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Environmental Health : a Global Access... May 2022To conduct a comprehensive systematic review and meta-analysis to estimate the relationship between endocrine-disrupting chemicals (EDCs), including polychlorinated... (Meta-Analysis)
Meta-Analysis
OBJECTIVE
To conduct a comprehensive systematic review and meta-analysis to estimate the relationship between endocrine-disrupting chemicals (EDCs), including polychlorinated biphenyls (PCBs), poly-brominated diphenyl ethers (PBDEs), phthalates (PAEs), and per- and polyfluoroalkyl substances (PFAS) exposure and risk of gestational diabetes mellitus (GDM).
METHODS
Relevant studies from their inception to November 2021 were identified by searching EMBASE, PubMed, and Web of Science. The cohort and case-control studies that reported effect size with 95% confidence intervals (CIs) of EDC exposure and GDM were selected. The heterogeneity among the included studies was quantified by I statistic. Publication bias was evaluated through the Begg and Egger tests.
RESULTS
Twenty-five articles with a total of 23,796 participants were found. Results indicated that exposure to PCBs has a significant influence on the incidence of GDM (OR = 1.14; 95% CI = 1.00--1.31; n = 8). The risk of GDM was found to be associated with PBDE exposure (OR = 1.32; 95% CI = 1.15-1.53; n = 4). PAEs and PFASs exposure were also positively associated with the risk of GDM, with summary ORs of 1.10 (95% CI = 1.03-1.16; n = 7 for PAEs) and 1.09 (95% CI = 1.02-1.16; n = 11 for PFASs), respectively. When only cohort studies were considered, the summary OR between PCBs exposure and the risk of GDM was 0.99 (95% CI = 0.91-1.09; n = 5). Meanwhile, the summary ORs from cohort studies for PBDEs, PAEs, and PFASs exposure were 1.12 (95% CI = 1.00-1.26; n = 2), 1.08 (95% CI = 1.02-1.15; n = 5), and 1.06 (95% CI = 1.00-1.12; n = 8), respectively. The Beggs and Egger tests did not show publication bias, and the sensitivity analyses did not change the results in this meta-analysis.
CONCLUSION
These results support that exposure to certain EDCs, including PCBs, PBDEs, PAEs, and PFAS, increase the risk of GDM. Further large-sample epidemiologic researches and mechanistic studies are needed to verify the potential relationship and biological mechanisms. These results are of public health significance because the daily EDC exposure is expected to increase the risk of GDM development.
Topics: Diabetes, Gestational; Endocrine Disruptors; Environmental Pollutants; Female; Fluorocarbons; Halogenated Diphenyl Ethers; Humans; Polychlorinated Biphenyls; Pregnancy
PubMed: 35578291
DOI: 10.1186/s12940-022-00858-8 -
Human Reproduction Update Feb 2021Despite increasing regulation, exposure to persistent organic pollutants (POPs) remains a serious public health concern due to their accumulation in the environment and...
BACKGROUND
Despite increasing regulation, exposure to persistent organic pollutants (POPs) remains a serious public health concern due to their accumulation in the environment and ability to biomagnify up the food chain. POPs are associated with endocrine-disrupting effects including adverse reproductive outcomes that could affect fecundability, i.e. the capacity to conceive a pregnancy, quantified as time to pregnancy (TTP).
OBJECTIVE AND RATIONALE
Results of epidemiologic studies that examine the impact of various chemical classes of POPs on TTP have not been synthesised. We undertook a systematic review to summarise the strength of evidence for associations of four common groups of POPs with couple fecundability and to identify gaps and limitations in the literature in order to inform policy decisions and future research.
SEARCH METHODS
We performed an electronic search of literature published between 1 January 2007 and 6 August 2019 in MEDLINE, EMBASE.com, Global Health, DART/TOXLINE and POPLINE. We included empirical research papers that examined human exposure to organochlorine (OC) pesticides, brominated flame retardants, polychlorinated organic compounds and/or per- and polyfluoroalkyl substances (PFAS) and considered TTP or fecundability as an outcome. Standardised forms for screening, data extraction and study quality were developed using DistillerSR software, and all reviews were completed in duplicate. We used the Newcastle-Ottawa Scale to assess risk of bias and devised additional quality metrics based on specific methodological features of fecundability studies.
OUTCOMES
The search returned 4573 articles, and 28 papers from 19 different studies met inclusion criteria. Among them, four studies measured TTP prospectively, three had data on participants' prenatal exposure, three examined associations in both male and female partners and one focused exclusively on males. Analyses varied widely in terms of exposure characterisation, precluding a meta-analytic approach. Evidence was strongest for adverse associations of female exposure to polychlorinated biphenyls with TTP, with some additional support for associations of female exposure to polybrominated diphenyl ethers and PFAS with longer TTP. Our review provided little or no support for associations between female exposure to OC pesticides or male exposure to any of the POP groups and TTP.
WIDER IMPLICATIONS
Evidence suggests that female exposure to at least some POPs may reduce fecundability. Although many of these chemicals are no longer in production, they are still detectable in human biosamples because of their persistence in the environment. Replacement chemicals that are being introduced as older ones are restricted may have similar reproductive consequences. Future studies should examine these newer POPs, assess interactions between POPs and other chemical and non-chemical exposures, investigate how POPs are distributed in and metabolised by the human body and focus on populations that may be disproportionately exposed.
Topics: Environmental Pollutants; Female; Halogenated Diphenyl Ethers; Humans; Male; Persistent Organic Pollutants; Pesticides; Polychlorinated Biphenyls; Pregnancy; Time-to-Pregnancy
PubMed: 33147335
DOI: 10.1093/humupd/dmaa037 -
Frontiers in Endocrinology 2023Exposure to endocrine-disrupting chemicals (EDCs) during critical neurodevelopmental windows has been associated with the risk of autistic traits. This systematic review...
AIMS
Exposure to endocrine-disrupting chemicals (EDCs) during critical neurodevelopmental windows has been associated with the risk of autistic traits. This systematic review of epidemiological studies examined the association between maternal exposure to EDCs during pregnancy and the risk of autism spectrum disorder (ASD) in the offspring.
METHODS
We searched PubMed, Web of Science, Scopus, and Google Scholar from inception to November 17, 2022, for studies investigating the association between prenatal exposure to EDCs and outcomes related to ASD. Two independent reviewers screened studies for eligibility, extracted data, and assessed the risk of bias. The review was registered in PROSPERO (CRD42023389386).
RESULTS
We included 27 observational studies assessing prenatal exposure to phthalates (8 studies), polychlorinated biphenyls (8 studies), organophosphate pesticides (8 studies), phenols (7 studies), perfluoroalkyl substances (6 studies), organochlorine pesticides (5 studies), brominated flame retardants (3 studies), dioxins (1 study), and parabens (1 study). The number of examined children ranged from 77 to 1,556, the age at the assessment of autistic traits ranged from 3 to 14 years, and most studies assessed autistic traits using the Social Responsiveness Scale. All but one study was considered to have a low risk of bias. Overall, there was no association between maternal exposure to specific ECDs during pregnancy and the occurrence of autistic traits in offspring.
CONCLUSIONS
Findings from the epidemiological studies evaluated here do not support an association between prenatal exposure to ECDs and the likelihood of autistic traits in later in life. These findings should not be interpreted as definitive evidence of the absence of neurodevelopment effects of EDCs affecting ASD risk, given the limitations of current studies such as representative exposure assessment, small sample sizes, inadequacy to assess sexually dimorphic effects, or the effects of EDC mixtures. Future studies should carefully address these limitations.
Topics: Child; Pregnancy; Female; Humans; Adolescent; Child, Preschool; Endocrine Disruptors; Autism Spectrum Disorder; Prenatal Exposure Delayed Effects; Autistic Disorder; Pesticides; Epidemiologic Studies
PubMed: 37361542
DOI: 10.3389/fendo.2023.1184546 -
Ecotoxicology and Environmental Safety Sep 2022Organophosphate flame retardants (OPFRs) are increasingly and widely used as substitutes for brominated flame retardants in daily life. The chemical structure of OPFRs... (Review)
Review
Organophosphate flame retardants (OPFRs) are increasingly and widely used as substitutes for brominated flame retardants in daily life. The chemical structure of OPFRs is very similar to that of organophosphorus pesticides, leading to concerns about their neurotoxicity. A few epidemiological studies have been published with inconsistent results on this topic, and a systematic scoping review is needed to provide an overview or map of the current evidence on the relationship of OPFRs with neurodevelopmental toxicity. Therefore, MEDLINE (accessed through PubMed), Web of Science, and CNKI (Chinese National Knowledge Infrastructure) were systematically searched for articles published in the last two decades. Nine eligible articles were included in the present systematic scoping review for adherence to the predefined PECOS (population, exposure, comparison, outcome, study design) statement. Six studies were conducted in the USA, and the remaining three studies were conducted in Austria, Norway and China. A total of 2 581 children (1 203 females and 1 378 males) were included. Half of the included studies focused on the adverse effects of OPFR exposure on cognition in children, while others primarily focused on the behaviors of children. In summary, the current evidence suggests inverse associations between early-life exposure to OPFRs and the childhood intelligence quotient and internalizing behavior and positive relationships of OPFR exposure with externalizing behavior. However, some differences in the timing of sample collection for exposure measurements, in the individual OPFR metabolites available, in the neurodevelopmental scales for outcome measurement, and in the statistical methods used to analyze the data are noted. In addition, further studies are warranted to evaluate some important issues, such as sex differences in the association, exposure-sensitive periods, and cumulative exposure risk assessment.
Topics: Child; Epidemiologic Studies; Female; Flame Retardants; Humans; Male; Organophosphates; Organophosphorus Compounds; Pesticides
PubMed: 35988382
DOI: 10.1016/j.ecoenv.2022.113973 -
Ecotoxicology and Environmental Safety Jan 2024Disinfection by-products (DBPs), including trihalomethanes (THMs) and haloacetic acids (HAAs), have attracted attention due to their carcinogenic properties, leading to... (Meta-Analysis)
Meta-Analysis Review
Disinfection by-products (DBPs), including trihalomethanes (THMs) and haloacetic acids (HAAs), have attracted attention due to their carcinogenic properties, leading to varying conclusions. This meta-analysis aimed to evaluate the dose-response relationship and the dose-dependent effect of DBPs on cancer risk. We performed a selective search in PubMed, Web of Science, and Embase databases for articles published up to September 15th, 2023. Our meta-analysis eventually included 25 articles, encompassing 8 cohort studies with 6038,525 participants and 10,668 cases, and 17 case-control studies with 10,847 cases and 20,702 controls. We observed a positive correlation between increased cancer risk and higher concentrations of total trihalomethanes (TTHM) in water, longer exposure durations, and higher cumulative TTHM intake. These associations showed a linear trend, with relative risks (RRs) and 95 % confidence intervals (CIs) being 1.02 (1.01-1.03), 1.04 (1.02-1.06), and 1.02 (1.00-1.03), respectively. Gender-specific analyses revealed slightly U-shaped relationships in both males and females, with males exhibiting higher risks. The threshold dose for TTHM in relation to cancer risk was determined to be 55 µg/L for females and 40 µg/L for males. A linear association was also identified between bladder cancer risk and TTHM exposure, with an RR and 95 % CI of 1.08 (1.05-1.11). Positive linear associations were observed between cancer risk and exposure to chloroform, bromodichloromethane (BDCM), and HAA5, with RRs and 95 % CIs of 1.02 (1.01-1.03), 1.33 (1.18-1.50), and 1.07 (1.03-1.12), respectively. Positive dose-dependent effects were noted for brominated THMs above 35 µg/L and chloroform above 75 µg/L. While heterogeneity was observed in the studies for quantitative synthesis, no publication bias was detected. Exposure to TTHM, chloroform, BDCM, or HAA5 may contribute to carcinogenesis, and the risk of cancer appears to be dose-dependent on DBP exposure levels. A cumulative effect is suggested by the positive correlation between TTHM exposure and cancer risk. Bladder cancer and endocrine-related cancers show dose-dependent and positive associations with TTHM exposure. Males may be more susceptible to TTHM compared to females.
Topics: Male; Female; Humans; Disinfection; Chloroform; Trihalomethanes; Urinary Bladder Neoplasms; Water Pollutants, Chemical; Disinfectants
PubMed: 38183752
DOI: 10.1016/j.ecoenv.2023.115925 -
Chemosphere Jul 2014Brominated flame retardants (BFRs), are chemicals widely used in consumer products including electronics, vehicles, plastics and textiles to reduce flammability.... (Review)
Review
BACKGROUND
Brominated flame retardants (BFRs), are chemicals widely used in consumer products including electronics, vehicles, plastics and textiles to reduce flammability. Experimental animal studies have confirmed that these compounds may interfere with thyroid hormone homeostasis and neurodevelopment but to date health effects in humans have not been systematically examined.
OBJECTIVES
To conduct a systematic review of studies on the health impacts of exposure to BFRs in humans, with a particular focus on children.
METHODS
A systematic review was conducted using the MEDLINE and EMBASE electronic databases up to 1 February 2012. Published cohort, cross-sectional, and case-control studies exploring the relationship between BFR exposure and various health outcomes were included.
RESULTS
In total, 36 epidemiological studies meeting the pre-determined inclusion criteria were included. Plausible outcomes associated with BFR exposure include diabetes, neurobehavioral and developmental disorders, cancer, reproductive health effects and alteration in thyroid function. Evidence for a causal relationship between exposure to BFRs and health outcomes was evaluated within the Bradford Hill framework.
CONCLUSION
Although there is suggestive evidence that exposure to BFRs is harmful to health, further epidemiological investigations particularly among children, and long-term monitoring and surveillance of chemical impacts on humans are required to confirm these relationships.
Topics: Behavioral Symptoms; Case-Control Studies; Child; Cohort Studies; Cross-Sectional Studies; Developmental Disabilities; Diabetes Mellitus; Environmental Exposure; Flame Retardants; Humans; Hydrocarbons, Brominated
PubMed: 24529398
DOI: 10.1016/j.chemosphere.2013.12.064 -
Environmental Health Perspectives Jan 2023Centralized chlorination of urban piped water supplies has historically contributed to major reductions in waterborne illness. In locations without effective centralized... (Review)
Review
BACKGROUND
Centralized chlorination of urban piped water supplies has historically contributed to major reductions in waterborne illness. In locations without effective centralized water treatment, point-of-use (POU) chlorination for households is widely promoted to improve drinking water quality and health. Realizing these health benefits requires correct, consistent, and sustained product use, but real-world evaluations have often observed low levels of use. To our knowledge, no prior reviews exist on adoption of chlorine POU products.
OBJECTIVES
Our objectives were to identify which indicators of adoption are most often used in chlorine POU studies, summarize levels of adoption observed, understand how adoption changes over time, and determine how adoption is affected by frequency of contact between participants and study staff.
METHODS
We conducted a systematic review of household POU chlorination interventions or programs from 1990 through 2021 that reported a quantitative measure of adoption, were conducted in low- and middle-income countries, included data collection at households, and reported the intervention start date.
RESULTS
We identified 36 studies of household drinking water chlorination products that met prespecified eligibility criteria and extracted data from 46 chlorine intervention groups with a variety of chlorine POU products and locations. There was no consensus definition of adoption of household water treatment; the most common indicator was the proportion of household stored water samples with free chlorine residual . Among studies that reported either free or total chlorine-confirmed adoption of chlorine POU products, use was highly variable (across all chlorine intervention groups at the last time point measured in each study; range: 1.5%-100%; sample size-weighted ; unweighted ). The median follow-up duration among intervention groups was 3 months. On average, adoption declined over time and was positively associated with frequency of contact between respondents and study staff.
DISCUSSION
Although prior research has shown that POU chlorine products improve health when correctly and consistently used, a reliance on individual adoption for effective treatment is unlikely to lead to the widespread public health benefits historically associated with pressurized, centralized treatment of piped water supplies. https://doi.org/10.1289/EHP10839.
Topics: Humans; Drinking Water; Halogenation; Chlorine; Water Purification; Water Quality; Water Supply
PubMed: 36715546
DOI: 10.1289/EHP10839 -
Environmental Science & Technology Feb 2020A credit value of virus inactivation has been assigned to the disinfection step in international and domestic guidelines for wastewater reclamation and reuse. To fulfill...
A credit value of virus inactivation has been assigned to the disinfection step in international and domestic guidelines for wastewater reclamation and reuse. To fulfill the credit value for water disinfection, water engineers need to apply an appropriate disinfection strength, expressed as a CT value (mg × min/L), which is a product of disinfectant concentration and contact time, against enteric viruses in wastewater. In the present study, we extracted published experimental data on enteric virus inactivation using free chlorine and monochloramine and applied the Tobit analysis and simple linear regression analysis to calculate the range of CT values (mg × min/L) needed for 4-log inactivation. Data were selected from peer-reviewed papers containing kinetics data of virus infectivity and chlorine residual in water. Coxsackie B virus and echovirus require higher CT values (lower susceptibility) for 4-log inactivation than adenovirus and a human norovirus surrogate (murine norovirus) with free chlorine. On the other hand, adenovirus has lower susceptibility to monochloramine compared to murine norovirus, coxsackievirus, and echovirus. The factors that influence the required CT value are virus type, pH, water temperature, and water matrix. This systematic review demonstrates that enteroviruses and adenovirus are appropriate representative enteric viruses to evaluate water disinfection using free chlorine and monochloramine, respectively.
Topics: Animals; Chlorine; Disinfectants; Disinfection; Enterovirus; Halogenation; Humans; Mice; Viruses; Water
PubMed: 31927958
DOI: 10.1021/acs.est.9b01685 -
Environmental Health : a Global Access... Jan 2012Although ozone-depleting methyl bromide was destined for phase-out by 2005, it is still widely applied as a consequence of various critical-use-exemptions and mandatory... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Although ozone-depleting methyl bromide was destined for phase-out by 2005, it is still widely applied as a consequence of various critical-use-exemptions and mandatory international regulations aiming to restrict the spread of pests and alien species (e.g. in globalized transport and storage). The withdrawal of methyl bromide because of its environmental risk could fortuitously help in the containment of its human toxicity.
METHODS
We performed a systematic review of the literature, including in vitro toxicological and epidemiological studies of occupational and community exposure to the halogenated hydrocarbon pesticide methyl bromide. We focused on toxic (especially chronic) or carcinogenic effects from the use of methyl bromide, on biomonitoring data and reference values. Eligible epidemiological studies were subjected to meta-analysis.
RESULTS
Out of the 542 peer reviewed publications between 1990-2011, we found only 91 referring to toxicity of methyl bromide and 29 using the term "carcinogenic", "neoplastic" or "mutagenic". Several studies provide new additional data pertaining to the mechanistic aspects of methyl bromide toxicity. Few studies have performed a detailed exposure assessment including biomonitoring. Three evaluated epidemiological studies assessed a possible association between cancer and methyl bromide. Overall, exposure to methyl bromide is associated with an increased risk of prostate cancer OR, 1.21; 95% CI (0,98-1.49), P = 0.076. Two epidemiological studies have analyzed environmental, non-occupational exposure to methyl bromide providing evidence for its health risk to the general public. None of the epidemiological studies addressed its use as a fumigant in freight containers, although recent field and case reports do refer to its toxic effects associated with its use in shipping and storage.
CONCLUSIONS
Both the epidemiological evidence and toxicological data suggest a possible link between methyl bromide exposure and serious health problems, including prostate cancer risk from occupational and community exposure. The environmental risks of methyl bromide are not in doubt, but also its health risks, especially for genetically predisposed subjects, should not be underestimated.
Topics: Conservation of Natural Resources; Environmental Exposure; Humans; Hydrocarbons, Brominated; Male; Occupational Exposure; Pesticides; Prostatic Neoplasms; Risk Assessment
PubMed: 22284215
DOI: 10.1186/1476-069X-11-5 -
Chemosphere Oct 2017Endocrine disrupting flame retardant (FR) chemicals form a human health concern, that is investigated mostly from the perspective of adult- and early life exposure. No... (Review)
Review
Toddler exposure to flame retardant chemicals: Magnitude, health concern and potential risk- or protective factors of exposure: Observational studies summarized in a systematic review.
Endocrine disrupting flame retardant (FR) chemicals form a human health concern, that is investigated mostly from the perspective of adult- and early life exposure. No overview of studies on toddler exposure and health effects exist. However, toddlerhood is a critical developmental period and toddlers are at increased risk for exposure because of their age-specific behavior. This systematic review encompasses toddler FR exposure studies in three countries, associated health effects and potential environmental, demographic, or behavioral risk- or protective factors for toddler exposure. A systematic literature search in four databases (PubMed, Embase.com, The Cochrane Library (via Wiley) and Web of Science Core collection) resulted in the identification of ten publications representing seven unique studies that measured brominated and/or phosphorylated FRs in toddlers' (8-24 month-old) serum, urine, hand wipes and feces. This review showed that toddlers are exposed to a range of FRs, that thyroid hormone disruption is associated with FR exposure and that factors in the indoor environment, including products such as plastic toys, might increase FR exposure. Considering the limited amount of studies, and the variety of biological matrices, FRs, and risk- and protective factors, this review did not reveal a uniform pattern of toddler exposure across the different cohorts studied. More evidence is necessary and considering the feasibility of invasive sampling in young children, we suggest to emphasize research on non-invasive matrices.
Topics: Child; Child, Preschool; Environment; Environmental Exposure; Environmental Pollution; Flame Retardants; Halogenation; Humans; Infant; Protective Factors
PubMed: 28645086
DOI: 10.1016/j.chemosphere.2017.06.041