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The Science of the Total Environment Apr 2022The etiology of sporadic amyotrophic lateral sclerosis (ALS) is still unclear. We evaluate environmental factors suspected to be associated with ALS for their potential... (Review)
Review
The etiology of sporadic amyotrophic lateral sclerosis (ALS) is still unclear. We evaluate environmental factors suspected to be associated with ALS for their potential linkage to disease causality and to model geographic distributions of susceptible populations and expected cases worldwide. A PRISMA systematic literature review was performed 2021. Bradford Hill criteria were used to identify and rank environmental factors and a secondary review of ALS diagnoses in population studies and ALS case or cohort studies was conducted. Prevalence rate projection informed estimates of impacted regions and populations. Among 1710 papers identified, 258 met the inclusion criteria, of which 173 responded to at least one of nine Bradford Hill criteria among 83 literature-identified ALS environmental factors. Environmental determinants of ALS in order of decreasing significance were β-N-methylamino-L-alanine (BMAA), formaldehyde, selenium, and heavy metals including manganese, mercury, zinc, and copper. Murine animal models were the most common methodology for exploring environmental factors. Another line of investigation of 62 population exposure studies implicated the same group of environmental agents (mean odds ratios): BMAA (2.32), formaldehyde (1.54), heavy metals (2.99), manganese (3.85), mercury (2.74), and zinc (2.78). An age-adjusted incidence model estimated current total ALS cases globally at ~85,000 people compared to only ~1600 cases projected from the reported ALS incidence in the literature. Modeling with the prevalence microscope equation forecasted an increase in U.S. ALS cases from 16,707 confirmed in 2015 to ~22,650 projected for 2040. Two orthogonal methods employed implicate BMAA, formaldehyde, manganese, mercury, and zinc as environmental factors with strong ALS associations. ALS cases likely are significantly underreported globally, and high vulnerability exists in regions with large aging populations. Recent studies on other diseases with environmental determinants suggest the need to consider additional potential triggers and mechanisms, including exposures to microbial agents and epigenetic modifications.
Topics: Amyotrophic Lateral Sclerosis; Animals; Formaldehyde; Humans; Mercury; Mice; Selenium; Zinc
PubMed: 34971691
DOI: 10.1016/j.scitotenv.2021.152504 -
Environmental Health Perspectives Nov 2022The Minamata Convention on Mercury (Article 4) prohibits the manufacture, import, or export of skin-lightening products containing mercury concentrations above .... (Review)
Review
BACKGROUND
The Minamata Convention on Mercury (Article 4) prohibits the manufacture, import, or export of skin-lightening products containing mercury concentrations above . However, there is a lack of knowledge surrounding the global prevalence of mercury-added skin-lightening products.
OBJECTIVE
The objective of this study was to increase our understanding of worldwide human mercury exposure from skin-lightening products.
METHODS
A systematic search of peer-reviewed scientific literature was performed for relevant articles in four databases (PubMed, Web of Science Core Collection, Scopus, and TOXLINE). The search strategy, eligibility criteria, and data-extraction methods were established . The search identified 2,303 unique scientific articles, of which 41 were ultimately deemed eligible for inclusion after iterative screens at the title, abstract, and whole-text levels. To facilitate data extraction and synthesis, all papers were organized according to four data groups ) "Mercury in products," ) "Usage of products," ) "Human biomarkers of exposure," and ) "Health impacts."
RESULTS
This review was based on data contained in 41 peer-reviewed scientific papers from 22 countries worldwide published between 2000 and 2022. In total, we captured mercury concentration values from 787 skin-lightening product samples [overall pooled central median mercury level was ; interquartile range (IQR): 0.02-5.9] and 1,042 human biomarker measurements from 863 individuals. We also synthesized usage information from 3,898 individuals and self-reported health impacts associated with using mercury-added products from 832 individuals.
DISCUSSION
This review suggests that mercury widely exists as an active ingredient in many skin-lightening products worldwide and that users are at risk of variable and often high exposures. These synthesized findings identify data gaps and help increase our understanding of the health risks associated with the use of these products. https://doi.org/10.1289/EHP10808.
Topics: Humans; Mercury; Biomarkers
PubMed: 36367779
DOI: 10.1289/EHP10808 -
International Journal of Environmental... Sep 2022Electronic waste (e-waste) recycling releases mercury (Hg) into the environment, though to our knowledge Hg levels at such sites have yet to be examined on a worldwide... (Meta-Analysis)
Meta-Analysis Review
Electronic waste (e-waste) recycling releases mercury (Hg) into the environment, though to our knowledge Hg levels at such sites have yet to be examined on a worldwide basis. A systematic review of scientific studies was conducted to extract, analyze, and synthesize data on Hg levels in e-waste products, environments near recycling sites, and in people. Data were extracted from 78 studies from 20 countries, and these included Hg levels in 1103 electrical and electronic products, 2072 environmental samples (soil, air, plant, food, water, dust), and 2330 human biomarkers (blood, hair, urine). The average Hg level in products was 0.65 μg/g, with the highest levels found in lamps (578 μg/g). Average soil and sediment Hg levels (1.86 μg/g) at e-waste sites were at least eight times higher than at control sites. Average urinary Hg levels (0.93 μg/g creatinine) were approximately two-fold higher among e-waste workers versus control groups. Collectively, these findings demonstrate that e-waste recycling may lead to Hg contamination in environments and human populations in close proximity to processing sites. These findings contribute to a growing knowledge base of mercury exposure through diverse source-exposure pathways, and the work has potential policy implications in the context of the Minamata Convention.
Topics: Biomarkers; Creatinine; Dust; Electronic Waste; Environmental Monitoring; Humans; Mercury; Soil; Waste Products; Water Pollutants, Chemical
PubMed: 36231146
DOI: 10.3390/ijerph191911843 -
Sleep Medicine Reviews Aug 2023Environmental exposures may influence sleep; however, the contributions of environmental chemical pollutants to sleep health have not been systematically investigated.... (Review)
Review
Environmental exposures may influence sleep; however, the contributions of environmental chemical pollutants to sleep health have not been systematically investigated. We conducted a systematic review to identify, evaluate, summarize, and synthesize the existing evidence between chemical pollutants (air pollution, exposures related to the Gulf War and other conflicts, endocrine disruptors, metals, pesticides, solvents) and dimensions of sleep health (architecture, duration, quality, timing) and disorders (sleeping pill use, insomnia, sleep-disordered breathing)). Of the 204 included studies, results were mixed; however, the synthesized evidence suggested associations between particulate matter, exposures related to the Gulf War, dioxin and dioxin-like compounds, and pesticide exposure with worse sleep quality; exposures related to the Gulf War, aluminum, and mercury with insomnia and impaired sleep maintenance; and associations between tobacco smoke exposure with insomnia and sleep-disordered breathing, particularly in pediatric populations. Possible mechanisms relate to cholinergic signaling, neurotransmission, and inflammation. Chemical pollutants are likely key determinants of sleep health and disorders. Future studies should aim to evaluate environmental exposures on sleep across the lifespan, with a particular focus on developmental windows and biological mechanisms, as well as in historically marginalized or excluded populations.
Topics: Child; Humans; Environmental Pollutants; Sleep Initiation and Maintenance Disorders; Dioxins; Sleep; Sleep Apnea Syndromes
PubMed: 37392613
DOI: 10.1016/j.smrv.2023.101805 -
Revista Brasileira de Ginecologia E... Dec 2022The present review aimed to synthesize the evidence regarding mercury (Hg) exposure and hypertensive disorders of pregnancy (HDP).
OBJECTIVE
The present review aimed to synthesize the evidence regarding mercury (Hg) exposure and hypertensive disorders of pregnancy (HDP).
DATA SOURCES
The PubMed, BVS/LILACS, SciELO and UFRJ's Pantheon Digital Library databases were systematically searched through June 2021.
STUDY SELECTION
Observational analytical articles, written in English, Spanish, or Portuguese, without time restriction.
DATA COLLECTION
We followed the PICOS strategy, and the methodological quality was assessed using the Downs and Black checklist.
DATA SYNTHESIS
We retrieved 77 articles, of which 6 met the review criteria. They comprised 4,848 participants, of which 809 (16.7%) had HDP and 4,724 (97.4%) were environmentally exposed to Hg (fish consumption and dental amalgam). Mercury biomarkers evaluated were blood (four studies) and urine (two studies). Two studies found a positive association between Hg and HDP in the group with more exposure, and the other four did not present it. The quality assessment revealed three satisfactory and three good-rated studies (mean: 19.3 ± 1.6 out 28 points). The absence or no proper adjustment for negative confounding factor, such as fish consumption, was observed in five studies.
CONCLUSION
We retrieved only six studies, although Hg is a widespread toxic metal and pregnancy is a period of heightened susceptibility to environmental threats and cardiovascular risk. Overall, our review showed mixed results, with two studies reporting a positive association in the group with more exposure. However, due to the importance of the subject, additional studies are needed to elucidate the effects of Hg on HDP, with particular attention to adjusting negative confounding.
Topics: Humans; Pregnancy; Female; Animals; Mercury; Hypertension, Pregnancy-Induced; Maternal Exposure; Biomarkers
PubMed: 36580940
DOI: 10.1055/s-0042-1760215 -
International Journal of Clinical... 2022Scopus and PubMed databases were systematically searched from their inception to November 2021 to obtain pertinent studies. Standardized mean differences (SMDs) with... (Meta-Analysis)
Meta-Analysis Review
METHODS
Scopus and PubMed databases were systematically searched from their inception to November 2021 to obtain pertinent studies. Standardized mean differences (SMDs) with corresponding 95% confidence intervals (CIs) were calculated to evaluate the difference in Hg levels between people with and without T2DM. The association of the Hg exposure with T2DM was assessed using a random-effects model by pooling the odds ratios (ORs) and 95% CIs.
RESULTS
A total of 17 studies, with 42,917 participants, aged ≥18 years, were analyzed. Overall, Hg levels were significantly higher in T2DM patients compared with non-T2DM controls (SMD = 1.07; 95%CI = 0.59 to 1.55, ≤ 0.001), with significant heterogeneity across studies (I = 96.1%; =≤0.001). No significant association was found between Hg exposure and risk of T2DM in the overall analysis and subgroup analysis based on the source of sample and study design. However, higher exposure to Hg was related to reduced risk of T2DM in men (OR = 0.71; 95%CI = 0.57 to 0.88), but not in women. No significant evidence for publication bias was detected.
CONCLUSIONS
Although the Hg level in T2DM is significantly higher than that of nondiabetics, there was no association between Hg exposure and the overall risk of T2DM. Nevertheless, our study shows that higher exposure to Hg might reduce the risk of T2DM in men.
Topics: Adolescent; Adult; Diabetes Mellitus, Type 2; Female; Humans; Male; Mercury; Odds Ratio
PubMed: 36101810
DOI: 10.1155/2022/7640227 -
The Science of the Total Environment Jan 2024Prenatal exposure to metal mixtures is associated with adverse pregnancy and birth outcomes like low birth weight, preterm birth, and small for gestational age. However,... (Review)
Review
BACKGROUND
Prenatal exposure to metal mixtures is associated with adverse pregnancy and birth outcomes like low birth weight, preterm birth, and small for gestational age. However, prior studies have used individual metal analysis, lacking real-life exposure scenarios.
OBJECTIVES
This systematic review aims to evaluate the strength and consistency of the association between metal mixtures and pregnancy and birth outcomes, identify research gaps, and inform future studies and policies in this area.
METHODS
The review adhered to the updated Preferred Reporting Items for Systematic Review and Meta-analysis (PRISMA) checklist, along with the guidelines for conducting systematic reviews and meta-analyses of observational studies of etiology (COSMOS-E). Our data collection involved searching the PubMed, MEDLINE, and SCOPUS databases. We utilized inclusion criteria to identify relevant studies. These chosen studies underwent thorough screening and data extraction procedures. Methodological quality evaluations were conducted using the NOS framework for cohort and case-control studies, and the AXIS tool for cross-sectional studies.
RESULTS
The review included 34 epidemiological studies, half of which focused on birth weight, and the others investigated neonate size, preterm birth, small for gestational age, miscarriage, and placental characteristics. The findings revealed significant associations between metal mixtures (including mercury (Hg), nickel (Ni), arsenic (As), cadmium (Cd), manganese (Mn), cobalt (Co), lead (Pb), zinc (Zn), barium (Ba), cesium (Cs), copper (Cu), selenium (Se), and chromium (Cr)) and adverse pregnancy and birth outcomes, demonstrating diverse effects and potential interactions.
CONCLUSION
In conclusion, this review consistently establishes connections between metal exposure during pregnancy and adverse consequences for birth weight, gestational age, and other vital birth-related metrics. This review further demonstrates the need to apply mixture methods with caution but also shows that they can be superior to traditional approaches. Further research is warranted to deeper understand the underlying mechanisms and to develop effective strategies for mitigating the potential risks associated with metal mixture exposure during pregnancy.
Topics: Female; Humans; Infant, Newborn; Pregnancy; Abortion, Spontaneous; Birth Weight; Cross-Sectional Studies; Fetal Growth Retardation; Mercury; Metals; Placenta; Premature Birth
PubMed: 37963536
DOI: 10.1016/j.scitotenv.2023.168380 -
Association Between Non-alcoholic Fatty Liver Disease and Heavy Metal Exposure: a Systematic Review.Biological Trace Element Research Dec 2023Non-alcoholic fatty liver disease (NAFLD) is a debilitating disease with adverse effects including cirrhosis and hepatocellular carcinoma. Heavy metals can cause severe... (Review)
Review
Non-alcoholic fatty liver disease (NAFLD) is a debilitating disease with adverse effects including cirrhosis and hepatocellular carcinoma. Heavy metals can cause severe dysfunction in different body organs including the liver. This review offers the study regarding the positive or negative association between heavy metals exposure and non-alcoholic fatty liver disease. The method used in this study is a systematic review based on searching in the PubMed, Scopus, and Science direct databases with the keywords of fatty liver, non-alcohol fatty liver, heavy metal, mercury, cadmium, arsenic, chromium, thallium, lead, iron, zinc, and nickel. There were 2200 articles searched in databases, and after assessment, 28 articles were selected. Positive association is established between arsenic, cadmium, iron, lead, mercury, and fatty liver disease. A negative relationship is found between zinc, copper, and progressive fatty liver disease. Furthermore, laboratory methods for NAFLD diagnosis were examined according to the obtained manuscripts. Among the different diagnostic methods, magnetic resonance imaging (MRI) is a sensitive method.
Topics: Humans; Non-alcoholic Fatty Liver Disease; Cadmium; Arsenic; Metals, Heavy; Mercury; Iron; Zinc
PubMed: 36929113
DOI: 10.1007/s12011-023-03629-9 -
Reproductive Toxicology (Elmsford, N.Y.) Jun 2024The primary route of mercury exposure for the general population is through consumption of contaminated seafood. There is a biological basis for an adverse effect of... (Review)
Review
The primary route of mercury exposure for the general population is through consumption of contaminated seafood. There is a biological basis for an adverse effect of mercury exposure on human fertility. The goal of this review was to evaluate the existing literature on the association between mercury and pregnancy, among men and women attempting to conceive with and without assisted reproductive technology (ART). Systematic searches were performed in PubMed, EMBASE, Scopus and Web of Science for papers published up to March 2023 with no early date restriction, only including studies with a biomarker measurement of mercury exposure. We identified 11 studies examining mercury and natural fertility and 12 studies examining mercury and outcomes of assisted reproduction (implantation or clinical pregnancy). The accumulated evidence provides some support for a null association between bodily mercury concentrations and natural fertility among women, however, a large proportion of studies did not report adjusted estimates or were extremely imprecise. The majority of studies of natural fertility were also cross-sectional in nature. There was no evidence for an inverse or null association between mercury and natural fertility among men, or mercury and ART outcomes among men or women. In spite of biological plausibility, the existing evidence includes studies that are imprecise and often conflicting and does not allow us to make definitive conclusions on the associations of mercury exposure with successful pregnancy. Additional, larger studies are warranted, especially among individuals with high concentrations of mercury exposure as these individuals may be underrepresented in the current literature.
PubMed: 38830454
DOI: 10.1016/j.reprotox.2024.108613 -
International Journal of Environmental... May 2022Mercury (Hg) is one of the most harmful metals and has been a public health concern according to the World Health Organization (WHO). Artisanal and small-scale gold... (Review)
Review
Mercury (Hg) is one of the most harmful metals and has been a public health concern according to the World Health Organization (WHO). Artisanal and small-scale gold mining (ASGM) is the world's fastest-growing source of Hg and can release Hg into the atmosphere, hydrosphere, and geosphere. Hg has been widely used in ASGM industries throughout Southeast Asia countries, including Cambodia, Indonesia, Laos, Malaysia, Myanmar, the Philippines, and Thailand. Here, 16 relevant studies were systematically searched by performing the PRISMA flow, combining the keywords of "Hg", "ASGM", and relevant study areas. Mercury concentrations exceeding the WHO and United States Environmental Protection Agency guideline values were reported in environmental (i.e., air, water, and soil) and biomonitoring samples (i.e., plants, fish, and human hair). ASGM-related health risks to miners and nonminers, specifically in Indonesia, the Philippines, and Myanmar, were also assessed. The findings indicated severe Hg contamination around the ASGM process, specifically the gold-amalgamation stage, was significantly high. To one point, Hg atmospheric concentrations from all observed studies was shown to be extremely high in the vicinity of gold operating areas. Attentions should be given regarding the public health concern, specifically for the vulnerable groups such as adults, pregnant women, and children who live near the ASGM activity. This review summarizes the effects of Hg in Myanmar and other Southeast Asian countries. In the future, more research and assessment will be required to investigate the current and evolving situation in ASGM communities.
Topics: Animals; Environmental Pollution; Female; Gold; Humans; Mercury; Mining; Myanmar; Pregnancy; United States
PubMed: 35627826
DOI: 10.3390/ijerph19106290