Maternal birth weight is an indicator of preterm delivery: the Japan environment and children's study.

This study aimed to investigate the association between maternal birth weight (MBW) with preterm delivery (PTD) in the Japanese population. To this end, a total of 78,972 Japanese pregnant women were included in a prospective birth cohort study. Multiple logistic regression and multinominal logistic regression models were applied to investigate the associations of MBW with PTD (delivery from 22 to < 37 weeks of gestation), early PTD (delivery from 22 to < 34 weeks), and late PTD (delivery from 34 to < 37 weeks). The results showed that MBW was inversely associated with PTD, early PTD, and late PTD (p-for-trend < 0.0001, 0.0014, and < 0.0001, respectively). The adjusted odds ratios per each 500 g of MBW decrease were 1.167 (95% confidence interval [CI]: 1.118-1.218) for PTD, 1.174 (95% CI: 1.070-1.287) for early PTD and 1.151 (95% CI: 1.098-1.206) for late PTD. The effect size of the association of MBW with early PTD was similar to that with late PTD. This study demonstrated for the first time an association of a low MBW with PTD, early PTD, and late PTD in a Japanese nationwide cohort.

Dietary intake of methylmercury by 0-5 years children using the duplicate diet method in Japan.

BACKGROUND: The developing brains are sensitive to methylmercury (MeHg). However, the exposure to MeHg in baby foods and toddler meals remains unknown. This study aimed to determine MeHg intake from baby food or toddler meals, and to investigate the relationship with child hair total mercury (THg). METHODS: A total of 3 days of 24-hour dietary diet and hair samples were collected from 260 consenting children aged 0-5 years. We measured the concentrations of THg and MeHg in the diet and THg in the hair. RESULTS: The results of measuring THg were below both the method detection and method quantification limits or either of both in powdered milk (93.8%), 5-6 months (53.3%), and 7-8 months (39.5%). The median daily THg intake was 20.3 (95% confidence interval 0.72-232.5) ng/kgbw. MeHg was not detected in 213 samples with dietary THg concentrations below 1 ng/g. The MeHg concentration with THg concentrations of 1 ng/g or higher was 1.70 (0.87-6.21) ng/g, and MeHg percentage in THg was 90.0%. To estimate MeHg intake, we multiplied the THg concentration by 90.0%, resulting in an estimated MeHg intake of 18.3 (0.65-209.2) ng/kgbw/day. The THg in children's hair was 1.05 (0.31-3.96) ppm, and a weak positive correlation was observed between hair THg and dietary MeHg (r = 0.170). CONCLUSIONS: This study highlights the accurate estimation of MeHg intake in children using a duplicate method. Japanese children consume fish, the MeHg intakes exceeded the reference dose and/or provisional tolerable weekly intake in several children. Further discussion based on epidemiological data is required.

Association between Maternal Birth Weight and Prevalence of Congenital Malformations in Offspring: The Japanese Environment and Children's Study.

Congenital malformations are functional and structural alterations in embryonic or foetal development resulting from a variety of factors including maternal health status. This study aimed to investigate the association between maternal birth weight (MBW) and the prevalence of congenital malformations in offspring using data from a nationwide birth cohort study in Japan including 103,060 pregnancies. A binary logistic regression model with adjustment for various covariates revealed that an MBW of <2500 g (low MBW) was associated with an increased risk of congenital heart disease (adjusted odds ratio: 1.388, [95% confidence interval: 1.075-1.792]), angioma (1.491 [1.079-2.059]), and inguinal hernia (1.746, [1.189-2.565]), while those with an MBW of ≥4000 g (high MBW) were associated with congenital anomalies of the urinary tract (2.194, [1.261-3.819]) and arrhythmia (1.775, [1.157-2.725]) compared with those with an MBW of 3000-3499 g. Low MBW was associated with cleft lip and/or palate (1.473, [1.052-2.064]), congenital heart disease (1.615, [1.119-2.332]), genital organs (1.648, [1.130-2.405]), hypospadias (1.804, [1.130-2.881]), and inguinal hernia (1.484, [1.189-1.851]) in male infants and CAKUT (1.619, [1.154-2.273]) in female infants, whereas high MBW was associated with congenital heart disease (1.745, [1.058-2.877]) and CAKUT (2.470, [1.350-4.517]) in male infants. The present study is the first to demonstrate a link between MBW and congenital malformations in Japanese children. While these results must be interpreted with caution, MBW should be considered a major predictor of congenital malformation risk.

Maternal birth weight as an indicator of early and late gestational diabetes mellitus: The Japan Environment and Children's Study.

AIMS: This study aimed to investigate the association of maternal birth weight (MBW) with early and late gestational diabetes mellitus (GDM). METHODS: A total of 69318 pregnant Japanese women were included in this birth cohort study. The associations between maternal birth weight and early gestational diabetes mellitus (diagnosed at <24 gestational weeks) and late GDM (diagnosed at ≥24 gestational weeks) were investigated using a multinomial logistic regression model, with an maternal birth weight of 3000-3499 g as the reference category. RESULTS: Lower maternal birth weight was associated with higher odds of developing early and late gestational diabetes mellitus (P < 0.0001 and P < 0.0001, respectively). The adjusted odds ratios (aORs) for early gestational diabetes mellitus in participants with a MBW of <2500 g and 2500-2999 g were 1.345 (95% confidence interval [CI]: 0.912-1.984) and 1.338 (95% CI: 1.098-1.629), respectively. The aORs for late gestational diabetes mellitus in participants with a MBW of <2500 g and 2500-2999 g were, 1.657 (95% CI: 1.298-2.115) and 1.218 (95% CI: 1.058-1.402), respectively. CONCLUSIONS: Regardless of the gestational age when gestational diabetes mellitus was diagnosed, a lower maternal birth weight was associated with an increased risk of gestational diabetes mellitus. Furthermore, the association of a MBW <2500 g with late gestational diabetes mellitus tended to be stronger than that with early gestational diabetes mellitus.

Environments affect blood pressure in toddlers: The Japan Environment and Children's Study.

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

Work engagement and associated factors among Japanese registered dietitians and dietitians: a cross-sectional study.

Healthcare services provided by registered dietitians and dietitians have been changing because of evolving lifestyles and population dynamics, leading to subsequent changes in the occupational status and experiences of these professionals. However, few studies have examined occupational stress among registered dietitians and dietitians. This study involved a cross-sectional survey to investigate the status and associated factors of work engagement among registered dietitians and dietitians, whose professions differ based on licensing processes and scope of work. A total of 3,593 questionnaires were distributed, 1,890 responses were received, and 1,654 valid questionnaires were analyzed. Work engagement was measured using the Utrecht Work Engagement Scale. Multiple regression analysis was conducted to examine the associations between work engagement and each factor. The work engagement scores of dietitians were significantly lower than those of registered dietitians. Further, work engagement was associated with age, workplace, coworker support, and effort-reward ratio for both registered dietitians and dietitians. However, exercise habit was a significant factor associated with work engagement only among dietitians. Work engagement among registered dietitians was comparable to that of typical Japanese workers, whereas it was lower among dietitians. The findings highlight the importance of considering associated factors to improve work engagement further, especially among dietitians.

Timing of Primary Tooth Eruption in Infants Observed by Their Parents.

BACKGROUND: The timing of primary teeth eruption is a visible indicator of infant physical growth other than body weight or height. It also reflects neurological integrity and development as well as nutrition, socioeconomic state, or underlying diseases. Therefore, the timing of primary teeth eruption is one of the major concerns for parents in health checkups for infants and children. However, the detailed developmental timing of teeth eruption differs depending on the survey methodology, country, or generation. We hypothesized that the timing of primary teeth eruption differs between the medical checkup by dentists and the daily records by parents. METHODS: We conducted a questionnaire survey on the date of eruption of primary teeth as an adjunct study among Miyagi Regional Center participants in the Japan Environment and Children's Study (JECS), a large-scale birth cohort study. A total of 1695 responses (3793 participants) were analyzed. RESULTS: The median ages of eruption were 7.1 months (male) and 7.6 months (female) for mandibular primary central incisors, 8.7 months (male) and 9.2 months (female) for maxillary primary central incisors, 10.0 months (male) and 10.3 months (female) for maxillary primary lateral incisors, and 10.4 months (male) and 10.8 months (female) for mandibular primary lateral incisors, which were earlier than the reported timings based on dental check-ups. Comparing the eruption time of preterm and term infants, the eruption time was earlier in preterm infants in the corrected ages. CONCLUSIONS: The eruption timing observed and described by the parents is earlier than that examined by dentists at regular check-ups. In addition to examining the primary teeth eruption of full-term birth children, we also examined that of preterm birth children because of the increasing number of premature births. To the best of our knowledge, this is the first report from a large cohort study to clarify the eruption time of primary teeth monitored by parents.

Maternal birth weight as an indicator of early-onset and late-onset hypertensive disorders of pregnancy: The Japan Environment and Children's study.

OBJECTIVES: This study aimed to investigate the association between maternal birth weight (MBW) and hypertensive disorders of pregnancy (HDP) according to the gestational age when HDP develops. STUDY DESIGN: A total of 77,345 subjects were included in this prospective birth cohort study. The association between MBW and HDP was investigated by a multinomial logistic regression model. MAIN OUTCOME MEASURES: Early-onset HDP (EO-HDP), preterm late-onset HDP (preterm LO-HDP), and term late-onset HDP (term LO-HDP). RESULTS: Lower MBW was associated with higher odds of preterm and term LO-HDP (p-values for trend < 0.0001 and = 0.0005, respectively). A linear association between MBW and EO-HDP was observed (p-values for trend = 0.0496). The shape of the association between MBW and preterm LO-HDP was a combination of the associations between MBW with EO-HDP or LO-HDP. The effect size of the association between MBW < 2,500 g and EO-HDP was lower than that of MBW < 2,500 g with preterm or term LO-HDP. The adjusted odds ratios for EO-HDP, preterm LO-HDP, and term LO-HDP in subjects with MBW < 2,500 g were 1.052 (95 % confidence interval [CI]: 0.665-1.664), 1.745 (95 % CI: 1.220-2.496), and 1.496 (95 % CI: 1.154-1.939), respectively. CONCLUSIONS: MBW was associated with HDP, regardless of gestational age when HDP developed. Furthermore, the association of MBW < 2,500 g with preterm or term LO-HDP was stronger than that with EO-HDP.

Factors associated with postpartum smoking relapse at early postpartum period of Japanese women in the Japan Environmental and Children's Study.

BACKGROUND: Postpartum smoking relapse is a serious public health concern. Previous studies have identified several risk factors for postpartum smoking relapse; however, very little is known about the predictors of early postpartum smoking relapse. This study aimed to determine postpartum smoking relapse status and its associated risk factors at 1 month postpartum among Japanese women. METHODS: Data were obtained from 93,851 mothers with live births in an ongoing birth cohort study, the Japan Environment and Children's Study. Data on smoking status and confounding variables were collected using self-administered questionnaires and medical record transcripts. Self-administered questionnaires were administered during the first trimester, second/third trimester, and 1 month after delivery. A multiple logistic regression analysis was performed. RESULTS: Among the 14,326 mothers who smoked during pregnancy, 10,917 (76.2%) quit smoking during pregnancy. Subsequently, 617 (5.7%) of the mothers who had quit relapsed smoking at 1 month postpartum. Maternal age (≤24, ≥35), maternal education (≤12 years), parity (≥Second), feeding method (Formula milk), partner smoking status during pregnancy (Smoker), number of cigarettes per day before the cessation of smoking (≥11), maternal alcohol consumption at 1-month postpartum (Drinker), postpartum depression (EPDS score ≥9), and spending time at the parents' home after delivery (≥14 days) were associated with smoking relapse. CONCLUSIONS: A certain number of mothers relapsed even 1 month postpartum. Besides mother's alcohol and smoking habit before pregnancy, breastfeeding and partner smoking are important factors in early postpartum smoking relapse in Japan.

Neurodevelopmental associations of prenatal and postnatal methylmercury exposure among first-grade children in the Kinan region, Japan.

The most severe effects of methylmercury (MeHg) exposure during child development are thought to result from exposure during fetal life and childhood. However, comparing the neurodevelopmental effects of prenatal and postnatal MeHg exposure (PreMeHg and PostMeHg, respectively) remains unclear. We aimed to investigate the associations between neurodevelopmental indicators and PreMeHg or PostMeHg. The participants were 134 children in the first grade of elementary schools aged 7-8 years from the Kinan region, an area with high consumption of MeHg-rich whales and tunas in Japan. We measured MeHg levels in preserved umbilical cord tissues and total mercury (T-Hg) levels in children's hair to estimate PreMeHg and PostMeHg levels, respectively. Neuropsychological (intelligence quotient testing and Boston Naming Test) and neurophysiological (brainstem auditory evoked potential [BAEP], visual evoked potential [VEP], and color vision tests) studies were performed to evaluate the neurodevelopmental status. Multiple regression analyses were conducted according to sex. The geometric mean MeHg levels in preserved umbilical cord tissues and T-Hg levels in children's hair were 0.11 µg/g and 2.94 µg/g, respectively. Neither PreMeHg nor PostMeHg was related to neuropsychological indicators. Some associations between MeHg exposure and neurophysiological results were observed only in boys. N145 latency in VEPs was significantly prolonged with increasing PreMeHg (ß: 12.01, 95% confidence interval [CI]: 0.648, 23.38). The III-V interpeak intervals in BAEP were significantly prolonged with increasing PreMeHg or PostMeHg (ß [95% CI]: 0.142 [0.041, 0.243] and 0.159 [0.052, 0.265], respectively). After adjusting for PreMeHg, the association between PostMeHg and BAEP latencies disappeared. In conclusion, the latency in the auditory and visual pathways was significantly prolonged with increasing PreMeHg in boys. These findings suggest that male fetuses may be more susceptible to MeHg exposure.

Secondhand smoke exposure is associated with the risk of hypertensive disorders of pregnancy: the Japan Environment and Children's Study.

Hypertensive disorders of pregnancy (HDP) are associated with poor maternal and neonatal prognoses. Although several studies have indicated an effect of secondhand smoke (SHS) exposure on HDP, such evidence is lacking in Japan. Therefore, we analyzed data from the Japan Environment and Children's Study, a large-scale epidemiological investigation, to elucidate a possible link between SHS exposure and HDP risk. Data were obtained from the all-birth fixed datasets and included information on 104,062 fetuses and their parents. SHS exposure was assessed in terms of the frequency (rarely, 1-3, or 4-7 days/week) and the daily duration of exposure (<1, 1-2, or ≥2 h(s)/day). Modified Poisson regression model analyses were performed with adjustment for known risk factors for HDP. Additionally, the population attributable fractions (PAFs) of SHS exposure and maternal smoking to HDP prevalence were estimated. The relative risks of developing HDP among individuals with SHS exposures of 4-7 days/week and ≥2 h/day were 1.18 and 1.27 (95% confidence interval: 1.02-1.36 and 0.96-1.67), respectively, compared to the reference groups (rare exposure and <1 h/day). The PAFs for the risk of HDP due to SHS exposure and perinatal smoking were 3.8% and 1.8%, respectively. Japanese women with greater exposure to SHS have a higher risk of HDP after adjustment for possible confounding factors; thus, relevant measures are required to reduce SHS exposure to alleviate HDP risk. The association between second-hand smoking exposure and hypertensive disorders of pregnancy risk was analyzed using the JECS data. The relative risks in 4-7 days/week and ≥2 h/day of SHS exposures were 1.18 and 1.27, respectively. The PAFs due to SHS exposure and maternal smoking were 3.80% and 1.81%, respectively.

Timing of Maternal Smoking Cessation and Newborn Weight, Height, and Head Circumference.

OBJECTIVE: To examine the relationship between timing of smoking cessation during pregnancy and anthropometric indices of newborns. METHODS: Mothers and neonates enrolled in the JECS (Japan Environment and Children's Study), a nationwide birth cohort study, were examined. Patients with full-term neonates were included in the analysis, and 73,025 mother-neonate pairs with complete data were identified. The mothers were classified into six groups according to smoking status during pregnancy (nonsmokers [Q1, n=44,198]; ex-smokers who quit before pregnancy [Q2, n=16,461]; ex-smokers who quit in the first trimester [Q3, n=8,948]; ex-smokers who quit in the second trimester [Q4, n=498]; ex-smokers who quit in the third trimester [Q5, n=651]; and smokers who smoked throughout pregnancy [Q6, n=2,269)]). Data on smoking were based on questionnaires administered in the first, second, or third trimester and 1 month after delivery. The primary outcomes were birth weight, height, and head circumference. RESULTS: Compared with nonsmokers (Q1), no adverse outcomes were observed for ex-smokers who quit before pregnancy (Q2). The mean adjusted weights of male and female neonates were 135 g and 125 g lower, respectively, in Q6 participants than in Q1 participants. Comparing Q1 and Q6 participants, height was 0.6 cm and 0.7 cm smaller for male and female neonates, respectively. Head circumference in neonates of Q6 participants was 0.3 cm and 0.3 cm smaller for male and female neonates, respectively, than that in Q1 participants. Across all three measures, smoking cessation in the first and second trimester reduced the differential in outcomes between nonsmokers and individuals who smoked throughout pregnancy. CONCLUSION: Smoking during pregnancy is associated with reduced newborn birth weight, height, and head circumference. Earlier smoking cessation during pregnancy reduces the adverse effects of smoking on fetal growth.

Social Capital and Physical Activity among Japanese Pregnant Women: Adjunct Study of Japan Environment and Children's Study in Miyagi Prefecture.

Adequate physical activity during pregnancy is crucial for maternal and fetal health. Although physical activity during pregnancy is restricted, social support and trust may have a favorable influence on physical activity. This study aimed to examine the association between cognitive social capital during pregnancy and prenatal physical activity among Japanese individuals. We also investigated whether social capital has an extended influence during pregnancy on physical activity 1.5 years after delivery. The cognitive social capital of 3,055 pregnant women in their second trimester was measured using nine questions on a self-administered questionnaire. Each cognitive social capital was classified into two or four groups based on their scores. Physical activity during pregnancy was measured using a validated questionnaire in the second trimester and at 1.5 years after delivery. Participants were classified as having adequate physical activity (≥ 150 min/week) or inadequate physical activity (< 150 min/week) based on the physical activity guidelines during pregnancy. After adjusting for confounders, emotional support was positively associated with the prevalence of adequate prenatal physical activity (P for trend = 0.002). Moreover, there was a positive association between emotional support during pregnancy and the prevalence of adequate physical activity 1.5 years after delivery. Among Japanese women, emotional support during pregnancy was associated with a higher prevalence of adequate prenatal physical activity during pregnancy and at 1.5 years after delivery.

The impact of maternal and paternal birth weights on infant birth weights: the Japan environment and children's study.

This study aimed to evaluate the association between parental and infant birth weights in Japan. In total, 37,504 pregnant Japanese women and their partners were included in this birth cohort study. A multinomial logistic regression model was used to evaluate the associations of parental birth weights with small-for-gestational-age (SGA) or large-for-gestational-age (LGA) infants. Associations between parental birth weight and low birth weight (LBW) infants or macrosomia were also examined, and linear associations between parental birth weight and SGA or LGA were found. The adjusted odds ratios (aORs) for SGA infants per 500 g decrease in maternal and paternal birth weights were 1.50 (95% confidence interval [CI],1.43-1.58) and 1.31 (95% CI, 1.25-1.38), respectively. The aORs for LGA infants per 500 g increase in maternal and paternal birth weights were 1.53 (95% CI, 1.47-1.60) and 1.41 (95% CI, 1.35-1.47), respectively. The association between parental birth weight and LBW infants or macrosomia was also linear. The aORs for LBW infants per 500 g decrease in maternal and paternal birth weights were 1.47 (95% CI, 1.40-1.55) and 1.25 (95% CI, 1.19-1.31), respectively. The aORs for macrosomia per 500 g increase in maternal and paternal birth weights were 1.59 (95% CI, 1.41-1.79) and 1.40 (95% CI, 1.23-1.60), respectively. Parental birth weight was found to be associated with infant birth weight even after adjusting for various parental factors. Furthermore, maternal birth weight was more strongly associated with infant birth weight than with paternal birth weight.

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.

Investigation of Maternal Diet and FADS1 Polymorphism Associated with Long-Chain Polyunsaturated Fatty Acid Compositions in Human Milk.

Increasing the amount of long-chain polyunsaturated fatty acids (LCPUFA) in human milk is an important strategy for infant growth and development. We investigated the associations of LCPUFA compositions in human milk with maternal diet (especially fish and shellfish intake), with fatty acid Δ5 desaturase gene (FADS1) polymorphisms, and with gene-diet interactions. The present study was performed as part of an adjunct study of the Japan Environment and Children's Study. The participants were 304 lactating females, who provided human milk 6−7 months after delivery. Fatty acids in human milk were analyzed by gas chromatography, and dietary surveys were conducted using a brief self-administered diet history questionnaire. We also analyzed a single nucleotide polymorphism of FADS1 (rs174547, T/C). There was a significant difference in arachidonic acid (ARA) composition in human milk among the genotype groups, and the values were decreasing in the order of TT > TC > CC. The concentrations of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) were also different between TT and CC genotype, indicating a tendency for decreasing values in the same order. The composition of ARA showed significant gene−dietary interactions in multiple regression analysis, and the positive correlation between fish and shellfish intake and ARA composition in human milk was significant only in the CC genotype. Moreover, the factor most strongly associated with EPA and DHA composition in human milk was fish and shellfish intake. Therefore, it was suggested that increasing fish and shellfish intake in mothers may increase EPA and DHA composition in human milk, while increasing fish and shellfish intake in CC genotype mothers may lead to increased ARA composition in human milk.

Global DNA Methylation in Cord Blood as a Biomarker for Prenatal Lead and Antimony Exposures.

DNA methylation is an epigenetic mechanism for gene expression modulation and can be used as a predictor of future disease risks. A prospective birth cohort study was performed to clarify the effects of neurotoxicants on child development, namely, the Tohoku Study of Child Development, in Japan. This study aimed to evaluate the association of prenatal exposure to five toxic metals-arsenic, cadmium, mercury, lead (Pb), antimony (Sb), and polychlorinated biphenyls (PCBs, N = 166)-with global DNA methylation in umbilical cord blood DNA. DNA methylation markers, 5-methyl-2'-deoxycytidine (mC) and 5-hydroxymethyl-2'-deoxycytidine (hmC), were determined using liquid chromatography-tandem mass spectrometry. The mC content in cord blood DNA was positively correlated with Pb and Sb levels (r = 0.435 and 0.288, respectively) but not with cord blood PCBs. We also observed significant positive correlations among Pb levels, maternal age, and hmC content (r = 0.155 and 0.243, respectively). The multiple regression analysis among the potential predictors demonstrated consistent positive associations between Pb and Sb levels and mC and hmC content. Our results suggest that global DNA methylation is a promising biomarker for prenatal exposure to Pb and Sb.

Association between whole blood metallic elements concentrations and gestational diabetes mellitus in Japanese women: The Japan environment and Children's study.

BACKGROUND: Exposure to several metallic elements has been suggested as a risk factor for gestational diabetes mellitus (GDM), but inconsistent findings have been reported. This study aimed to examine the association between the maternal whole blood concentration of metallic elements (Hg, Pb, Cd, Mn, and Se) and GDM using the dataset of the Japan Environment and Children's Study (JECS), a nationwide birth cohort study, which was designed to examine the adverse effects of pre/post-natal exposure to hazardous environment. METHODS: The data of 78,964 pregnant women who were participants of JECS were used. Blood samples were collected from the pregnant women at second/third trimester of gestation. We employed logistic regression analysis, quantile g-computation (QGC) and a distributed lag nonlinear model (DLNM) to examine the association between the blood concentration of metallic elements and the risk of GDM. RESULTS: The prevalence of GDM was 2.1%. In the logistic regression analyses, maternal blood Hg was associated with an increased risk of GDM. In QGC analysis, although metallic elements mixtures were not related to an increased risk of GDM, Hg (52.6%) may be the main contributor. According to the results of DLNM, for maternal exposure to Hg, 4.99 ng/g was identified as its susceptible minimum window for elevated risk of GDM. CONCLUSIONS: Our findings highlighted an association between Hg exposure and an increased risk of GDM. Studies of the underlying mechanisms and potential contributing factors, including fish intake, of this association are warranted.