Associations among perfluorooctanesulfonic/perfluorooctanoic acid levels, nuclear receptor gene polymorphisms, and lipid levels in pregnant women in the Hokkaido study.

The effect of interactions between perfluorooctanesulfonic (PFOS)/perfluorooctanoic acid (PFOA) levels and nuclear receptor genotypes on fatty acid (FA) levels, including those of triglycerides, is not clear understood. Therefore, in the present study, we aimed to analyse the association of PFOS/PFOA levels and single-nucleotide polymorphisms (SNPs) in nuclear receptors with FA levels in pregnant women. We analysed 504 mothers in a birth cohort between 2002 and 2005 in Japan.

Prenatal exposure to 11 perfluoroalkyl substances and fetal growth: A large-scale, prospective birth cohort study.

Background: Prenatal maternal exposure to perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) has been reportedly associated with decreased birth weight. Although a majority of epidemiological studies concerning perfluoroalkyl substances (PFAS) have focused on PFOS and PFOA, epidemiological studies of PFAS with longer carbon chains are scarce. In this study, we investigated whether prenatal maternal exposure to 11 PFAS, in particular those with longer carbon chains, is associated with fetal growth.

Prenatal tobacco exposure and ADHD symptoms at pre-school age: the Hokkaido Study on Environment and Children's Health.

Background: There have been inconsistent findings reported on maternal passive smoking during pregnancy and child risk of ADHD. In this study, ADHD symptoms at pre-school age children in association with prenatal passive and active tobacco smoke exposure determined by maternal plasma cotinine levels in the third trimester were investigated.

Methods: This was a follow-up study of the birth cohort: the Hokkaido Study on Environment and Children's Health.

Effects of prenatal sex hormones on behavioral sexual dimorphism.

Background: We investigated the association between the hormone environment during the prenatal period using cord blood, and gender-role play behavior in school-aged children.

Methods: A total of 879 school-aged children (433 boys and 446 girls) in a prospective birth cohort study in Hokkaido were enrolled to analyze the relationship between cord blood level of the sex hormones estradiol (E), testosterone (T), progesterone (P), and dehydroepiandrosterone (DHEA), and the Pre-School Activities Inventory (PSAI) score. The PSAI evaluated sex-typical characteristics, the type of preferred toys and play activities.

Association Between Maternal Serum Folate Concentrations in the First Trimester and the Risk of Birth Defects: The Hokkaido Study of Environment and Children's Health.

Background: Low red blood cell folate concentrations during early pregnancy might cause neural tube defects. However, the association between folate concentrations and birth defects of other neural crest cell-derived organs remains unknown. We investigated the associations between birth defects and first-trimester serum folate concentrations in a birth-cohort study in Japan.

Association of maternal serum concentration of hydroxylated polychlorinated biphenyls with maternal and neonatal thyroid hormones: The Hokkaido birth cohort study.

Background: Evidence on the toxicity of hydroxylated metabolites of polychlorinated biphenyls (OH-PCBs) for thyroid hormones (TH) is limited, and the underlying mechanism remains unknown.

Objectives: We aimed to investigate the effects of environmental prenatal exposure to OH-PCBs and maternal and neonatal TH levels, taking the maternal-fetal TH transfer into account.

Methods: In this prospective birth cohort (the "Hokkaido study") we included 222 mother-neonate pairs.

Sex-related differences in the associations between maternal dioxin-like compounds and reproductive and steroid hormones in cord blood: The Hokkaido study.

Background: Prenatal exposure to dioxin-like compounds (DLCs) irreversibly affects fetal reproductive and steroid hormone synthesis.

Objective: This study aimed to assess the relationships between maternal DLCs and cord blood reproductive and steroid hormones.

Methods: Participants in this study were pregnant women who enrolled in the Sapporo Cohort of the Hokkaido Study between 2002 and 2005.

Association of prenatal exposure to PCDD/Fs and PCBs with maternal and infant thyroid hormones: The Hokkaido Study on Environment and Children's Health.

Polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs) and biphenyls (PCBs) are persistent organic pollutants that are universally detected. Some congeners of PCDDs, PCDFs or PCBs have dioxin-like toxicity, whereas non-dioxin-like PCBs are considered to have different toxicity. Reports of the relationships between prenatal exposure to PCDDs, PCDFs or PCBs and thyroid homeostasis in pregnant women and infants have been inconsistent.

Relationship between adrenal steroid hormones in cord blood and birth weight: The Sapporo Cohort, Hokkaido Study on Environment and Children's Health.

Objectives: We investigated the relationship between steroid hormone levels in cord blood and birth weight.

Methods: Among 514 participants in a prospective birth cohort study in Sapporo, the following hormone levels were measured in 294 stored cord blood samples from 135 males and 159 females: androstenedione, dehydroepiandrosterone (DHEA), cortisol, and cortisone. Birth weight information was obtained from medical records.

Effects of prenatal di(2-ethylhexyl) phthalate exposure on childhood allergies and infectious diseases: The Hokkaido Study on Environment and Children's Health.

Phthalates are widely used in consumer products, and experimental studies suggest that exposure to phthalates increase the risk of allergies. However, epidemiologic evidence on the associations between prenatal phthalate exposure and allergies/infectious diseases and cord blood immunoglobulin E (IgE) levels is limited. This study aimed to evaluate the associations between maternal mono(2-ethylhexyl) phthalate (MEHP) levels and cord blood IgE levels at birth (n=127), as well as the risk of allergies/infectious diseases in participants up to 7years of age; the participants were 1.

Prenatal organochlorine pesticide exposure and the disruption of steroids and reproductive hormones in cord blood: The Hokkaido study.

Certain organochlorine pesticides (OCPs) are designated as persistent organic pollutants and are regulated in many countries. The effects of OCPs on pediatric endocrinology are a concern; however, only limited data exist from human studies on maternal OCP exposure and its effects on infants' hormone levels. This study was conducted as part of the Hokkaido Study Sapporo Cohort, a prospective birth cohort study in Japan.

Cord Blood Bisphenol A Levels and Reproductive and Thyroid Hormone Levels of Neonates: The Hokkaido Study on Environment and Children's Health.

Background: Bisphenol A (BPA) is widely used and BPA exposure is nearly ubiquitous in developed countries. While animal studies have indicated adverse health effects of prenatal BPA exposure including reproductive dysfunction and thyroid function disruption possibly in a sex-specific manner, findings from epidemiologic studies have not been enough to prove these adverse effects. Given very limited research on human, the aim of this study was to investigate associations between cord blood BPA levels and reproductive and thyroid hormone levels of neonates and whether associations differed by neonate sex.

Effects of low-level prenatal exposure to dioxins on cognitive development in Japanese children at 42months.

Background: Prenatal exposure to polychlorinated dibenzo-p-dioxins (PCDDs) or polychlorinated dibenzofurans (PCDFs) and dioxin-like polychlorinated biphenyls (dioxin-like compounds [DLCs]) through environmental chemicals may affect the neurodevelopment of children. In our previous study, an inverse association was observed between prenatal DLCs and neurodevelopment of infants aged 6months in both sexes. However, studies are yet to determine how long these adverse effects last.

Modification of adverse health effects of maternal active and passive smoking by genetic susceptibility: Dose-dependent association of plasma cotinine with infant birth size among Japanese women-The Hokkaido Study.

Objectives: We aimed to assess the individual dose-response effects of eight maternal polymorphisms encoding polycyclic aromatic hydrocarbon-metabolizing and DNA-repair genes on prenatal cotinine levels according to infant birth size.

Methods: In total, 3263 Japanese pregnant women were assigned to five groups based on plasma cotinine levels during the 8th month of pregnancy, as measured using ELISA (cut-offs: 0.21, 0.

Sex-specific differences in effect of prenatal exposure to dioxin-like compounds on neurodevelopment in Japanese children: Sapporo cohort study.

Background: Consistent reports are not available on the effects of dioxin-like polychlorinated biphenyls (PCBs) and polychlorinated dibenzo-p-dioxins (PCDD)/ polychlorinated dibenzofurans (PCDF) (dioxin-like compounds [DLCs]) on child neurodevelopment. Further, the effect of background-level exposure to individual DLC isomers is not known.

Objectives: We carried out the Sapporo cohort study to evaluate the effect of prenatal exposure to each DLC isomer on child neurodevelopment at 6 and 18 months of age, and assessed sex-specific differences in these effects.

Association of prenatal passive smoking and metabolic gene polymorphisms with child growth from birth to 3years of age in the Hokkaido Birth Cohort Study on Environment and Children's Health.

Although the effects of prenatal passive smoking on birth weight have been reported, the effects of metabolic gene polymorphisms on passive smoking have not been studied. Therefore, we investigated the effects of maternal passive smoking and metabolic gene polymorphisms on child growth up to 3years of age using cotinine as a biomarker. We included 1356 Japanese participants in a prospective cohort between 2003 and 2007 (cotinine levels at the third trimester≤0.

Interaction between maternal caffeine intake during pregnancy and CYP1A2 C164A polymorphism affects infant birth size in the Hokkaido study.

BackgroundCaffeine, 1,3,7-trimethylxanthine, is widely consumed by women of reproductive age. Although caffeine has been proposed to inhibit fetal growth, previous studies on the effects of caffeine on infant birth size have yielded inconsistent findings. This inconsistency may result from failure to account for individual differences in caffeine metabolism related to polymorphisms in the gene for CYP1A2, the major caffeine-metabolizing enzyme.

Association of prenatal exposure to perfluoroalkyl substances with cord blood adipokines and birth size: The Hokkaido Study on environment and children's health.

Perfluoroalkyl substances (PFASs) are synthetic chemicals that persist in the environment and in humans. There is a possible association between prenatal PFASs exposure and both neonate adipokines and birth size, yet epidemiological studies are very limited. The objective of this study was to examine associations of prenatal exposure to PFASs with cord blood adipokines and birth size.

Prenatal di(2-ethylhexyl) phthalate exposure and disruption of adrenal androgens and glucocorticoids levels in cord blood: The Hokkaido Study.

Di(2-ethylhexyl) phthalate (DEHP) is known for its endocrine disrupting properties. We previously demonstrated that prenatal DEHP exposure is associated with decreased progesterone levels and testosterone/estradiol ratio in the cord blood. However, evidence of the effects of prenatal DEHP exposure on adrenal androgen and glucocorticoids in infants is scarce.

Dioxin-metabolizing genes in relation to effects of prenatal dioxin levels and reduced birth size: The Hokkaido study.

Objectives: We investigated the effects of maternal polymorphisms in 3 genes encoding dioxin-metabolizing enzymes in relation to prenatal dioxin levels on infant birth size in Japan.

Methods: We examined the relationship between dioxin exposure and birth size in relation to the polymorphisms in the genes encoding aromatic hydrocarbon receptor (AHR [G>A, Arg554Lys]), cytochrome P450 (CYP) 1A1 (T6235C), and glutathione S-transferase mu 1 (GSTM1; Non-null/null) in 421 participants using multiple linear regression models.

Results: In mothers carrying the GSTM1 null genotype, a ten-fold increase in total dioxin toxic equivalency was correlated with a decrease in birth weight of -345g (95% confidence interval: -584, -105).

Prenatal di-2-ethylhexyl phthalate exposure and cord blood adipokine levels and birth size: The Hokkaido study on environment and children's health.

Di-2-ethylhexyl phthalate (DEHP) is one of the most widely used phthalates. Metabolites of DEHP are detectable in majority of the population. Findings on adverse health outcomes, particularly birth weight in association with prenatal exposure to DEHP remain equivocal.

Combined effects of AHR, CYP1A1, and XRCC1 genotypes and prenatal maternal smoking on infant birth size: Biomarker assessment in the Hokkaido Study.

Objectives: We investigated the individual and combined effects of maternal polymorphisms encoding the aromatic hydrocarbon receptor (AHR; rs2066853), cytochrome P450 (CYP) 1A1 (rs1048963), and the X-ray-complementing gene 1 (XRCC1; rs1799782) and prenatal smoking in relation to infant birth size.

Methods: Totally, 3263 participants (1998 non-smokers and 1265 smokers) were included in the study between 2003 and 2007. Two groups of mothers were distinguished by plasma cotinine levels by ELISA measured during the third trimester (cut-off=11.

Quantifying bisphenol A in maternal and cord whole blood using isotope dilution liquid chromatography/tandem mass spectrometry and maternal characteristics associated with bisphenol A.

Bisphenol A (BPA) is endocrine disrupting chemical that have been detected among general population. Exposure levels among pregnant women and their fetus are yet largely unknown among Japanese. We have developed a new method of measuring total BPA in whole blood samples by using isotopic dilution liquid chromatography-tandem mass spectrometry (ID-LC/MS/MS).