森 千里

Postpartum depressive symptoms (PDS) are a common mental health condition among women after delivery. Although various causative factors have been reported, PDS remains a challenging condition to predict and prevent. The disruption of the gut microbiota due to antibiotic exposure has been reported to affect psychiatric conditions. Similarly, previous research suggests that antibiotic exposure during pregnancy could be related to PDS. Therefore, this prospective study examines the association between antibiotic exposure during pregnancy and PDS for 6 months after delivery. Data were obtained from 65,272 mothers from the Japan environment and children's study, a prospective birth cohort study. The ratios of maternal PDS at 1 and 6 months after delivery were 12.3% and 10.1%, respectively. During pregnancy, 10.7% of women took antibiotics orally. Antibiotic exposure during pregnancy was associated with an increased risk of PDS only at 6 months after delivery (OR = 1.13, 95% CI [1.00, 1.26]), adjusted for potential confounding factors. An increase in Edinburgh Postnatal Depression Scale scores in relation to antibiotic exposure during pregnancy was primarily observed via psychological distress during pregnancy. Although a causal link was not established, antibiotic exposure during pregnancy may be a contributing risk factor for PDS. Therefore, when antibiotic administration is required, clinical practitioners and perinatal care providers should consider the potential risk for PDS.

PURPOSE: Epidemiological studies have reported that environmental factors from fetal period to early childhood can influence the risk of non-communicable diseases in adulthood. This concept has been termed the developmental origins of health and disease (DOHaD). The Chiba study of Mother and Child Health (C-MACH) is a DOHaD concept-based birth cohort study which started in 2014. This study aims to investigate the effects of genetic and environmental factors, particularly fetal and postnatal living environment, on children's health. We also aim to identify candidate biomarkers for their health status. Moreover, the second phase study of C-MACH which was initiated in 2021 aimed at expanding the sample size, especially for gut microbiota and epigenomic analysis; it also aimed at clarifying the impact of the coronavirus disease 2019 (COVID-19) pandemic on children's health. PARTICIPANTS: This study consists of four hospital-based cohorts. Women who were <13 weeks pregnant and their partners were enrolled in the study. All data and biological samples will be stored in the Chiba University Centre for Preventive Medical Sciences. FINDINGS TO DATE: A total of 561 women and their partners provided their consent to participate in this study. Of these women, 505 completed the questionnaire during the early gestational period. The mean age of the 505 women at enrolment was 33.0 (SD, 4.5) years. The mean prepregnancy body mass index (BMI) was 21.7 (SD, 3.6) kg/m2, with 74.5% of the women having a BMI of 18.5-24.9 kg/m2. About 5.2% of the women smoked cigarettes during the early stages of pregnancy. FUTURE PLANS: The primary study outcomes are allergies, obesity, endocrine and metabolic disorders and developmental difficulties in children. Variables related to genome, metabolome, epigenome, gut microbiota and exposome will be evaluated as health-related factors. The relationships between these outcomes and the health-related factors will be analysed.

The increasing exposure to environmental chemicals calls for comprehensive non-targeted analysis to detect unrecognized substances in human samples. We examined human serum samples to classify compounds as endogenous or exogenous using public databases and to explore the relationships between exposure markers and metabolic patterns. Serum samples from 84 pregnant women at 32 weeks gestation were analyzed using LC-QToFMS. Using the PubChemLite for Exposomics database, we annotated and classified 106 compounds (51 endogenous, 55 exogenous). The compound patterns were analyzed using three dimensional reduction methods: Principal Component Analysis (PCA), regularized Generalized Canonical Correlation Analysis (rGCCA), and Uniform Manifold Approximation and Projection (UMAP). OPTICS clustering applied to these methods revealed two distinct clusters, with 89 % of significant compounds overlapping between clusters. The detected exogenous compounds included dietary substances, phthalates, nitrogenous compounds, and parabens. Pathway enrichment analysis showed that chemical exposure was linked to changes in amino acid metabolism, protein and mineral transport, and energy metabolism. While we found associations between exposure and metabolite changes, we could not establish causality. Our approach of analyzing both exogenous and endogenous chemicals from the same dataset using PubChemLite database presents a new method for exposome research, despite limitations in sample size and peak annotation accuracy. These findings contribute to understanding multiple chemical exposures and their metabolic effects in human biomonitoring.

BackgroundParents' educational background is presumed to influence the incidence of vaccine-preventable diseases in children through their decisions about vaccinations and other family lifestyle choices. Regarding voluntary vaccination, a household's economic situation may also be associated with non-vaccination. Therefore, this study investigated the association between parental education and vaccine-preventable diseases (varicella, mumps, influenza [flu], pertussis, measles, and rubella) in children, which currently remains elusive.MethodsWe used datasets from the Japan Environment and Children's Study, which included 104,062 fetal records; our study population comprised 80,930 children up to the age of three years. The associations between parental educational background and children's infectious diseases were examined using binomial logistic regression analysis. The mediating effects of household income, vaccination, and smoking were examined using a path analysis.ResultsFor varicella, mumps, and influenza covered by voluntary vaccination, a higher education level of the father was associated with a lower incidence of infection. The association between mothers' education and children's infection was limited. There were both income-mediated and non-income-mediated pathways between parental education and voluntary vaccination. For pertussis, measles, and rubella, which are covered by routine vaccines, there was no association between parental education and the child's infection.ConclusionAn association between parental education and childhood infections was observed. Additionally, providing financial support for vaccination and communicating the benefits of vaccination in a way that parents at all levels of education can understand will help reduce the incidence of infectious diseases among children.

Background Childhood asthma is known to be affected by a range of factors, including conditions in the indoor environment. While flooring material influences indoor air conditions, the potential association between flooring materials and childhood asthma remains poorly understood in Japan. Objective The present study aims to assess the association between childhood asthma incidence and the primary flooring material with the ongoing prospective nationwide birth cohort data of the Japan Environment and Children’s Study (JECS). Methods The JECS gathered data on mothers and children through 15 Regional Centres across Japan. The present study assessed flooring materials used in the home and asthma incidence at age four among children born between 2011 and 2014. We implemented logistic regressions, setting asthma incidence among the children as the outcome and home floor type as the exposure. Additional analyses were conducted, stratifying the home’s age as a proxy for tatami age, to assess whether the potential effect of tatami flooring on asthma risk is influenced by its age. Results The present study included total of 75,629 infants. For tatami flooring, the main multivariable regression and additional sub-group regression for homes over ten years old produced odds ratios of 1.09; 95% Confidence Interval (CI) [1.01–1.17] and 1.10; 95% CI [1.00–1.21] compared with flooring, respectively. Conclusion These results imply that exposure to tatami flooring, particularly in older homes, may be associated with childhood asthma incidence. Moreover, our study highlights the importance of evaluating the relationship between regional and cultural differences between asthma and flooring materials.

One-carbon metabolism (OCM) is a complex and interconnected network that undergoes drastic changes during pregnancy. In this study, we investigated the longitudinal distribution of OCM-related metabolites in maternal and cord blood and explored their relationships. Additionally, we conducted cross-sectional analyses to examine the interrelationships among these metabolites. This study included 146 healthy pregnant women who participated in the Chiba Study of Mother and Child Health. Maternal blood samples were collected during early pregnancy, late pregnancy, and delivery, along with cord blood samples. We analyzed 18 OCM-related metabolites in serum using stable isotope dilution liquid chromatography/tandem mass spectrometry. We found that serum S-adenosylmethionine (SAM) concentrations in maternal blood remained stable throughout pregnancy. Conversely, S-adenosylhomocysteine (SAH) concentrations increased, and the total homocysteine/total cysteine ratio significantly increased with advancing gestational age. The betaine/dimethylglycine ratio was negatively correlated with total homocysteine in maternal blood for all sampling periods, and this correlation strengthened with advances in gestational age. Most OCM-related metabolites measured in this study showed significant positive correlations between maternal blood at delivery and cord blood. These findings suggest that maternal OCM status may impact fetal development and indicate the need for comprehensive and longitudinal evaluations of OCM during pregnancy.

The quality of indoor environment is a risk factor for early childhood eczema and atopic dermatitis; however, its influence during pregnancy on childhood eczema in Japan has not been investigated. In this study, we aimed to determine the indoor environmental factors that are associated with eczema in children up to 3 years of age, using national birth cohort data from the Japan Environment and Children's Study (JECS). Information on indoor environments and eczema symptoms until 3 years of age was collected using self-administered questionnaires to the mothers. A total of 71,883 and 58,639 mother-child pairs at 1.5- and 3-years-old, respectively, were included in the former analyses. To account for prenatal indoor risk factors, 17,568 (1.5-years-old) and 7063 (3-years-old) children without indoor mold and/or ETS exposure were included in the final analysis. A higher mold index, gas heater use, parquet flooring use, and frequent insecticide use showed significantly increased risks for childhood eczema up to 3 years of age. These associations were consistent after stratification analysis among children whose parents did not have a history of allergies. The updated WHO guidelines on indoor air quality should be implemented based on recent findings regarding the effects of prenatal exposure to indoor dampness on health effects of children further in life, including asthma, respiratory effects, eczema, and other immunological effects.

Abstract Background Catch-up growth issues among children born small for gestational age (SGA) present a substantial public health challenge. Prenatal exposure to heavy metals can cause adverse effects on birth weight. However, comprehensive studies on the accurate assessment of individual blood concentrations of heavy metals and their effect on the failure to achieve catch-up growth remain unavailable. This study aimed to evaluate the effects of uterine exposure to toxic metals cadmium, lead, and mercury and essential trace metals manganese and selenium at low concentrations on the postnatal growth of children born SGA. Methods Data on newborn birth size and other factors were obtained from the medical record transcripts and self-administered questionnaires of participants in the Japan Environment and Children’s Study. The blood concentrations of lead, cadmium, mercury, selenium, and manganese in pregnant women in their second or third trimester were determined by inductively coupled plasma mass spectrometry. These heavy metal concentrations were also assessed in pregnant women’s cord blood. Furthermore, the relationship between each heavy metal and height measure/catch-up growth in SGA children aged 4 years was analyzed using linear and logistic regression methods. These models were adjusted for confounders. Results We studied 4683 mother–child pairings from 103,060 pregnancies included in the Japan Environment and Children’s Study. Of these, 278 pairs were also analyzed using cord blood. At 3 and 4 years old, 10.7% and 9.0% of children who were born below the 10th percentile of body weight had height standard deviation scores (SDSs) below 2, respectively. Cord blood cadmium concentrations were associated with the inability to catch up in growth by 3 or 4 years old and the height SDS at 3 years old. In maternal blood, only manganese was positively associated with the height SDS of SGA children aged 2 years; however, it was not significantly associated with catch-up growth in these children. Conclusion Cadmium exposure is associated with failed catch-up development in SGA children. These new findings could help identify children highly at risk of failing to catch up in growth, and could motivate the elimination of heavy metal (especially cadmium) pollution to improve SGA children’s growth.

Volatile organic compounds (VOCs) have been suspected to cause building-related symptoms (BRSs). Although some studies investigated the association between BRSs and VOCs in indoor air, those results were inconsistent. This study investigated the contamination status of VOCs in the indoor air of 154 houses in Japan. Additionally, these samples were grouped by hierarchical clustering analysis based on the VOC composition, and the relationship between a VOC cluster and the BRSs was investigated. The median concentration of the sum of VOCs (ΣVOCs) was 140 μg m-3 (range: 18-3500 μg m-3). The levels of acetaldehyde in four samples and p-dichlorobenzene in one sample exceeded the guideline value. As a result of the hierarchical clustering analysis, the samples in this study were divided into six characteristic clusters based on the VOC composition. The ΣVOCs in cluster 1 were significantly lower than those in other clusters. In cluster 2, acyclic and aromatic hydrocarbons were dominant. Cluster 3 had a relatively high proportion of limonene. In cluster 4, the concentrations and composition ratios of α-pinene were higher than those of other clusters. In cluster 5, p-dichlorobenzene accounted for 42 %-72 % of the total VOCs. Cluster 6 had a relatively high proportion of decamethyl cyclopentasiloxane. This clustering likely depended on the construction of houses and lifestyles. As a result of logistic regression analysis, cluster 5 was associated with the cough symptoms of the BRSs. The results of the present study suggest that investigating the association between VOCs and BRSs is necessary to consider not only total concentrations such as TVOC and ΣVOCs but also VOC composition.

A fetal growth restriction is related to adverse child outcomes. We investigated risk ratios and population-attributable fractions (PAF) of small-for-gestational-age (SGA) infants in the Japanese population. Among 28,838 infants from five ongoing prospective birth cohort studies under the Japan Birth Cohort Consortium, two-stage individual-participant data meta-analyses were conducted to calculate risk ratios and PAFs for SGA in advanced maternal age, pre-pregnancy underweight, and smoking and alcohol consumption during pregnancy. Risk ratio was calculated using modified Poisson analyses with robust variance and PAF was calculated in each cohort, following common analyses protocols. Then, results from each cohort study were combined by meta-analyses using random-effects models to obtain the overall estimate for the Japanese population. In this meta-analysis, an increased risk (risk ratio, [95% confidence interval of SGA]) was significantly associated with pre-pregnancy underweight (1.72 [1.42-2.09]), gestational weight gain (1.95 [1.61-2.38]), and continued smoking during pregnancy (1.59 [1.01-2.50]). PAF of underweight, inadequate gestational weight gain, and continued smoking during pregnancy was 10.0% [4.6-15.1%], 31.4% [22.1-39.6%], and 3.2% [-4.8-10.5%], respectively. In conclusion, maternal weight status was a major contributor to SGA births in Japan. Improving maternal weight status should be prioritized to prevent fetal growth restriction.

Background: Placental weight to birthweight ratio (PW/BW ratio), or its inverse, is used as an indicator of placental efficiency. Past studies have shown an association between an abnormal PW/BW ratio and adverse intrauterine environment, however, no previous studies have examined the effect of abnormal lipid levels during pregnancy on PW/BW ratio. We aimed to evaluate the association between maternal cholesterol levels during pregnancy and placental weight to birthweight ratio (PW/BW ratio). Methods: This study was a secondary analysis using the data from the Japan Environment and Children’s Study (JECS). 81 781 singletons and their mothers were included in the analysis. Maternal serum total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C) levels during pregnancy were obtained from participants. Associations between maternal lipid levels and placental weight and PW/BW ratio were assessed by regression analysis using restricted cubic splines. Results: Dose–response relationships were observed between maternal lipid level during pregnancy and placental weight and PW/BW ratio. High TC and LDL-C levels were associated with heavy placental weight and high PW/BW ratio, i.e., inappropriately heavy placenta for birthweight. Low HDL-C level was also associated with inappropriately heavy placenta. Low TC and LDL-C levels were associated with low placental weight and low PW/BW ratio, i.e., inappropriately light placenta for birthweight. High HDL-C was not associated with PW/BW ratio. These findings were independent of pre-pregnancy body mass index and gestational weight gain. Conclusions: Abnormal lipid levels such as elevated TC and LDL-C, and low HDL-C level, during pregnancy were associated with inappropriately heavy placental weight.

Teenage pregnancy increases the threat of depression because of its many factors. Pregnancy during young adulthood may also have several risk factors for depression compared to older pregnancies. However, data on depression in young adult pregnancies are lacking. This study investigated the association between teenage and young adult pregnancy and depression. Data from the Japan Environment and Children's study was used as a nationwide multicenter prospective cohort study. A multivariate logistic regression was performed to investigate the association between age groups (14-19, 20-24, 25-29, 30-34, ≥ 35 years) and depression, adjusted for behavioral and sociodemographic characteristics. Depression was assessed using the Kessler Psychological Distress Scale. In total, 96,808 pregnant women responded to the questionnaire. Teenage (14-19 years) and young adult (20-24 years) pregnancy were associated with an increased risk of depression compared to older pregnancy (≥ 35 years) (teenage: OR 4.28, 95% confidence interval, CI [3.24-5.64]; young adult: OR 3.00, 95% CI [2.64-3.41]). After adjusting for covariates, the magnitude of the risk of depression was attenuated. However, teenage and young adult pregnancy remained at a significantly increased risk of depression compared to older pregnancy (teenage: OR 2.38, 95% CI [1.77-3.21]; young adult: OR 2.14, 95% CI [1.87-2.46]). Our findings indicate that teenage and young adults' pregnancy are at an increased risk of depression compared to older pregnancy. These findings suggest prioritizing teenage and young pregnant women for prevention and interventions related to depression.

Importance It is unclear whether increased television (TV) and DVD viewing in early childhood from age 1 year decreases development or whether poor development increases TV/DVD viewing. Objective To investigate the directional association between TV/DVD screen time and performance on developmental screeners in children aged 1 to 3 years. Design, Setting, and Participants This longitudinal cohort study analyzed data from 57 980 children and mothers from a national birth cohort, the Japan Environment and Children’s Study. Data were collected in collaboration with 15 regional centers across Japan. The mothers were recruited between January 2011 and March 2014. Analyses using random intercept, cross-lagged panel models were performed for children aged 1, 2, and 3 years. Of 100 303 live births, children with missing developmental screening test scores and screen time data, those with congenital diseases or cerebral palsy, and those diagnosed with an autism spectrum disorder were excluded. Statistical analyses were conducted from October 2022 to July 2023. Exposures TV and DVD screen time. Main Outcomes and Measures Child development at ages 1, 2, and 3 years was assessed via the mother’s or guardian’s report using the Ages and Stages Questionnaire, third edition. Results Of 57 980 included children, 29 418 (50.7%) were male, and the mean (SD) maternal age at delivery was 31.5 (4.9) years. A negative association between screen time and developmental scores was observed. Increased TV/DVD screen times at age 1 and 2 years were associated with lower developmental scores at age 2 and 3 years, respectively (2 years: β = −0.05; 95% CI, −0.06 to −0.04; 3 years: β = −0.08; 95% CI, −0.09 to −0.06). An obverse association was observed from the Ages and Stages Questionnaires, third edition, score in the communication domain at age 1 and 2 years to subsequent screen time (2 years: γ = −0.03; 95% CI, −0.04 to −0.02; 3 years: γ = −0.06; 95% CI, −0.07 to −0.04). Conclusions and Relevance In this study, increased TV/DVD screen time from age 1 year negatively affected later development. To reduce the negative consequences of excessive media use, researchers and health care professionals should encourage family media management and recommend social support for parents who tend to rely on the media.

Recently, prediction of gestational diabetes mellitus (GDM) using artificial intelligence (AI) from medical records has been reported. We aimed to evaluate GDM-predictive AI-based models using birth cohort data with a wide range of information and to explore factors contributing to GDM development. This investigation was conducted as a part of the Japan Environment and Children's Study. In total, 82,698 pregnant mothers who provided data on lifestyle, anthropometry, and socioeconomic status before pregnancy and the first trimester were included in the study. We employed machine learning methods as AI algorithms, such as random forest (RF), gradient boosting decision tree (GBDT), and support vector machine (SVM), along with logistic regression (LR) as a reference. GBDT displayed the highest accuracy, followed by LR, RF, and SVM. Exploratory analysis of the JECS data revealed that health-related quality of life in early pregnancy and maternal birthweight, which were rarely reported to be associated with GDM, were found along with variables that were reported to be associated with GDM. The results of decision tree-based algorithms, such as GBDT, have shown high accuracy, interpretability, and superiority for predicting GDM using birth cohort data.

Abstract Background The primary objective of this study was to examine risk factors for toddler’s hypertension. Methods Subjects of this study were children and parents participating in a national birth cohort study in Japan, the Japan Environment and Children’s Study. We measured the children’s blood pressure (BP) at 2 and 4 years old. We obtained children’s and parents’ backgrounds from the questionnaire. We investigated the factors that affect BP elevation. Results Within 4988 participants, the mean systolic BP at 2 years old was 91.2 mmHg for boys and 90.0 mmHg for girls. The mean systolic BP at 4 years old was 93.8 mmHg for boys and 93.1 mmHg for girls. Parental smoking was associated with elevated values of BP at 2 and 4 years old. Obesity, gestational hypertension, and parental lower education were associated with elevated values of BP at 4 years old. Hypertensive group had a significantly higher obesity rate. The mother’s lower education and parental smoking were involved in hypertensive groups. Conclusion Parental smoking had a significant effect on BP even in early toddlers. We emphasize the importance of avoiding second-hand smoking from early infancy to prevent future lifestyle-related illnesses including hypertension. Impact The mean systolic BP at 2 years old was 91.2 mmHg for boys and 90.0 mmHg for girls. The mean systolic BP at 4 years old was 93.8 mmHg for boys and 93.1 mmHg for girls. Obesity, parental smoking, and lower education were associated with hypertension at 4 years old. Parental smoking was associated with hypertension at 2 and 4 years old. We emphasize the importance of avoiding second-hand smoking from early infancy.

Abstract Infants make spontaneous movements from the prenatal period. Several studies indicate that an atypical pattern of body motion during infancy could be utilized as an early biomarker of autism spectrum disorders (ASD). However, to date, little is known about whether the body motion pattern in neonates is associated with ASD risk. The present study sought to clarify this point by examining, in a longitudinal design, the link between features of spontaneous movement at about two days after birth and ASD risk evaluated using the Modified Checklist for Autism in Toddlers by their caregivers at 18 months old. The body movement features were quantified by a recently developed markerless system of infant body motion analysis. Logistic regression analysis revealed that ASD risk at 18 months old is associated with the pattern of spontaneous movement at the neonatal stage. Further, logistic regression based on body movement features during sleep shows better performance in classifying high- and low-risk infants than during the awake state. These findings raise the possibility that early signs of ASD risk may emerge at a developmental stage far earlier than previously thought.

Constipation is common in children and can significantly affect quality of life. Prebiotics are reportedly helpful for constipation in adults, but few studies have examined their use in young children. In this study, the effect of 1-kestose (kestose), which has excellent bifidobacterial growth properties, on constipation in kindergarten children (n = 11) was compared with that of maltose (n = 12) in a randomized, double-blind study. Three grams of kestose per day for 8 weeks did not affect stool properties, but significantly increased the number of defecations per week (Median; 3 → 4 times/week, p = 0.017, effect size = 0.53). A significant decrease in Intestinibacter, a trend toward increased bifidobacteria, and a trend toward decreased Clostridium sensu stricto were observed after kestose ingestion, while concentrations of short-chain fatty acids in stools were unchanged.

Abstract Background The long-term effects of a Cesarean section (CS) birth on child neurodevelopment are of increasing interest. In this study, we examined the associations between mode of delivery and presence of neurodevelopmental disorders in toddlers. Moreover, given that the prevalence of several neurodevelopmental disorders such as autism spectrum disorder (ASD) is known to differ by sex, we also investigated these associations separately in male and female toddlers. Methods We investigated 65,701 mother–toddler pairs from the Japan Environment and Children’s Study, a nationally representative children’s cohort study. To investigate the associations between mode of delivery (CS or vaginal delivery) and neurodevelopmental disorders (motor delay, intellectual disability, and ASD) in 3-year-old toddlers as a whole and stratified by sex, we used logistic regression models to calculate adjusted odds ratios (aORs) with 95% confidence intervals (CIs). Results The morbidity of ASD at age 3 years was higher for children delivered by CS than those delivered vaginally (aOR 1.38, 95% CI 1.04–1.83). However, no such difference was evident in the case of motor delay or intellectual disability (aOR 1.33, 95% CI 0.94–1.89; aOR 1.18, 95% CI 0.94–1.49, respectively). In the analysis by sex, CS was not associated with increased risk of any of the neurodevelopmental disorders in males, but it was associated with increased risks of motor delay (aOR 1.88, 95% CI 1.02–3.47) and ASD (aOR 1.82, 95% CI 1.04–3.16) in females. Conclusions This study provides evidence of significant associations between mode of delivery and neurodevelopmental disorders in early childhood. Females may be more sensitive to the effects of CS than males.

Abstract Background Sleep problems and irritable temperaments are common among infants with autism spectrum disorder (ASD). The prospective association between such sleep problems and irritable temperaments and ASDs needs to be determined for elucidating the mechanism and exploring the future intervention study. Thus, in this study, we investigated whether sleep quality and temperament in 1-month-old infants are associated with the onset of ASD in 3-year-old children. We also assessed its sex-stratified associations. Methods We conducted a longitudinal study using data from 69,751 mothers and infants from a large-cohort study, the Japan Environment and Children’s Study. We examined the prospective association between infant sleep quality and temperament at 1 month of age and ASD diagnosis by 3 years of age. Results Here we show infants with longer daytime sleep have a higher risk of later ASD than those with shorter daytime sleep (risk ratio [RR]: 1.33, 95% confidence interval [CI]: 1.01–1.75). Infants who experienced intense crying have a higher risk of ASD than those who did not (RR: 1.31, 95% CI: 1.00–1.72). There is a difference in sex in the association between a bad mood and later ASD. In particular, female infants experiencing bad moods have a higher risk of ASD than others (RR: 3.59, 95% CI: 1.91–6.75). Conclusions The study findings provide important information for future intervention to reduce the risk of future ASD.

Semi-volatile organic compounds (SVOCs), such as phthalates and organophosphate flame retardants (OPFRs), are used in plastic products and electrical and electronic applications as plasticisers or flame retardants. There has been a growing concern that exposure to SVOCs can have an adverse impact on human health. Several large-scale epidemiological studies employ the sampling of house dust using household vacuum cleaners as the standard method. However, in this method, house dust samples might be contaminated by flame retardants and plasticisers because of the presence of these chemicals in the plastic materials of cleaners. Therefore, this study aimed to develop a low-cost, easy-to-distribute sampling method to collect house dust using a mop and analyse OPFRs, phthalate esters, and alternative plasticisers in house dust. Our findings show that the proposed mop sampling method can be easily distributable and lower contamination from a sampling tool. Moreover, the proposed house dust sampling method is extremely useful for a large-scale survey such as a cohort study.

BACKGROUND: Although a history of miscarriage or stillbirth has been reported to negatively affect quality of life (QOL) during the subsequent pregnancy, the association between the number of previous miscarriages or stillbirths and QOL, as well as trends in QOL during pregnancy, has not been clarified. This study sought to determine this association during early and mid- to late pregnancy. METHODS: Data from 82,013 pregnant women who participated in the Japan Environment and Children's Study (JECS) from January 2011 to March 2014 were analyzed. In early and mid/late pregnancy, participants completed questionnaires and QOL was assessed using the Physical and Mental Component Summary (PCS and MCS, respectively) scores from the 8-item Short-Form Health Survey (SF-8). The pregnant women were divided into four groups according to number of previous miscarriages or stillbirths (0, 1, 2, and ≥ 3), and the PCS and MCS scores in early pregnancy and mid/late pregnancy were compared between group 0 and groups 1, 2, and ≥ 3. Generalized linear mixed models were used for analysis. RESULTS: PCS score in early pregnancy was lower in group 1 (β =  - 0.29, 95% confidence interval [CI] - 0.42 to - 0.15), group 2 (β =  - 0.45, 95% CI - 0.73 to - 0.18), and group ≥ 3 (β =  - 0.87, 95% CI - 1.39 to - 0.35) than in group 0. Group 1 and group ≥ 3 showed a trend for increased PCS score during pregnancy (β = 0.22, 95% CI 0.07 to 0.37 and β = 0.75, 95% CI 0.18 to 1.33, respectively) compared with group 0. CONCLUSIONS: PCS score in early pregnancy was lower with a more frequent history of miscarriage or stillbirth. However, in terms of changes in QOL during pregnancy, pregnant women with a history of miscarriage or stillbirth showed greater increases in PCS score during mid/late pregnancy than pregnant women with no history of miscarriage or stillbirth.

Abstract Caesarean section (CS) birth is widely reported to be a risk factor for childhood obesity. Although susceptibility to childhood obesity is influenced by race and ethnicity, it is unclear whether this risk of childhood obesity with CS birth also applies in the Japanese population. We investigated the impact of CS birth on obesity at 3 years of age in Japanese children. We obtained data from 60,769 mother–toddler pairs in the Japan Environment and Children’s Study, a large-scale birth cohort study. Obesity was determined by body mass index measured at 3 years of age. Analysis revealed that 11,241 toddlers (18.5%) had a CS birth and that 4912 toddlers (8.1%) were obese. The adjusted risk ratio for obesity at 3 years of age when born by CS compared with vaginal delivery, estimated using inverse probability of treatment weighting, was 1.16 (95% confidence interval 1.08–1.25). These results suggest that CS birth modestly increases the risk of obesity at 3 years of age in Japanese children.

Abstract The association between maternal pre-pregnancy smoking status and asthma risk is unclear. This study aimed to investigate the association between pre- and post-pregnancy maternal smoking status and bronchial asthma at 3 years of age in a large birth cohort. Data of 75,411 mother–child pairs from the Japan Environment and Children's Study (JECS) were analysed using multivariate logistic regression analysis. Overall, 7.2% of the children had bronchial asthma. The maternal smoking status before childbirth was as follows: Never = 60.0%, Quit before recognising current pregnancy = 24.1%, Quit after finding out about current pregnancy = 12.3%, and Still smoking = 3.6%. Children of mothers who sustained smoking during pregnancy had an increased risk of bronchial asthma at 3 years of age even after adjusting for pre- and postnatal covariates (adjusted odds ratio [aOR] 1.34, 95% confidence interval [CI] 1.15–1.56). Children of mothers who quit before (aOR 1.09, 95% CI 1.02–1.18) or after (aOR 1.11, 95% CI 1.01–1.23) recognising the current pregnancy had an increased risk of bronchial asthma at 3 years of age. Maternal smoking throughout pregnancy and smoking exposure pre-pregnancy or in early pregnancy increases the risk of bronchial asthma in children.

Abstract Background Atopic dermatitis (AD) is reported to be more prevalent in children who were born in autumn than in spring. Here, we investigated how early the association between season of birth and eczema or AD can be observed in the postnatal period. We also examined whether specific prevalence outcomes for infant eczema and AD differed according to sex and maternal history of allergic disease in a large Japanese cohort. Methods Using data of 81,615 infants from the Japan Environment and Children’s Study, we examined the associations of birth month or season with four different outcomes—eczema at 1 month, 6 months, and 1 year of age and physician-diagnosed AD up to 1 year of age—using multiple logistic regression analysis. We also analyzed the effect of maternal history of allergic disease on these outcomes stratified by infant sex. Results The risk of eczema at 1 month was highest in infants born in July. In contrast, infants born in autumn had higher risks of eczema at 6 months (adjusted odds ratio [aOR], 2.19; 95% confidence interval [CI], 2.10–2.30) and at 1 year (aOR, 1.08; 95% CI, 1.02–1.14) and of physician-diagnosed AD up to 1 year of age (aOR, 1.33; 95% CI, 1.20–1.47) compared with infants born in spring. Eczema and AD were more prevalent in infants with a maternal history of allergic disease, particularly boys. Conclusions Our findings suggest that the prevalence of AD is associated with the season of observation. Eczema is prevalent in infants born in autumn, and this phenomenon was observed in infants as young as 6 months old. The risk associated with being born in autumn was particularly clear in boys with a maternal history of allergic disease. Trial registration UMIN000030786

The spleen is a key immune-related organ that plays a role in communication between the brain and the immune system through the brain-spleen axis and brain-gut-microbiota axis. However, how the gut microbiota affects spleen and brain function remains unclear. Here, we investigated whether microbiome depletion induced by administration of an antibiotic cocktail (ABX) affects spleen and brain function. Treatment with ABX for 14 days resulted in a significant decrease in spleen weight and significant alterations in splenic functions, including the percentage of neutrophils, NK cells, macrophages, and CD8+ T cells. Furthermore, ABX treatment resulted in the depletion of a large portion of the gut microbiota. Untargeted metabolomics analysis showed that ABX treatment caused alterations in the levels of certain compounds in the plasma, spleen, and brain. Moreover, ABX treatment decreased the expression of microglia marker Iba1 in the cerebral cortex. Interestingly, correlations were found between the abundance of different microbiome components and metabolites in various tissues, as well as splenic cell populations and spleen weight. These findings suggest that ABX-induced microbiome depletion and altered metabolite levels may affect spleen and brain function through the gut-microbiota-spleen-brain axis.

The increase in fetal requirements of long-chain polyunsaturated fatty acids (LCPUFAs) during pregnancy alters maternal fatty acid metabolism, and therefore, fatty acid desaturase (FADS) gene polymorphisms may change blood fatty acid composition or concentration differently during pregnancy. We investigated the relationship between a FADS1 single-nucleotide polymorphism (SNP) and maternal serum LCPUFA levels in Japanese pregnant women during the first and third trimesters and at delivery. Two hundred and fifty-three pregnant women were included, and fatty acid compositions of glycerophospholipids in serum (weight %) and the FADS1 SNP rs174547 (T/C) were analyzed. LCPUFAs, including arachidonic acid (ARA) and docosahexaenoic acid (DHA), significantly decreased from the first to the third trimester of pregnancy. Furthermore, DHA significantly decreased from the third trimester of pregnancy to delivery. At all gestational stages, linoleic acid (LA) and α-linolenic acid were significantly higher with the number of minor FADS1 SNP alleles, whereas γ-linolenic acid and ARA and the ARA/LA ratio were significantly lower. DHA was significantly lower with the number of minor FADS1 SNP alleles only in the third trimester and at delivery, suggesting that genotype effects become more obvious as pregnancy progresses.

The α7 subtype of the nicotinic acetylcholine receptor (α7 nAChR: coded by Chrna7) is known to regulate the cholinergic ascending anti-inflammatory pathway. We previously reported that Chrna7 knock-out (KO) mice show depression-like behaviors through abnormal composition of gut microbiota and systemic inflammation. Given the role of subdiaphragmatic vagus nerve in gut-microbiota-brain axis, we investigated whether subdiaphragmatic vagotomy (SDV) could affect depression-like behaviors, abnormal composition of gut microbiota, and microbes-derived metabolites in Chrna7 KO mice. SDV blocked depression-like behaviors and reduced expression of synaptic proteins in the medial prefrontal cortex (mPFC) of Chrna7 KO mice. LEfSe (linear discriminant analysis effect size) analysis revealed that the species Lactobacillus sp. BL302, the species Lactobacillus hominis, and the species Lactobacillus reuteri, were identified as potential microbial markers in the KO + SDV group. There were several genus and species altered among the three groups [wild-type (WT) + sham group, KO + sham group, KO + SDV group]. Furthermore, there were several plasma metabolites altered among the three groups. Moreover, there were correlations between relative abundance of several microbiome and behavioral data (or synaptic proteins). Network analysis showed correlations between relative abundance of several microbiome and plasma metabolites (or behavioral data). These data suggest that Chrna7 KO mice produce depression-like behaviors and reduced expression of synaptic proteins in the mPFC through gut-microbiota-brain axis via subdiaphragmatic vagus nerve.

Otitis media, one of the most common childhood diseases, is characterized by inflammation or infection of the middle ear. Due to their ease of access, daily probiotics are recommended for the prevention of early childhood otitis media. This study aimed to assess the impact of probiotics on the incidence of otitis media using a dataset (n = 95,380) from the Japan Environment and Children’s Study, a nationwide birth cohort study. After multiple imputations, the association between the incidence of otitis media in early childhood and the daily frequency of yogurt intake in children and mothers was examined using a generalized linear model after adjusting for several confounders. Repeated incidence of otitis media during the 2 years after birth was found in 14,874 participants (15.6%). Based on participants with the lowest frequency of yogurt intake (“almost never”) as the reference group, risk ratios for otitis media incidence decreased with higher frequencies of yogurt intake in children at one year of age, but also independently in mothers during pregnancy. The lowest risk ratio (95% confidence interval) for otitis media incidence at six months of age was observed with the most frequent yogurt intake (once/day or more) (0.54 [0.46–0.63]). Additionally, although a similar association was observed in the subgroup of those with cleft lip and/or palate (CL/P), a high-risk group for severe recurrent otitis media, no statistical significance was observed. Thus, increased regular yogurt intake in both children and mothers was associated with a decrease of otitis media during early childhood.

The indoor environment, particularly indoor air quality (IAQ), is significantly associated with building-related symptoms (BRSs) in humans. In our previous studies, we demonstrated a significant relationship between BRSs and indoor chemical concentrations. In Japan, the Ministry of Health, Labor, and Welfare (MHLW) guideline recommends an air quality target of 13 volatile organic compounds (VOCs) and a provisional target of 400 μg/m3 for total VOCs (TVOC). The objective of this study was to determine the relationship between TVOC levels and the risk of BRSs using the Japanese provisional target TVOC level of 400 μg/m3. The relationship between odor intensity and BRSs while the TVOC levels were under 400 μg/m3 was also examined. The study was conducted in a laboratory house (LH) on the campus of Chiba University from 2017-2019. The study included 149 participants who spent 60 minutes in the LH. The participants were asked to evaluate the IAQ of the LH. A significant relationship between the risk of BRSs and the provisional target TVOC level was observed (odds ratio: 2.94, 95% confidence interval: 1.18-7.35). Furthermore, a significant relationship between odor intensity and risk of BRSs in spaces with TVOC levels less than 400 μg/m3 was detected (odds ratio: 6.06, 95% confidence interval: 1.21-30.44). In conclusion, the risk of BRSs is significantly lower in spaces with low TVOC levels and low odor intensity. Reducing the concentration of airborne chemicals and odor intensity may improve IAQ and prevent BRSs.

Abstract Evidence regarding the long-term risk of infections in preterm infants is lacking. In this study, we examined whether preterm infants developed various common childhood infections more frequently than full-term infants by the age of 2 years by analyzing data from a questionnaire completed by 67,282 mother–toddler pairs in a nationwide birth cohort study. Of the target population, 2885 (4.3%) were born prematurely. After covariate adjustment for maternal and children factors, lower respiratory tract infections appeared more frequent in preterm than in full-term infants at both 1 and 2 years (adjusted odds ratio [aOR] 1.21, 95% confidence interval [CI] 1.05–1.41, and aOR 1.27, 95% CI 1.11–1.46, respectively). However, there was no significant difference in the frequencies of lower respiratory tract infection between preterm and full-term infants after Palivizumab administration. The risk of other common infections, such as in the upper respiratory tract infection, otitis media, urinary tract infection, gastroenteritis, herpangina, hand-foot-and-mouth disease, chickenpox, influenza virus, and adenovirus infections, was not higher in preterm than in full-term infants after covariates adjustment for maternal and children factors. These findings suggest Palivizumab prophylaxis could reduce the frequencies of lower respiratory tract infection in preterm to the same level as in full-term infants.

3,4-Methylenedioxymethamphetamine (MDMA), the most widely used illicit compound worldwide, is the most attractive therapeutic drug for post-traumatic stress disorder (PTSD). Recent observational studies of US adults demonstrated that lifetime MDMA use was associated with lower risk of depression. Here, we examined whether repeated administration of MDMA can affect resilience versus susceptibility in mice exposed to chronic social defeat stress (CSDS). CSDS produced splenomegaly, anhedonia-like phenotype, and higher plasma levels of interleukin-6 (IL-6) in the saline-treated mice. In contrast, CSDS did not cause these changes in the MDMA-treated mice. Analysis of gut microbiome found several microbes altered between saline + CSDS group and MDMA + CSDS group. Untargeted metabolomics analysis showed that plasma levels of N-epsilon-methyl-L-lysine in the saline + CSDS group were significantly higher than those in the control and MDMA + CSDS groups. Interestingly, there were positive correlations between plasma IL-6 levels and the abundance of several microbes (or plasma N-epsilon-methyl-L-lysine) in the three groups. Furthermore, there were also positive correlations between the abundance of several microbes and N-epsilon-methyl-L-lysine in the three groups. In conclusion, these data suggest that repeated administration of MDMA might contribute to stress resilience in mice subjected to CSDS through gut-microbiota-brain axis.

Multiple sclerosis (MS) is the most common demyelinating disease that attacks the central nervous system. Dietary intake of cuprizone (CPZ) produces demyelination resembling that of patients with MS. Given the role of the vagus nerve in gut-microbiota-brain axis in development of MS, we performed this study to investigate whether subdiaphragmatic vagotomy (SDV) affects demyelination in CPZ-treated mice. SDV significantly ameliorated demyelination and microglial activation in the brain compared with sham-operated CPZ-treated mice. Furthermore, 16S ribosomal RNA analysis revealed that SDV significantly improved the abnormal gut microbiota composition of CPZ-treated mice. An untargeted metabolomic analysis demonstrated that SDV significantly improved abnormal blood levels of metabolites in CPZ-treated mice compared with sham-operated CPZ-treated mice. Notably, there were correlations between demyelination or microglial activation in the brain and the relative abundance of several microbiome populations, suggesting a link between gut microbiota and the brain. There were also correlations between demyelination or microglial activation in the brain and blood levels of metabolites. Together, these data suggest that CPZ produces demyelination in the brain through the gut-microbiota-brain axis via the subdiaphragmatic vagus nerve.

Background: Extra energy intake is commonly recommended for pregnant women to support fetal growth. However, relevant data regarding variations in energy intake and expenditure, body mass index and gestational weight gain (GWG) are frequently not considered. This study aimed to investigate how energy intake during pregnancy and gestational weight gain (GWG) are associated with birth weight. Methods: Early pregnant women were recruited into a Japanese nationwide prospective birth cohort study between 2011 and 2014. We analysed data of 89,817 mother-child pairs of live-born non-anomalous singletons after excluding births before 28 weeks or after 42 weeks. Energy intake during pregnancy was estimated from self-administered food frequency questionnaires (FFQ) and was stratified into low, medium, and high. Participants completed the FFQ in mid-pregnancy (mean 27.9 weeks) by recalling food consumption at the beginning of pregnancy. Effects of energy intake on birth weight and mediation by GWG were estimated using the Karlson–Holm–Breen method; the method separates the impact of confounding in the comparison of conditional and unconditional parameter estimates in nonlinear probability models. Relative risks and risk differences for abnormal birth size were calculated. Results: Mean daily energy intake, GWG, and birth weight were 1682.1 (533.6) kcal, 10.3 (4.0) kg, and 3032.3 (401.4) g, respectively. 6767 and 9010 women had small-for-gestational-age and large-for-gestational-age infants, respectively. Relative to low energy intake, moderate and high intakes increased adjusted birth weights by 13 g and 24 g, respectively: 58 and 69% of these effects, respectively, were mediated by GWG. Compared with the moderate energy intake group, the low energy intake group had seven more women per 1000 women with a small-for-gestational-age birth, whereas the high energy intake group had eight more women per 1000 women with a large-for-gestational-age birth. Conclusion: GWG mediates the effect of energy intake on birth weight. All pregnant women should be given adequate nutritional guidance for optimal GWG and fetal growth.

Background: Our recent observational study showed that regular consumption of cow’s milk (CM) formula during early infancy (3–6 months old) was associated with a reduced risk of CM allergy (CMA) at 12 months old. However, the long-term association is unclear. The present study was aimed to examine how long this inverse association persists after 12 months old. Methods: This study used the dataset of an ongoing nationwide prospective cohort, the Japan Environment and Children’s Study, in which participants were registered between January 2011 and March 2014. We analyzed 65,568 children followed-up until 36 months old. The exposure factors were the consumption statuses of formula milk from 0–3, 3–6, and 6–12 months old. The primary outcome was the prevalence of CMA at 6, 12, 18, 24 and 36 months old. CMA was defined as an allergic reaction and sensitization to CM protein in an individual with no or limited intake of this protein at the evaluation time, combined with physician-diagnosed food allergy. Multivariable regression models were used to estimate the association between the periods of formula consumption and the prevalence of CMA. Results: The prevalence of CMA increased with a peak of 1.51% at 18 months old and then declined to 0.79% at 36 months old. Formula milk from 3–6 months old was associated with a reduced risk of CMA throughout the first 3 years of life, although the extent of the reduction was mitigated with age (adjusted relative risk: [95% confidence interval]: 0.19 [0.10–0.34] at 12 months old, 0.23 [0.16–0.33] at 18 months old, 0.41 [0.26–0.64] at 24 months old, and 0.47 [0.26–0.80] at 36 months old). The association between early formula and CMA were observed in both children with and without eczema, but more prominent and long-lasting in the former than the latter. Conclusions: Regular exposure to CM protein during infancy was associated with a reduced prevalence of CMA during early childhood. At present, however, this observational study does not necessarily encourage formula feeding, and randomized controlled trials are warranted to confirm the findings and their significance.