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Toxicology Letters Apr 2024The incidence of endocrine-related cancer, which includes tumors in major endocrine glands such as the breast, thyroid, pituitary, and prostate, has been increasing year... (Meta-Analysis)
Meta-Analysis
BACKGROUND
The incidence of endocrine-related cancer, which includes tumors in major endocrine glands such as the breast, thyroid, pituitary, and prostate, has been increasing year by year. Various studies have indicated that brominated flame retardants (BFRs) are neurotoxic, endocrine-toxic, reproductive-toxic, and even carcinogenic. However, the epidemiological relationship between BFR exposure and endocrine-related cancer risk remains unclear.
METHODS
We searched the PubMed, Google Scholar, and Web of Science databases for articles evaluating the association between BFR exposure and endocrine-related cancer risk. The odds ratio (OR) and its corresponding 95% confidence interval (95% CI) were used to assess the association. Statistical heterogeneity among studies was assessed with the Q-test and I statistics. Begg's test was performed to evaluate the publication bias.
RESULTS
We collected 15 studies, including 6 nested case-control and 9 case-control studies, with 3468 cases and 4187 controls. These studies assessed the risk of breast cancer, thyroid cancer, and endocrine-related cancers in relation to BFR levels. Our findings indicate a significant association between BFR exposure in adipose tissue and an increased risk of breast cancer. However, this association was not observed for thyroid cancer. Generally, BFR exposure appears to elevate the risk of endocrine-related cancers, with a notable increase in risk linked to higher levels of BDE-28, a specific polybrominated diphenyl ether congener.
CONCLUSIONS
In conclusion, although this meta-analysis has several limitations, our results suggest that BFR exposure is a significant risk factor for breast cancer, and low-brominated BDE-28 exposure could significantly increase the risk of endocrine-related cancers. Further research is essential to clarify the potential causal relationships between BFRs and endocrine-related cancers, and their carcinogenic mechanisms.
Topics: Male; Humans; Flame Retardants; Polybrominated Biphenyls; Halogenated Diphenyl Ethers; Risk Factors; Breast Neoplasms; Hydrocarbons, Brominated
PubMed: 38387762
DOI: 10.1016/j.toxlet.2024.02.002 -
Environmental Research Mar 2024Persistent organic pollutants (POPs) are chemicals characterized by their environmental persistence. Evidence suggests that exposure to POPs, which is ubiquitous, is... (Review)
Review
Per- and polyfluoroalkyl substances, polychlorinated biphenyls, organochlorine pesticides, and polybrominated diphenyl ethers and dysregulation of MicroRNA expression in humans and animals-A systematic review.
BACKGROUND
Persistent organic pollutants (POPs) are chemicals characterized by their environmental persistence. Evidence suggests that exposure to POPs, which is ubiquitous, is associated with microRNA (miRNA) dysregulation. miRNA are key regulators in many physiological processes. It is thus of public health concern to understand the relationships between POPs and miRNA as related to health outcomes.
OBJECTIVES
This systematic review evaluated the relationship between widely recognized, intentionally manufactured, POPs, including per- and polyfluoroalkyl substances (PFAS), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and organochlorine pesticides (dichlorodiphenyltrichloroethane [DDT], dichlorodiphenyldichloroethylene [DDE], hexachlorobenzene [HCB]), with miRNA expression in both human and animal studies.
METHODS
We used PubMed and Embase to systematically search the literature up to September 29th, 2023. Search results for human and animal studies were included if they incorporated at least one POP of interest in relation to at least one miRNA. Data were synthesized to determine the direction and significance of associations between POPs and miRNA. We utilized ingenuity pathway analysis to review disease pathways for miRNA that were associated with POPs.
RESULTS
Our search identified 38 eligible studies: 9 in humans and 29 in model organisms. PFAS were associated with decreased expression of miR-19, miR-193b, and miR-92b, as well as increased expression of miR-128, miR-199a-3p, and miR-26b across species. PCBs were associated with increased expression of miR-15a, miR-1537, miR-21, miR-22-3p, miR-223, miR-30b, and miR-34a, as well as decreased expression of miR-130a and let-7b in both humans and animals. Pathway analysis for POP-associated miRNA identified pathways related to carcinogenesis.
DISCUSSION
This is the first systematic review of the association of POPs with miRNA in humans and model organisms. Large-scale prospective human studies are warranted to examine the role of miRNA as mediators between POPs and health outcomes.
Topics: Animals; Humans; Polychlorinated Biphenyls; Halogenated Diphenyl Ethers; Prospective Studies; Hydrocarbons, Chlorinated; Environmental Pollutants; Pesticides; MicroRNAs; Fluorocarbons
PubMed: 38056610
DOI: 10.1016/j.envres.2023.117832 -
Frontiers in Endocrinology 2023There are conflicting reports on the association between environmental endocrine disruptors (EEDs) and thyroid cancer. This meta-analysis aimed to elucidate the... (Meta-Analysis)
Meta-Analysis
INTRODUCTION
There are conflicting reports on the association between environmental endocrine disruptors (EEDs) and thyroid cancer. This meta-analysis aimed to elucidate the relationship between EEDs and thyroid cancer.
METHODS
We searched for epidemiological studies on EEDs and thyroid cancer published in PubMed and Web of Science up to December 2022. We then screened the articles that could extract data on EEDs concentration levels in both thyroid cancer patients and healthy controls. We excluded articles that could not calculate effect sizes, focused on other thyroid diseases, or lacked controls. Standardized mean difference (SMD) was calculated to analyze the association between EEDs and thyroid cancer. We measured the heterogeneity among the included studies using I2, assessed publication bias by Egger's and Begg's test, and evaluated article quality using the Newcastle-Ottawa Quality Score (NOS). In the end, fifteen eligible case-control studies were included.
RESULTS
Our comprehensive analysis revealed that polychlorinated biphenyls (PCBs) were negatively associated with thyroid cancer{ SMD = -0.03, 95% confidence interval (CI) = (-0.05, -0.00), P = 0.03}, while polybrominated diphenyl ethers (PBDEs), phthalates (PAEs), and heavy metals were positively associated with thyroid cancer{PBDEs: SMD = 0.14, 95%CI = (0.04, 0.23), P = 0.007; PAEs: SMD = 0.30, 95%CI = (0.02, 0.58), P = 0.04; heavy metals: SMD = 0.21, 95%CI = (0.11, 0.32), P < 0.001}. We did not find a statistically significant relationship between bisphenol A (BPA) and thyroid cancer. Most of the included studies did not show publication bias, except for those on PCBs.
DISCUSSION
Our results indicate that exposure to certain EEDs, such as PBDEs, PAEs, and heavy metals, increases the risk of thyroid cancer. However, further large-scale epidemiological studies and mechanism studies are needed to verify these potential relationships and understand the underlying biological mechanisms.
Topics: Humans; Polychlorinated Biphenyls; Endocrine Disruptors; Halogenated Diphenyl Ethers; Thyroid Neoplasms; Metals, Heavy
PubMed: 38027118
DOI: 10.3389/fendo.2023.1283087 -
Environmental Research Dec 2023Per- and polyfluoroalkyl substances (PFAS), polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), and polybrominated diphenyl ethers (PBDEs) are... (Meta-Analysis)
Meta-Analysis
Associations of per- and polyfluoroalkyl substances, polychlorinated biphenyls, organochlorine pesticides, and polybrominated diphenyl ethers with oxidative stress markers: A systematic review and meta-analysis.
BACKGROUND
Per- and polyfluoroalkyl substances (PFAS), polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), and polybrominated diphenyl ethers (PBDEs) are intentionally produced persistent organic pollutants (POPs) that are resistant to environmental degradation. Previous in-vitro and in-vivo studies have shown that POPs can induce oxidative stress, which is linked to neurodegenerative diseases, cardiovascular diseases, and cancer. However, findings in epidemiological studies are inconsistent and an evidence synthesis study is lacking to summarize the existing literature and explore research gaps.
OBJECTIVE
We evaluated the effects of PFAS, PCBs, OCPs, and PBDEs, on oxidative stress biomarkers in epidemiological studies.
METHODS
A literature search was conducted in PubMed, Embase, and Cochrane CENTRAL to identify all published studies related to POPs and oxidative stress up to December 7, 2022. We included human observational studies reporting at least one exposure to POPs and an oxidative stress biomarker of interest. Random-effects meta-analyses on standardized regression coefficients and effect direction plots with one-tailed sign tests were used for quantitative synthesis.
RESULTS
We identified 33 studies on OCPs, 35 on PCBs, 49 on PFAS, and 12 on PBDEs. Meta-analyses revealed significant positive associations of α-HCH with protein carbonyls (0.035 [0.017, 0.054]) and of 4'4-DDE with malondialdehyde (0.121 [0.056, 0.187]), as well as a significant negative association between 2'4-DDE and total antioxidant capacity (TAC) (-0.042 [-0.079, -0.004]), all β [95%CI]. Sign tests showed a significant positive association between PCBs and malondialdehyde (p = 0.03). Additionally, we found significant negative associations of OCPs with acetylcholine esterase (p = 0.02) and paraoxonase-1 (p = 0.03). However, there were inconsistent associations of OCPs with superoxide dismutase, glutathione peroxidase, and catalase.
CONCLUSIONS
Higher levels of OCPs were associated with increased levels of oxidative stress through increased pro-oxidant biomarkers involving protein oxidation, DNA damage, and lipid peroxidation, as well as decreased TAC. These findings have the potential to reveal the underlying mechanisms of POPs toxicity.
Topics: Humans; Antioxidants; Biomarkers; Environmental Pollutants; Fluorocarbons; Halogenated Diphenyl Ethers; Hydrocarbons, Chlorinated; Malondialdehyde; Oxidative Stress; Pesticides; Polychlorinated Biphenyls
PubMed: 37813138
DOI: 10.1016/j.envres.2023.117308 -
Environmental Pollution (Barking, Essex... Nov 2023Accumulating number of epidemiological studies has recently proposed that improvement in the risk of autism spectrum disorders (ASD) is associated with persistent... (Review)
Review
Accumulating number of epidemiological studies has recently proposed that improvement in the risk of autism spectrum disorders (ASD) is associated with persistent organic pollutants (POPs) exposure. However, evidence from current researches is limited and inconsistent. Thus, we conducted a systematic review and meta-analysis to investigate the potential associations comprehensively. We systematically and extensively searched two electronic databases (PubMed and EMBASE) from inception to July 3, 2022 and an updated search was performed before submission. Summary odds ratios (ORs) and 95% confidence intervals (CIs) were derived from stratified random-effects meta-analyses by type of exposure and outcome. We also tested the potential heterogeneity across studies, conducted sensitivity analysis and evaluated publication bias. A total of 20 studies were finally included in our study. Meta-analytical effect estimates indicated a positive association between prenatal exposure to PCB-138, PCB-153 and PCB-170 and an increased risk of ASD, with OR of 1.89 (95% CI = 1.21-2.95, I = 0%), 1.61 (95% CI = 1.05-2.47, I = 0%) and 1.46 (95% CI = 1.03-2.06, I = 0%) respectively. In contrast, PFDA was found inversely associated with the risk of ASD (OR = 0.70, 95% CI = 0.52-0.94, I = 0%). The level of evidence supporting a link between ASD risk and exposure to PCB-138, PCB-153, PCB-170, and PFDA was respectively categorized as low, low, moderate, and low. In summary, this systematic review and meta-analysis suggest that exposure to PCB-138, PCB-153, and PCB-170 correlates with a heightened risk of ASD, with evidence levels rated as "low", "low", and "moderate", respectively. In contrast, PFDA exposure appears to be inversely associated with ASD risk, with a "low" level of supporting evidence. However, due to the limited number of studies available for each exposure and outcome pairing, these results should be interpreted with caution. Sufficiently powered studies are needed to validate our findings.
PubMed: 37619697
DOI: 10.1016/j.envpol.2023.122439 -
Chemosphere Aug 2023Except for known sociodemographic factors, long-term exposure to environmental pollutants has been shown to contribute to the development of gestational diabetes... (Meta-Analysis)
Meta-Analysis Review
Except for known sociodemographic factors, long-term exposure to environmental pollutants has been shown to contribute to the development of gestational diabetes mellitus (GDM), but the conclusions remain controversial. To provide a comprehensive overview of the association between environmental pollutants and GDM, we performed a systematic review and meta-analysis. Several electronic databases (PubMed, Embase, Web of Science, Medline and Cochrane) were searched for related epidemiological and experimental studies up to September 2022. For epidemiological studies, a meta-analysis was carried out to appraise the effect of environmental pollutants, including polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), per- and polyfluoroalkyl substances (PFASs), phenols, phthalates (PAEs), polybrominated diphenyl ethers (PBDEs) and parabens exposure on GDM. Moreover, we also summarized possible biological mechanisms linking pollution exposure and GDM based on the included experimental studies. A total of 80 articles were enrolled, including 38 epidemiological studies and 42 experimental studies. Meta-analysis results showed that exposure to PAEs [OR (95%CI) = 1.07 (1.00, 1.14)], PFASs [OR (95%CI) = 1.10 (1.01, 1.19)], as well as PCBs [OR (95%CI) = 1.18 (1.02, 1.36)] and PBDEs [OR (95%CI) = 1.33 (1.17, 1.50)] significantly increased the risk of GDM, but no significant effects were found for phenols, OCPs, and parabens. In addition, experimental studies suggested that the potential biological mechanisms of environmental pollutants contributing to GDM may involve insulin resistance, β-cell dysfunction, neurohormonal dysfunction, inflammation, oxidative stress, epigenetic modification, and alterations in gut microbiome. In conclusion, long-term environmental pollutants exposure may induce the development of GDM, and there may be a synergistic effect between the homologs. However, studies conducted on the direct biological link between environmental pollutants and GDM were few. More prospective studies and high-quality in vivo and in vitro experiments were needed to investigate the specific effects and mechanisms.
Topics: Pregnancy; Female; Humans; Diabetes, Gestational; Environmental Pollutants; Polychlorinated Biphenyls; Prospective Studies; Halogenated Diphenyl Ethers; Parabens; Environmental Exposure; Hydrocarbons, Chlorinated; Phenols; Pesticides; Fluorocarbons
PubMed: 37164202
DOI: 10.1016/j.chemosphere.2023.138866 -
Chemosphere Feb 2023Much attention has been paid on polybrominated diphenyl ethers (PBDEs) in household dust due to their ubiquitous occurrences in the environment. Based on the data from... (Review)
Review
Much attention has been paid on polybrominated diphenyl ethers (PBDEs) in household dust due to their ubiquitous occurrences in the environment. Based on the data from 59 articles sampled from 2005 to 2020, we investigated the spatio-temporal distribution, sources, and health risk of 8 PBDE homologues in household dusts worldwide. BDE-209 is the predominant PBDE in household dusts, followed by BDE-99 and BDE-47. The total concentrations of PBDEs (∑PBDEs) are found to be high in household dusts sampled from 2005 to 2008 and show a significant decline trend from 2009 to 2016 (p < 0.05) and a little upward tendency from 2017 to 2020. The concentrations of PBDEs in household dusts vary greatly in different countries of the world. The use of penta-BDE is the main source of three to five bromo-biphenyl ether monomers contributing 17.4% of ∑PBDEs, while BDE-209 and BDE-183 are derived from the use of household appliances contributing 82.6% of ∑PBDEs. Ingestion is the main exposure route for adults and toddlers, followed by dermal contact. The values of hazard index (HI) exposed to PBDEs in household dusts are all less than 1 for both adults and toddlers, indicating a low non-cancer risk. The incremental lifetime cancer risks (ILCRs) of BDE-209 are less than 10 for both adults and toddlers, suggesting a negligible risk. However, the total carcinogenic risk of toddlers is higher than that of adults, indicating that much attention should be paid to toddlers exposed to BDE-209 in household dust.
Topics: Adult; Humans; Halogenated Diphenyl Ethers; Dust; Air Pollution, Indoor; Risk Assessment; Neoplasms; Environmental Monitoring; Environmental Exposure
PubMed: 36584828
DOI: 10.1016/j.chemosphere.2022.137641 -
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 -
Obesity Reviews : An Official Journal... Jan 2022We conducted a systematic review and meta-analysis of the associations between prenatal exposure to persistent organic pollutants (POPs) and childhood obesity. We... (Meta-Analysis)
Meta-Analysis
We conducted a systematic review and meta-analysis of the associations between prenatal exposure to persistent organic pollutants (POPs) and childhood obesity. We focused on organochlorines (dichlorodiphenyltrichloroethane [DDT], dichlorodiphenyldichloroethylene [DDE], hexachlorobenzene [HCB], and polychlorinated biphenyls [PCBs]), perfluoroalkyl and polyfluoroalkyl substances (PFAS), and polybrominated diphenyl ethers (PBDEs) that are the POPs more widely studied in environmental birth cohorts so far. We search two databases (PubMed and Embase) through July/09/2021 and identified 33 studies reporting associations with prenatal organochlorine exposure, 21 studies reporting associations with prenatal PFAS, and five studies reporting associations with prenatal PBDEs. We conducted a qualitative review. Additionally, we performed random-effects meta-analyses of POP exposures, with data estimates from at least three prospective studies, and BMI-z. Prenatal DDE and HCB levels were associated with higher BMI z-score in childhood (beta: 0.12, 95% CI: 0.03, 0.21; I : 28.1% per study-specific log increase of DDE and beta: 0.31, 95% CI: 0.09, 0.53; I : 31.9% per study-specific log increase of HCB). No significant associations between PCB-153, PFOA, PFOS, or pentaPBDEs with childhood BMI were found in meta-analyses. In individual studies, there was inconclusive evidence that POP levels were positively associated with other obesity indicators (e.g., waist circumference).
Topics: Child; Environmental Pollutants; Female; Humans; Pediatric Obesity; Persistent Organic Pollutants; Polychlorinated Biphenyls; Pregnancy; Prenatal Exposure Delayed Effects; Prospective Studies
PubMed: 34766696
DOI: 10.1111/obr.13383 -
The Science of the Total Environment Jul 2021Toxicity of compounds belonging to persistent organic pollutants (POPs) is widely known, and their re-emission from glaciers has been conclusively demonstrated. However,... (Review)
Review
Toxicity of compounds belonging to persistent organic pollutants (POPs) is widely known, and their re-emission from glaciers has been conclusively demonstrated. However, the harmful effects associated with such secondary emissions have yet to be thoroughly understood, especially in the spatial and temporal context, as the existing literature has a clear sampling bias with the best recognition of sites in the European Alps. In this review, we elaborated on the hazards associated with the rapid melting of glaciers releasing organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and polycyclic aromatic hydrocarbons (PAHs). To this end, we collated knowledge on: (1) the varying glacier melt rate across the Northern Hemisphere, (2) the content of POPs in the glacial system components, including the less represented areas, (3) the mechanisms of POPs transfer through the glacial system, including the importance of immediate emission from snow melt, (4) risk assessment associated with POPs re-emission. Based on the limited existing information, the health risk of drinking glacial water can be considered negligible, but consuming aquatic organisms from these waters may increase the risk of cancer. Remoteness from emission sources is a leading factor in the presence of such risk, yet the Arctic is likely to be more exposed to it in the future due to large-scale processes shifting atmospheric pollution and the continuous supply of snow. For future risk monitoring, we recommend to explore the synergistic toxic effects of multiple contaminants and fill the gaps in the spatial distribution of data.
PubMed: 33832784
DOI: 10.1016/j.scitotenv.2021.145244