims/Introduction Gut microbiota have various effects on human health. Some previous reports have shown that gut microbiota change during pregnancy and affect metabolism, but others have shown that microbiota do not change. Here, we examined the gut microbiota and glycoalbumin levels of 45 healthy Japanese women during pregnancy. Materials and Methods We carried out 16S rRNA gene sequencing analyses of maternal stool samples and compared the gut microbiota composition of samples from women in early and late pregnancy. We also examined the association between gut microbiota and maternal characteristics, including glycoalbumin. Results Microbiota composition in early and late pregnancy did not differ, according to principal coordinate analysis of weighted and unweighted UniFrac distances. Shannon indices were not different between early and late pregnancy. The proportion of one phylum, TM7, significantly decreased in late pregnancy compared with early pregnancy, but the proportions of other major phyla did not change. The Shannon index of late pregnancy was negatively associated with pregestational body mass index and positively correlated with glycoalbumin level, with adjustment of covariates. Conclusions We concluded that Japanese women did not show obvious differences in gut microbiota during pregnancy, except for TM7, and that the diversity of gut microbiota might affect maternal metabolism. As this study had limited statistical power, further large‐scale studies are required., This study attempted to confirm whether gut microbiota change during pregnancy, by comparing the gut microbiota in stool samples from 45 women, both early and late in their pregnancies. The composition of microbiota in early and late pregnancy did not differ, except that the proportion of the phylum, TM7, significantly decreased in late pregnancy. The Shannon index of late pregnancy was negatively associated with pregestational body mass index and positively correlated with glycoalbumin levels.

To avoid recycling plastic waste containing polybrominated diphenyl ethers (PBDEs) or hexabromocyclododecane (HBCD), which are listed in the Stockholm Convention on Persistent Organic Pollutants (POPs), a simple method to determine their contents at the time of waste disposal is needed. Herein, we developed a rapid analytical method using a gas chromatograph coupled with quadrupole mass spectrometry or electron capture detection to simultaneously detect PBDEs and HBCD in plastic waste. PBDEs and HBCD were ultrasonically extracted from plastic samples using toluene. The dissolved polymer matrix was then removed using n-hexane and 44% H2SO4-impregnated silica gel before analysis of the extract. A run time of less than 10 min was achieved using a custom, short GC column (5 m). The detection limits of the method were below the upper threshold of the low POP content limits defined by the Basel Convention (

Maternal exposure to high levels of persistent organic pollutants (POPs) and trace elements is an important concern for fetal growth. In our previous study, we showed the polychlorinated biphenyl (PCB) levels in maternal serum from the Chiba Study of Mother and Child Health (C-MACH) cohort and their relationships between PCB levels in cord serum with birth weight of newborn. Various reports on the relationship between chemical exposure and birth status have been published; however, studies that analyze the effects of both PCB and metal exposure together in one cohort are still limited. In this study, we aimed to determine the relationship of maternal serum levels of PCBs and toxic and essential trace elements [mercury (Hg), manganese (Mn), selenium (Se), and cadmium (Cd)], with birth weight and head circumference, in the C-MACH cohort. The median concentration of total PCBs in maternal serum around 32 gestational weeks (n = 62) was 360 pg g−1 wet wt (41 ng g−1 lipid wt). The levels of Hg, Mn, Se, and Cd in maternal serum were 0.89, 0.84, 100, and 0.024 ng g−1, respectively. In this study, the Bayesian linear model determined the relationships of the birth weight and head circumference with combinations of PCB levels, toxic and essential trace elements, and questionnaire data. We found that PCB concentrations in maternal serum were weakly and negatively related to birth weight, whereas trace elements were not associated with birth weight. Serum PCB and Mn levels were negatively associated with head circumference, whereas other trace elements were not associated with head circumference. These results showed that maternal exposure to PCBs may be related to birth weight and head circumference, while maternal exposure to Mn is related to head circumference, even when adjusted based on the exposure levels of other contaminants, and maternal and fetal characteristics. Therefore, our findings indicate that maternal exposure to PCBs and Mn might be negatively related with birth weight and head circumference.

The present study aims to predict the maternal–fetal transfer rates of the polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), and polybrominated diphenyl ethers (PBDEs), and dioxin-like compounds using a quantitative structure–activity relationship model. The relation between the maternal–fetal transfer rate and the contaminants’ physicochemical properties was investigated by multiple linear regression (MLR), partial least square regression (PLS), and random forest regression (RF). The 10-fold cross-validation technique estimated low predictive performances for both MLR and PLS models (R 2 CV = 0.425 ± 0.0964 for MLR and R 2 CV = 0.492 ± 0.115 for PLS) and is in agreement with an external test (R 2 pred = 0.129 for MLR and R 2 pred = 0.123 for PLS). In contrast, the RF model exhibits good predictive performance, estimated through 10-fold cross-validation (R 2 CV = 0.566 ± 0.0885) and an external test set (R 2 pred = 0.519). Molecular weight and polarity were selected in all models as important parameters that may predict the ability of a molecule to cross the placenta to the fetus.

Information on accumulation of halogenated phenolic contaminants in the blood of marine mammal is limited. The present study, we determined the residue levels and patterns of chlorinated and brominated phenolic contaminants (OH-PCBs, OH-PBDEs and bromophenols) in the blood collected from pinnipeds (northern fur seal, spotted seal, Steller sea lion and ribbon seal) and small cetaceans (harbor porpoise and Dall's porpoise) from Japanese coastal waters. Concentrations of PCBs and OH-PCBs found in pinnipeds were the same as in small cetaceans living in the same coastal area. However, significantly lower concentrations of brominated compounds (PBDEs, MeO-PBDEs, OH-PBDEs) were found in the blood of pinnipeds than the levels found in cetacean species which live same area (p

The present study measured the concentrations of 25 elements (Li, Mg, V, Cr, Mn, Co, Ni, Cu, Zn, As, Se, Rb, Sr, Mo, Ag, Cd, In, Sn, Sb, Cs, Ba, Hg, Tl, Pb and Bi) in the whole body of Isaza which is an endemic fish species to Lake Biwa, Japan, and compared the values in the specimens from the mass mortality Isaza (MMI) and normal fresh Isaza (NFI). The mean levels of Mn and total As (T-As) were relatively higher in MMI than in NFI. In the T-As, highly toxic inorganic As was detected in MMI. Moreover we found Mn and As concentrations in surface sediment were extremely high and temporally increased. From all these results, we could infer that the dissolution of Mn and As from surface sediment of Lake Biwa might have been one of the cause for the mass mortality of Isaza.

Purpose Recent epidemiological studies have shown that environmental factors during the fetal period to early childhood might affect the risk of non-communicable diseases in adulthood. This is referred to as the developmental origins of health and disease (DOHaD) concept. The Chiba study of Mother and Children's Health (C-MACH) is a birth cohort study based on the DOHaD hypothesis and involves multiomics analysis. This study aims to explore the effects of genetic and environmental factors—particularly the fetal environment and postbirth living environment—on children's health, and to identify potential biomarkers for these effects. Participants The C-MACH consists of three hospital-based cohorts. The study participants are pregnant women at

Perchlorate (ClO4 −) and thiocyanate (SCN−) interfere with iodide (I−) uptake by the sodium/iodide symporter, and thereby these anions may affect the production of thyroid hormones (THs) in the thyroid gland. Although human exposure to perchlorate and thiocyanate has been studied in the United States and Europe, few investigations have been performed in Asian countries. In this study, we determined concentrations of perchlorate, thiocyanate, and iodide in 131 serum samples collected from 2 locations in Northern Vietnam, Bui Dau (BD; electrical and electronic waste [e−waste] recycling site) and Doung Quang (DQ; rural site) and examined the association between serum levels of these anions with levels of THs. The median concentrations of perchlorate, thiocyanate, and iodide detected in the serum of Vietnamese subjects were 0.104, 2020, and 3.11 ng mL−1, respectively. Perchlorate levels were significantly greater in serum of the BD population (median 0.116 ng mL−1) than those in the DQ population (median 0.086 ng mL−1), which indicated greater exposure from e-waste recycling operations by the former. Serum concentrations of thiocyanate were not significantly different between the BD and DQ populations, but increased levels of this anion were observed among smokers. Iodide was a significant positive predictor of serum levels of FT3 and TT3 and a significant negative predictor of thyroid-stimulating hormone in males. When the association between serum levels of perchlorate or thiocyanate and THs was assessed using a stepwise multiple linear regression model, no significant correlations were found. In addition to greater concentrations of perchlorate detected in the e-waste recycling population, however, given that lower concentrations of iodide were observed in the serum of Vietnamese females, detailed risk assessments on TH homeostasis for females inhabiting e-waste recycling sites, especially for pregnant women and their neonates, are required.

We determined the residue levels and patterns of hydroxylated polybrominated diphenyl ethers (OH-PBDEs), and related compounds, such as PBDEs, methoxylated PBDEs (MeO-PBDEs), and bromophenols (BPhs) in the blood of eleven cetacean species stranded along the Japanese coasts. The dominant OH- and MeO-PBDE isomers found in all cetaceans were 6OH-BDE47 and 6MeO-BDE47. Additionally, 2,4,6-triBPh was dominant isomer in all cetaceans. In contrast, specific differences in the distribution of para- and meta- OH-PBDE isomers and some BPhs (potential PBDEs metabolites) were found among the cetaceans. Residue levels of ΣMeO-PBDEs and 6OH-BDE47 + 2'OH-BDE68, and 2,4,6-triBPh and 6OH-BDE47 + 2'OH-BDE68 showed a significant positive correlation. These results may suggest that the large percentages of OH-PBDEs, MeO-PBDEs and 2,4,6-triBPh might share common source (i.e. biosynthesis by marine organisms), or metabolic pathway in cetacean species. Significant correlations were found between the concentrations of BDE99 and 2,4,5-triBPh. This result suggested that 2,4,5-triBPh in cetaceans could be a metabolite of BDE99.

Information on accumulation of polychlorinated biphenyl metabolites (OH-PCBs) and hydroxylated polybrominated diphenyl ethers (OH-PBDEs) in the blood of marine fish is limited. The present study, we determined the residue levels and patterns of PCBs, OH-PCBs, PBDEs, OH-PBDEs and methoxylated PBDEs (MeO-PBDEs) in the blood collected from scalloped hammerhead shark ( Sphyrna lewini ) and Japanese amberjack ( Seriola quinqueradiata ), species of predatory fish at Japanese coastal waters. The predominant homologues found in Japanese amberjacks were mono- and di-chlorinated OH-PCBs, and scalloped hammerhead sharks were octa-chlorinated OH-PCBs. The predominant OH-PCB isomers were lower-chlorinated OH-PCBs such as 6OH-CB2 and 2′OH-CB9 in Japanese amberjacks. This result suggests that exposure of Japanese amberjacks to lower-chlorinated OH-PCBs might be from the ambient aquatic environment. In scalloped hammerhead sharks, 4,4′diOH-CB202, 4OH-CB201 and 4OH-CB146 were the predominant isomers accounting for approximately 60% of the total OH-PCBs. The predominant MeO-PBDE isomers were 6MeO-BDE47 followed by 2′MeO-BDE68 in both species. As for OH-PBDE isomers, 6OH-BDE47 was predominant followed by 2′OH-BDE68 in Japanese amberjacks and scalloped hammerhead sharks. Residue levels of ΣMeO-PBDEs and ΣOH-PBDEs showed a significant positive correlation ( p = 0.029). This result suggests that MeO-PBDEs and OH-PBDEs share a common source or a metabolic pathway in fishes. Characteristic differences found in the profiles of OH-PCBs and OH-PBDEs in Japanese amberjack and scalloped hammerhead shark show the need for further studies on the differences in exposure profiles, metabolic capacities and toxic effects in fish.

We investigated the relationship between food frequency questionnaire (FFQ) responses and serum polychlorinated biphenyl (PCB) levels of mothers and fathers recruited from the Chiba Regional Center, which is one of the 15 regional centers of the Japan Environment and Children’s Study (mothers: n = 1477, fathers: n = 219). The expected PCB values were estimated from the participants’ FFQ answers and medical records (age, body mass index and number of deliveries). Based on the stepwise forward selection results of Bayesian regression models, age and fish and egg consumption were positively associated with PCB concentrations and a number of deliveries were negatively associated with PCB concentrations in mothers, whereas only age was positively associated with PCB concentrations in fathers. These findings indicated that the estimation of daily dietary intake may be useful for the prediction of PCB concentration for mothers.

Objectives On March 28, the Japanese government decided on the "Basic Policies for Novel Coronavirus Disease (COVID-19) Control", and called on the public to thoroughly implement social distance measures (i.e. behavioral restrictions to limit the frequency and intensity of human contact), especially telework. Methods We used population-level questionnaire data from a social networking service (SNS) with 275,560 respondents from March 5 to April 6 to evaluate the relationship between telework implementation and the presence of a fever (body temperature above 37.5°C) within one month as a surrogate indicator of COVID-19 infection, by occupation type and age group. Results Among company employees, a statistical significance was identified in the 15–29 and 30–59 age groups, showing higher fever rates in the non-teleworker group (for 15–29 age group, non-teleworkers: 7.64%; teleworkers: 6.45%; p=0.02; for 30–59 age group, non-teleworkers: 3.46%; teleworkers: 3.14%; p=0.02). Conclusions Telework remains a controversial topic in Japan as the government called for emergency measures. While caution is warranted in interpreting our findings because our data is limited to the voluntary SNS users, they will be essential to push forward with more measures to promote social distancing measures in the midst of Japan's current tense political climate., Highlights • Slow progress in the introduction of telework as a COVID-19 measure in Japan. • Analysis using COVID-19 monitoring responses from over 270,000 SNS users in Japan. • Statistical relationship between teleworking and fever among company employees. • The urgent need for social support in the implementation of telework in Japan.