Prenatal urinary triclosan concentrations and child neurobehavior

Background: Exposure to triclosan, an antimicrobial chemical, is ubiquitous among pregnant women and may reduce thyroid hormone levels that are important for fetal neurodevelopment. Few studies have examined the association between prenatal triclosan exposure and children's neurobehavior. Objective: We investigated the relationship of prenatal urinary triclosan concentrations with children's behavior and cognitive abilities at age three years in a prospective pregnancy and birth cohort in Canada. Methods: We measured triclosan in urine samples collected at ~12 weeks of gestation in 794 Canadian women enrolled in a prospective pregnancy and birth cohort study (MIREC) from 2008 to 2011. Around age 3 years, we assessed children's cognitive abilities using the Wechsler Primary and Preschool Scale of Intelligence-III (WPPSIIII), and two scales of the Behavior Rating Inventory of Executive Function-Preschool (BRIEF-P). Parents reported children's problem and reciprocal social behaviors using the Behavior Assessment System for Children-2 (BASC-2) and Social Responsiveness Scale-2 (SRS-2), respectively. Results: After adjusting for confounders using multivariable linear regression, triclosan was not associated with most of the 30 examined neurobehavioral scales. Each 10-fold increase in triclosan was associated with better WPPSI-III picture completion scores (β: 0.2; 95% CI: 0,0.5) and BASC-2 externalizing (β: −0.5; 95% CI: −1.1, 0) and hyperactivity (β: −0.6; 95% CI: −1.2, −0.1) scores, suggesting less externalizing and hyperactive behaviors. Child sex did not modify these associations. Conclusions: In this cohort, urinary triclosan concentrations measured once in early pregnancy were not associated with most assessed aspects of neurobehavior and weakly associated with a few others, but not in the hypothesized direction

Determinants of urinary concentrations of dialkyl phosphates among pregnant women in Canada — Results from the MIREC study

AbstractOrganophosphate (OP) insecticides are commonly used in agriculture. Their use decreased in recent years as they were gradually replaced by other pesticides, but some OPs are still among the insecticides most used in Canada. Exposure to elevated levels of OPs during pregnancy has been associated with adverse birth outcomes and poorer neurodevelopment in children. The objective of the present study was to examine the relationship between the concentrations of OP pesticides urinary dialkyl phosphate (DAP) metabolites and various factors that are potential sources of exposure or determinants of DAP levels. In the Maternal-Infant Research on Environmental Chemicals (MIREC) Study, six DAPs were measured in 1st trimester urine samples of 1884 pregnant women living in Canada. They were grouped into sums of dimethyl alkyl phosphates (DMAP) and diethyl alkyl phosphates (DEAP) for statistical analysis. We found that 93% of women had at least one DAP detected in their urine. Geometric means (GM) of specific gravity-corrected levels for urine dilution were 59 (95% CI 56–62) and 21 (95% CI 20–22) nmol/L for DMAP and DEAP, respectively. The following characteristics were significantly associated with higher urinary concentrations of DMAP or DEAP: higher education, nulliparous, normal pre-pregnancy body mass index, non-smoker, not fasting at sampling, winter season at sampling, and early and late day collection times. Dietary items that were significantly related with higher urinary concentrations included higher intake of citrus fruits, apple juice, sweet peppers, tomatoes, beans and dry peas, soy and rice beverages, whole grain bread, white wine and green and herbal teas. This study indicates that exposure to these compounds is quasi-ubiquitous. The factors associated with greater DAP levels identified here could be useful to regulatory agencies for risk analysis and management. However, some exposure misclassification might occur due to the single DAP measurement available, and to the presence of preformed DAPs in the environment

An examination of sex differences in associations between cord blood adipokines and childhood adiposity

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/154308/1/ijpo12587.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154308/2/ijpo12587_am.pd

Prenatal, concurrent, and sex-specific associations between blood lead concentrations and IQ in preschool Canadian children

Background: Lead exposure predicts altered neurodevelopment and lower intelligence quotient (IQ) in children, but few studies have examined this association in children who have relatively low blood lead concentrations. Objectives: To test the associations between blood lead concentrations and cognitive function in Canadian preschoolers, with a possible moderation by sex. Methods: The data were gathered from 609 mother-child pairs from the Maternal–Infant Research on Environmental Chemicals (MIREC) Study. Lead was measured in umbilical and maternal blood, and in children's venous blood at age 3–4 years. Cognitive function was measured with the Wechsler Preschool and Primary Scale of Intelligence (WPPSI-III) at 3–4 years. We tested the relationship between WPPSI-III scores and blood lead concentrations with multiple linear regression, adding child sex as a moderator. Results: Median blood lead concentrations for the mother at 1st trimester and 3rd trimester of pregnancy, and for cord and child blood were 0.60 μg/dL, 0.58 μg/dL, 0.79 μg/dL and 0.67 μg/dL, respectively. We found no association between cord blood lead concentrations and WPPSI-III scores in multivariable analyses. However, cord blood lead concentrations showed a negative association with Performance IQ in boys but not in girls (B = 3.44; SE = 1.62; 95% CI: 0.82, 5.98). No associations were found between WPPSI-III scores and prenatal maternal blood or concurrent child blood lead concentrations. Conclusions: Prenatal blood lead concentrations below 5 μg/dL were still associated with a decline in cognitive function in this Canadian cohort, but only for boys

Biomonitoring Data for 2,4-Dichlorophenoxyacetic Acid in the United States and Canada: Interpretation in a Public Health Risk Assessment Context Using Biomonitoring Equivalents

Background: Several extensive studies of exposure to 2,4- dichlorophenoxyacetic acid (2,4-D) using urinary concentrations in samples from the general population, farm applicators, and farm family members are now available. Reference doses (RfDs) exist for 2,4-D, and Biomonitoring Equivalents (BEs; concentrations in urine or plasma that are consistent with those RfDs) for 2,4-D have recently been derived and published. Objective: We reviewed the available biomonitoring data for 2,4-D from the United States and Canada and compared them with BE values to draw conclusions regarding the margin of safety for 2,4-D exposures within each population group. Data sources: Data on urinary 2,4-D excretion in general and target populations from recent published studies are tabulated and the derivation of BE values for 2,4-D summarized. Data synthesis: The biomonitoring data indicate margins of safety (ratio of BE value to biomarker concentration) of approximately 200 at the central tendency and 50 at the extremes in the general population. Median exposures for applicators and their family members during periods of use appear to be well within acute exposure guidance values. Conclusions: Biomonitoring data from these studies indicate that current exposures to 2,4-D are below applicable exposure guidance values. This review demonstrates the value of biomonitoring data in assessing population exposures in the context of existing risk assessments using the BE approach. Risk managers can use this approach to integrate the available biomonitoring data into an overall assessment of current risk management practices for 2,4-D

Urinary And Breast Milk Biomarkers To Assess Exposure Ro Naphthalene In Pregnant Women: An Investigation Of Personal And Indoor Air Sources

Naphthalene exposures for most non-occupationally exposed individuals occur primarily indoors at home. Residential indoor sources include pest control products (specifically moth balls), incomplete combustion such as cigarette smoke, woodstoves and cooking, some consumer and building products, and emissions from gasoline sources found in attached garages. The study aim was to assess naphthalene exposure in pregnant women from Canada, using air measurements and biomarkers of exposure

Assessing exposure in epidemiologic studies to disinfection by-products in drinking water: report from an international workshop.

The inability to accurately assess exposure has been one of the major shortcomings of epidemiologic studies of disinfection by-products (DBPs) in drinking water. A number of contributing factors include a) limited information on the identity, occurrence, toxicity, and pharmacokinetics of the many DBPs that can be formed from chlorine, chloramine, ozone, and chlorine dioxide disinfection; b) the complex chemical interrelationships between DBPs and other parameters within a municipal water distribution system; and c) difficulties obtaining accurate and reliable information on personal activity and water consumption patterns. In May 2000, an international workshop was held to bring together various disciplines to develop better approaches for measuring DBP exposure for epidemiologic studies. The workshop reached consensus about the clear need to involve relevant disciplines (e.g., chemists, engineers, toxicologists, biostatisticians and epidemiologists) as partners in developing epidemiologic studies of DBPs in drinking water. The workshop concluded that greater collaboration of epidemiologists with water utilities and regulators should be encouraged in order to make regulatory monitoring data more useful for epidemiologic studies. Similarly, exposure classification categories in epidemiologic studies should be chosen to make results useful for regulatory or policy decision making

Meeting Report: Measuring Endocrine-Sensitive Endpoints within the First Years of Life

An international workshop titled “Assessing Endocrine-Related Endpoints within the First Years of Life” was held 30 April–1 May 2007, in Ottawa, Ontario, Canada. Representatives from a number of pregnancy cohort studies in North America and Europe presented options for measuring various endocrine-sensitive endpoints in early life and discussed issues related to performing and using those measures. The workshop focused on measuring reproductive tract developmental endpoints [e.g., anogenital distance (AGD)], endocrine status, and infant anthropometry. To the extent possible, workshop participants strove to develop or recommend standardized measurements that would allow comparisons and pooling of data across studies. The recommended outcomes include thigh fat fold, breast size, vaginal cytology, AGD, location of the testis, testicular size, and growth of the penis, with most of the discussion focusing on the genital exam. Although a number of outcome measures recommended during the genital exam have been associated with exposure to endocrine-disrupting chemicals, little is known about how predictive these effects are of later reproductive health or other chronic health conditions

Prenatal triclosan exposure and cord blood immune system biomarkers

AbstractTriclosan is widely used as an antimicrobial agent and preservative that has been hypothesized to play a role in asthma and allergic disease. The limited body of literature regarding the allergenicity of triclosan has not evaluated prenatal exposure and subsequent potential effects on the developing immune system. The objective of the present study was to determine the association between prenatal urinary triclosan concentrations and cord blood immune system biomarker concentrations. Umbilical cord blood samples were obtained from the Maternal-Infant Research on Environmental Chemicals (MIREC) Biobank and were tested for three immune system biomarkers: immunoglobulin E (IgE), thymic stromal lymphopoietin (TSLP), and interleukin-33 (IL-33). Triclosan concentrations were measured in urine at 6–13 weeks gestation. No statistically significant associations were observed between prenatal triclosan concentrations and elevated concentrations of any immune system biomarker (n=1219 participants). Longitudinal studies are necessary to determine how the observed findings at birth translate into childhood

Tea consumption in pregnancy as a predictor of pesticide exposure and adverse birth outcomes: The MIREC Study

AbstractIntroductionPesticide residues in tea may contribute to exposure during pregnancy; however, the impact on maternal and infant health is not well understood. The aim of this study was to determine whether tea intake in the first trimester was associated with elevated concentrations of various pesticides in maternal blood or urine. Further, we examined the relationship between tea consumption and adverse birth outcomes.MethodsData from the Maternal–Infant Research on Environmental Chemicals (MIREC) Study, a pan-Canada pregnancy cohort, were used. All singleton, live births (n=1898) with available biomarkers were included in the analyses. Descriptive statistics were used to characterize the population. The geometric means (GM) of organochlorine (OC) pesticide constituents or metabolites in maternal plasma (lipid adjusted) and organophosphate (OP) pesticide metabolites (adjusted for specific gravity) in maternal urine were calculated for participants who drank regular, green or herbal tea in the first trimester and for those who did not. Differences between groups were examined using chi-square or t-tests. Associations between frequency of drinking tea and adverse birth outcomes were examined using logistic regression (preterm birth and small-for-gestational-age) or generalized linear models (birthweight decile and head circumference).ResultsThe GM of the OC pesticide constituent trans-nonachlor was 2.74mg/g lipid, and for metabolites oxychlordane and p,p′-DDE this was 1.94ng/g lipid and 55.8ng/g lipid, respectively. OP pesticide metabolite concentrations adjusted for specific gravity, were dimethylphosphate (GM: 3.19µg/L), dimethylthiophosphate (GM: 3.29µg/L), dimethyldithiophosphate (GM: 0.48µg/L), diethlphosphate (GM: 2.46), and diethylthiophosphate (GM: 0.67µg/L). There was no significant difference in mean concentrations for these OC or OP pesticide constituents or metabolites between tea drinkers — of any type — and non-tea drinkers. Further, no association was found between tea intake and adverse birth outcomes.ConclusionsPesticide concentrations did not differ by tea intake. Further, tea intake in the first trimester was not associated with adverse birth outcomes. In this study population, there was no evidence for concern about tea intake being a source of the OP or OC pesticide metabolites measured or adversely affecting birth outcomes; however, tea intake was lower than national Canadian data for women of reproductive age