Japan Environment Research Articles

Infants’ early recovery from sleep disturbance is associated with a lower risk of developmental delay in the Japan Environment and Children’s Study

To examine whether patterns, such as the timings of onset or recovery from sleep disturbance, are associated with later developmental problems, including autism spectrum disorder (ASD). Mothers participating in the Japan Environment and Children’s Study with a child aged 3 years were included in the analyses. Children were assessed for short sleep and frequent awakenings at 1 month, 6 months, and 1 year of age. Developmental problems were evaluated at 3 years of age based on ASD diagnosis and developmental delay, using the Japanese translation of the Ages and Stages Questionnaire (ASQ) 3rd edition. Sleep disturbance patterns were classified by onset age, and developmental problem risks were examined based on onset/recovery ages. Among 63,418 mother-infant dyads, 0.4% of infants were later diagnosed with ASD, and 14.4% had abnormal scores on any ASQ domains. The later the onset of short sleep, the lower the risk of abnormal ASQ scores (RR of short sleep onset at 1 year: 1.41; 6 months: 1.52; 1 month: 1.57). The earlier the infants recovered from short sleep persistence, the lower the risk of developmental delay (RR of remittance of sleep problems identified at 1 month by 6 months: 1.07; 1 year: 1.31; not before 1 year: 1.57). Although not all patterns were significant, later short sleep onset and earlier recovery were associated with lower ASD risk. These findings may have significant implications for future interventions in infant development.

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

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. 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). 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. 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. 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.

Association Between Atopic Dermatitis in Pregnant Women and Preterm Births: The Japan Environment and Children's Study.

This study aimed to evaluate the association between atopic dermatitis in pregnant women and preterm births, accounting for maternal ritodrine hydrochloride administration status. Data of 83,796 women with singleton pregnancies at andafter 22weeks of gestation (enrolled between 2011 and 2014) were analyzed. These data were obtained from the Japan Environment and Children's Study. Atopic dermatitis was defined based on self-reported questionnaire responses obtained during the first trimester. The primary outcome measures were preterm births before 37, 32, and 28weeks of gestation. Using a multivariable logistic regression model, odds ratios for preterm births in pregnant women with atopic dermatitis were calculated, with women without atopic dermatitis included in the reference group. This analysis considered confounding factors and maternal ritodrine hydrochloride administration. Among pregnant women with atopic dermatitis, the adjusted odds ratios (95% confidence intervals) for preterm births before 37, 32, and 28weeks of gestation were 0.89 (0.81-0.98), 0.98 (0.74-1.30), and 0.88 (0.50-1.55), respectively. This trend remained consistent after excluding participants who receivedritodrine hydrochloride. Atopic dermatitis in pregnant women was significantly associated with a decreased incidence of preterm births before 37weeks of gestation, even after accounting for the effects of maternal ritodrine hydrochloride administration.

Associations between paternal autism traits and parenting from the Japan environment and children’s study

There are few studies on the parenting of fathers with autism traits. To investigate this issue, we examined the type of parenting performed by fathers with autism traits using data from a nationwide birth cohort study, the Japan Environment and Children’s Study. Paternal parenting was evaluated by mothers or caregivers when the child was 2 years old. Father’s autism traits were measured using the Japanese version of the self-administered Autism Spectrum Quotient. Logistic regression analysis was performed to statistically analyze the data. Fathers with autism traits were significantly less likely to prepare meals for their child and helping them eat (adjusted OR (aOR): 1.11, 95% confidence interval (CI): 1.01–1.23), to helping the child change clothes (aOR: 1.17, 95% CI: 1.04–1.31). However, there were no associations between some parenting behaviors and autism traits (not changing diapers, not bathing with the child, and not playing with the child). Father’s communication skill difficulties by autism traits associated with a lower tendency to perform all types of parenting. Interestingly, there were association between difficulties with social skills or attention-switching and more performing change diapers. These results indicate it is important to respect the child-rearing that fathers with autistic tendencies are able to do, while supporting them in child-rearing that they are significantly less able to do than fathers without autistic tendencies.

Growth and respiratory status at 3 years of age after moderate preterm, late preterm and early term births: the Japan Environment and Children’s Study

ObjectiveTo assess the association between gestational age at birth and the risk of growth failure and respiratory symptoms at 3 years of age.DesignCohort study using the Japan Environment and Children’s...

Infantile Peanut Introduction and Peanut Allergy in Regions With a Low Prevalence of Peanut Allergy: The Japan Environment and Children's Study (JECS).

In regions with a high prevalence of peanut allergy (PA), there is a consensus that the introduction of peanuts in early infancy is preventive against the development of PA. However, few studies have investigated whether the introduction of peanuts to infants is associated with PA in regions with a low prevalence of PA, including Japan. We used data from 74,240 mother-child pairs who participated in the Japan Environment and Children's Study, a prospective birth cohort recruited between January 2011 and March 2014. A logistic regression model was used to analyze the association between infantile peanut introduction and PA at the age of 4 years with non-infantile peanut introduction as the reference group, adjusted for potential confounders. The percentage of infantile peanut introduction was 4.9% (n = 3,294), and 286 (0.4%) participants had allergic symptoms to peanuts at 4 years of age. Of all participants, 129 (0.2%) had PA at 4 years of age, which was defined as allergic symptoms and sensitization to peanuts. Those with infantile peanut introduction had a lower prevalence of PA than those without infantile peanut introduction, although this did not reach statistical significance (adjusted odds ratio 0.53; 95% confidence interval, 0.17-1.68). Sensitivity analysis using IgE-mediated symptoms caused by peanuts as the outcome showed a similar result in relation to infantile peanut introduction. In countries with a low prevalence of PA, the effect of infantile peanut introduction on PA prevention was unclear.

Maternal excessive weight gain as a potential risk factor for prolonged labor in Japanese pregnant women: The Japan Environment and Children's Study.

This study aimed to determine whether excessive maternal weight gain during pregnancy was associated with a higher risk of prolonged labor. We analyzed the data regarding maternal weight gain during pregnancy for the participants of Japan Environment and Children's Study (JECS), which is an ongoing nationwide prospective birth cohort study in Japan. After excluding participants with multiple pregnancies, with deliveries before 37 or beyond 42 weeks of gestation, or who had undergone cesarean section, 71,154 (nulliparous, n = 28,442) Japanese women were included. Prolonged labor was defined by a cutoff ranking at the 95th percentile and consequently defined as labor duration exceeding 12.7 h in multiparous women and exceeding 23.2 h in nulliparous women. These classifications were made according to labor curves established by the Japanese Society of Obstetrics and Gynecology Perinatal Committee developed in June 2021. Considering that no studies have conducted an investigation based on this new guideline, we analyzed the association between excessive maternal weight gain during pregnancy and prolonged labor by parity. The overall incidence of prolonged labor was 10.2% (2,907/28,442) in nulliparous women and 6.1% (2,597/42,712) in multiparous women. Multivariable analysis indicated that excessive maternal weight gain was significantly associated with prolonged labor in nulliparous (adjusted odds ratio, 1.21; 95% confidence interval, 1.10-1.32) and multiparous women (adjusted odds ratio, 1.15; 95% confidence interval, 1.05-1.27). Kaplan-Meier survival analysis showed that as labor progressed, the percentage of women who had not yet delivered was higher among those with excessive maternal weight gain than among those with normal maternal weight gain in both the nulliparous (median labor duration 12.9 h vs 12.2 h, p<0.001) and multiparous (median labor duration 6.2 h vs 5.8 h, p<0.001) groups. Excessive maternal weight gain was significantly associated with prolonged labor in Japanese women.

Relationship between maternal consumption of fermented foods and the development of the offspring at the age of 3 years: The Japan Environment and Children's Study.

It is well known that maternal diet affects the development of offspring. Herein, the relationship between maternal intake of fermented foods during pregnancy and offspring development was investigated. The diet of 103,060 pregnant women at >4 months of gestation who were enrolled in the Japan Environment and Children's Study was analyzed. Their intake levels of fermented soybeans (miso and natto), yogurt, and cheese were investigated. The developmental status of the offspring at 3 years of age was assessed using the Ages and Stages Questionnaires (ASQ-3). Multivariable logistic regression analysis was performed to determine the risk of maternal intake levels of the fermented foods associated with subsequent developmental delay in the offspring. Intake of cheese was associated with a reduced risk of child developmental delay in all intake level groups from the second quartile onward. Intakes of miso and yogurt were associated with a reduced risk of developmental delay in communication skills in the fourth quartile. There was no association between intake of natto and developmental delay. Maternal consumption of fermented foods during pregnancy may reduce the risk of later developmental delay in offspring. It is therefore important to review the mother's diet for fermented foods during pregnancy. However, further studies are warranted to evaluate the factors influencing the association between diet and offspring development.

Association between preconception dietary fiber intake and hypertensive disorders of pregnancy: The Japan Environment and Children’s Study

ObjectivesHypertensive disorders of pregnancy (HDP) are a significant cause of morbidity and mortality. This study aimed to investigate whether preconception dietary fiber intake is associated with new-onset HDP. Study designWe identified 84,873 (primipara, 33,712; multipara, 51,161) normotensive participants from the Japan Environmental Children’s Study database who delivered between 2011 and 2014. The participants were subsequently categorized into five groups based on their preconception dietary fiber intake quintiles (Q1–Q5). Main outcome measuresThe main obstetric outcome was HDP, and the secondary obstetric outcomes included early-onset (Eo, <34 weeks)-HDP, late-onset (Lo, ≥34 weeks)-HDP, small for gestational age (SGA) births, and HDP with/without SGA. ResultsMultiple logistic regression analysis showed that in primiparas, the risks of HDP, Lo-HDP, and HDP without SGA were lower in the Q5 group compared with the Q3 group (HDP: adjusted odds ratio [aOR] = 0.73, 95 % confidence intervals [95 % CI] = 0.58–0.93; Lo-HDP: aOR = 0.72, 95 % CI = 0.55–0.94; and HDP without SGA: aOR = 0.68, 95 % CI = 0.53–0.88). However, the risks of Eo-HDP and HDP with SGA were higher in the Q1 group compared with the Q3 group (Eo-HDP: aOR = 1.66, 95 % CI = 1.02–2.70; and HDP with SGA: aOR = 1.81, 95 % CI = 1.04–3.17). In multiparas, the risks of Lo-HDP and SGA were higher in the Q1 group compared with the Q3 group (Lo-HDP: aOR = 1.47, 95 % CI = 1.10–1.97; SGA: aOR = 1.17, 95 % CI = 1.02–1.35). ConclusionsPreconception dietary fiber intake is beneficial in preventing HDP onset. Therefore, new recommendations should be considered to encourage higher dietary fiber intake as part of preconception care.

Occurrence and ecological risk assessment of 16 plasticizers in the rivers and estuaries in Japan

Owing to growing concerns about the adverse effects of phthalate plasticizers, non-phthalate plasticizers are being increasingly used as their replacement. However, information on the residual environmental concentrations and ecological risks posed by these plasticizers is limited. In this study, we analyzed the environmental contamination of 11 phthalates and 5 non-phthalate plasticizers in Class A and B rivers in Japan. In the considered river water samples, phthalates and non-phthalates were detected in the following order of detection frequency: phthalates (DEHP > DMP > DMEP > BBP > DNPP > DNP > DEEP > DBEP = DNOP) and non-phthalates (ATBC > DEHS > DEHA > TOTM = DIBA). Phthalate plasticizers were the most abundant and included DEHP (157–859 ng/L), DMP (<MQL–3680 ng/L), DMEP (<MQL–4600 ng/L), and BBP (<MQL–1080 ng/L); non-phthalates included ATBC (<MQL–1550 ng/L) and DEHS (<MQL–220 ng/L). The risk quotient for DEHP and ATBC was found to be more than one, suggesting an emerging concern regarding their contamination and adverse effects on aquatic organisms. This study is the first to shed light on the persistence of non-phthalate plasticizers in freshwater environments in Japan; the findings could help develop strategies to mitigate the environmental effects of plasticizers.

Association between general anesthesia in early childhood and neurodevelopment up to 4 years of age: the Japan Environment and Children’s Study

PurposeThe effects of general anesthesia on neurodevelopment in children remain controversial. We explored the relationship between general anesthesia and neurodevelopment in children participating in the Japan Environment and Children’s Study (JECS).MethodsThis study enrolled children born between 37 and 41 weeks of pregnancy via single-vaginal delivery to pregnant women registered in the JECS between January 2011 and March 2014. Data were collected from mother-completed questionnaires and medical transcripts. Neurodevelopment in five domains was assessed every 6 months between 12 and 48 months of age, using the Ages and Stages Questionnaires. The associations between general anesthesia exposure during early childhood and neurodevelopment in children were evaluated at each time point. Adjusted odds ratios and 95% confidence intervals were estimated after covariate adjustment using logistic regression models.ResultsChildren who received general anesthesia before age 1 year had higher risks of neurodevelopmental delay in all five domains throughout the observational period. The largest risk was for gross motor delay at 18 months (adjusted odds ratio: 3.51; 95% confidence interval: 2.75–4.49). The effects on the incidence of neurodevelopmental delays after age 3 were not observed except for problem solving at 48 months. The risk of neurodevelopmental delay in children who first received general anesthesia after age 1 was considerably small.ConclusionsThis study suggests that general anesthesia administration before age 1 is associated with neurodevelopmental delay during 1–4 years of age. The risk of general anesthesia after age 1 may be small.

Association of longitudinal pet ownership with wheezing in 3-year-old children using the distributed lag model: the Japan Environment and Children’s Study

BackgroundTime-varying exposures like pet ownership pose challenges for identifying critical windows due to multicollinearity when modeled simultaneously. The Distributed Lag Model (DLM) estimates critical windows for time-varying exposures, which are mainly continuous variables. However, applying complex functions such as high-order splines and nonlinear functions within DLMs may not be suitable for situations with limited time points or binary exposure, such as in questionnaire surveys.Objectives(1) We examined the estimation performance of a simple DLM with fractional polynomial function for time-varying binary exposures through simulation experiments. (2) We evaluated the impact of pet ownership on childhood wheezing onset and estimate critical windows.Methods(1) We compared logistic regression including time-varying exposure in separate models, in one model simultaneously, and using DLM. For evaluation, we employed bias, empirical standard error (EmpSE), and mean squared error (MSE). (2) The Japan Environment and Children's Study (JECS) is a prospective birth cohort study of approximately 100,000 parent-child pairs, registered across Japan from 2011 to 2014. We applied DLM to the JECS data up to age 3. The estimated odds ratios (OR) were considered to be within critical windows when they were significant at the 5% level.Results(1) DLM and the separate model exhibited lower bias compared to the simultaneously model. Additionally, both DLM and the simultaneously model demonstrated lower EmpSEs than the separate model. In all scenarios, DLM had lower MSEs than the other methods. Specifically, where critical windows is clearly present and exposure correlation is high, DLM showed MSEs about 1/2 to 1/200 of those of other models. (2) Application of DLM to the JECS data showed that, unlike other models, a significant exposure effect was observed only between the ages of 0 and 6 months. During that periods, the highest ORs were 1.07 (95% confidence interval, 1.01 to 1.14) , observed between the ages of 2 and 5 months.Conclusions(1) A simple DLM improves the accuracy of exposure effect and critical windows estimation. (2) 0–6 months may be the critical windows for the effect of pet ownership on the wheezing onset at 3 years.

Maternal pre-pregnancy body mass index and related factors: A cross-sectional analysis from the Japan Environment and Children's Study.

Socioeconomic status and smoking are reportedly associated with underweight and obesity; however, their associations among pregnant women are unknown. This study aimed to investigate whether socioeconomic factors, namely educational attainment, household income, marital status, and employment status, were associated with pre-pregnancy body mass index (BMI) categories, including severe-moderate underweight (BMI ≤ 16.9 kg/m2), mild underweight (BMI, 17.0-18.4 kg/m2), overweight (BMI, 25.0-29.9 kg/m2), and obese (BMI ≥ 30.0 kg/m2) among Japanese pregnant women using data from the Japan Environment and Children's Study (JECS). In total, pregnant women were included 96,751. Age- and parity-adjusted multivariable multinomial logistic regression analyses assessed socioeconomic factors and smoking associations with falling within abnormal BMI categories (normal BMI as the reference group). Lower education and lower household were associated with overweight and obesity, and, especially, lowest education and household income had relatively higher point estimate relative ratios (RRs) of 3.97 and 2.84, respectively. Regarding the risks for underweight, however, only junior high school education had a significantly higher RR for severely to moderately underweight. Regarding occupational status, homemakers or the unemployed had a higher RR for severe-moderate underweight, overweight, and obesity. Unmarried, divorced, or bereaved women had significantly higher RRs for mildly underweight status. Quitting smoking early in pregnancy/still smoking had higher RRs for all four not having normal BMI outcomes; however, quitting smoking before pregnancy had a higher RR only for obese individuals. Lower educational attainment and smoking are essential intervention targets for obesity and severe-moderate underweight prevention in younger women. Lower household income is also a necessary target for obesity.

Neonatal transfer and duration of hospitalization of newborns as potential risk factors for impaired mother-infant bonding: The Japan Environment and Children's Study

BackgroundCurrently, there is no consensus regarding the relationship between neonatal transfer and duration of hospitalization in cases of impaired mother-infant bonding (MIB). This study aimed to determine whether neonatal transfer and duration of hospitalization of newborns increase the risk for impaired MIB. MethodsThe MIB Scale was used to assess impaired MIB 1 year after delivery, using data from the Japan Environment and Children's Study. A score ≥ 5 points indicated impaired MIB. Multiple logistic regression analyses were performed to estimate the association between neonatal transfer and duration of hospitalization of newborns with the risk of impaired MIB. ResultsA total of 66,402 pregnant women were included in the study. The overall incidence rate of impaired MIB was 11.2 %. The mean duration of hospitalization of newborns was 7.1 ± 6.4 days. After adjusting for potential confounders, neonatal transfer (adjusted odd ratio (OR): 1.13 [95 % confidence interval (CI)), 1.01–1.27]) and duration of hospitalization of newborns (adjusted OR 1.007; 95 % CI 1.003–1.010) were associated with impaired MIB. The area under the receiver operating characteristic curve for the duration of hospitalization of newborns for impaired MIB was 0.53. LimitationsMaternal childhood abuse and neglect history were not evaluated, and information regarding whether the infants were admitted to the neonatal intensive care unit was unavailable. ConclusionsJapanese women whose newborns underwent neonatal transfer should be followed up for at least 1 year after delivery, regardless of the duration of hospitalization of newborns.

Effects of the COVID-19 pandemic and the introduction of information and communication technology in emergency scenes on the emergency transport environment in Japan

Effects of the COVID-19 pandemic and the introduction of information and communication technology in emergency scenes on the emergency transport environment in Japan

Association of placental weight at birth with maternal whole blood concentration of heavy metals (cadmium, lead, mercury, selenium, and manganese): The Japan Environment and Children’s Study (JECS)

BackgroundLifelong health is dependent on prenatal growth and development, influenced by the placental intrauterine environment. Charged with dual functions––exchange of oxygen and nutrients as well as a barrier against toxins––the placenta itself is susceptible to environmental exposure to heavy metals. ObjectiveTo examine the use of placenta weight as a biomarker for heavy metal exposure using a large Japanese cohort of pregnant women. MethodsThe placenta weight, as a biomarker of exposure to heavy metals (cadmium, lead, and mercury), was investigated using data from the Japan Environment and Children’s Study (2011–2014). Selenium and manganese were included as factors directly affecting fetal growth or heavy metal toxicity. Maternal blood samples collected in the second or third trimester were used to measure heavy metal concentrations. The association between maternal blood metal concentrations and placenta weight was explored by applying Z scores and multivariable logistic regression analysis and classifying participants into quartiles (Q1, Q2, Q3, and Q4) according to metal concentrations. ResultsThis study included a total of 73,005 singleton pregnant women who delivered via live births and met the inclusion criteria. The median heavy metal concentrations in the maternal whole blood were 0.662 ng/g cadmium, 5.85 ng/g lead, 3.61 ng/g mercury, 168 ng/g selenium, and 15.3 ng/g manganese. Regression analysis revealed a significant correlation between placenta weight Z scores and maternal blood metal concentrations: cadmium, 0.0660 (standard error = 0.0074, p < 0.001); selenium, −0.3137 (standard error = 0.0276, p < 0.001); and manganese, 0.1483 (standard error = 0.0110, p < 0.001). ConclusionThis study provides a robust examination of the association between heavy metal exposure and placenta weight. Cadmium and manganese showed a positive correlation with significant differences, whereas selenium showed a negative correlation. Essential elements notably affect placenta weight differently. No significant association was noted between lead or mercury and placenta weight.

The effect of parental age on child development at 36 months: Insights from the Japan environment and children's study

BackgroundThe impact of parent-childbearing age on child development at 36 months of age is controversial. AimsWe used data from a large cohort study with multiple imputation and mediation analyses of variables. Methods and ProceduresA total of 72,606 parent–child pairs from the Japan Environment and Children's Study were included in the study. Parents' ages were categorized into five groups. We used five domains of the Japanese translation of the Ages and Stages Questionnaire, Third Edition (J-ASQ-3). Scores below the cutoff value at 36 months were defined as developmental delays in each domain. We used three logistic analysis models. In Model 3, we analyzed maternal and paternal age using other variables and covariates. Outcomes and ResultsThe outcome was a developmental delay in the five domains of J-ASQ-3. In Model 3, ORs for the developmental delay scores regarding parental age were significantly associated with all five domains of J-ASQ-3. The mediation analysis showed a significant mediation interaction effect for mothers but localized for fathers. ConclusionAdvanced paternal and maternal ages were associated with developmental delay in children. Awareness of the risks of childbearing at an advanced age is crucial. What’s the paper addsThis manuscript used data from a large cohort study with multiple imputation and mediation analyses. With these analyses, we identified the pure effect of advanced parental age on their children’s development at 36 months.

Risk of gestational diabetes in women with PCOS based on body mass index: The Japan Environment and Children's Study.

Women with polycystic ovary syndrome (PCOS), which is the most common endocrine disorder in women of reproductive age, have a potentially increased risk of gestational diabetes mellitus (GDM). To examine the impact of PCOS on GDM based on maternal body mass index (BMI) using data from a large birth cohort study in Japan. Prospective observational study using data from the Japan Environment and Children's Study (JECS). Singleton pregnancies in the JECS during 2011-2014 were included. Mothers with HbA1c levels of ≥6.5% in the first trimester and history of DM or steroid use during pregnancy were excluded. Participants were categorized according to their pre-pregnancy BMIs: G1 (<18.5 kg/m2), G2 (18.5-19.99 kg/m2), G3 (20.0-22.99 kg/m2), G4 (23.0-24.99 kg/m2), and G5 (≥25.0 kg/m2). The impact of PCOS on early (Ed) and late-onset (Ld) GDM for each group was estimated using a multiple logistic regression model. We included 92774 participants, comprising 2012 PCOS(+) cases. GDM occurrence was higher in women with PCOS (p<0.001). PCOS had no effect on GDM in G1, G2, and G3. In G4, PCOS increased the risk of Ed GDM (adjusted odds ratio [aOR]: 3.27, 95% confidence interval [CI]: 1.29-8.29). In G5, PCOS increased the risk of both Ed (aOR: 2.48, 95% CI: 1.53-4.02) and Ld GDM (aOR: 1.94, 95% CI: 1.23-3.07). The impact of PCOS on GDM occurrence depended on the pre-pregnancy BMIs, which may facilitate personalized preconception counseling among women with PCOS.

Association between maternal heavy metal exposure and Kawasaki Disease, the Japan Environment and Children's Study (JECS).

Kawasaki disease (KD) is an acute systemic vasculitis primarily affecting young children, with an unclear etiology. We investigated the link between maternal heavy metal exposure and KD incidence in children using the Japan Environment and Children's Study, a large-scale nationwide prospective cohort with approximately 100,000 mother-child pairs. Maternal blood samples collected during the second/third trimester were analyzed for heavy metals [mercury (Hg), cadmium (Cd), lead (Pb), selenium (Se), manganese (Mn)], divided into four quartiles based on concentration levels. KD incidence within the first year of life was tracked via questionnaire. Among 85,378 mother-child pairs, 316 children (0.37%) under one year were diagnosed with KD. Compared with the lowest concentration group (Q1), the highest (Q4) showed odds ratios (95% confidence interval) for Hg, 1.29 (0.82-2.03); Cd, 0.99 (0.63-1.58); Pb, 0.84 (0.52-1.34); Se, 1.17 (0.70-1.94); Mn, 0.70 (0.44-1.11), indicating no concentration-dependent increase. Sensitivity analyses with logarithmic transformation and extended outcomes up to age 3 yielded similar results. No significant association was found between maternal heavy metal levels and KD incidence, suggesting that heavy metal exposure does not increase KD risk.

에도시대 두창의 예방과 치료: 인두법의 수용을 중심으로

This paper explores the introduction of smallpox variolation (人痘法) as a means of addressing the smallpox epidemic during the Edo period in Japan. It also investigates the impact of smallpox variolation on Japanese society during the late Edo period. I begin by outlining the history of smallpox epidemics in Japan. Subsequently, I document the process of introducing and developing smallpox variolation, which was considered a valuable preventive measure against smallpox during that period. While smallpox variolation was introduced in the mid-18th century, it took about half a century for the practice to be effectively implemented. Several physicians attempted variolation during this period, but Ogata Shunsaku (緖方春朔) was renowned as the first to succeed on a large scale, particularly with children. He authored works such as “Shutohissunben (種痘必順辨)” to advocate for the effectiveness of variolation. Additionally, rather than simply adopting the Chinese method of variolation, he developed his own method that took into consideration Japan's unique climate and environment, hoping to enhance the efficacy of variolation. During that time, the prevailing response to the smallpox epidemic focused on diagnosis and treatment using medicine rather than variolation. While Ogata Shunsaku actively practiced variolation, the shogunate established an institution within the medical department tasked with the prevention and treatment of smallpox. This institution propagated the Ikeda-ryu (池田流) method, which specialized in diagnosing and treating smallpox. Despite disparities in approaches, competition between smallpox prevention and treatment catalyzed the accumulation of relevant medical knowledge and experience in Japan during the early 19th century. Initially, variolation was introduced from China; however, over time, researchers experimented with it in various ways, integrating knowledge from Rangaku (蘭學) and cowpox inoculation (牛痘法). Responding to academic and technical developments, Ranpoi (蘭方醫) made diverse attempts at variolation that served as precursors to the eventual adoption of cowpox inoculation. Examining the process of variolation’s introduction and implementation elucidates the characteristics of early 19th-century Japanese medicine that transcended disciplinary boundaries.