The Japan Environment and Children's Study (JECS): A Preliminary Report on Selected Characteristics of Approximately 10 000 Pregnant Women Recruited During the First Year of the Study

Advancing Understanding of Chemical Exposures and Maternal-child Health Through the U.S. Environmental Influences on Child Health Outcomes (ECHO) Program: A Scoping Review

PURPOSE OF REVIEW

Environmental chemical exposures may disrupt child development, with long-lasting health impacts. To date, U.S. studies of early environmental exposures have been limited in size and diversity, hindering power and generalizability. With harmonized data from over 60,000 participants representing 69 pregnancy cohorts, the National Institutes of Health's Environmental influences on Child Health Outcomes (ECHO) Program is the largest study of U.S. children's health. Here, we: (1) review ECHO-wide studies of chemical exposures and maternal-child health; and (2) outline opportunities for future research using ECHO data.

RECENT FINDINGS

As of early 2024, in addition to over 200 single-cohort (or award) papers on chemical exposures supported by ECHO, ten collaborative multi-cohort papers have been made possible by ECHO data harmonization and new data collection. Multi-cohort papers have examined prenatal exposure to per- and polyfluoroalkyl substances (PFAS), phthalates, phenols and parabens, organophosphate esters (OPEs), metals, melamine and aromatic amines, and emerging contaminants. They have primarily focused on describing patterns of maternal exposure or examining associations with maternal and infant outcomes; fewer studies have examined later child outcomes (e.g., autism) although follow up of enrolled ECHO children continues. The NICHD's Data and Specimen Hub (DASH) database houses extensive ECHO data including over 470,000 chemical assay results and complementary data on priority outcome areas (pre, peri-, and postnatal, airway, obesity, neurodevelopment, and positive health), making it a rich resource for future analyses. ECHO's extensive data repository, including biomarkers of chemical exposures, can be used to advance our understanding of environmental influences on children's health. Although few published studies have capitalized on these unique harmonized data to date, many analyses are underway with data now widely available.

Association between maternal multimorbidity and neurodevelopment of offspring: a prospective birth cohort study from the Japan Environment and Children's Study

OBJECTIVES

To investigate the association between multimorbidity during pregnancy and neurodevelopmental delay in offspring using data from a Japanese nationwide birth cohort study.

DESIGN

This study was a prospective birth cohort study.

SETTING

This study population included 104 059 fetal records who participated in The Japan Environment and Children's Study from 2011 to 2014.

PARTICIPANTS

Pregnant women whose children had undergone developmental testing were included in this analysis.

PRIMARY AND SECONDARY OUTCOME MEASURES

Neurodevelopment of offspring was assessed using the Japanese version of the Ages and Stages Questionnaire, third edition, comprising five developmental domains. The number of comorbidities among the pregnant women was categorised as zero, single disease or multimorbidity (two or more diseases). Maternal chronic conditions included in multimorbidity were defined as conditions with high prevalence among women of reproductive age. A multivariate logistic regression analysis was conducted to examine the association between multimorbidity in pregnant women and offspring development.

RESULTS

Pregnant women with multimorbidity, single disease and no disease accounted for 3.6%, 30.6% and 65.8%, respectively. The ORs for neurodevelopmental impairment during the follow-up period were similar for infants of mothers with no disease comorbidity and those with a single disease comorbidity. However, the ORs for neurodevelopmental impairment were significantly higher for children born to mothers with multimorbidity compared with those born to healthy mothers.

CONCLUSION

An association was observed between the number of comorbidities in pregnant women and developmental delay in offspring. Multimorbidity in pregnant women may be associated with neurodevelopmental delay in their offspring. Further research is required in this regard in many other regions of the world.

The association between flooring materials and childhood asthma: A prospective birth cohort in the Japan Environment and Children's Study

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.

Prenatal risk factors of indoor environment and incidence of childhood eczema in the Japan Environment and Children's Study

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.

Validity of the ESSENCE-Q neurodevelopmental screening tool in Japan

AIM

To assess the validity of the Early Symptomatic Syndromes Eliciting Neurodevelopmental Clinical Examinations-Questionnaire (ESSENCE-Q), a simple screening tool for neurodevelopmental problems, in Japan.

METHOD

Parents/caregivers completed the 11-item ESSENCE-Q for 77 612 children aged 2 years 6 months included in a national birth cohort study. Information about neurodevelopmental disorders (NDDs: autism spectrum disorder; intellectual disability and/or developmental language disorder; motor delay/motor disorder) was collected at age 3 years. Each ESSENCE-Q item was scored on a binary (0,1) scale, with a total score range of 0 to 11. Total scores and individual items were compared across children with and without NDDs.

RESULTS

NDDs were recorded in 854 children (1.1%). With a total ESSENCE-Q score cut-off of ≥3, receiver operating characteristic curve analysis showed an area under the curve of 0.91, with sensitivity 84.9%, specificity 84.8%, positive predictive value 5.9%, and negative predictive value 99.8%. The proportion of parental concerns at 2 years 6 months differed significantly by NDD status for communication (89.5% vs 14.2%) and general development (80.2% vs 7.4%). ESSENCE-Q total scores were moderately negatively correlated (-0.36, p < 0.001) with Japanese Ages and Stages Questionnaire scores.

INTERPRETATION

The parent/caregiver-completed ESSENCE-Q is useful as a tool for screening out children with neurotypical development at this early age. Further research into longer-term predictive validity will be possible as more NDD diagnoses are given as the children grow up.

Early childhood neurodevelopmental milestones in children with allergic diseases: the Japan Environment and Children's Study (JECS)

This study investigated the potential link between early childhood allergic diseases and neurodevelopmental milestone attainment during the first 3 years of life. Utilizing data from a large-scale prospective birth cohort study in Japan, encompassing 87,986 children, we examined physician-diagnosed and caregiver-reported allergic conditions, including atopic dermatitis (AD), asthma, and food allergy (FA). Neurodevelopmental milestones were assessed using the Ages and Stages Questionnaires at 1, 1.5, 2, 2.5, and 3 years of age. Stabilized inverse probability-weighted generalized estimating equation models were employed to estimate odds ratios (ORs). Our analysis revealed no significant association of AD and asthma with delay in communication, gross motor, fine motor, problem-solving, and personal-social skills during the initial 3 years of life. However, children with FA showed an increased likelihood of experiencing gross motor delay compared with that shown by those without FA (weighted adjusted OR: 1.14). Despite this, no significant association of FA with other developmental domains was observed. Early childhood allergies may not influence neurodevelopmental delays. However, there is a potential association between FA and delays, specifically in gross motor skills, that warrants routine developmental monitoring and additional investigations.

Neurodevelopmental outcomes at age 3 years after moderate preterm, late preterm and early term birth: the Japan Environment and Children's Study

OBJECTIVE

To assess the association between gestational age classification at birth and the risk of neurodevelopmental impairments at age 3 years.

DESIGN

Cohort study using the Japan Environment and Children's Study database.

PATIENTS

A total of 86 138 singleton children born without physical abnormalities at 32-41 weeks of gestation enrolled between January 2011 and March 2014.

MAIN OUTCOME MEASURES

Neurodevelopmental impairment, evaluated using the Ages and Stages Questionnaire (third edition).

METHODS

Logistic regression analysis was used to evaluate the risk of neurodevelopmental impairment in moderate preterm, late preterm and early term children compared with term children after adjusting for socioeconomic and perinatal factors.

RESULTS

The respective adjusted ORs (95% CIs) of incidence of scores below the cut-off value (<-2.0 SD) at age 3 years for moderate preterm, late preterm and early term births, compared with full-term births, were as follows: communication, 2.40 (1.54 to 3.73), 1.43 (1.19 to 1.72) and 1.11 (1.01 to 1.21); gross motor, 2.55 (1.69 to 3.85), 1.62 (1.36 to 1.93) and 1.20 (1.10 to 1.30); fine motor, 1.93 (1.34 to 2.78), 1.55 (1.35 to 1.77) and 1.08 (1.01 to 1.15); problem solving, 1.80 (1.22 to 2.68), 1.36 (1.19 to 1.56) and 1.07 (1.00 to 1.14) and personal-social, 2.09 (1.29 to 3.40), 1.32 (1.07 to 1.63) and 1.00 (0.91 to 1.11).

CONCLUSION

Moderate preterm, late preterm and early term births were associated with developmental impairment at age 3 years compared with full-term births, with increasing prematurity. Careful follow-up of non-full-term children by paediatricians and other healthcare providers is necessary for early detection of neurodevelopmental impairment and implementation of available intervention.

Association between maternal blood or cord blood metal concentrations and catch-up growth in children born small for gestational age: an analysis by the Japan environment and children's study

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.

Maternal Autistic Traits and Adverse Birth Outcomes

Importance

Women with a high level of autistic traits in the general population may experience larger health disparities during pregnancy, particularly women diagnosed with autism spectrum disorder (ASD), which in turn may be associated with increased risk of adverse birth outcomes.

Objective

To investigate the association between maternal autistic traits and the risk of adverse birth outcomes in the general population.

Design, Setting, and Participants

This cohort study included mothers of singletons from a nationwide, multicenter prospective birth cohort, the Japan Environmental Children's Study. Expecting mothers were recruited between January 2011 and March 2014. Data were analyzed between June 2021 and November 2023.

Exposures

Autistic traits were self-reported during the second and third trimesters using the short form of the Autism-Spectrum Quotient Japanese version (AQ-J10) (score range, 0-10; clinical range, ≥7).

Main Outcomes and Measures

Data on preterm birth (<37 weeks' gestation) and neonates born small for gestational age (SGA) were transcribed from medical records. Additional analysis of gestational age groups (very preterm birth, <32 weeks' gestation; moderate-to-late preterm birth, 32-36 weeks' gestation) was also performed.

Results

Among 87 687 women (mean [SD] age, 31.2 [5.0] years) included in the study, 2350 (2.7%) had AQ-J10 scores within the clinical range yet only 18 (0.02%) were diagnosed with ASD. A higher AQ-J10 score was associated with an increased risk of all birth outcomes, including preterm births (relative risk [RR] per 1-SD increase, 1.06; 95% CI, 1.03-1.09), moderate-to-late preterm births (RR per 1-SD increase, 1.05; 95% CI, 1.01-1.08), very preterm births (RR per 1-SD increase, 1.16; 95% CI, 1.06-1.26), and child born SGA (RR per 1-SD increase, 1.04; 95% CI, 1.01-1.06) after adjusting for maternal and pregnancy-related factors. The risks of all outcomes increased with higher AQ-J10 scores; compared with women below the clinical range, women within the clinical range had greater risk of preterm births (RR, 1.16; 95% CI, 1.07-1.26), moderate-to-late preterm births (RR, 1.12; 95% CI, 1.03-1.22), very preterm births (RR, 1.49; 95% CI, 1.18-1.89), and a child born SGA (RR, 1.11; 95% CI, 1.04-1.19).

Conclusions and Relevance

In this cohort study, higher level of maternal autistic traits was associated with increased risk of adverse birth outcomes, particularly very preterm birth. Acknowledging the risks and providing tailored and timely antenatal care support to women with a high level of autistic traits in the general population, particularly women with autistic traits within the clinical range, regardless of formal diagnosis, is warranted.

Screen Time and Developmental Performance Among Children at 1-3 Years of Age in the Japan Environment and Children's Study

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.

Prediction of gestational diabetes mellitus using machine learning from birth cohort data of the Japan Environment and Children's Study

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.

Neurodevelopmental Outcomes Among Offspring Exposed to Corticosteroid and B2-Adrenergic Agonists In Utero

Importance

Corticosteroids and β2-adrenergic agonists are commonly used during pregnancy to treat asthma. However, offspring neurodevelopmental outcomes following in utero exposure to these medications remain unclear.

Objective

To investigate the association between timing of in utero exposure to corticosteroids and β2-adrenergic agonists and offspring neurodevelopmental milestones during the first 3 years of life.

Design, Setting, and Participants

This cohort study obtained data from the Japan Environment and Children's Study, an ongoing birth cohort study conducted in collaboration with 15 Regional Centers across Japan. Participants were mother-offspring pairs who were recruited between January 1, 2011, and March 31, 2014. Data were analyzed between January and February 2023.

Exposure

Corticosteroids and β2-adrenergic agonists were the exposure of interest. Timing of corticosteroid and β2-adrenergic agonist exposure included early pregnancy (weeks 0-12), mid- to late pregnancy (weeks >12), and both stages of pregnancy.

Main Outcomes and Measures

Offspring neurodevelopmental milestones (communication, gross motor, fine motor, problem-solving, and personal-social skills) were assessed using the Japanese version of the Ages and Stages Questionnaires, 3rd edition, at 6, 12, 18, 24, 30, and 36 months.

Results

In total, 91 460 mother-offspring pairs were analyzed. Among mothers, the mean (SD) age at delivery was 31.20 (5.05) years. Among offspring, 46 596 (50.9%) were males and 44 864 (49.1%) were females, of whom 66.4% had a gestational age of 39 to 41 weeks. During early, mid- to late, and both stages of pregnancy, 401 (0.4%), 935 (1.0%), and 568 (0.6%) offspring, respectively, were exposed to corticosteroids, whereas 170 (0.2%), 394 (0.4%), and 184 (0.2%), respectively, were exposed to β2-adrenergic agonists. No association of corticosteroid exposure during early, mid- to late, and both stages of pregnancy with all 5 neurodevelopmental milestones was found. Similarly, no association between β2-adrenergic agonist use during early pregnancy and all 5 neurodevelopmental milestones was observed. An association was found between β2-adrenergic agonist exposure during mid- to late pregnancy and delayed personal-social skills (adjusted odds ratio, 1.48; 95% CI, 1.01-2.32; P = .045).

Conclusions and Relevance

Results of this study found no association between in utero corticosteroid and β2-adrenergic agonist exposure and offspring neurodevelopmental outcomes, regardless of the timing of exposure. Despite the limitations and low power of the study, the findings suggest that corticosteroids and β2-adrenergic agonists are safe for pregnant individuals with asthma and the neurodevelopment of their offspring.

Obesity as a potential risk factor for stillbirth: The Japan Environment and Children's Study

The relationship between high body mass index (BMI) >25 kg/m2 and risk for stillbirth in the Japanese population remains unclear. This study aimed to estimate the impact of maternal obesity on the risk of stillbirth in a Japanese population. This prospective cohort study used data from the Japan Environment and Children's Study, which recruited pregnant individuals between 2011 and 2014. A total of 93,772 fetuses were considered eligible for inclusion in this study. Stillbirth (fetal death before or during labor at ≥22 completed weeks of gestation) rates were compared among four pre-pregnancy BMI groups: underweight (<18.5 kg/m2), reference (18.5 to <25.0 kg/m2), overweight (25.0 to <30.0 kg/m2), and obese (≥30.0 kg/m2). The association between pre-pregnancy BMI and the risk of stillbirth was estimated using multiple logistic regression analyses. The overall stillbirth incidence was 0.33% (305/93,722). Compared with the reference group, the risk of stillbirth was significantly higher in the overweight group (adjusted odds ratio [aOR]: 1.55; 95% confidence interval [CI]: 1.08-2.23) and the obese group (aOR: 2.60; 95% CI: 1.59-4.24). The overall incidence of early stillbirth (i.e., <28 weeks) was 0.17% (155/93,722). Similarly, after adjusting for potential confounding factors, the risk of early stillbirth was significantly higher in the obese group (aOR: 4.33; 95% CI: 2.44-7.70). Increased maternal BMI was associated with an increased risk of stillbirth in the Japanese population. Therefore, counselling women planning for pregnancy on the importance of an appropriate pre-pregnancy BMI to minimize the risk of stillbirth is important.

Refractive Error and Axial Length and Their Related Factors in 8-Year-Old Japanese Children: The Yamanashi Adjunct Study of the Japan Environment and Children's Study (JECS)

PURPOSE

To investigate the distribution of visual acuity, refractive error, and axial length in 8-year-old children who participated in an additional survey in Yamanashi Prefecture of the Japan Environmental Children's Study (hereafter referred to as JECS-Y) conducted from 2019 to 2021.

PARTICIPANTS AND METHODS

Eight-year-old children who participated in the JECS-Y study were subjected to noncycloplegic measurements of refractive error and axial length. If the uncorrected visual acuity was less than 20/20, the best corrected visual acuity was evaluated in accordance with the autorefraction data. A questionnaire was administered regarding the parent's history of eyeglass wear or contact lens use.

RESULTS

Among the 400 participating children, the rate of uncorrected visual acuity of 20/20 or better in both eyes was 70.4%. The mean equivalent spherical equivalent error for both eyes was -0.366 ± 1.016 D. The mean axial length was 23.08 ± 0.225 mm in all patients. The males showed significantly longer axial length than the females despite no differences in body height. There was a significant correlation between axial length, spherical refractive, and uncorrected visual acuity. The children of parents with a history of wearing eyeglasses or contact lenses showed a significantly more myopic equivalent refractive error than those without a history.

CONCLUSIONS

This study clarified the current state of refractive error in 8-year-old children and the association of inheritance with refractive error. In addition, the axials were significantly longer in male patients.

Prenatal exposure to selenium, mercury, and manganese during pregnancy and allergic diseases in early childhood: The Japan Environment and Children's study

BACKGROUND

Prenatal exposure to metallic elements may adversely affect early childhood health. However, more evidence is needed as population-based cohort studies are currently limited.

OBJECTIVES

We aimed to examine the associations between prenatal metallic (mercury, selenium, and manganese) exposure and the risk of allergic diseases in early childhood until three years of age.

METHODS

The data from 94,794 mother-infant pairs, who participated in the Japan Environment and Children's study, were used in this study. Prenatal metallic element exposure was measured in maternal blood collected during mid-pregnancy. The incidence of atopic dermatitis, food allergies, asthma, and allergic rhinitis during the first three years of life was prospectively investigated using self-reports of physician-diagnosed allergies. A multivariable modified Poisson regression model was used to estimate the cumulative incidence ratio and their 95% confidence intervals of allergic diseases associated with prenatal exposure to mercury, selenium, and manganese. We further evaluated the interaction between mercury and selenium exposures in this association.

RESULTS

We confirmed 26,238 cases of childhood allergic diseases: atopic dermatitis, food allergies, asthma, and allergic rhinitis in 9,715 (10.3%), 10,897 (11.5%), and 9,857 (10.4%), 4,630 (4.9%), respectively. No association was found between prenatal mercury or manganese exposure and the risk of allergic diseases. Prenatal selenium exposure was inversely associated with atopic dermatitis, food allergies, allergic rhinitis, and any allergic diseases, but not with asthma. These inverse associations were more pronounced for lower mercury exposures than for higher exposures.

CONCLUSIONS

Our findings suggest that prenatal exposure to selenium may be beneficial for reducing the risk of atopic dermatitis, food allergies, allergic rhinitis, and any allergic diseases in early childhood, especially with lower prenatal mercury exposure.

Maternal dietary fiber intake during pregnancy and child development: the Japan Environment and Children's Study

Background

Animal studies have shown that maternal low-fiber diets during pregnancy may impair brain development and function in offspring, but this has not been validated by epidemiological studies. The aim of this study was to investigate the link between maternal dietary fiber intake during pregnancy and neurodevelopmental delay in offspring using a large birth cohort.

Methods

A total of 76,207 mother-infant pairs were analyzed using data from the Japan Environment and Children's Study, a nationwide prospective cohort study. Maternal dietary fiber intake was estimated using the food frequency questionnaire in mid-pregnancy. Maternal dietary fiber intake was adjusted for energy and classified into quintiles. Developmental delay was assessed in five domains using the Japanese version of the Ages and Stages Questionnaire, Third Edition at the age of 3 years. The logistic regression analysis was performed to estimate the odds ratio (OR) and 95% confidence interval (CI) for the link between dietary fiber intake during pregnancy and developmental delay at the age of 3 years.

Results

The lowest intake group of total dietary fiber had a higher risk of delayed communication [adjusted OR (aOR), 1.51; 95% CI, 1.32-1.74], fine motor (aOR, 1.45; 95% CI, 1.32-1.61), problem-solving (aOR, 1.46; 95% CI, 1.32-1.61), and personal-social skills (aOR, 1.30; 95% CI, 1.12-1.50) than did the highest intake group. An analysis that excluded the effects of insufficient folic acid intake during pregnancy also showed a similar trend.

Conclusion

This study showed that maternal dietary fiber deficiency during pregnancy might influence an increased risk of neurodevelopmental delay in offspring.

Longitudinal study of the relationship between number of prior miscarriages or stillbirths and changes in quality of life of pregnant women: the Japan Environment and Children's Study (JECS)

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.

Association between frequency of breakfast intake before and during pregnancy and infant birth weight: the Tohoku Medical Megabank Project Birth and Three-Generation Cohort Study

BACKGROUND

Low birth weight is associated with an increased risk of developing chronic diseases in adulthood, with a particularly high incidence in Japan among developed countries. Maternal undernutrition is a risk factor for low birth weight, but the association between the timing of food intake and infant birth weight has not been investigated. This study aimed to examine the association between breakfast intake frequency among Japanese pregnant women and infant birth weight.

METHODS

Of all pregnant women who participated in the Tohoku Medical Megabank Project Three Generation Cohort Study, 16,820 who answered the required questions were included in the analysis. The frequency of breakfast intake from pre- to early pregnancy and from early to mid-pregnancy was classified into four groups: every day and 5-6, 3-4, and 0-2 times/week. Multivariate linear regression models were constructed to examine the association between breakfast intake frequency among pregnant women and infant birth weight.

RESULTS

The percentage of pregnant women who consumed breakfast daily was 74% in the pre- to early pregnancy period and 79% in the early to mid-pregnancy period. The average infant birth weight was 3,071 g. Compared to women who had breakfast daily from pre- to early pregnancy, those who had breakfast 0-2 times/week had lower infant birth weight (β = -38.2, 95% confidence interval [CI]: -56.5, -20.0). Similarly, compared to women who had breakfast daily from early to mid-pregnancy, those who had breakfast 0-2 times/week had lower infant birth weight (β = -41.5, 95% CI: -63.3, -19.6).

CONCLUSIONS

Less frequent breakfast intake before and mid-pregnancy was associated with lower infant birth weight.

Association between maternal socioeconomic status and breastfeeding: Results from the Japan environment and children's study

Although breastfeeding has various benefits for mothers and children, there are several barriers to continuing breastfeeding practices. However, little is known about the relationship between breastfeeding in Japan and maternal socioeconomic circumstances. Based on data from the Japan Environment and Children's Study (n = 75,742), we evaluated maternal socioeconomic factors associated with breastfeeding 1 year after giving birth. Socioeconomic status (education, employment status, and household income), working hours, and breastfeeding were assessed using a self-administered questionnaire. After descriptive analysis, a logistic regression analysis was conducted with adjustments for age, educational level, employment status, and household income. Mothers with higher education and full-time homemakers were more likely to breastfeed one-year-old children. Mothers working long hours (both part-time and full-time) were less likely to breastfeed their one-year-old children. To improve breastfeeding among working mothers, it may be helpful to promote awareness of breastfeeding for every mother as well as to make the workplace environment conducive for working mothers to breastfeed.

Maternal smoking status before and during pregnancy and bronchial asthma at 3 years of age: a prospective cohort study

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.

Associations between fetal or infancy pet exposure and food allergies: The Japan Environment and Children's Study

The hygiene hypothesis suggests that pet exposure is effective in preventing allergic disease, and some studies have reported the beneficial effects of dog exposure during fetal development or early infancy on food allergy. However, the effects of exposure to pets other than dogs on the kinds of food allergies remains unaddressed. This study aimed to explore the effect of exposure to various species of pets on the risk of food allergies. We obtained information on pet exposure and food allergy from the Japan Environment and Children's Study, a nationwide, prospective birth cohort study that included 97,413 mothers and their children. We examined the associations between exposure to various species of pets during fetal development or early infancy and the incidence risk of food allergies. We conducted logistic regression analysis for each pet species, causative food, and timing of exposure. Exposure to dogs or cats during fetal development or early infancy was estimated to reduce the incidence risk of food allergies until the age of 3 years. Dog exposure was estimated to reduce the incidence risk of egg, milk, and nut allergies, and cat exposure was estimated to reduce the incidence risk of egg, wheat, and soybean allergies. However, hamster exposure was estimated to increase the incidence risk of nut allergy. In conclusion, the association between pet exposure and food allergies might differ depending on the pet species and causative food. Continued dog and cat exposure from fetal development to infancy was estimated to reduce the incidence risk of food allergies. The findings of this study shall aid in the design of future studies.

Comparison of physician- and self-assessed pubertal onset in Japanese children

Introduction

Physical examinations to assess pubertal development are challenging in large epidemiological surveys. This study aimed to assess the reliability of judgment of pubertal onset in Japanese children by the original pubertal self-assessment sheet.

Methods

A total of 144 children aged 10 or 12 years were recruited between March 2019 and September 2020 from the pediatric endocrine outpatient clinics of participating institutions. Agreement between the physician- and participantassessed pubertal onsets was determined using unweighted kappa (UK) and Gwet's agreement coefficient (AC1).

Results

The physician's assessment of pubertal onset was in slight agreement with that of the self-assessment sheet in 10-year-old boys (UK: 0.23 and AC1: 0.14), whereas the agreement between the physician's assessment and self-assessment sheet results was good and the physician's assessment was fair (UK: 0.64 and AC1: 0.94) in 12-year-old boys. The physician's assessment of pubertal onset were in good and moderate agreement with the self-assessment sheet in 10-year-old girls (UK/AC1: 0.74/0.78, respectively). In 12-year-old girls, although it showed poor agreement with UK (0.46), there was a very good agreement with AC1 (0.88).

Conclusions

Although self-assessment of breast development was in good agreement with that of the physician's assessment for determining pubertal onset in girls, large-scale epidemiological studies are difficult to conduct for adolescent boys, especially for those in the early pubertal stage.

Skipping breakfast during pregnancy and hypertensive disorders of pregnancy in Japanese women: the Tohoku medical megabank project birth and three-generation cohort study

BACKGROUND

Hypertensive disorders of pregnancy (HDP) adversely affect the prognosis of mother and child, and the prognosis depends on the subtype of HDP. Skipping breakfast may be associated with increased blood pressure due to disruption of the circadian clock, but the association with the development of HDP has not been studied. The purpose of this study was to examine the association between skipping breakfast and the development of HDP and HDP subtypes in Japanese pregnant women.

METHODS

Of the pregnant women who participated in the Tohoku Medical Megabank Project Three-Generation Cohort Study, 18,839 who answered the required questions were included in the analysis. This study had a cross-sectional design. The breakfast intake frequency from pre-pregnancy to early pregnancy was classified into four groups: daily, 5-6 times per week, 3-4 times per week, and 0-2 times per week. HDP was classified into gestational hypertension (GH), chronic hypertension (CH), preeclampsia (PE), and severe preeclampsia (SuPE). Multiple logistic regression analysis and multinomial logistic analysis were used to calculate odds ratios (ORs) and 95% confidence intervals (CIs) for breakfast intake frequency and development of HDP or HDP subtypes. We performed a stratified analysis based on energy intake.

RESULTS

Of the participants, 74.3% consumed breakfast daily, and 11.1% developed HDP. Women who consumed breakfast 0-2 times per week had a higher risk of HDP (OR: 1.33, 95% CI: 1.14-1.56), CH (OR: 1.63, 95% CI: 1.21-2.19), and PE (OR: 1.68, 95% CI: 1.27-2.21) than those who consumed breakfast daily. No association was found between skipping breakfast and the risk of developing GH (OR: 1.26, 95% CI: 0.99-1.61) and SuPE (OR: 0.91, 95% CI: 0.55-1.49). Stratified analysis showed that the risk of developing HDP due to skipping breakfast was highest in the group with the highest daily energy intake.

CONCLUSIONS

Skipping breakfast during pre-to early pregnancy is associated with the development of HDP. Further longitudinal studies are required to clarify the causal association between skipping breakfast and HDP.

How a Family History of Allergic Diseases Influences Food Allergy in Children: The Japan Environment and Children's Study

The influence of family allergic history on food allergy in offspring in Japan is unknown. We analyzed data from a nationwide birth cohort study using logistic regression models to examine the associations of maternal, paternal, and both parental histories of allergic diseases (food allergy, atopic dermatitis, asthma, and rhinitis) with their child’s food allergy at 1.5 and 3 years of age. This analysis included 69,379 singleton full-term mothers and 37,179 fathers and their children. All parental histories of allergic diseases showed significant positive associations with their child’s food allergy. When both parents had a history of allergic diseases, the adjusted odds ratio (aOR) tended to be higher than when either parent had allergic diseases (p for trend < 0.0001). The highest aOR was detected when both parents had food allergy (2.60; 95% confidential interval, 1.58−4.27), and the aOR was 1.71 when either parent had food allergy (95% confidential interval, 1.54−1.91). The aORs were attenuated but still had significant positive associations after adjusting for the child’s atopic dermatitis, a risk factor for allergy development. In conclusion, all parental allergic diseases were significantly positively associated with their child’s food allergy. The effect of family history showed a stepwise increase in risk from either parent to both parents, and the highest risk of allergic disease was a parental history of food allergy.

Association of fish intake with menstrual pain: A cross-sectional study of the Japan Environment and Children’s Study

The relationship between fish eating habits and menstrual pain is unknown. Elucidating this relationship can inform dietary guidance for reproductive age women with menstrual pain. The aim of this study was to clarify the relationship between fish intake frequency/preference and menstrual pain. This cross-sectional study was conducted at the Miyagi Regional Center as an adjunct study of the Japan Environment and Children’s Study, and 2060 eligible women (mean age, 31.9 years) participated. Fish intake frequency (“< 1 time/week,” “1 time/week,” “2–3 times/week,” or “≥ 4 times/week”), preference (“like,” “neutral,” or “dislike”), and menstrual pain (no/mild or moderate-to-severe) were assessed at 1.5 years after the last delivery through self-administered questionnaires. The association between fish intake frequency/preference and prevalence of moderate-to-severe menstrual pain was evaluated through logistic regression analyses. Our results show that, compared with the “< 1 time/week” (38.0%) group, the “1 time/week” (26.9%), “2–3 times/week” (27.8%), and “≥ 4 times/week” (23.9%) groups showed a lower prevalence of moderate-to-severe menstrual pain (p < 0.01). The prevalence of moderate-to-severe menstrual pain was 27.7%, 27.6%, and 34.4% in the “like,” “neutral,” and “dislike” groups, respectively. Multivariate logistic regression showed that frequent fish intake was associated with a lower prevalence of moderate-to-severe menstrual pain (“1 time/week”: odds ratio [OR] = 0.59; 95% confidence interval [CI], 0.41–0.86, “2–3 times/week”: OR = 0.64; 95% CI, 0.45–0.90 and “≥ 4 times/week”: OR = 0.52; 95% CI, 0.34–0.80; trend p = 0.004). Multivariate logistic regression showed no association between fish preference and moderate-to-severe menstrual pain (“dislike” vs “like”: OR = 1.16; 95% CI, 0.78–1.73). There was a significant negative association between fish intake frequency and menstrual pain. It is suggested that fish intake can reduce or prevent menstrual pain.

Individual and mixed metal maternal blood concentrations in relation to birth size: An analysis of the Japan Environment and Children's Study (JECS)

BACKGROUND

Growth restriction in the prenatal period is a significant public health concern. Metals can negatively affect birth size, and pregnant women may be exposed to metal mixtures. Comprehensive studies analyzing the effects of combined metal exposure with accurate individual blood metal concentrations are limited. The current study investigated the associations between maternal metal exposure and birth size in a large, nationwide Japanese cohort using individual and mixed model approaches.

METHODS

Lead, cadmium, mercury, selenium, and manganese blood concentrations were measured in pregnant women in the Japan Environment and Children's Study (JECS). Measurements of infant birth size-including body weight, body length, and head and chest circumference-were collected. Linear and logistic regressions were used for birth size measurements and the odds of an infant being small in size for gestational age, respectively. Associations between combined metal mixtures and measurements at birth were evaluated using quantile g-computation and Bayesian kernel machine regression (BKMR).

RESULTS

Of the 103,060 JECS pregnancies, 93,739 mother-infant pairs were analyzed. The linear regression models showed that lead, selenium, cadmium, and manganese-but not mercury-were associated with body weight. Cadmium was associated with length and chest circumference and mercury was associated with head circumference. Quantile g-computation revealed that manganese increased infant birth weight, length, head circumference, and chest circumference. Lead was the strongest negative factor for infant birth weight, length, head circumference, and chest circumference. The BKMR analysis revealed that the metals had an additive, rather than a synergistic effect.

CONCLUSION

Metal exposure is associated with infant birth size, with lead and manganese playing a more significant role in Japan. The effects of prenatal combined metal exposure at low levels warrant public health attention.

Harmonization of Human Biomonitoring Studies in Europe: Characteristics of the HBM4EU-Aligned Studies Participants

Human biomonitoring has become a pivotal tool for supporting chemicals' policies. It provides information on real-life human exposures and is increasingly used to prioritize chemicals of health concern and to evaluate the success of chemical policies. Europe has launched the ambitious REACH program in 2007 to improve the protection of human health and the environment. In October 2020 the EU commission published its new chemicals strategy for sustainability towards a toxic-free environment. The European Parliament called upon the commission to collect human biomonitoring data to support chemical's risk assessment and risk management. This manuscript describes the organization of the first HBM4EU-aligned studies that obtain comparable human biomonitoring (HBM) data of European citizens to monitor their internal exposure to environmental chemicals. The HBM4EU-aligned studies build on existing HBM capacity in Europe by aligning national or regional HBM studies. The HBM4EU-aligned studies focus on three age groups: children, teenagers, and adults. The participants are recruited between 2014 and 2021 in 11 to 12 primary sampling units that are geographically distributed across Europe. Urine samples are collected in all age groups, and blood samples are collected in children and teenagers. Auxiliary information on socio-demographics, lifestyle, health status, environment, and diet is collected using questionnaires. In total, biological samples from 3137 children aged 6-12 years are collected for the analysis of biomarkers for phthalates, HEXAMOLL® DINCH, and flame retardants. Samples from 2950 teenagers aged 12-18 years are collected for the analysis of biomarkers for phthalates, Hexamoll® DINCH, and per- and polyfluoroalkyl substances (PFASs), and samples from 3522 adults aged 20-39 years are collected for the analysis of cadmium, bisphenols, and metabolites of polyaromatic hydrocarbons (PAHs). The children's group consists of 50.4% boys and 49.5% girls, of which 44.1% live in cities, 29.0% live in towns/suburbs, and 26.8% live in rural areas. The teenagers' group includes 50.6% girls and 49.4% boys, with 37.7% of residents in cities, 31.2% in towns/suburbs, and 30.2% in rural areas. The adult group consists of 52.6% women and 47.4% men, 71.9% live in cities, 14.2% in towns/suburbs, and only 13.4% live in rural areas. The study population approaches the characteristics of the general European population based on age-matched EUROSTAT EU-28, 2017 data; however, individuals who obtained no to lower educational level (ISCED 0-2) are underrepresented. The data on internal human exposure to priority chemicals from this unique cohort will provide a baseline for Europe's strategy towards a non-toxic environment and challenges and recommendations to improve the sampling frame for future EU-wide HBM surveys are discussed.

Association Between Screen Time Exposure in Children at 1 Year of Age and Autism Spectrum Disorder at 3 Years of Age: The Japan Environment and Children's Study

IMPORTANCE

It is unclear to what extent the duration of screen time in infancy is associated with the subsequent diagnosis of autism spectrum disorder.

OBJECTIVE

To examine the association between screen time in infancy and the development of autism spectrum disorder at 3 years of age.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study analyzed data from mother-child dyads in a large birth cohort in Japan. This study included children born to women recruited between January 2011 and March 2014, and data were analyzed in December 2020. The study was conducted by the Japan Environment and Children's Study Group in collaboration with 15 regional centers across Japan.

EXPOSURES

Screen time at 1 year of age.

MAIN OUTCOMES AND MEASURES

The outcome variable, children diagnosed with autism spectrum disorder at 3 years of age, was assessed using a questionnaire administered to mothers of the participating children.

RESULTS

A total of 84 030 mother-child dyads were analyzed. The prevalence of children with autism spectrum disorder at 3 years of age was 392 per 100 000 (0.4%), and boys were 3 times more likely to have been diagnosed with autism spectrum disorder than were girls. Logistic regression analysis showed that among boys, when "no screen" was the reference, the adjusted odds ratios were as follows: less than 1 hour, odds ratio, 1.38 (95 % CI, 0.71-2.69; P = .35), 1 hour to less than 2 hours, odds ratio, 2.16 (95 % CI, 1.13-4.14; P = .02), 2 hours to less than 4 hours, odds ratio, 3.48 (95% CI, 1.83-6.65; P < .001), and more than 4 hours, odds ratio, 3.02 (95% CI, 1.44-6.34; P = .04). Among girls, however, there was no association between autism spectrum disorder and screen time.

CONCLUSIONS AND RELEVANCE

Among boys, longer screen time at 1 year of age was significantly associated with autism spectrum disorder at 3 years of age. With the rapid increase in device usage, it is necessary to review the health effects of screen time on infants and to control excessive screen time.

Baseline Complete Blood Count and Chemistry Panel Profile from the Japan Environment and Children's Study (JECS)

BACKGROUND

The Japan Environment and Children's Study (JECS) is a nationwide birth cohort study of environmental factors affecting children's health and development. We summarize the complete blood count and chemistry panel statistical data from pregnant women enrolled in JECS.

METHODS

Statistical data of up to 58,056 mother's sample in their first (gestational age ≤ 13 weeks) and second trimester (22-27 weeks) were calculated.

RESULTS

Mean (SD) values in the first trimester were: white blood cell count, 7866 (1906)/μL; red blood cell count, 417 (33) 10⁴/μL; hemoglobin, 12.4 (1.0) g/dL; hematocrit, 37.1 (2.6)%; mean corpuscular volume, 89.2 (4.7) fL; mean corpuscular hemoglobin, 29.8 (1.9) pg; mean corpuscular hemoglobin concentration, 33.3 (0.9)%; platelet count, 24.8 (5.2) 10⁴/μL; HbA1c, 5.26 (0.26)%; total cholesterol, 181 (28) mg/dL; low density lipoprotein cholesterol, 95 (23) mg/dL; high density lipoprotein cholesterol, 73 (13) mg/dL; free cholesterol, 41 (7) mg/dL; triglycerides, 109 (47) mg/dL; total protein, 6.9 (0.4) g/dL; and albumin, 4.1 (0.2) g/dL. Mean values (SD) in the second trimester were: total cholesterol, 246 (38) mg/dL; free cholesterol, 61 (9) mg/dL; triglycerides, 183 (70) mg/dL; total protein, 6.5 (0.4) g/dL; and albumin, 3.6 (0.2) g/dL.

CONCLUSIONS

These data will be useful for future JECS studies.

The role of bullying victimization in the pathway between autistic traits and psychotic experiences in adolescence: Data from the Tokyo Teen Cohort study

Autistic traits are associated with psychotic experiences in adolescence; however, the mechanisms underlying this relationship are not well understood. Prior research indicates that bullying victimization increases the risk of psychotic experiences in general adolescent populations, and autistic youth are at higher risk of being bullied than their non-autistic peers. Using longitudinal data from general population adolescents aged 10-14 in the Tokyo Teen Cohort study, we tested the hypothesis that bullying is responsible for the association between autistic traits and psychotic experiences in adolescence. We identified an indirect effect (estimate = 0.033 [95% CIs: 0.014-0.057], p < 0.001) between autistic traits and psychotic experiences via bullying victimization, even after controlling for known confounders. Prevention of bullying victimization may be one avenue for reducing risk of psychosis among adolescents with high levels of autistic traits.

Elective cesarean delivery at term and its effects on respiratory distress at birth in Japan: The Japan Environment and Children's Study

BACKGROUND AND AIMS

Early-term birth between 37 and 38 weeks of gestation increases the risk of mortality and morbidity. This study investigated the status and impact of early-term birth among neonates born by cesarean section in Japan.

METHODS

All singleton live births that had data of gestational age at birth available in the Japan Environment and Children's Study (JECS), a nationwide birth cohort study launched in 2011, were eligible for this study. Neonates born by cesarean delivery at term without indications for early delivery were included to examine the association between early-term birth and respiratory distress at birth. The gestational age at birth was categorized as 37 weeks 0 day to 38 weeks 6 days (early-term), 39 weeks 0 day to 40 weeks 6 day (full-term), and 41 weeks 0 day to 41 weeks 6 days (late-term). Respiratory distress at birth included respiratory distress syndrome, transient tachypnea, and difficulty in breathing after birth. Univariable and multivariable analyses were performed using logistic regression models with a two-tailed significance level of 5%. All statistical analyses were performed using SAS, version 9.4, for Windows (SAS Institute, Cary, NC).

RESULTS

In total, 32 078 of 100 011 (32.1%) neonates had early-term birth. At 37 gestational weeks, 49.7% of the deliveries were via cesarean section, and half of the cesarean deliveries were due to a previous cesarean section. Among the 10 051 neonates born by elective cesarean delivery at term, neonates with early-term births were more likely to have respiratory distress at birth (adjusted odds ratio: 4.19; 95% confidence interval, 1.70, 10.34) than those born at full term.

CONCLUSIONS

Early-term birth is associated with a high risk of respiratory distress in births involving cesarean delivery without indication for early delivery. There is a need for guidelines for early delivery considering adverse effects of early-term births.

Influence of Maternal Active and Secondhand Smoking during Pregnancy on Childhood Obesity at 3 Years of Age: A Nested Case-Control Study from the Japan Environment and Children's Study (JECS)

Maternal smoking during pregnancy is a risk factor for childhood obesity; however, the combined effect of secondhand smoking during pregnancy on children in the early years is unclear. We examined the effects of maternal active and secondhand smoking during pregnancy on childhood obesity in a large population-based cohort. A nested case–control study originating from the Japan Environment and Children’s Study was performed. The maternal smoking status was collected via self-administered questionnaires during mid/late pregnancy. Obesity in children was determined based on BMI measured at 3 years of age. In total, 4875 cases and 19,491 controls were included in the analyses. Conditional logistic regression models with a significance level of 5% (two-tailed test) were used to test the association. The proportion of mothers who continued smoking and who were exposed to secondhand smoking daily during pregnancy were 3.9% and 13.0% in cases and 2.9% and 10.8% in controls, respectively. Continuous maternal smoking was associated with increased odds of obesity compared to those who never smoked or quit smoking before the pregnancy (adjusted odds ratio, 1.39; 95% confidence interval, 1.01–1.92). The odds increased further when combined with secondhand smoking. The promotion of non-smoking among family members, in public and workplace could benefit pregnant women and offspring.

Association between Maternal Exposure to Chemicals during Pregnancy and the Risk of Foetal Death: The Japan Environment and Children's Study

Scarce knowledge is available on the relationship between maternal chemical exposure during pregnancy and foetal deaths. We studied the association of spontaneous abortions and stillbirths with occupational or daily maternal exposure to chemicals commonly used by pregnant women. Data from the Japan Environment and Children’s Study (JECS), a nationwide prospective birth cohort study, were used. The participants of the study were asked about the frequency of their use of gasoline, pesticides, hair dye, and chlorine bleach during the first and the second to third trimesters of pregnancy. We investigated the relationship between the frequency of the use of chemicals and foetal death. Of the 104,065 foetuses, 923 (0.91%) were spontaneous abortions and 379 (0.37%) were stillbirths. Any type of exposure during the first trimester was not significantly associated with spontaneous abortions. Nevertheless, a more than weekly occupational use of hair dye from the first to the second/third trimester was significantly associated with stillbirth. The results of this study suggest that the frequent use of hair dye during pregnancy can have severe adverse effects on the foetus. These findings can help pregnant women, especially hairdressers, refrain from the continuous use of hair dyes.

Effect estimate of time-varying social support and trust on the physical and mental health of mothers at 2.5 years postpartum: The Japan Environment and Children's Study (JECS)

BACKGROUND

Many epidemiological studies have reported the association between various social factors and health status in mothers during and after pregnancy. However, little is known about their joint and longitudinal impact. We therefore examined the association of lack of social support and trust during pregnancy and at 2.5 years postpartum with health status in mothers.

METHODS

To adequately address time-varying exposure, marginal structural models were fitted to a pseudopopulation constructed by inverse probability weighting. The model included records of 90,071 mothers participating in the Japan Environment and Children's Study. Social support and trust were measured using a 9-item questionnaire (Q1-9). Mental and physical health were measured using Mental and Physical Component Summary scores from the 8-item Short-Form Health Survey.

RESULTS

For the Mental Component Summary, the magnitude of the effect estimate was largest when participants lacked close friends/neighbors (Q4) at only 2.5 years postpartum (= -6.23), followed by a lack in emotional support (Q2) at the same time point (= -4.94). For the Physical Component Summary, effect estimates were negligible. The magnitude of the effect estimates of lack of social support and trust tended to be larger when there was a lack at only 2.5 years postpartum than at both time points.

CONCLUSIONS

These findings suggest that, after childbirth, a loss in social support, particularly in a concrete or instrumental aspect, carries high risk, especially for mental health. Our results highlight the importance of supporting mothers for more than a few years after pregnancy.

Association between mode of delivery and postpartum depression: The Japan Environment and Children's Study (JECS): a prospective cohort study

BACKGROUND

Postpartum depression (PPD) has been associated with adverse health outcomes including maternal suicide. Mode of delivery has been suggested to be a risk factor for PPD, but no large cohort study has examined the association between mode of delivery and PPD. We aimed to examine the association between mode of delivery and risks of PPD at 1 and 6 months after childbirth.

METHODS

In a nationwide study of 89,954 mothers with a live singleton birth, we examined the association between mode of delivery and risks of PPD. PPD was measured by the Edinburgh Postnatal Depression Scale (≥13) at 1 and 6 months after childbirth. Odds ratios (ORs) with 95% confidence intervals (CIs) of PPD were calculated using multivariable logistic regression analyses after adjustment of antenatal physical, socioeconomic, and mental factors.

RESULTS

Among 89,954 women, 3.7% and 2.8% had PPD at 1 and 6 months after childbirth, respectively. Compared with unassisted vaginal delivery, cesarean section (CS) was marginally associated with PPD at 1 month, but not at 6 months; adjusted ORs were 1.10 (95% CI, 1.00-1.21) and 1.01 (95% CI, 0.90-1.13), respectively. The association with PPD at 1 month was evident in women with antenatal psychological distress: adjusted OR was 1.15 (95% CI, 1.03-1.28). The observed associations were attenuated after adjusting for infant feeding method.

CONCLUSIONS

Women who had antenatal psychological distress and underwent CS delivery may be regarded as a target for monitoring PPD.

Association between Early Life Child Development and Family Dog Ownership: A Prospective Birth Cohort Study of the Japan Environment and Children's Study

Pets may play a role in the social-emotional development of children. In particular, some studies have suggested that family dog ownership is associated with better health outcomes. To date, no study has assessed child development in association with dog ownership of different time points. The purpose of the current study was primary to investigate whether “ever” family dog ownership was associated with early child development, and secondary to further examine whether associations between family dog ownership and early child development differ among family dog ownership of status, including “past only”, “current only”, and “always” groups, using the data of family dog ownership obtained at multiple time points. Associations between family dog ownership and infant development at 3 years of age were examined using data from a nationwide prospective birth cohort study, the Japan Environment and Children’s Study (n = 78,941). “Ever” family dog ownership was categorized to “past only”, “current only”, and “always”. We observed that children with “ever” family dog ownership showed a significantly decreased risk of developmental delay in the communication (odds ratio [OR] = 0.87; 95% confidence interval [CI]: 0.78, 0.96), gross motor (OR = 0.83; 95% CI: 0.76, 0.92), problem-solving (OR = 0.89; 95% CI: 0.83, 0.96) and personal-social (OR = 0.86; 95% CI: 0.72, 0.92) domains compared to children with “never” family dog ownership. Furthermore, a significantly decreased risk of developmental delay in gross motor function was observed in association with living with dogs in the “past only” (OR = 0.83; 95% CI: 0.73, 0.95) and “always” (OR = 0.86; 95% CI: 0.75, 0.98). In addition, a decreased risk of developmental delay in the problem-solving domain was associated with “past” family dog ownership (OR = 0.87; 95% CI: 0.79, 0.97) and in the personal-social domain was associated with “always” family dog ownership (OR = 0.81; 95% CI = 0.68, 0.95). Given the possible positive association between early life child development and family dog ownership, living with dogs may be an important factor to be considered when assessing child development.

Association of prenatal maternal blood lead levels with birth outcomes in the Japan Environment and Children's Study (JECS): a nationwide birth cohort study

BACKGROUND

Despite dramatic declines in prenatal maternal blood lead levels (BLLs) in most developed countries, little is known about the effects of extremely low-level (<1.0 µg/dL) lead exposure on fetal growth.

METHODS

We measured maternal BLL during the second or third trimester of pregnancy and assessed birth outcomes, including birthweight, preterm birth (<37 gestational weeks) risk, small for gestational age births (SGA; birthweight <10th percentile) and low birthweight (LBW; <2500 g). The association between birthweight and maternal BLL was estimated using linear and quadratic spline models. Multivariable logistic models were used to examine the risk of binary responses.

RESULTS

From 103 099 pregnant women, 20 000 blood samples were randomly selected for analysis. The maternal BLL range was 0.16-7.4 µg/dL, and the median was 0.63 µg/dL. After adjusting for covariates, the linear model showed that each 0.1 μg/dL increase in maternal BLL was associated with a 5.4 g decrease in mean birthweight [95% confidence interval (CI), 3.4 to 7.5 g]. The risk of SGA [adjusted odds ratio (aOR), 1.03; 95% CI, 1.02 to 1.05) and LBW (aOR, 1.03; 95% CI, 1.02 to 1.05) increased, whereas the risk of preterm delivery did not (aOR, 0.99; 95% CI, 0.97 to 1.02).

CONCLUSIONS

Even at a maternal BLL below 1.0 µg/dL, prenatal lead exposure was associated with decreased birthweight and increased risk of SGA and LBW, but not preterm delivery. The adverse effect estimates of prenatal lead exposure on birth outcomes were quantitatively small and clinically limited at this low level.

Association of Maternal History of Allergic Features with Preterm Pregnancy Outcomes in the Japan Environment and Children's Study

INTRODUCTION

Previous studies have reported that maternal asthma increases the risk of preterm birth. We hypothesized that inflammatory reactions caused by allergic diseases might affect the uterine environment and, subsequently, perinatal outcomes. The objective of this study was to examine the associations between allergic features among mothers and preterm pregnancy outcomes in a nationwide birth cohort.

METHODS

We analyzed data from pregnant women obtained from the Japanese Environment and Children's Study (JECS), a nationwide general birth cohort study. We used binomial and multinomial logistic regression models to examine the associations between maternal allergic features and preterm birth, threatened preterm labor (TPL), and preterm premature rupture of the membrane (PPROM).

RESULTS

A total of 97,683 pregnant women were included. Prevalence of preterm birth, TPL, and PPROM was 4.7, 19.6, and 1.2%, respectively. Maternal history of allergic diseases (asthma, allergic rhinitis, allergic conjunctivitis, food allergy, drug allergy, and contact dermatitis) increased the risk of TPL(adjusted odds ratio [aOR] = 1.11 [95% CI: 1.06-1.17], aOR = 1.12 [1.08-1.16], aOR = 1.10 [1.04-1.16], aOR = 1.17 [1.09-1.26], aOR = 1.35 [1.23-1.48], and aOR = 1.34 [1.20-1.49], respectively). Although some maternal allergic features showed a negative association with preterm birth, the variables affecting preterm birth differed according to the gestational age of the fetus (22-33 weeks vs. 34-36 weeks). There were no significant associations between maternal allergic features and PPROM.

CONCLUSION

Maternal allergic disease, except atopic dermatitis, may increase the risk of TPL. Comorbidity of maternal allergic disorders and perinatal adverse outcomes require further investigation.

Risk of postpartum depression and very early child mistreatment among mothers reporting higher autistic traits: Evidence from the Japan Environment and Children's Study

BACKGROUND

Little is known about how mothers who report higher autistic traits face new parenthood. This study examined the association between antenatal non-clinical autistic traits and the risks of both postpartum depression (PPD) and child mistreatment at one-month postpartum and if these associations were mediated by preexisting social support.

METHODS

Participants included 73,532 singleton mothers without histories of psychiatric conditions from the Japan Environment and Children's Study, a nationwide birth cohort. Autistic traits were measured during the second/third trimesters using the short-version of the Autism Quotient-Japanese version. Participants were classified into three groups (i.e., typical-range, moderate-range, and high-range). PPD was measured using the Japanese version of the Edinburgh Postnatal Depression Scale, while participants self-reported experiences of child mistreatment (i.e., hit or shake the child); both assessments were conducted at one-month postpartum. Individual social support was reported during pregnancy. Data analyses were conducted through Poisson regressions.

RESULTS

A total of 7,147 (9.7%) participants reported PPD, while 12,994 (17.7%) reported child mistreatment at one-month postpartum. Autistic traits were associated with increased PPD risk (adjusted-relative risk [aRR] =1.74, 95%CI=1.64-1.84 for moderate-range; aRR=2.33, 2.13-2.55 for high-range) and child mistreatment (aRR=1.19, 1.13-1.24 for moderate-range; aRR=1.39, 1.28-1.50 for high-range) independently of confounders. Social support mediated 26-31% of these associations for moderate/high-range groups (both risks).

LIMITATIONS

Self-reported measurements were used.

CONCLUSIONS

Mothers who reported moderate-to-high autistic traits in the general population were vulnerable to PPD and newborn mistreatment at one-month postpartum, which was partially explained by the lack of social support during pregnancy.

Allergy and immunology in young children of Japan: The JECS cohort

BACKGROUND

Capturing epidemiological signatures is essential to document burdens of disease and to design health care services, including prevention measures, clinical interventions, and policies. There are large geographical and ethnic variations in the epidemiology of allergic and immunological diseases. Various data are available from North America and Europe, but the epidemiology of allergic and immunological diseases in Asia is not well documented.

OBJECTIVE

To characterize epidemiological signatures of allergic and immunological disease in young children in Japan.

METHODS

This was a national, multicenter, prospective birth cohort study: Japan Environment and Children's Study (JECS). A general population of 103,060 women was enrolled during pregnancy. Allergic and immunological outcomes were assessed among young children using questionnaire data.

RESULTS

The prevalence of caregiver-reported immediate food allergy was 7.6%, 6.7%, and 4.9% at age 1, 2, and 3 years, respectively. Hen egg allergy was most common (5.4% prevalence at age 1 year) followed by allergies to cow milk and wheat. Several patterns of allergic symptom clusters were identified. Physician diagnosed, as reported by the caregiver, non-IgE mediated gastrointestinal food allergy affected 0.5% of infants. By contrast, caregiver-reported gastrointestinal food allergies affected 1.4% of children. Kawasaki disease affected 0.3% and 0.4% children, respectively, at age 1 and 3 years. Primary immunodeficiency disorders affected 0.005% children at age 3 years.

CONCLUSION

These data provide important epidemiological signatures of allergy and immunology in young Japanese children including the age-specific prevalence of allergic disease, Kawasaki disease, and primary immune deficiency.

Determinants of Alcohol Consumption in Women Before and After Awareness of Conception

OBJECTIVES

We examined the socio-demographic and behavioral factors associated with alcohol consumption before and after pregnancy awareness in pregnant women.

METHODS

This cross-sectional study included 91,828 pregnant women in a nationwide Japanese birth cohort study from 2011 to 2014. Alcohol consumption before and after pregnancy awareness, and sociodemographic behavioral characteristics were assessed through self-reported questionnaires. Determinants of alcohol consumption were investigated using logistic regression.

RESULTS

Prevalence of alcohol consumption before and after pregnancy awareness was 50.0% and 2.8%, respectively. Most women consumed low to moderate levels of alcohol. Before pregnancy awareness, high educational level (odds ratios [OR] 1.11, 95% confidence interval [CI] 1.07 to 1.15), high household income (OR 1.16, 95% CI 1.09 to 1.24), and smoking (OR 1.77, 95% CI 1.65 to 1.90) were significantly associated with increased odds of alcohol consumption. After pregnancy awareness, older age (OR 1.73, 95% CI 1.54 to 1.94) and smoking (OR 5.57, 95% CI 4.88 to 6.37) were significantly associated with increased odds of alcohol consumption, and high education level (OR 0.72, 95% CI 0.64 to 0.81) and high household income (OR 0.75, 95% CI 0.63 to 0.89) were significantly associated with decreased odds of alcohol consumption.

CONCLUSION

A half of women consumed alcohol before pregnancy awareness. Guidelines recommend abstinence from alcohol consumption in pregnant women for precaution, although influence of low to moderate levels of prenatal alcohol exposure on the fetus is inconclusive. Social-demographic characteristics differed between women who consumed alcohol before pregnancy awareness and women who continued alcohol after pregnancy awareness.

Pregnancy in GNE myopathy patients: a nationwide repository survey in Japan

BACKGROUND

GNE myopathy is an autosomal recessive adult-onset distal myopathy. While a few case reports have described the progression of GNE myopathy during pregnancy, to our knowledge, none have examined disease progression after delivery or obstetric complications.

OBJECTIVE

This study aimed to reveal maternal complications, newborn complications, and the impact of pregnancy on disease progression in GNE myopathy patients.

METHODS

We conducted a questionnaire survey on pregnancy, delivery, and newborns involving female GNE myopathy patients who are currently registered in a national registry in Japan.

RESULTS

The response rate for the questionnaire survey was 60.0% (72/120). Of the 72 respondents, 44 (61.1%) had pregnancy experience (average, 1.8 pregnancies; 53 pregnancies before onset and 28 after onset). The incidence of threatened abortion was 26.9% among post-onset pregnancies, which was higher compared to those of the general Japanese population (p = 0.03). No other maternal or infant complications were commonly observed. Over 80% were unaware of changes in disease progression during pregnancy (mean age, 32.8 ± 3.5 years) or after delivery (32.9 ± 3.8 years), while 19.0% experienced disease exacerbation within a year after delivery (30.0 ± 1.0 years). Six patients developed myopathy within a year after delivery (29.7 ± 4.6 years), while none developed myopathy during pregnancy.

CONCLUSIONS

There were no serious maternal or newborn complications, and subjective progression did not differ during or after delivery in the majority of GNE myopathy patients. However, our findings suggest the importance of considering the possibility of threatened abortion and disease progression after delivery.

Impact of individual and neighborhood social capital on the physical and mental health of pregnant women: the Japan Environment and Children's Study (JECS)

Background

Previous studies revealed positive, negative, and no influence of social capital on the health outcomes of pregnant women. It was considered that such differences were caused by the disparities of outcome measures and sample sizes between studies. Our chief aim was to verify the positive influence of social capital on the health condition of pregnant women using established health outcome measures and large-scale nationwide survey data.

Methods

We employed questionnaire survey data from 79,210 respondents to the Japan Environment and Children’s Study, and physical and mental component summary scores from the 8-Item Short-Form Health Survey as outcome measures. We estimated the effect of individual and neighborhood social capitals on physical and mental component summary scores. To consider the property that the richness of social capital would be generally determined by individual characteristics, and to estimate the causal influence of social capital on health without bias caused by said property, we adopted average treatment effect estimation with inverse probability weighting. Generally, average treatment effects are based on the difference of average outcomes between treated and untreated groups in an intervention. In this research, we reckoned individuals’ different levels of social capital as a kind of non-randomized treatment for respective individuals, and we applied average treatment effect estimation. The analysis regarded pregnant women with the lowest level of social capital as untreated samples and women with other levels of social capitals as treated samples.

Results

For mental component summary score, the maximum average treatment effects in the comparison between the lowest and highest levels of social capital were approximately 4.4 and 1.6 for individual and neighborhood social capital, respectively. The average treatment effects for the physical component summary score were negligible for both social capital types.

Conclusions

Social capital particularly contributes to improving mental component summary score in pregnant women. The likelihood of a mentally healthy pregnancy may be increased by enhancing social capital.

Dietary patterns during pregnancy and health-related quality of life: The Japan Environment and Children's Study

Background

Limited research exists on how dietary pattern (DP) influences pregnant women’s health-related quality of life (HRQOL). This study aimed to identify DPs in a cohort of 92,448 pregnant Japanese women using fixed data from the Japan Environment and Children’s Study (JECS) to investigate the associations of DP with HRQOL.

Methods

During the first trimester, DPs were assessed using the Food Frequency Questionnaire (FFQ), and HRQOL was assessed using the 8-Item Short-Form Health Survey (SF-8). DPs such as Western, Japanese and Unbalanced DP were identified through principal component analysis (PCA). Multivariable logistic model analysis was used to assess the associations between DP and HRQOL as good or poor.

Results

We found a significant association between poor mental HRQOL in the univariate analysis for the Western DP (p = 0.014). However, this association was not significant in the multivariate analysis adjusted for basic confounders (p = 0.078). Western DP was not highly associated with poor physical HRQOL (from low-medium to high levels of intake; adjusted odds ratio [OR] 0.87–0.88, all p≤0.001, when comparing highest to lowest intake levels). A high intake of the Japanese DP was significantly associated with poor mental HRQOL and physical HRQOL (adjusted OR 1.20, p<0.0001 and adjusted OR 1.12, p = 0.005, respectively). A medium-high intake of the Unbalanced DP was not highly associated with poor physical HRQOL (adjusted OR 0.93, p = 0.048) but with poor mental HRQOL (adjusted OR 1.29, p<0.0001).

Conclusion

This is the first known prospective study to establish an association between DP and HRQOL in pregnant women. We hope that our findings will help in the field of nutritional science.

Cumulative inactivated vaccine exposure and allergy development among children: a birth cohort from Japan

Background

Adjuvants used in inactivated vaccines often upregulate type 2 immunity, which is dominant in allergic diseases. We hypothesised that cumulative adjuvant exposure in infancy may influence the development of allergies later in life by changing the balance of type 1/type 2 immunity. We examined the relationship between immunisation with different vaccine types and later allergic disease development.

Methods

We obtained information regarding vaccinations and allergic diseases through questionnaires that were used in The Japan Environment and Children’s Study (JECS), which is a nationwide, multicentre, prospective birth cohort study that included 103,099 pregnant women and their children. We examined potential associations between the initial vaccination before 6 months of age and symptoms related to allergies at 12 months of age.

Results

Our statistical analyses included 56,277 children. Physician-diagnosed asthma was associated with receiving three (aOR 1.395, 95% CI 1.028–1.893) or four to five different inactivated vaccines (aOR 1.544, 95% CI 1.149–2.075), compared with children who received only one inactivated vaccine. Similar results were found for two questionnaire-based symptoms, i.e. wheeze (aOR 1.238, 95% CI 1.094–1.401; three vaccines vs. a single vaccine) and eczema (aOR 1.144, 95% CI 1.007–1.299; four or five vaccines vs. a single vaccine).

Conclusions

Our results, which should be cautiously interpreted, suggest that the prevalence of asthma, wheeze and eczema among children at 12 months of age might be related to the amount of inactivated vaccine exposure before 6 months of age. Future work should assess if this association is due to cumulative adjuvant exposure. Despite this possible association, we strongly support the global vaccination strategy and recommend that immunisations continue.

Trial registration

UMIN000030786.

Prevalence and cumulative incidence of autism spectrum disorders and the patterns of co-occurring neurodevelopmental disorders in a total population sample of 5-year-old children

Backgrounds

Whether there is a true increase in autism spectrum disorder (ASD) frequency or not remains unclear. Additionally, the rates of co-existing neurodevelopmental disorders (NDD) in a total population sample has not been fully examined before. Therefore, using a total population sample in Japan, we aimed to estimate the prevalence and cumulative incidence of autism spectrum disorder (ASD) annually, to determine whether there is a true increase in ASD prevalence by estimating the cumulative incidence of ASD annually, and to examine the rates of co-existing neurodevelopmental disorders (NDD).

Method

In this cross-sectional sequential design study, all 5-year-old children in the catchment area underwent the screening annually from the year 2013–2016. Screen-positive children were invited to participate in a comprehensive assessment, including child and parent interview, behavioral observation, and cognitive and motor function testing. All cases were reviewed by a multidisciplinary research team.

Results

Caregivers of 3954 children returned the screening, among which 559 children underwent the assessment with 87 children receiving an ASD diagnosis. Adjusted ASD prevalence was 3.22% (95% confidence interval (CI) 2.66–3.76%). The male to female ratio of the crude prevalence was 2.2:1. The cumulative incidence of ASD up to 5 years of age for the total study years was 1.31% (95% CI 1.00–1.62%). A generalized linear model revealed no significant linear trends in 5-year cumulative incidence over the study years. Only 11.5% of children had ASD alone; the remaining 88.5% were found to have at least one co-existing NDD.

Limitations

Modest sample size for a total population study.

Conclusions

Our findings demonstrate the stability of the 5-year cumulative incidence of ASD, implying no true rise in ASD incident cases over the 4-year study period in the study catchment area. High rates of co-existing NDDs reflect the importance of investigating broad developmental challenges in children with ASD.

Association between Sleep Disturbances and Emotional/Behavioral Problems in Chinese and Japanese Preschoolers

Objectives: Sleep disturbances are often associated with emotional/behavioral problems in young children, but whether the association differs among Asian countries remains unknown. This study aimed to investigate the association between sleep disturbances and emotional/behavioral problems in Chinese and Japanese preschoolers and to explore potential differences.Methods: Participants were 1,020 Chinese preschoolers from 10 cities and 438 Japanese preschoolers from 1 city aged 4 to 5 years. Parents filled out the Children's Sleep Habits Questionnaire (CSHQ) and the Strengths and Difficulties Questionnaire (SDQ).Results: Chinese children with sleep disturbances (defined as total CSHQ score >41) demonstrated more peer problems than children without, while there was no such difference in Japanese preschoolers. Domains of sleep disturbances associated with emotional/behavioral problems in Chinese children were sleep disordered breathing and daytime sleepiness, yet in Japanese children were sleep anxiety and night wakings. Children with a higher score of sleep anxiety showed more emotional problems in Japan, but fewer conduct problems in China.Conclusions: Sleep disturbances were associated with emotional/behavioral problems in preschoolers with differences between China and Japan, indicating subcultural differences in preschoolers' sleep within Asian countries.Abbreviations: CSHQ: Children's Sleep Habits Questionnaire; SDQ: Strengths and Difficulties Questionnaire; ANCOVA: analysis of covariance; SD: standard deviation; CI: confidence interval.

Skipping breakfast before and during early pregnancy and incidence of gestational diabetes mellitus: the Japan Environment and Children's Study

BACKGROUND

There is little evidence linking breakfast skipping to the incidence of gestational diabetes mellitus (GDM).

OBJECTIVES

We aimed to evaluate the prospective association of breakfast consumption with the incidence of GDM.

METHODS

A total of 103,099 pregnancies were registered during study enrollment (January 2011 to March 2014), involving 97,454 pregnant women from 15 areas across Japan. Singleton pregnant women free of GDM, stroke, heart disease, cancer, and type 1 or type 2 diabetes at the study enrollment were eligible for analysis. We used a self-administered questionnaire to obtain data on demographic information, socioeconomic status, self-rated health status, disease history, lifestyle, and dietary habits of each woman at study enrollment. A semiquantitative FFQ was used for dietary assessment. We used logistic regression to obtain the OR of GDM in relation to breakfast consumption.

RESULTS

Among 84,669 pregnant women for analysis, 1935 cases of GDM were documented. After adjustment for potential confounding factors including prepregnancy BMI, the multivariable-adjusted ORs of GDM for women who consumed breakfast 5-6 times/wk, 3-4 times/wk, and 0-2 times/wk were 1.09 (95% CI: 0.93, 1.27), 1.14 (95% CI: 0.96, 1.34), and 1.21 (95% CI: 1.05, 1.41), respectively, compared with daily breakfast eaters. The association appeared to be dose dependent (P-trend = 0.006) and was not significantly modified by prepregnancy BMI.

CONCLUSIONS

Breakfast consumption <3 times/wk before and during early pregnancy, compared with daily consumption, was associated with an increased odds of developing GDM.