Sex steroid hormones and allergic diseases in children: a pilot birth cohort study in the Japan Environment and Children's Study cohort.

BACKGROUND: Numerous studies suggest that sex steroids might play a role in sex disparity observed in allergic diseases in adults. However, whether sex hormones influence allergic diseases in children remains unclear. The aim of the present study was to examine the association of sex steroid hormones with allergic disease in Japanese children. METHODS: The present cross-sectional study included 145 6-year-old children participating in a pilot birth cohort study in the Japan Environment and Children's Study. Data on allergic diseases were obtained from questionnaires, and serum levels of sex steroid hormones and allergen-specific IgE were measured. Logistic regression was performed to evaluate the association of sex hormones with allergic diseases. RESULTS: After adjusted sex, amount of body fat at 6 years, parental history of allergic disease, and exposure to tobacco smoke, serum dehydroepiandrosterone sulfate level was significantly associated with reduced odds of any allergic disease (adjusted odds ratio, 0.58; 95% confidence interval, 0.36-0.93; P = 0.024) and serum follicle-stimulating hormone level was significantly associated with increased odds of any allergic disease (adjusted odds ratio, 2.04; 95% confidence interval, 1.01-4.11, P = 0.046). Dehydroepiandrosterone sulfate level showed a significant association with number of allergic diseases. CONCLUSIONS: The current study findings suggest that sex hormones may play an important role in the development of allergic diseases in prepubertal children.

Short-term association of air pollution with lung cancer mortality in Osaka, Japan.

Long-term air pollution exposure has been linked to increased lung cancer mortality. However, little is known about whether day-to-day fluctuations in air pollution levels are in relation to lung cancer mortality, particularly in low-exposure settings. This study aimed to evaluate the short-term associations between air pollution and lung cancer mortality. Daily data on lung cancer mortality, fine particulate matter (PM2.5), nitrogen dioxide (NO2), sulfur dioxide (SO2), carbon monoxide (CO), and weather conditions were collected from Osaka Prefecture, Japan, from 2010 to 2014. Generalized linear models were combined with quasi-Poisson regression were applied to evaluate the associations between each air pollutant and lung cancer mortality after adjusting for potential confounders. Mean (standard deviation) concentrations of PM2.5, NO2, SO2, and CO were 16.7 (8.6) µg/m3, 36.8 (14.2) µg/m3, 11.1 (4.0) µg/m3, and 0.51 (0.16) mg/m3, respectively. Interquartile range increases in concentrations of PM2.5, NO2, SO2, and CO (2-d moving average) were associated with 2.65% (95% confidence intervals [CIs]: 0.96%-4.37%), 4.28% (95% CIs: 2.24%-6.36%), 3.35% (95% CIs: 1.03%-5.73%), and 4.60% (95% CIs: 2.19%-7.05%) increased risk of lung cancer mortality, respectively. Stratified analyses showed that the associations were strongest in the older population and men. Exposure‒response curves showed a continuously increasing mortality risk from lung cancer with elevation of air pollution levels, without discernible thresholds. In summary, we found evidence of increased lung cancer mortality in relation to short-term elevations in ambient air pollution. These findings may merit further research to better understand this issue.

Population attributable fraction of risk factors for low birth weight in the Japan Environment and Children's Study.

BACKGROUND: Low birth weight (LBW), which is considered a birth weight of <2500  g, poses significant health problems for children. However, population attributable fraction (PAF) of risk factors for LBW have not been well studied. OBJECTIVE: We aimed to re-evaluate associations between risk factors for LBW reported in previous studies that used the Japan Environment and Children's Study (JECS) data, and to estimate the magnitude of risk using PAF. METHODS: Data including 91,559 mother-child dyads were obtained from JECS. Risk factors identified by previous studies that used JECS data were used to calculate odds ratios for LBW using a Bayesian logistic regression model. Based on calculated odds ratios, the PAF was calculated. RESULTS: Parity, history of adenomyosis, hypertension disorder of pregnancy, maternal age at birth, prepregnancy body mass index, gestational weight gain (GWG), maternal smoking and lead (Pb) exposure were all significantly associated with LBW. The sum of the PAF of all factors was 79.4 %, with the largest PAF among single risk factors being GWG (16.5 %); the environmental portion of the PAF (Pb exposure, 14.6 % + maternal smoking, 12.1 %) surpassed the PAF of GWG. CONCLUSION: Our findings suggest that the number of births classified as LBW can be reduced by approximately 27% if Pb exposure is reduced to the lowest quartile and maternal smoking is eliminated. Further investigations are needed to identify unknown risk factors for LBW.

Association between Heated Tobacco Product Use during Pregnancy and Fetal Growth in Japan: A Nationwide Web-Based Survey.

Combustible cigarette smoking impacts fetal growth during pregnancy. However, the risk associated with heated tobacco products (HTPs) remains unclear. This nationwide cross-sectional study investigated whether HTP use during pregnancy is associated with small for gestational age (SGA) outcomes among 5647 post-delivery women with singleton pregnancies, which were divided into four groups: lifetime never-smokers, former smokers before pregnancy, and current smokers for each of the tobacco products during pregnancy (sole HTP and sole combustion smokers). Information on the prevalence of SGA, defined as birth weight and height below the 10th percentile, was retrieved from the Maternal and Child Health Handbooks of post-delivery women. Using logistic regression, the association between sole HTP smokers during pregnancy and SGA, adjusted for covariates, with lifetime never-smokers as reference, was investigated. The prevalence was: current sole HTP smokers during pregnancy, 1.8% (102/5647); and SGA, 2.9% (164/5647). Sole HTP smokers during pregnancy had a higher prevalence of SGA (5.9% [6/102] vs. 2.7% [111/4144]) with an adjusted odds ratio (OR) of 2.50 (95% confidence interval [CI], 1.03-6.05) than lifetime never-smokers. Among sole combustion smokers, the adjusted OR for SGA was 1.95 (95% CI, 0.81-4.67). In Japan, HTP smoking during pregnancy may be associated with an increased risk for SGA.

Evaluating postnatal exposure to six heavy metals in a Chinese e-waste recycling area.

This study is the first to assess postnatal exposure to heavy metals using breast milk in an electronic waste (e-waste) recycling area. From January to April 2021, 102 and 97 breastfeeding women were recruited from an e-waste recycling area and a control area, respectively. Four weeks after delivery, medical staff collected 20 mL of breast milk from each participant. The breast milk was tested for six heavy metals (lead, cadmium, chromium, arsenic, copper, and manganese) using inductively coupled plasma mass spectrometry (ICP-MS). The estimated daily intake (EDI) of infants during breastfeeding was calculated to assess the impact of postnatal exposure to heavy metals on infant health. The concentrations of chromium and lead in the breast milk were significantly higher in the e-waste recycling area than in the control area. Chromium concentrations in breast milk was 34.3%, exceeding the permissible limits set by the World Health Organization (WHO), in the e-waste recycling area, which is 16 times higher than that in the control areas. The EDIs of lead and chromium in the e-waste area were twice as those in the control area. This strongly indicates that the potential impact of postnatal exposure to lead and chromium on infant and child health in e-waste recycling areas cannot be ignored. Infants and children in e-waste recycling areas are at risk of long-term exposure to heavy metals. Therefore, ongoing health monitoring is necessary.

Relationship between dioxins and steroid hormone in 6-year-olds: A follow-up study in an e-waste region of China.

We conducted a follow-up observational study on the effects of dioxin exposure on the synthesis of steroid hormones in infants during the perinatal period. The participants included 42 pairs of mothers and infants that were previously studied in 2015. We analyzed four types of steroid hormones including progesterone, testosterone, androstenedione (A-dione), and dehydroepiandrosterone (DHEA) in the serum samples of 6-year-olds and the concentration of dioxins in breast milk. A multivariate linear regression was performed to associate steroid hormones (dependent variables) and dioxins with the body mass index (BMI), sex, age, and residence of participants (independent variables). The results were reported as ß (standardized coefficient) and p-values. We found that dioxins have a significant negative correlation with DHEA and A-dione but no significant relationship with progesterone and testosterone. However, in previous studies, we found that testosterone and progesterone levels were significantly related to dioxins in 4-year-olds. We concluded that dioxins can affect the level of steroid hormones, but their effects fluctuate, and the harm caused by dioxins in children requires further long-term monitoring.

Selective Recovery of Estrogenic Endocrine Disruptors from 48 Environmental Samples Using a Substrate for Activity-Specific Concentration.

hER-MIP is a molecularly imprinted polymer (MIP) that has been shown to selectively collect human estrogen receptor (hER) binding active substances. However, environmental samples contain various chemicals depending on the location and regional differences, and the hER binding activity depends on the sample type. Thus, the general applicability of hER-MIP to actual environmental samples must be elucidated. In this study, 48 environmental samples were collected and screened with hER-MIP, and a yeast assay was performed to evaluate the adsorption characteristics of the samples according to the adsorption and elution fractions. The results showed that hER-MIP collects hER binding active substances almost selectively but does not collect constitutive androstane receptor (CAR) binding active substances selectively. CAR binding activity was detected in the adsorbed fraction because several hER binding active substances also demonstrate CAR binding activity.

Association of prenatal exposure to cadmium with neurodevelopment in children at 2 years of age: The Japan Environment and Children's Study.

BACKGROUND: Prenatal cadmium exposure has been associated with adverse neurodevelopmental outcomes. However, previous findings are contradictory, and little is known about the potential modifiers of the cadmium-related neurodevelopmental risk. We investigated the associations between prenatal cadmium exposure and neurodevelopment in 2-year-old children and examined the influence of mother/child characteristics. METHODS: We recruited 3545 mother-child pairs from the Japan Environment and Children's Study. We collected maternal blood during mid/late pregnancy and cord blood at delivery, and measured cadmium concentrations using inductively coupled plasma mass spectrometry. Neurodevelopment was assessed using the Kyoto Scale of Psychological Development (KSPD), which includes cognitive-adaptive (C-A), language-social (L-S), postural-motor (P-M) and developmental quotient (DQ) domains. Associations between cadmium and KSPD scores were tested using multivariable models after controlling for confounders. RESULTS: Median levels (interquartile ranges) of cadmium in maternal and cord blood were 0.70 (0.52-0.95) and 0.04 (0.03-0.06) µg/L, respectively. Maternal blood cadmium concentrations were inversely associated with P-M scores in boys (ß = -1.4, 95% confidence interval (CI): -2.7, -0.038), DQ in children of mothers who smoked during pregnancy (ß = -2.9, 95% CI: -5.7, -0.12), P-M (ß = -5.4, 95% CI: -10, -0.67), C-A (ß = -6.1, 95% CI: -11, -1.8), L-S (ß = -9.0, 95% CI: -13, -4.8) and DQ scores (ß = -6.4, 95% CI: -9.6, -3.1) in children born to mothers with gestational diabetes. Cord blood cadmium concentrations were negatively associated with L-S scores (ß = -6.0., 95% CI: -11, -0.91) in children born to mothers with gestational diabetes. CONCLUSIONS: Prenatal cadmium exposure was negatively associated with neurodevelopment in boys, in children whose mothers smoked, and in children born to mothers with gestational diabetes. Further studies in other populations are needed to confirm our findings.

Urinary Metabolites of Organophosphate Pesticides among Pregnant Women Participating in the Japan Environment and Children's Study (JECS).

Organophosphate pesticides (OPPs) exhibit neurodevelopmental toxicity. To evaluate the effect of prenatal exposure to OPPs in the Japan Environment and Children's Study, a nationally representative birth cohort study, 4575 maternal urine samples were analysed for six OPP metabolites, i.e., dialkylphosphates (DAPs). This study aimed to investigate predictors of urinary DAPs using machine learning approaches and to assess the cumulative risk based on relative potency factors among Japanese pregnant women. The median creatinine-normalised urinary concentrations (interquartile ranges) of dimethylphosphate, dimethylthiophosphate and diethylphosphate, which had a detection rate of 50% or higher, were 3.53 (1.91-6.78), 4.09 (1.66-10.8) and 3.28 (1.88-5.98) µg/g-creatinine, respectively. Possible predictors of urinary DAP concentrations were the month of urine sampling, consumption of apple and maternal body mass index. When fenitrothion was used as an index chemical for cumulative risk assessment, 0.36% of participants exceeded the lower 95% confidence limit of the benchmark dose10.

Indoor air quality of 5,000 households and its determinants. Part A: Particulate matter (PM2.5 and PM10-2.5) concentrations in the Japan Environment and Children's Study.

Exposure to particulate matter (PM) is one of the important risk factors for morbidity and mortality. Although PM concentrations have been assessed using air quality monitoring stations or modelling, few studies have measured indoor PM in large-scale birth cohorts. The Japan Environment and Children's Study (JECS) measured indoor and outdoor air quality in approximately 5000 households when the participating children were aged 1.5 and 3 years. PM was collected using portable pumps for 7 days (total of 24 h), inside and outside each home. Prediction models for indoor PM concentrations were built using data collected at age 1.5 years and post-validated against data collected at age 3 years. Median indoor/outdoor PM2.5 and PM10-2.5 concentrations at age 1.5 years [3 years] were 12.9/12.7 [12.5/11.3] µg/m3 and 5.0/6.3 [5.1/6.1] µg/m3, respectively. Random forest regression analysis found that the major predictors of indoor PM2.5 were indoor PM10-2.5, outdoor PM2.5, indoor smoking, observable smoke and indoor/outdoor temperature. Indoor PM2.5, outdoor PM10-2.5, indoor humidity and opening room windows were important predictors of indoor PM10-2.5 concentrations. Indoor benzene, acetaldehyde, ozone and nitrogen dioxide concentrations were also found to predict indoor PM2.5 and PM10-2.5 concentrations, possibly due to the formation of secondary organic aerosols. These findings demonstrate the importance of reducing outdoor PM concentrations, avoiding indoor smoking, using air cleaner in applicable and diminishing sources of VOCs that could form secondary organic aerosols, and the resulting models can be used to predict indoor PM concentrations for the rest of the JECS cohort.

Determination of Urinary Cotinine Cut-Off Concentrations for Pregnant Women in the Japan Environment and Children's Study (JECS).

Few studies have assessed the accuracy of self-reported questionnaires to determine smoking habits relative to urinary biomarkers. This study investigated urinary cotinine cut-off concentrations distinguishing active, passive and non-smokers among pregnant women who participated in the Japan Environment and Children's Study, a nationwide birth cohort study. Pregnant participants with measured urinary cotinine concentrations (UCCs) and who completed self-reported questionnaires on smoking status were included (n = 89,895). The cut-off values (COVs) for active and passive smokers were calculated by fitting mixed normal distribution functions to UCCs. The sensitivity and specificity of the questionnaires were subsequently evaluated. The median (interquartile range) UCC was 0.24 (0.083-0.96) µg/g-creatinine, with the detection rate of 89%. The COV for distinguishing active smokers from passive and non-smokers was 36.8 µg/g-creatinine. When this COV was considered to represent the true condition, the questionnaire had a sensitivity of 0.523, a specificity of 0.998, a positive predictive value (PPV) of 0.967 and a negative predictive value (NPV) of 0.957. The COV for distinguishing passive smokers from non-smokers was 0.31 µg/g-creatinine, with the questionnaire having a sensitivity of 0.222, a specificity of 0.977, a PPV of 0.868 and an NPV of 0.644. As many as 78% of passive smokers might be misclassified as non-smokers.

Association of blood cadmium levels in pregnant women with infant birth size and small for gestational age infants: The Japan Environment and Children's study.

BACKGROUND: There is growing evidence of an association between cadmium (Cd) and unfavorable birth outcomes. The effect of Cd exposure on anthropometric measures at birth or small for gestational age (SGA) infants in a large, nationwide Japanese cohort remains to be clarified. OBJECTIVES: To analyze the association between maternal blood Cd levels at different sampling times and sex-dependent infant birth size, weight, body length, chest, and head circumferences, in addition to SGA. METHODS: Data of 17,584 pregnant women in the Japan Environment and Children's Study were analyzed for anthropometric measurements. For SGA determination, 13,969 cases of vaginal delivery were analyzed after excluding infants born by cesarean section. Maternal blood Cd levels were categorized into quartiles (Q1-Q4), and the Q1 was used as a reference. Multiple linear regression analysis was performed for anthropometric measurements, and multiple logistic regression analysis was used to investigate the association of maternal blood Cd levels with the risk of SGA. RESULTS: Birth weight tended to decrease according to the increase in quartiles of blood Cd levels (15.63 g decrease [95% confidence level (CI): -33.26, 2.01] for Q4). The overall analysis revealed no decreases in body length and head and chest circumference, but subgroup analysis revealed that chest circumference tended to decrease according to the increase in quartiles in the female sex/third-trimester stratification (0.16 cm decrease [95% CI: -0.32, 0.00] for Q4). SGA risk was also higher and paralleled the increase in blood Cd levels associated with the female sex/third-trimester group (Odds Ratio 1.90 [95% CI: 1.23, 2.94] for Q4). CONCLUSION: Our results provide further evidence of sex-specific health risks associated with Cd exposure in early life in a large Japanese pregnancy cohort.

Endocrine-disrupting chemicals: implications for human health.

Since reports published in 2015 and 2016 identified 15 probable exposure-outcome associations, there has been an increase in studies in humans of exposure to endocrine-disrupting chemicals (EDCs) and a deepened understanding of their effects on human health. In this Series paper, we have reviewed subsequent additions to the literature and identified new exposure-outcome associations with substantial human evidence. Evidence is particularly strong for relations between perfluoroalkyl substances and child and adult obesity, impaired glucose tolerance, gestational diabetes, reduced birthweight, reduced semen quality, polycystic ovarian syndrome, endometriosis, and breast cancer. Evidence also exists for relations between bisphenols and adult diabetes, reduced semen quality, and polycystic ovarian syndrome; phthalates and prematurity, reduced anogenital distance in boys, childhood obesity, and impaired glucose tolerance; organophosphate pesticides and reduced semen quality; and occupational exposure to pesticides and prostate cancer. Greater evidence has accumulated than was previously identified for cognitive deficits and attention-deficit disorder in children following prenatal exposure to bisphenol A, organophosphate pesticides, and polybrominated flame retardants. Although systematic evaluation is needed of the probability and strength of these exposure-outcome relations, the growing evidence supports urgent action to reduce exposure to EDCs.

Reassessment of early 131I inhalation doses by the Fukushima nuclear accident based on atmospheric 137Cs and 131I/137Cs observation data and multi-ensemble of atmospheric transport and deposition models.

The Fukushima Dai-ichi Nuclear Power Plant accidents following the March 11, 2011 Tohoku earthquake, and subsequent tsunami released radioactive materials into the atmosphere and caused significant public health concerns, particularly thyroid cancers in children. However, the lack of measurement data for atmospheric concentrations of 131I has caused persistent and widespread uncertainty. This study estimated the maximum potential thyroid doses of inhaled 131I in the early post-accident phase between March 12 and 23, 2011 by using the hourly measured data of the 137Cs concentrations at 101 suspended particulate matter (SPM) monitoring sites, a new multi-model ensemble (MME) method of simulating 137Cs concentrations using two Atmospheric Transport and Deposition Models (ATDMs), the 131I/137Cs ratio obtained from measurement data analysis, and the internal exposure model. Based on the measurements, the maximum potential thyroid doses were estimated at 3.1-160 mSv at 5 sites in the Fukushima-Hamadori area for 1-year-old children assumed to remain outdoors, whereas they were less than 4.3 mSv at the other sites in the base case of the 131I/137Cs ratio. The spatial distribution of the maximum potential of early inhalation doses was estimated by using the MME and measurements. The inhalation thyroid doses in the evacuation scenarios were compared to the estimates reported by previous studies. The results of the present study were almost congruent with the outcomes of previous investigations except for thyroid doses contributed by highly contaminated plumes on March 12 and 15. The sensitivity analysis for the 131I/137Cs ratio indicated that these plumes carried the potential to significantly increase the thyroid doses of residents.

Health Risk Assessment and Source Apportionment of Mercury, Lead, Cadmium, Selenium, and Manganese in Japanese Women: An Adjunct Study to the Japan Environment and Children's Study.

Toxic element pollution is a serious global health concern that has been attracting considerable research. In this study, we elucidated the major routes of exposure to three toxic elements (mercury, cadmium, and lead) and two essential elements (manganese and selenium) through diet, soil, house dust, and indoor air and assessed the potential health risks from these elements on women from the coastal area of Miyagi prefecture, Japan. Twenty-four-hour duplicate diet, house dust, soil, and indoor air samples were collected from 37 participants. Cd, Pb, Mn, and Se concentrations were measured using inductively coupled plasma mass spectrometry, and Hg concentrations using cold vapor atomic absorption spectrometry. We found that soil and house dust were the primary reservoirs of these elements. Diet contributed most strongly to the daily intake of these elements, with mean values of 0.72, 0.25, 0.054, 47, and 0.94 µg/kg/day for Hg, Cd, Pb, Mn, and Se, respectively. The mean hazard quotient of Hg was 1.53, indicating a high potential health risk from Hg exposure in daily lives. The intakes of other elements were below the tolerable limits. Future studies with a larger sample size are warranted to confirm our findings.

Estrogenic action by tris(2,6-dimethylphenyl) phosphate impairs the development of female reproductive functions.

Developmental exposure to environmental chemicals with estrogen-like activity is suspected to permanently impair women's health. In this study, a mouse model was used to evaluate whether tris(2,6-dimethylphenyl) phosphate (TDMPP), a chemical with a putative estrogen-like action, impairs sexual differentiation of the brain. Either TDMPP and 17ß-estradiol (E2) as positive controls or sesame oil as a negative control were administered subcutaneously to dams from gestational day (GD) 14 to parturition, and to pups from postnatal day (PND) 0 to 9. Precocious puberty, irregular estrous cycles, and a lowered lordosis response were found in the TDMPP- and E2-treated groups. A certain amount of TDMPP and its metabolites in the perinatal brain and the masculinization of sexual dimorphic nuclei in the hypothalamus of female mice after treatment were also detected. The experimental evidence demonstrates that TDMPP directly enters the fetal and neonatal brain, thereby inducing changes of sex-related brain structures and impairing female reproductive functions.

Maternal urinary bisphenol A concentration and thyroid hormone levels of Chinese mothers and newborns by maternal body mass index.

Animal studies indicated that bisphenol A (BPA) exposure during pregnancy may disrupt thyroid function which is critical for fetal development. However, few epidemiological studies have examined this topic and the results were inconsistent. We aimed to evaluate whether prenatal BPA exposure is associated with thyroid hormone levels in Chinese mothers and newborns with stratification by maternal body mass index (BMI). BPA concentration were measured in urine samples collected from 555 women at late pregnancy. Maternal serum free thyroxin (FT4), thyroid-stimulating hormone (TSH) and thyroid peroxidase antibody (TPO-Ab) concentrations at the third trimester were abstracted from medical records. Cord serum-free triiodothyronine (FT3), FT4, TSH, and TPO-Ab levels were measured in 398 newborns. Prenatal urinary BPA was detected in 98.5% of mothers with a geometric mean of 1.32 ng/mL (95% CI 1.17-1.49 ng/mL). With each 10-fold increase in BPA concentrations, maternal log10_(TSH) mIU/L was 0.10 lowered (95% CI - 0.20, - 0.005, p < 0.05) among pre-pregnancy BMI > 23 kg/m2, with adjustment for maternal age, maternal education, gestation diabetes mellitus (GDM), husband smoking during pregnancy, parity, and gestational age at thyroid parameters measured, but no association was observed in pre-pregnancy BMI < 18.5, or 18.5-22.9 kg/m2 stratum. No BPA-associated changes were observed in maternal FT4 level or odds of positive TPO-Ab in all BMI stratum. Also, no associations were observed between prenatal urinary BPA concentration and cord serum FT4, FT3, TSH levels, and odds of positive TPO-Ab in both male and female newborns among pre-pregnancy BMI < 18.5, 18.5-22.9 or > 23 kg/m2 stratum. In this study, prenatal urinary BPA concentration was associated with lower maternal TSH among women with overweight, but not associated with other maternal thyroid parameters or cord serum thyroid parameters across maternal BMI categories. More research on pregnant women and newborns cohort with BPA exposure are warranted.

Estimation of the radiation dose via indoor dust in the Ibaraki and Chiba prefectures, 150-200 km south from the Fukushima Daiichi Nuclear Power Plant.

The radiation dose effects due to the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident are of public concern. Although indoor dust is an important exposure route for some hazardous chemicals, the radiation exposure dose from the radioactive caesium (Cs) in it has not been well investigated. Hence, in this study, we measured the radioactive Cs in the indoor dust of private houses in order to estimate the resulting human exposure. We collected vacuum cleaner dust twice (in April and June 2012, n = 250 and 241, respectively) in the prefectures of Chiba and Ibaraki, from houses located 150-200 km south from the FDNPP. The activity concentrations of 134Cs and 137Cs in the indoor dust were measured using germanium γ-ray detectors, and the exposure dose was calculated and the household-to-household variations were analysed. The median activity concentrations of 134Cs + 137Cs in the indoor dust collected in April and June were 1470 and 1340 Bq kg-1, respectively. The median committed effective doses via indoor dust ingestion were estimated as 0.73, 0.66, and 0.43 × 10-3 mSv year-1, and those via inhalation were estimated as 0.03, 0.04, and 0.06 × 10-3 mSv year-1 for one- and ten-year-old children and adults, respectively. Those were much smaller than the annual dose limit of 1 mSv year-1, which was set as a goal to be achieved in the a few years or decades (clear period has not been set). Within the detached houses, multiple regression analysis showed that wet wiping of floor was a significant reduction factor of the Cs concentration in dust; however, the small determination coefficient implies the presence of factors that were not considered in this study.

Psychometric profile of the Ages and Stages Questionnaires, Japanese translation.

BACKGROUND: This study assessed the psychometric profile of 10 questionnaires (every 6 months, from 6 to 60 months) from the Japanese translation of the Ages and Stages Questionnaires, third edition (J-ASQ-3). METHODS: Data from 439 children in a birth cohort were used to identify the J-ASQ-3 score distribution, establish cut-off scores, and calculate the instrument's internal consistency. Data were also collected from 491 outpatients to examine J-ASQ-3 test-retest reliability and concurrent validity, which was examined using the Kyoto Scale of Psychological Development (KSPD) and the Japanese version of the Denver Developmental Screening Test II (J-Denver II). Both the original and the alternative screening criteria of the ASQ-3 were used (failure in at least one and at least two domains, respectively). RESULTS: Cronbach's alpha for each J-ASQ-3 subscale on each questionnaire ranged from 0.45 to 0.89. Test-retest reliability was >0.75 for the subscales on almost all questionnaires. Concurrent validity was also adequate. In comparison with the screening results of the KSPD, the overall sensitivity and specificity were 96.0% and 48.8%, respectively, when the ASQ-3 original criterion was used, and 92.1% and 74.9%, respectively, when the alternative criterion was used. In comparison with the screening results of the J-Denver II, the overall sensitivity and specificity were 75.6% and 74.7%, respectively, when the ASQ-3 original criterion was used, and 56.3% and 93.0%, respectively, when the alternative criterion was used. CONCLUSIONS: This study quantified the psychometric profiles of the Japanese translations of 10 ASQ-3 questionnaires. We demonstrated the validity of the J-ASQ-3 and determined new cut-off scores. Further studies with larger samples from a greater range of locations are required to clarify the suitability of this tool for all Japanese children.

Benefits of cooperation among large-scale cohort studies and human biomonitoring projects in environmental health research: An exercise in blood lead analysis of the Environment and Child Health International Birth Cohort Group.

A number of prospective cohort studies are ongoing worldwide to investigate the impact of foetal and neonatal exposures to chemical substances on child health. To assess multiple exposure (mixture) effects and low prevalence health outcomes it is useful to pool data from several studies and conduct mega-data-analysis. To discuss a path towards data harmonization, representatives from several large-scale birth cohort studies and a biomonitoring programme formed a collaborative group, the Environment and Child Health International Birth Cohort Group (ECHIBCG). In this study, an intra-laboratory trial was performed to harmonize existing blood lead measurements within the groups' studies. Then, decentralized analyses were conducted in individual countries' laboratories to evaluate blood lead levels (BLL) in each study. The measurements of pooled BLL samples in French, German and three Japanese laboratories resulted in an overall mean blood lead concentration of 8.66 µg l-1 (95% confidence interval: 8.59-8.72 µg l-1) with 3.0% relative standard deviation. Except for China's samples, BLL from each study were comparable with mean concentrations below or close to 10 µg l-1. The decentralized multivariate analyses revealed that all models had coefficients of determination below 0.1. Determinants of BLL were current smoking, age >35 years and overweight or obese status. The three variables were associated with an increase in BLL in each of the five studies, most strongly in France by almost 80% and the weakest effect being in Norway with only 15%; for Japan, with the far largest sample (~18,000), the difference was 36%. This study successfully demonstrated that the laboratory analytical methods were sufficiently similar to allow direct comparison of data and showed that it is possible to harmonize the epidemiological data for joint analysis. This exercise showed the challenges in decentralized data analyses and reinforces the need for data harmonization among studies.