Association of maternal leukocyte, monocyte, and neutrophil counts with hypertensive disorders of pregnancy: the Japan Environment and Children's Study (JECS).

Hypertensive disorders of pregnancy (HDP) increase the risk of preterm births and cesarean delivery. This study aimed to investigate whether maternal blood leukocyte, monocyte, or neutrophil counts in the first trimester are related to the development of HDP. Data were collected from the Japan Environment and Children's Study, a large birth cohort study (n = 38,194) that recruited pregnant women in 15 Regional Centers across Japan (from January 2011 to March 2014). The odds ratios (ORs) for mild/severe HDP according to the cut-off value of leukocyte/neutrophil/monocyte counts by the receiver operating characteristic curve showed high ORs. Furthermore, pregnant women with the highest quartiles of leukocyte and monocyte counts had higher adjusted ORs (aORs) for mild (leukocyte: aOR = 1.27, 95% confidence interval [CI]: 1.02-1.58; monocyte: aOR = 1.30, 95% CI 1.04-1.63) and severe HDP (leukocyte: aOR = 1.51, 95% CI 1.08-2.13; monocyte: aOR = 1.44, 95% CI 1.03-2.01) compared with those with the lowest quartiles of those counts. In addition, pregnant women with the highest neutrophil counts had higher aOR for mild HDP (aOR = 1.26, 95% CI 1.02-1.56) compared with those with the lowest count. In conclusion, high leukocyte and monocyte counts in the first trimester are associated with the development of HDP. Thus, they may be used to predict subsequent HDP.

Association between filaggrin gene mutations and the clinical features of molluscum contagiosum: The Yamanashi Adjunct Study of the Japan Environment and Children's Study.

Previous studies have reported swimming, atopic dermatitis, and filaggrin (FLG) gene mutations as risk factors for molluscum contagiosum (MC) infection. FLG gene mutations impair skin barrier function. The aim of this study was to determine the impact of FLG mutations on the incidence and clinical features of MC. We used data from 2036 children who participated in the Yamanashi Adjunct Study of the Japan Environment and Children's Study, a prospective, birth cohort study. A questionnaire for caregivers (when children were 4 and 8 years of age) asked about clinical features including previous MC incidence and treatment, number of MC lesions at first visit, and time to resolution. Participants underwent genotyping to detect six FLG mutations that are common in the Japanese population. A logistic regression model was used to analyze the association between MC incidence and FLG mutations, adjusted for potential confounders. The cumulative incidence of MC at age 8 years was 47.1%. Among participants with a history of MC, 67.6% had undergone curettage. FLG mutation was a significant risk factor for MC incidence (adjusted odds ratio [aOR] 1.69, 95% confidence interval [CI] 1.18-2.42). Swimming and atopic dermatitis were also significant risk factors for MC. There was no significant association between FLG mutation and the number of MC lesions at the first visit or the time to resolution of lesions. FLG mutation is a risk factor for MC incidence; however, FLG mutations do not affect the number of MC lesions at presentation or the time to resolution.

Mother-child correlation of kidney function: data from the Yamanashi Adjunct Study of Japan Environment and Children's Study (JECS).

BACKGROUND: Individual variation in kidney function can be affected by both congenital and acquired factors, and kidney function in children is possibly correlated with that in their mothers. However, the mother-child correlation in kidney function remains directly unconfirmed. METHODS: We conducted a cross-sectional study of 655 healthy pairs of 7- or 8-year-old children and their mothers as an adjunct study of a nationwide epidemiological study (Japan Environment and Children's Study). RESULTS: Both serum creatinine level (all children, r = 0.324, p < 0.001; girls, r = 0.365, p < 0.001; boys, r = 0.278, p < 0.001) and estimated glomerular filtration rate (eGFR) (r = 0.274, p < 0.001; r = 0.352, p < 0.001; r = 0.195, p < 0.001, respectively) in children were weakly associated with their maternal values. In the single linear regression analyses, maternal values of serum creatinine and eGFR were significantly associated with the children's values. Moreover, several body composition values in children, such as weight-SDS, fat (%), and predicted muscle weight, were also significantly associated with kidney function values in children. In the multiple linear regression analysis for serum creatinine levels in children, in which weight-SDS and predicted muscle weight in children were selected as adjustment factors, maternal serum creatinine level showed a significant positive association (B = 0.214, p < 0.001 in the adjusted model). Moreover, in the multiple linear regression analysis for eGFR value in children, in which fat (%) and predicted muscle weight in children were selected as adjustment factors, maternal eGFR values showed a significant positive association (B = 0.319, p < 0.001). CONCLUSIONS: We directly confirmed mother-child correlations in both serum creatinine levels and eGFR values, particularly in girls. Graphical abstract A higher resolution version of the Graphical abstract is available as Supplementary information.

Infantile peanut introduction and peanut allergy in regions with a low prevalence of peanut allergy: the Japan Environment and Children's Study (JECS).

BACKGROUND: 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. METHODS: 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. RESULTS: The percentage of infantile peanut introduction was 4.9% (n=3294) 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. CONCLUSIONS: In countries with a low prevalence of PA, the effect of infantile peanut introduction on PA prevention was unclear.

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.

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.

A nationwide, prospective, cohort study on exogenous oxytocin and delays in early child development: the Japan environment and children's study.

Although it remains debatable, exogenous oxytocin, commonly used for labour induction and augmentation, reportedly increases risks of neurodevelopment delay, attention-deficit/hyperactivity disorder, and autism spectrum disorder among children prenatally exposed to exogenous oxytocin. However, only few studies have objectively examined exogenous oxytocin's impact on early childhood development through scoring evaluations. This study investigated the association between exogenous oxytocin exposure and neurodevelopment in 3-year-old children using the Ages and Stages Questionnaires, Third Edition. In this nationwide prospective cohort study, we extracted data from 104,062 foetal records regarding exogenous oxytocin use during labour from the Japan Environment and Children's Study. Participants completed questionnaires throughout the pregnancy and postpartum periods. Outcomes comprised the developmental status less than each cut-off value for the five domains of the Ages and Stages Questionnaire, Third Edition. We conducted multivariable logistic regression analyses on the data of 55,400 children after controlling for confounders. Among the 55,400 included women, 19.0% (n = 10,506) used exogenous oxytocin during labour and 81.0% (n = 44,894) did not. Children exposed to exogenous oxytocin showed no significantly increased risk of developmental delay in any domain (communication: odds ratio [OR] 1.04, 95% confidence interval [CI] 0.92-1.16; gross motor: OR 0.97, 95% CI 0.87-1.08; fine motor: OR 1.00, 95% CI 0.92-1.09; problem-solving: OR 1.02, 95% CI 0.94-1.11; personal-social: OR 0.91, 95% CI 0.80-1.03).   Conclusion: Exogenous oxytocin for labour induction did not adversely affect early childhood development. Further studies accounting for the degree of exogenous oxytocin exposure are required to confirm these results. What is Known: • In developed countries, labour is induced in 20-25% of all pregnancies, for which oxytocin is commonly used. • Studies have associated risks of neurodevelopment delay, attention-deficit/hyperactivity disorder, and autism spectrum disorder with exposure to exogenous oxytocin. What is New: • Evaluation with the Ages and Stages Questionnaire, Third Edition, revealed that exogenous oxytocin use did not adversely affect early childhood development. • This prospective study reinforced the lack of evidence of an association between exogenous oxytocin use and early childhood development after adjustment for confounding and rigorous bias elimination.

Association of influenza vaccination or influenza virus infection history with subsequent infection risk among children: The Japan Environment and Children's Study (JECS).

We measured the association between history of influenza vaccination by age 2 years and influenza virus (IFV) infection at ages 3 and 4 years by relative risk reduction. We also examined the association between history of IFV infection by age 2 years and recurrent IFV infection at age 3 years. This study included 73,666 children from a large Japanese birth cohort. Among children vaccinated never, once or twice when aged under 2 years, 16.0%, 10.8% and 11.3%, respectively, had been infected with IFV by age 3 years, and 19.2%, 14.5% and 16.0%, respectively, by age 4 years. Compared with no history of influenza vaccination, vaccination at ages 1 and/or 2 years reduced the risk of IFV infection at age 3 by 30%-32% and at age 4 by 17%-24%. The relative risk of recurrent IFV infection at ages 3 and 4 years increased in proportion to the number of prior infections by age 2. One-season-prior influenza vaccination history reduced the IFV infection risk at age 3 years by 25%-42%. Influenza vaccination most effectively protected children at age 3 who lacked older sibling(s) and did not attend nursery school. One-season-prior IFV infection increased the relative risk of recurrent infection at age 3 years (1.72-3.33). In conclusion, influenza vaccination-induced protection may partly extend to the next season. Owing to the relative risk reduction by influenza vaccination and the increased relative risk of IFV infection from prior-season infection, annual influenza vaccination is recommended.

Interpregnancy weight change as a potential risk factor for large-for-gestational-age infants: the Japan Environment and Children's Study.

OBJECTIVE: This study aimed to estimate the impact of interpregnancy weight change from the first to the second pregnancy on the risk of infants being large for gestational age (LGA). METHODS: This nationwide prospective birth cohort analysis included 3245 women who delivered their first two live singletons between 2011 and 2014. Interpregnancy weight change was calculated as the difference between the prepregnancy body mass index (BMI) of the first and second pregnancies. LGA infants were compared among three interpregnancy weight change groups: weight loss (a BMI loss >1 unit), weight gain (a BMI gain >1 unit), and stable weight (BMI maintained within - 1 to <1 unit). Interpregnancy weight change was assessed in mothers with a BMI <25 and ≥25 kg/m2, and adjusted odds ratios (ORs) were calculated for LGA infants by multiple logistic regression. RESULTS: The incidence of LGA infants was 8.6% (279 out of 3245). Compared with the stable weight group, interpregnancy weight gain was associated with an increased risk of infants being LGA (adjusted OR: 1.69, 95% confidence interval: 1.21-2.36) in the normal BMI (<25 kg/m2) group. In contrast, in the overweight/obese BMI (≥25 kg/m2) group, interpregnancy BMI was not a significant risk factor for LGA infants. CONCLUSIONS: Accurate risk stratification using interpregnancy BMI could assist the clinical management of women with a normal BMI who are at risk of delivering LGA infants.

Relationship between floating toes condition and lower limb muscle weight in 8-year-old children: the Yamanashi adjunct study of the Japan Environment and Children's Study (JECS-Y).

[Purpose] Floating toe is a condition in which the toes make insufficient contact with the ground. Weak muscle strength is reportedly one cause of floating toe. However, little evidence exists regarding the relationship between foot muscle strength and floating toe. Here we examined the relationship between foot muscle strength and floating toe by investigating the children' lower extremity muscle mass and floating toe conditions. [Participants and Methods] This cohort study enrolled 118 8-year-old children (62 females, 56 males) with recorded footprints and muscle mass evaluations using dual-energy X-ray absorptiometry. We calculated the floating toe score using the footprint. We measured the muscle weights and the muscle weights divided by the lengths of the lower limbs separately on the left and right sides using dual-energy X-ray absorptiometry. [Results] No significant correlations were observed between the floating toe score and muscle weights or muscle weights divided by lower-limb lengths for either gender or side. [Conclusion] In this study, no significant correlation was found between floating toe degree and lower limb muscle mass, suggesting that lower limb muscle strength is not the primary cause of floating toe, at least in children.

Multiple pregnancy as a potential risk factor for postpartum depression: The Japan Environment and Children's Study.

BACKGROUND: Postpartum depression (PPD) results in adverse consequences for both mother and infant. However, the association between multiple pregnancy and PPD is unknown because of the difference in the estimated prevalence rate of PPD based on country, ethnicity, and study type. Thus, this study aimed to determine whether Japanese women with multiple pregnancy were at a high risk of developing PPD at 1 and 6 months postpartum. METHODS: In this nationwide prospective cohort study (the Japan Environment and Children's Study), conducted between January 2011 and March 2014, 77,419 pregnant women were enrolled. PPD was assessed using the Edinburgh Postnatal Depression Scale (EPDS) 1 and 6 months postpartum. A score of ≥13 points implied "positive" for PPD. Multiple logistic regression analyses estimated the association between multiple pregnancy and PPD risk. RESULTS: Overall, 77,419 pregnancies (singleton, n = 76,738; twins, n = 676; triplets, n = 5) were included; 3.6 % and 2.9 % of pregnant women had PPD at 1 and 6 months postpartum, respectively. Compared with singleton pregnancy, multiple pregnancy was not associated with PPD at 1 month, but at 6 months postpartum (adjusted odd ratios: 0.968 [95 % confidence interval {CI}, 0.633-1.481] and 1.554 [95 % CI, 1.046-2.308], respectively). LIMITATIONS: 1) Some potential PPD risk factors could not be evaluated, 2) PPD was not diagnosed by psychiatrists, and 3) depressive symptoms at 6 months postpartum were considered PPD; however, definitions may vary. CONCLUSIONS: Japanese women with multiple pregnancy may be regarded as a target group for follow-up and postpartum depression screening for at least 6 months during the initial postpartum period.

Effect of birth season on allergic rhinitis and cedar pollinosis considering allergen and vitamin D exposure: The Japan Environment and Children's study (JECS).

BACKGROUND: The relationship between the season of birth, allergen sensitization, and allergic rhinitis have been inconsistent, and there are no studies that simultaneously consider vitamin D and allergen exposure. This study aimed to determine the associations between the season of birth, house dust mite (HDM) and Japanese cedar pollen (JCP) sensitization, and allergic rhinitis and pollinosis, while taking vitamin D levels and allergen exposure into account. METHODS: This study included 4323 participants in the Sub-Cohort Study of the Japan Environment and Children's Study. A logistic regression model was used to analyze the association between the season of birth and sensitization to JCP or HDM (judged by specific immunoglobulin E) at age 2 and allergic rhinitis or pollinosis at age 3, adjusted for HDM or JCP exposure and vitamin D levels with potential confounders. RESULTS: Participants born in spring or summer were more likely to have pollinosis than were those born in winter (adjusted odds ratio [aOR]: 2.08, 95% confidence interval [CI]: 1.13-3.82 for spring; aOR: 1.89, 95% CI: 1.03-3.47 for summer). Participants born in summer were more likely to have HDM sensitization than were those born in winter (Der p 1, aOR: 1.53, 95% CI: 1.10-2.15; Der f 1, aOR: 1.44, 95% CI: 1.03-2.01). Exposure to JCP and HDM were associated with pollinosis and HDM sensitization, respectively. CONCLUSIONS: Spring and summer births were associated with the development of pollinosis, and summer birth was associated with HDM sensitization, even when vitamin D and allergen exposure were considered. Further studies on mechanisms other than vitamin D and allergen exposure are required.

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.

Appropriate procedures to increase the adherence of children to blood collection: A cross-sectional study.

Background and Aim: Venipuncture for blood collection elicits fear and pain in children. We investigated factors that affect satisfaction with health checkups that included blood collection in healthy 7-8-year-old children who underwent blood collection with topical anesthesia. Method: Two studies, one questionnaire survey, and the other structured interviews were conducted to gather insights and understand the emotions of 492 and 20 children, respectively. Results: We found that the following six points can be applied to encourage children to assess their experience of blood collection positively: (1) prior information using a pamphlet; (2) telling the children that the volume of blood drawn will be small; (3) carefully explaining the risk and benefit of topical anesthesia; (4) conducting the blood collection process swiftly; (5) praising and thanking the children's effort and cooperation; and (6) explaining the results of the research to the children if their blood is going to be used for research. Conclusion: The findings indicate that with appropriate measures to reduce pain and fear, children's initial negative feelings toward blood collection can be replaced by positive feelings after the procedure.

Maternal protein intake in early pregnancy and child development at age 3 years.

BACKGROUND: The current study aimed to assess the association between low maternal protein intake during pregnancy and child developmental delay at age 3 years. METHODS: This research used data obtained from the Japan Environment and Children's Study. In total, we analyzed 77,237 mother-child pairs. Dietary intake was assessed using the Food Frequency Questionnaire. Developmental outcomes at age 3 years were evaluated with the Japanese version of the Ages and Stages Questionnaire, Third Edition. A multivariate logistic regression analysis was performed to assess the association between maternal protein intake during pregnancy and child development delays at age 3 years. RESULTS: Based on the protein-to-total energy intake ratio during early pregnancy, the participants were categorized into three groups: <9.39% (>2 standard deviation below the mean), the severely low protein (SLP) group; 9.39-<13%, the low protein group; and ≥13%, the normal protein group. After adjusting for potential confounding factors, SLP intake was found to be significantly correlated with a higher risk of developmental delay according to the communication, fine motor and problem-solving skill domains. CONCLUSIONS: SLP intake caused by inadequate diet during early pregnancy was associated with a higher risk of child developmental delay at age 3 years. IMPACT: Animal studies have shown that maternal protein restriction during pregnancy and lactation causes abnormal brain development among offspring. Birth cohort studies to date have not assessed the effects of maternal low protein exposure during pregnancy on child development. Severely low protein intake during early pregnancy was associated with a higher risk of child developmental delay at age 3 years. Since nutritional imbalance in early pregnancy affects not only fetal growth but also postnatal neurodevelopment, nutritional management before pregnancy is considered important.

Exposure to House Dust Mite Allergen and Endotoxin in Early Life and Sensitization and Allergic Rhinitis: The JECS.

The association between endotoxin and allergic rhinitis (AR) is not conclusive. The aim of this study was to determine the association between endotoxin and house dust mite (HDM) allergens in dust, and HDM sensitization and AR among Japanese infants. This study included 4188 participants in the Sub-Cohort Study of the Japan Environment and Children's Study. Dust was collected from children's mattresses at age 18 months and endotoxin and HDM allergen levels were measured. A logistic regression model was used to analyze the association between endotoxin or HDM allergen and the sensitization to HDM (specific-IgE) at age 2 and AR at age 3. The median (interquartile range) endotoxin level was 375.1(186.9-826.5) EU/m2 and the Der 1 (Der p 1 + Der f 1) level was 51.2 (14.8-168.6) ng/m2. There were significant positive associations between endotoxin and HDM sensitization (Der f 1, adjusted odds ratio [aOR] quartile [Q] 4 vs. Q1, 1.44, 95% CI, 1.04-2.00; Der p 1, aOR Q4 vs. Q1, 1.56, 95% CI, 1.12-2.16). There were also significant positive associations between Der 1 exposure and HDM sensitization (Der f 1, aOR Q3 vs. Q1, 1.75, 95% CI, 1.26-2.44; aOR Q4 vs. Q1, 2.98, 95% CI, 2.15-4.13; Der p 1, aOR Q3 vs. Q1, 1.91, 95% CI, 1.37-2.66; aOR Q4 vs. Q1, 2.91, 95% CI, 2.09-4.05). There were, however, no associations between endotoxin or Der 1 and AR. In the population residing mostly in non-farming settings, both endotoxin and HDM allergens in dust were associated with an increased risk of HDM allergen sensitization, but not with AR.

Association of egg protein levels in dust with allergy status and related factors.

BACKGROUND: Levels of peanut protein in dust have been reported to be associated with sensitization and allergy to it, so controlling food protein in dust may help prevent food allergy. However, studies of factors associated with egg protein levels in dust are scarce. This study aimed to determine the factors contributing to egg protein levels in dust. METHODS: This cross-sectional study included 159 participants in the Sub-Cohort Study of the Japan Environment and Children's Study in Yamanashi Prefecture at a 6 year follow up. House dust at 6 years was collected and egg protein concentrations were measured for whole egg protein. Household factors, including the maternal frequency of egg consumption, were assessed by questionnaires. A linear regression model was used to analyze the effect of household environmental factors on egg protein in dust. RESULTS: In multivariate analysis, frequent maternal egg consumption (≥5 times a week) was associated with higher egg protein concentrations in house dust (ß = 0.96, P = 0.01). The egg protein load was significantly associated with a higher number of cohabitants (≥5, ß = 0.85, P = 0.02) in addition to frequent maternal egg consumption. Among the participants, 140 (88.1%) had no egg allergy, 15 (9.4%) were egg tolerant, and 4 (2.5%) had an egg allergy at 6 years old. There was no significant association between the current egg allergy status and egg protein concentrations in dust. CONCLUSIONS: The frequency of maternal egg consumption and the number of inhabitants are contributing factors to egg protein levels in dust.

Gestational age, birth weight, and perinatal complications in mothers with diabetes and impaired glucose tolerance: Japan Environment and Children's Study cohort.

We aimed to determine the risk of perinatal complications during delivery in mothers with non-normal glucose tolerance in a large Japanese birth cohort. We analysed data of 24,295 neonate-mother pairs in the Japan Environment and Children's Study cohort between 2011 and 2014. We included 67 mothers with type 1 diabetes, 102 with type 2 diabetes (determined by questionnaire), 2,045 with gestational diabetes (determined by diagnosis), and 2,949 with plasma glucose levels ≥140 mg/dL (shown by a screening test for gestational diabetes). Gestational age, birth weight, placental weight, and proportions of preterm birth, and labour and neonatal complications at delivery in mothers with diabetes were compared with those in mothers with normal glucose tolerance. Mean gestational age was shorter in mothers with any type of diabetes than in mothers without diabetes. Birth weight tended to be heavier in mothers with type 1 diabetes, and placental weight was significantly heavier in mothers with type 1 and gestational diabetes and elevated plasma glucose levels (all p<0.05). The relative risks of any labour complication and any neonatal complication were 1.49 and 2.28 in type 2 diabetes, 1.59 and 1.95 in gestational diabetes, and 1.22 and 1.30 in a positive screening test result (all p<0.05). The relative risks of preterm birth, gestational hypertension, and neonatal jaundice were significantly higher in mothers with types 1 (2.77; 4.07; 2.04) and 2 diabetes (2.65; 5.84; 1.99) and a positive screening test result (1.29; 1.63; 1.12) than in those without diabetes (all p<0.05). In conclusion, placental weight is heavier in mothers with non-normal glucose tolerance. Preterm birth, gestational hypertension, and jaundice are more frequent in mothers with types 1 and 2 diabetes. A positive result in a screening test for gestational diabetes suggests not only a non-normal glucose tolerance, but also a medium (middle-level) risk of perinatal complications.

Association of the incidence of atopic dermatitis until 3 years old with climate conditions in the first 6 months of life: Japan Environment and Children's Study (JECS).

OBJECTIVE: To determine the climate conditions that affect the incidence of atopic dermatitis from infancy to 3 years old. STUDY DESIGN: We analyzed 100,303 children born from 2011 to 2014 for follow-up until 3 years old using cohort data from the Japan Environment and Children's Study. The study included 15 Regional Centers, including 19 prefectures across Japan. We used meteorological data of the Japan Meteorological Agency. We calculated the hazard ratio (HR) of the standard deviation and low vs. high mean values of several climate conditions in children in their first 6 months of life to determine the incidence of atopic dermatitis. RESULTS: The Kaplan-Meier curve showed that children born in the months of October to December had the highest incidence of atopic dermatitis. Among climate conditions, a one standard deviation increase in the temperature (HR = 0.87), minimum temperature (HR = 0.87), and vapor pressure (HR = 0.87) showed the lowest HRs for the incidence of atopic dermatitis. These results were confirmed by an analysis by strata of the birth season. A low vapor pressure (HR = 1.26, p<0.0001) and the combination of a low mean temperature or low mean minimum temperature and low vapor pressure (HR = 1.26, p<0.0001) were associated with the highest incidence of atopic dermatitis. These results were consistent when they were adjusted for a maternal and paternal history of allergy and the prefecture of birth. CONCLUSION: Among climate conditions, a low vapor pressure is the most strongly associated with a high incidence of atopic dermatitis. Measuring vapor pressure may be useful for preventing atopic dermatitis.