Glenys M Webster

• PhD
• Adjunct Professor at Simon Fraser University

Background Toxicological studies have raised concerns regarding the neurotoxic effects of per- and polyfluoroalkyl substances (PFAS). However, observational evidence from human studies investigating the association between childhood PFAS and neurobehavior is limited and remains unclear. Objectives To examine whether childhood PFAS concentrations a...

Background Studies of prenatal poly- and perfluoroalkyl substances (PFAS) and attention deficit hyperactivity disorder (ADHD)-related behaviors in children are inconsistent. Objectives To examine associations between maternal serum PFAS concentrations and child behavior in 241 mother-child dyads within the Health Outcomes and Measures of the Envir...

BACKGROUND: The etiology of autism spectrum disorder is poorly understood. Few studies have investigated the link between endocrine-disrupting chemicals and autistic traits. We examined the relationship between gestational phthalates and autistic traits in 3-to 4-y-old Canadian children. We also investigated potential effect modification by sex and...

Background: The etiology of autism spectrum disorder is poorly understood. Few studies have investigated the link between endocrine-disrupting chemicals and autistic traits. We examined the relationship between gestational phthalates and autistic traits in 3- to 4-y-old Canadian children. We also investigated potential effect modification by sex a...

Background: Gestational cadmium exposure may impair fetal growth. Coal smoke has largely been unexplored as a source of cadmium exposure. We investigated the relationship between gestational cadmium exposure and fetal growth, and assessed coal smoke as a potential source of airborne cadmium, among non-smoking pregnant women in Ulaanbaatar, Mongoli...

Background: Animal studies suggest polybrominated diphenyl ethers (PBDEs) may be obesogens. However, epidemiologic studies investigating childhood exposure to PBDEs and adiposity are limited, with several reporting an inverse association. Objectives: To investigate associations between repeated childhood PBDE concentrations and adiposity measure...

Background: Toxicological studies indicate that poly- and perfluoroalkyl substances (PFAS) may be neurotoxic, but human studies have yet to provide compelling evidence for PFAS' impact on cognitive abilities. Objective: To test whether prenatal and childhood PFAS are associated with cognitive abilities at 8 years and whether sex modifies these a...

Background: Polybrominated diphenyl ethers (PBDEs) exist extensively in the environment and human beings. PBDE concentrations are higher in children than adults. A previous study found that prenatal PBDE exposure was associated with decreased reading skills in children; however, evidence is limited on the potential impact of childhood exposure to...

Background: Fine particulate matter (PM2.5) exposure may impair fetal growth. Aims/objectives: Our aim was to assess the effect of portable high efficiency particulate air (HEPA) filter air cleaner use during pregnancy on fetal growth. Methods: The Ulaanbaatar Gestation and Air Pollution Research (UGAAR) study is a single-blind randomized cont...

Organophosphate esters (OPEs) are commonly used as flame retardants (FRs) and plasticizers. The usage of OPEs has increased recently due to the ban of several brominated flame retardants, but information on levels in the environment, including the indoor environment is still limited. We investigated the occurrence and distribution of 12 OPEs in urb...

Background: Despite evidence from toxicological studies describing the potential neurotoxicity of perfluoroalkyl substances (PFAS), their role in neurodevelopment remains uncertain amid inconsistent findings from epidemiological studies. Methods: Using data from 218 mother-child dyads from the Health Outcomes and Measures of the Environment Stud...

Background: Toxicological studies highlight the potential neurotoxicity of perfluoroalkyl substances (PFAS) during fetal development. However, few epidemiological studies have examined the impact of childhood PFAS on neurodevelopment. Methods: We employed data from 208 children in the Health Outcomes and Measures of the Environment Study, a birt...

Background: Polybrominated diphenyl ethers (PBDEs) reduce serum thyroid hormone concentrations in animal studies, but few studies have examined the impact of early-life PBDE exposures on thyroid hormone disruption in childhood. Methods: We used data from 162 mother-child pairs from the Health Outcomes and Measures of the Environment Study (2003-...

Background: Portable HEPA filter air cleaners can reduce indoor fine particulate matter (PM2.5), but their use has not been adequately evaluated in high pollution settings. We assessed air cleaner effectiveness in reducing indoor residential PM2.5 and second hand smoke (SHS) exposures among non-smoking pregnant women in Ulaanbaatar, Mongolia. Met...

Background: Humans are exposed to poly- and perfluoroalkyl substances (PFASs) from diverse sources and this has been associated with negative health impacts. Advances in analytical methods have enabled routine detection of more than 15 PFASs in human sera, allowing better profiling of PFAS exposures. The composition of PFASs in human sera reflects...

Background: Prenatal polybrominated diphenyl ether (PBDE) exposure has been associated with decrements in IQ and increased attention deficit/hyperactivity disorder related behaviors in children; however, data are limited for the role of postnatal exposures. Objectives: We investigated the association between a series of childhood PBDE concentrat...

Prenatal exposure to polybrominated diphenyl ethers (PBDEs) have been reported to impair executive function in children, but little is known whether childhood PBDE exposures play a role. Using the Health Outcomes and Measures of the Environment (HOME) Study, a prospective birth cohort in the greater Cincinnati area, we investigated the association...

Exposure to polybrominated diphenyl ethers (PBDEs) during fetal development may be associated with deficits in attention and impulse control. However, studies examining postnatal PBDE exposures and inattention and impulsivity have been inconsistent. Using data from 214 children in the Health Outcomes and Measures of the Environment (HOME) Study, a...

[This corrects the article DOI: 10.1289/EHP478.].

Background: Prenatal bisphenol A (BPA) exposure has been associated with adverse neurodevelopment in epidemiological studies. However, prior studies had limited statistical power to examine sex-specific effects, and few examined child cognition. Objectives: We estimated the association between prenatal BPA exposure and child neurobehavior at 3 y...

Human exposure to persistent perfluoroalkyl acids (PFAAs), including perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA) and perfluorooctane sulfonate (PFOS), can occur directly from contaminated food, water, air and dust. However, precursors to PFAAs (PreFAAs), such as di-polyfluoroalkyl phosphates (diPAPs), fluorotelomer alcohols (FTOHs)...

Background: Prenatal polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) exposures may influence children's neurodevelopment. Objective: To examine the association of prenatal PBDE and PCB exposures with children's reading skills at ages 5 and 8 years, Full-Scale Intelligence Quotient (FSIQ) and Externalizing Problems at...

Polybrominated diphenyl ethers (PBDEs) are associated with impaired visual spatial abilities in toxicological studies, but no epidemiologic study has investigated PBDEs and visual spatial abilities in children. The Health Outcomes and Measures of the Environment Study, a prospective birth cohort (2003–2006, Cincinnati, OH), was used to examine pren...

Background: Prenatal exposure to endocrine disruptors has been associated with increased risk of childhood obesity. However, epidemiologic studies on polybrominated diphenyl ethers (PBDEs) are limited despite animal studies indicating its potential role as an obesogen. Objectives: We investigated whether maternal concentrations of BDE-28, -47, -...

Executive function is a critical behavioral trait rarely studied in relation to potential neurotoxicants. Prenatal exposure to polybrominated diphenyl ethers (PBDEs) and perfluoroalkyl substances (PFASs) has been associated with adverse neurodevelopment, but there is limited research on executive function. Data from 256 mother–child pairs in the He...

Objective: To examine relationships between prenatal perfluoroalkyl substance (PFAS) exposure and adiposity in children born to women who lived downstream from a fluoropolymer manufacturing plant. Methods: Data are from a prospective cohort in Cincinnati, Ohio (HOME Study). Perfluorooctanoic (PFOA), perfluorooctane sulfonic (PFOS), perfluoronona...

Background: Perfluoroalkyl acids (PFASs) are suspected thyroid toxicants, but results from epidemiological studies are inconsistent. Objectives: We examined associations between serum PFASs and thyroid hormones (THs) in a representative, cross-sectional sample of US adults. We hypothesized that people with high thyroid peroxidase antibodies and...

Background: Polybrominated diphenyl ethers (PBDEs) reduce blood concentrations of thyroid hormones in laboratory animals, but it is unclear whether PBDEs disrupt thyroid hormones in pregnant women or newborn infants. Objectives: We investigated the relationship between maternal PBDE levels and thyroid hormone concentrations in maternal and cord ser...

Data on predictors of gestational exposure to poly- and perfluoroalkyl substances (PFASs) in the United States are limited. To fill in this gap, in a multiethnic cohort of Ohio pregnant women recruited in 2003-2006, we measured perfluorooctane sulfonate (PFOS), perfluorooctanoate (PFOA), and six additional PFASs in maternal serum at ~16 weeks gesta...

Background: Polybrominated diphenyl ethers (PBDEs) are persistent chemicals that have been widely used as flame retardants in furniture, carpet padding, car seats, and other consumer products during the past three decades. Objective: We examined whether in utero exposure to PBDEs is associated with child cognitive function and behavior in a U.S. st...

Endocrine disrupting chemicals (EDCs) may be involved in the etiology of autism spectrum disorders, but identifying relevant chemicals within mixtures of EDCs is difficult. To identify gestational EDC exposures associated with autistic behaviors. We measured the concentrations of 8 phthalate metabolites, bisphenol A, 25 polychlorinated biphenyls (P...

Indoor dust is thought to be a source of human exposure to perfluorocarboxylates (PFCAs) and perfluorosulfonates (PFSAs) but exposures to emerging organofluorine compounds, including precursors to PFCAs and PFSAs via indoor dust remain unknown. We report an analytical method for measuring several groups of emerging phosphorus-containing fluorinated...

Prenatal alcohol exposure is the leading cause of intellectual disability in the Western world. Due to the organic brain damage caused by alcohol, and the resulting cognitive, functional, and behavioural deficits, people with Fetal Alcohol Spectrum Disorder (FASD) are at high risk for becoming involved in the legal system, either as offenders or as...

Polybrominated diphenyl ethers (PBDEs) are flame retardants with widespread exposure. Although PBDEs are known thyroid toxicants in animal studies, human studies are sparse, especially during pregnancy and infancy when thyroid hormones are critical for early brain development. This study will examine associations between PBDE levels in maternal ser...

Perfluorochemicals (PFCs) are detectable in the general population and in the human environment, including house dust. Sources are not well characterized, but isomer patterns should enable differentiation of historical and contemporary manufacturing sources. Isomer-specific maternal-fetal transfer of PFCs has not been examined despite known develop...

To describe and evaluate recruitment techniques used to enroll 152 healthy pregnant women fewer than 15 weeks gestation into a prospective study of environmental chemical exposure during pregnancy. Posters, a website, online and print advertising, recruitment emails, media coverage, recruitment from clinic waiting rooms, networking within the pregn...

Perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) are widely detected in human blood and serum and are of concern due to their potential toxicity. This study investigated the indoor sources of these compounds and their neutral precursors through a survey of 152 homes in Vancouver, Canada. Samples were collected of indoor air, outdoor a...

To describe and evaluate recruitment techniques used to enroll 152 healthy pregnant women fewer than 15 weeks gestation into a prospective study of environmental chemical exposure during pregnancy. Posters, a website, online and print advertising, recruitment emails, media coverage, recruitment from clinic waiting rooms, networking within the pregn...

This chapter explores the bioaccumulation behavior of several phthalate esters in aquatic food-webs. It includes: (i) a compilation of bioconcentration data from reported laboratory studies in the literature, (ii) an overview and discussion of the results from a recently completed food-web bioaccumulation field study, and (iii) an analysis of the r...