Background: The Japan Environment and Children’s Study (JECS), known as Ecochil-Chosa in Japan, is a nationwide birth cohort study investigating the environmental factors that might affect children’s ...health and development. We report the baseline profiles of the participating mothers, fathers, and their children. Methods: Fifteen Regional Centres located throughout Japan were responsible for recruiting women in early pregnancy living in their respective recruitment areas. Self-administered questionnaires and medical records were used to obtain such information as demographic factors, lifestyle, socioeconomic status, environmental exposure, medical history, and delivery information. In the period up to delivery, we collected bio-specimens, including blood, urine, hair, and umbilical cord blood. Fathers were also recruited, when accessible, and asked to fill in a questionnaire and to provide blood samples. Results: The total number of pregnancies resulting in delivery was 100,778, of which 51,402 (51.0%) involved program participation by male partners. Discounting pregnancies by the same woman, the study included 95,248 unique mothers and 49,189 unique fathers. The 100,778 pregnancies involved a total of 101,779 fetuses and resulted in 100,148 live births. The coverage of children in 2013 (the number of live births registered in JECS divided by the number of all live births within the study areas) was approximately 45%. Nevertheless, the data on the characteristics of the mothers and children we studied showed marked similarity to those obtained from Japan’s 2013 Vital Statistics Survey. Conclusions: Between 2011 and 2014, we established one of the largest birth cohorts in the world.
Numerous poly- and perfluoroalkyl substances (PFAS) have been manufactured and distributed on the world market. Research on PFAS has highlighted their global distribution and impacts on ecosystems ...and human health. Following regulations and public concern, PFAS production has shifted toward novel molecules in recent years. New classes of PFAS have been identified in the environment and are gaining worldwide attention. The development of an efficient strategy for identification and quantification of emerging PFAS is essential for risk assessment. This review presents and discusses the most recent analytical method development for PFAS in air, water, abiotic solid matrices and biological matrices, and addresses non-target approaches. Various methods are covered including sampling, pre-treatment (enrichment, extraction and clean-up) and instrumental analysis, and their applications, advantages, shortcomings and future needs are explored.
•We discuss recent trends in analytical methods for PFAS in various matrices.•PFAS in air, water, abiotic solids and biological samples are investigated.•Our review covers various methods including sampling, pretreatment and measurement.•We review current analytical techniques and their performance to help future PFAS research.
The effects of prenatal exposure to toxic elements on birth outcomes and child development have been an area of concern. This study aimed to assess the profile of prenatal exposure to toxic elements, ...arsenic (As), bismuth (Bi), cadmium (Cd), mercury (total mercury (THg), methylmercury (MHg), inorganic mercury (IHg)), lead (Pb), antimony (Sb) and tin (Sn), and essential trace elements, copper (Cu), selenium (Se) and zinc (Zn), using the maternal blood, cord blood and placenta in the Tohoku Study of Child Development of Japan (N = 594-650).
Inductively coupled plasma mass spectrometry was used to determine the concentrations of these elements (except mercury). Levels of THg and MeHg were measured using cold vapour atomic absorption spectrophotometry and a gas chromatograph-electron capture detector, respectively.
Median concentrations (25th-75th) of As, Cd, Pb, Sb, Sn and THg in the maternal blood were 4.06 (2.68-6.81), 1.18 (0.74-1.79), 10.8 (8.65-13.5), 0.2 (0.06-0.40) and 0.2 (0.1-0.38) ng mL
and 5.42 (3.89-7.59) ng g
, respectively. Median concentrations (25th-75th) of As, Cd, Pb, Sb, Sn and THg in the cord blood were 3.68 (2.58-5.25), 0.53 (0.10-1.25), 9.89 (8.02-12.5), 0.39 (0.06-0.92) and 0.2 (0.2-0.38) ng mL
and 9.96 (7.05-13.8) ng g
, respectively.
THg and Sb levels in the cord blood were twofold higher than those in the maternal blood. Cord blood to maternal blood ratios for As, Cd and Sb widely varied between individuals. To understand the effects of prenatal exposure, further research regarding the variations of placental transfer of elements is necessary.
To our knowledge, the association of maternal exposure to metallic elements with weight trajectory pattern from the neonatal period has not been investigated.
The goals of this study were to identify ...infant growth trajectories in weight in the first 3 y of life and to determine the associations of maternal blood levels of lead, cadmium, mercury, selenium, and manganese with growth trajectory.
This longitudinal study, part of the Japan Environment and Children Study, enrolled 103,099 pregnant women at 15 Regional Centres across Japan between 2011 and 2014. Lead, cadmium, mercury, selenium, and manganese levels were measured in blood samples collected in the second (14-27 wk gestational age) or third trimester (
). Growth trajectory of 99,014 children was followed until age 3 y. Raw weight values were transformed to age- and sex-specific weight standard deviation (SD) scores, and latent-class group-based trajectory models were estimated to determine weight trajectories. Associations between maternal metallic element levels and weight trajectory were examined using multinomial logistic regression models after confounder adjustment.
We identified 5 trajectory patterns based on weight SD score: 4.74% of infants were classified in Group I, very small to small; 31.26% in Group II, moderately small; 21.91% in Group III, moderately small to moderately large; 28.06% in Group IV, moderately large to normal; and 14.03% in Group V, moderately large to large. On multinomial logistic regression, higher maternal lead and selenium levels tended to be associated with increased odds ratios (ORs) of poor weight SD score trajectories (Groups I and II), in comparison with Group III. Higher levels of mercury were associated with decreased ORs, whereas higher levels of manganese were associated with increased ORs of "moderately large" trajectories (Groups IV and V).
Maternal lead, mercury, selenium, and manganese blood levels affect infant growth trajectory pattern in the first 3 y of life. https://doi.org/10.1289/EHP10321.
The developing brains are sensitive to methylmercury (MeHg). However, the exposure to MeHg in baby foods and toddler meals remains unknown. This study aimed to determine MeHg intake from baby food or ...toddler meals, and to investigate the relationship with child hair total mercury (THg).
A total of 3 days of 24-hour dietary diet and hair samples were collected from 260 consenting children aged 0-5 years. We measured the concentrations of THg and MeHg in the diet and THg in the hair.
The results of measuring THg were below both the method detection and method quantification limits or either of both in powdered milk (93.8%), 5-6 months (53.3%), and 7-8 months (39.5%). The median daily THg intake was 20.3 (95% confidence interval 0.72-232.5) ng/kgbw. MeHg was not detected in 213 samples with dietary THg concentrations below 1 ng/g. The MeHg concentration with THg concentrations of 1 ng/g or higher was 1.70 (0.87-6.21) ng/g, and MeHg percentage in THg was 90.0%. To estimate MeHg intake, we multiplied the THg concentration by 90.0%, resulting in an estimated MeHg intake of 18.3 (0.65-209.2) ng/kgbw/day. The THg in children's hair was 1.05 (0.31-3.96) ppm, and a weak positive correlation was observed between hair THg and dietary MeHg (r = 0.170).
This study highlights the accurate estimation of MeHg intake in children using a duplicate method. Japanese children consume fish, the MeHg intakes exceeded the reference dose and/or provisional tolerable weekly intake in several children. Further discussion based on epidemiological data is required.
The Japan Environment and Children's Study (JECS) is a birth-cohort study of 100,000 mother-child dyads that aims to investigate the effect of the environment on child health and development. Mercury ...(Hg), lead (Pb), cadmium (Cd), manganese (Mn) and selenium (Se) are considered to be important co-exposures when examining the effect of other chemical substances on child development. The levels of these elements in the blood of 20,000 randomly selected mid/late-term pregnant women from the whole JECS cohort were analysed using inductively coupled plasma-mass spectrometry. The median concentrations (interquartile ranges) for Pb, Hg, Cd, Mn and Se were 0.63 (0.51-0.78) µg dl
, 3.83 (2.70-5.43) µg l
, 0.70 (0.52-0.95) µg l
, 16.1 (13.2-19.6) µg l
and 178 (165-192) µg l
, respectively. Hg and Se correlated positively with each other (Spearman's ρ = 0.287), as did Pb and Cd (ρ = 0.239) and Cd and Mn (ρ = 0.267). The blood Pb levels decreased by 5-10-fold over the past 25 years. The main predictors of the blood levels of each element were fish consumption for Hg, maternal age and non-alcoholic beverage consumption for Pb, maternal age and smoking for Cd, gestational age at sampling for Mn and serum protein levels for Se. These results revealed the historical trends and current predictors of the blood levels of these elements in pregnant Japanese women.
The hair-to-blood ratio and biological half-life of methylmercury in a one-compartment model seem to differ between past and recent studies. To reevaluate them, 27 healthy volunteers were exposed to ...methylmercury at the provisional tolerable weekly intake (3.4 µg/kg body weight/week) for adults through fish consumption for 14 weeks, followed by a 15-week washout period after the cessation of exposure. Blood was collected every 1 or 2 weeks, and hair was cut every 4 weeks. Total mercury (T-Hg) concentrations were analyzed in blood and hair. The T-Hg levels of blood and hair changed with time (p < 0.001). The mean concentrations increased from 6.7 ng/g at week 0 to 26.9 ng/g at week 14 in blood, and from 2.3 to 8.8 µg/g in hair. The mean hair-to-blood ratio after the adjustment for the time lag from blood to hair was 344 ± 54 (S.D.) for the entire period. The half-lives of T-Hg were calculated from raw data to be 94 ± 23 days for blood and 102 ± 31 days for hair, but the half-lives recalculated after subtracting the background levels from the raw data were 57 ± 18 and 64 ± 22 days, respectively. In conclusion, the hair-to-blood ratio of methylmercury, based on past studies, appears to be underestimated in light of recent studies. The crude half-life may be preferred rather than the recalculated one because of the practicability and uncertainties of the background level, though the latter half-life may approximate the conventional one.
Fish contain nutrients essential to the developing fetal brain, but they are contaminated with methylmercury. The Tohoku Study of Child Development, now underway in the Sanriku coastal area of Miyagi ...prefecture, Japan, follows mother-child pairs to examine the risks and benefits of fish consumption during pregnancy, especially the effects of prenatal exposures to methylmercury, selenium, and docosahexaenoic acid (DHA) on child neurodevelopment. Children aged 18 months were administered the Bayley Scales of Infant Development second edition (BSID-II) and Kyoto Scale of Psychological Development (KSPD) in 2004-2008. Complete data of cord-blood total mercury (THg), cord-plasma selenium, maternal-plasma DHA, the above test scores, and confounders for 566 mother-child pairs were available. The median cord-blood THg level was 15.7 (range, 2.7-96.1) ng/g. Since the BSID-II and KSPD scores were significantly lower in the 285 boys than in the 281 girls, analyses were conducted separately. The Psychomotor Development Index (PDI) of BSID-II was significantly correlated with cord-blood THg only in the boys, and significance of the association remained unchanged after adjusting for possible confounders; i.e., a 10-fold increase in cord-blood THg was associated with a 8.3-point decrease in the score of the PDI. Other significant correlations of THg were not seen in the boys or girls. Selenium and DHA showed no significant correlations with the BSID-II or KSPD scores in either sex. In conclusion, intrauterine methylmercury exposure may affect psychomotor development, and boys appear to be more vulnerable to the exposure than girls.
Background: Many studies have investigated the devastating health effects of heat waves, but less is known about health risks related to cold spells, despite evidence that extreme cold may contribute ...to a larger proportion of deaths. Objectives: We aimed to systematically investigate the association between cold spells and mortality in Japan. Methods: Daily data for weather conditions and 12 common causes of death during the 1972-2015 cold seasons (November- March) were obtained from 47 Japanese prefectures. Cold spells were defined as greater than or equal to2 consecutive days with daily mean temperatures less than or equal to5th percentile for the cold season in each prefecture. Quasi-Poisson regression was combined with a distributed lag model to estimate prefecture-specific associations, and pooled associations at the national level were obtained through random-effects meta-analysis. The potential influence of cold spell characteristics (intensity, duration, and timing in season) on associations between cold spells and mortality was examined using a similar two-stage approach. Temporal trends were investigated using a meta-regression model. Results: A total of 18,139,498 deaths were recorded during study period. Mortality was significantly higher during cold spell days vs. other days for all selected causes of death. Mortality due to age-related physical debilitation was more strongly associated with cold spells than with other causes of death. Associations between cold spells and mortality from all causes and several more specific outcomes were stronger for longer and more intense cold spells and for cold spells earlier in the cold season. However, although all outcomes were positively associated with cold spell duration, findings for cold spell intensity and seasonal timing were heterogeneous across the outcomes. Associations between cold spells and mortality due to cerebrovascular disease, cerebral infarction, and age-related physical debility decreased in magnitude over time, whereas temporal trends were relatively flat for all-cause mortality and other outcomes. Discussion: Our findings may have implications for establishing tailored public health strategies to prevent avoidable cold spell-related health consequences.
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•Cadmium exposure during pregnancy may pose a neurodevelopmental risk to children.•Cadmium concentrations were measured in maternal and cord blood.•Child’s sex, maternal smoking, and ...gestational diabetes modified the associations.•Identification of high-risk groups is important for tailoring health interventions.
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.
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.
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 (β = −1.4, 95% confidence interval (CI): −2.7, −0.038), DQ in children of mothers who smoked during pregnancy (β = −2.9, 95% CI: −5.7, −0.12), P-M (β = −5.4, 95% CI: −10, −0.67), C-A (β = −6.1, 95% CI: −11, −1.8), L-S (β = −9.0, 95% CI: −13, −4.8) and DQ scores (β = −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 (β = −6.0., 95% CI: −11, −0.91) in children born to mothers with gestational diabetes.
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.
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