-
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 Research Nov 2017Neurodegenerative processes encompass a large variety of diseases with different pathological patterns and clinical presentation such as Amyotrophic Lateral Sclerosis... (Review)
Review
Neurodegenerative processes encompass a large variety of diseases with different pathological patterns and clinical presentation such as Amyotrophic Lateral Sclerosis (ALS), Alzheimer Disease (AD) and Parkinson's disease (PD). Genetic mutations have a known causative role, but the majority of cases are likely to be probably caused by a complex gene-environment interaction. Exposure to metals has been hypothesized to increase oxidative stress in brain cells leading to cell death and neurodegeneration. Neurotoxicity of metals has been demonstrated by several in vitro and in vivo experimental studies and it is likely that each metal could be toxic through specific pathways. The possible pathogenic role of different metals has been supported by some epidemiological evidences coming from occupational and ecological studies. In order to assess the possible association between metals and neurodegenerative disorders, several case-control studies have also been carried out evaluating the metals concentration in different biological specimens such as blood/serum/plasma, cerebrospinal fluid (CSF), nail and hair, often reporting conflicting results. This review provides an overview of our current knowledge on the possible association between metals and ALS, AD and PD as main neurodegenerative disorders.
Topics: Alzheimer Disease; Amyotrophic Lateral Sclerosis; Environmental Pollutants; Humans; Metals; Parkinson Disease, Secondary
PubMed: 28777965
DOI: 10.1016/j.envres.2017.07.048 -
The American Journal of Clinical... Jun 2023Dietary interventions are a widely available mediation for depression and anxiety among pregnant and/or postpartum (i.e., perinatal) persons, but their effectiveness is... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Dietary interventions are a widely available mediation for depression and anxiety among pregnant and/or postpartum (i.e., perinatal) persons, but their effectiveness is not well known.
OBJECTIVES
We performed a systematic review and meta-analysis to assess the effectiveness of dietary interventions for the treatment of perinatal depression and/or anxiety.
METHODS
We searched MEDLINE, EMBASE, PsycINFO, CINAHL, and Web of Science from their inception to 2 November, 2022. Studies were included if they were available in English and examined the effectiveness of a dietary intervention for perinatal depression and/or anxiety in a randomized controlled trial.
RESULTS
Our search identified 4246 articles, of which 36 were included and 28 were eligible for meta-analysis. Random-effects meta-analyses were performed. Polyunsaturated fatty acids (PUFAs) were not found to improve symptoms of perinatal depression compared to control conditions [standardized mean differences (SMD): -0.11; 95% CI: -0.26 to 0.04]. These results neither changed when examined during pregnancy or the postpartum period separately nor varied according to the fatty acid (FA) ratio. Elemental metals (iron, zinc, and magnesium) were also not found to be superior to placebo (SMD: -0.42; 95% CI: -1.05 to 0.21), although vitamin D yielded a small to medium effect size improvement (SMD: -0.52; 95% CI: -0.84 to -0.20) in postpartum depression. Iron may help in those with confirmed iron deficiency. Narrative synthesis was performed for studies ineligible for meta-analyses.
CONCLUSIONS
Despite their widespread popularity, PUFAs and elemental metals do not appear to effectively reduce perinatal depression. Vitamin D taken in doses of 1800-3500 International Units per day may be, to some extent, promising. Additional high-quality, large-scale randomized controlled trials are needed to determine the true effectiveness of dietary interventions on perinatal depression and/or anxiety. This study was registered at PROSPERO (registration date: 5 July, 2020; CRD42020208830).
Topics: Pregnancy; Female; Humans; Depression; Randomized Controlled Trials as Topic; Anxiety; Fatty Acids, Unsaturated; Iron; Vitamin D
PubMed: 37019362
DOI: 10.1016/j.ajcnut.2023.03.025 -
Environmental Research Feb 2023Endocrine disrupting chemicals (EDCs) are exogenous substances recognised as relevant tumourigenic chemicals. Studies show that even EDCs which were long abolished are... (Review)
Review
INTRODUCTION
Endocrine disrupting chemicals (EDCs) are exogenous substances recognised as relevant tumourigenic chemicals. Studies show that even EDCs which were long abolished are still contributing to the increasing incidence of neoplasia.
AIM
To investigate the association between human exposure to EDCs and the risk of endocrine-related tumours: breast, prostate, thyroid, uterus, testis, and ovary.
METHODS
A systematic review using PubMed, Scopus, and Embase was conducted, searching for original observational studies published between 1980 and 2020, approaching EDCs exposure and endocrine tumourigenic risk in humans. We comprised neoplasia of six endocrine organs. We included all the studies on EDCs reporting tumour odds ratio, risk ratio, or hazard ratio. Study levels of confidence and risk of bias were accessed applying accredited guidelines. Human-made accidents and natural EDCs were not considered in the present study.
RESULTS
Our search returned 3271 papers. After duplicate removal and screening, only 237 papers were included (corresponding to 268 records). EDCs were grouped from the most frequently (pesticides) to the least frequently studied (salts). The most tumourigenic EDC groups were phthalates (63%), heavy metals (54%), particulate matter (47%), and pesticides (46%). Pesticides group comprised the highest number of retrieved studies (n = 133). Increased neoplasia risk was found in 43-67% of the studies, with a lower value for ovary (43%) and a higher value for thyroid (67%).
CONCLUSIONS
The innovative nature of our review comes from including human studies of six endocrine-related neoplasia aiming to understand the contribution of specific EDCs groups to each organ's tumourigenesis. Thyroid was the organ presenting the highest cancer risk after EDC exposure which may explain the increasing thyroid cancer incidence. However, detailed and controlled works reporting the effects of EDCs are scarce, probably justifying conflicting results. Multinational and multicentric human studies with biochemical analysis are needed to achieve stronger and concordant evidence.
Topics: Male; Female; Humans; Endocrine Disruptors; Endocrine System; Pesticides; Testis; Metals, Heavy
PubMed: 36460069
DOI: 10.1016/j.envres.2022.114869 -
Clinical Oral Implants Research Sep 2009The objective of this systematic review was to assess the 5-year survival rates and incidences of complications associated with ceramic abutments and to compare them... (Comparative Study)
Comparative Study Review
OBJECTIVES
The objective of this systematic review was to assess the 5-year survival rates and incidences of complications associated with ceramic abutments and to compare them with those of metal abutments.
METHODS
An electronic Medline search complemented by manual searching was conducted to identify randomized-controlled clinical trials, and prospective and retrospective studies providing information on ceramic and metal abutments with a mean follow-up time of at least 3 years. Patients had to have been examined clinically at the follow-up visit. Assessment of the identified studies and data abstraction was performed independently by three reviewers. Failure rates were analyzed using standard and random-effects Poisson regression models to obtain summary estimates of 5-year survival proportions.
RESULTS
Twenty-nine clinical and 22 laboratory studies were selected from an initial yield of 7136 titles and data were extracted. The estimated 5-year survival rate of ceramic abutments was 99.1% [95% confidence interval (CI): 93.8-99.9%] and 97.4% (95% CI: 96-98.3%) for metal abutments. The estimated cumulative incidence of technical complications after 5 years was 6.9% (95% CI: 3.5-13.4%) for ceramic abutments and 15.9% (95% CI: 11.6-21.5%) for metal abutments. Abutment screw loosening was the most frequent technical problem, occurring at an estimated cumulative incidence after 5 years of 5.1% (95% CI: 3.3-7.7%). All-ceramic crowns supported by ceramic abutments exhibited similar annual fracture rates as metal-ceramic crowns supported by metal abutments. The cumulative incidence of biological complications after 5 years was estimated at 5.2% (95% CI: 0.4-52%) for ceramic and 7.7% (95% CI: 4.7-12.5%) for metal abutments. Esthetic complications tended to be more frequent at metal abutments. A meta-analysis of the laboratory data was impossible due to the non-standardized test methods of the studies included.
CONCLUSION
The 5-year survival rates estimated from annual failure rates appeared to be similar for ceramic and metal abutments. The information included in this review did not provide evidence for differences of the technical and biological outcomes of ceramic and metal abutments. However, the information for ceramic abutments was limited in the number of studies and abutments analyzed as well as the accrued follow-up time. Standardized methods for the analysis of abutment strength are needed.
Topics: Alveolar Bone Loss; Animals; Crowns; Dental Abutments; Dental Porcelain; Dental Prosthesis, Implant-Supported; Dental Restoration Failure; Dental Stress Analysis; Denture, Partial, Fixed; Gingival Recession; Gold Alloys; Humans; Survival Analysis; Titanium
PubMed: 19663946
DOI: 10.1111/j.1600-0501.2009.01787.x -
Environmental Pollution (Barking, Essex... Mar 2024Exposure to toxic metals is a global public health threat. Among other adverse effects, exposure to the heavy metal cadmium has been associated with greater risk of... (Meta-Analysis)
Meta-Analysis Review
Exposure to toxic metals is a global public health threat. Among other adverse effects, exposure to the heavy metal cadmium has been associated with greater risk of cardiovascular disease (CVD). Nonetheless, the shape of the association between cadmium exposure and CVD risk is not clear. This systematic review summarizes data on the association between cadmium exposure and risk of CVD using a dose-response approach. We carried out a literature search in PubMed, Web of Science, and Embase from inception to December 30, 2023. Inclusion criteria were: studies on adult populations, assessment of cadmium exposure, risk of overall CVD and main CVD subgroups as endpoints, and observational study design (cohort, cross-sectional, or case-control). We retrieved 26 eligible studies published during 2005-2023, measuring cadmium exposure mainly in urine and whole blood. In a dose-response meta-analysis using the one-stage method within a random-effects model, we observed a positive association between cadmium exposure and risk of overall CVD. When using whole blood cadmium as a biomarker, the association with overall CVD risk was linear, yielding a risk ratio (RR) of 2.58 (95 % confidence interval-CI 1.78-3.74) at 1 μg/L. When using urinary cadmium as a biomarker, the association was linear until 0.5 μg/g creatinine (RR = 2.79, 95 % CI 1.26-6.16), after which risk plateaued. We found similar patterns of association of cadmium exposure with overall CVD mortality and risks of heart failure, coronary heart disease, and overall stroke, whereas for ischemic stroke there was a positive association with mortality only. Overall, our results suggest that cadmium exposure, whether measured in urine or whole blood, is associated with increased CVD risk, further highlighting the importance of reducing environmental pollution from this heavy metal.
Topics: Adult; Humans; Cardiovascular Diseases; Cadmium; Cross-Sectional Studies; Metals, Heavy; Biomarkers; Observational Studies as Topic
PubMed: 38295933
DOI: 10.1016/j.envpol.2024.123462 -
Medicina (Kaunas, Lithuania) May 2021HIV has been a serious global health concern since its discovery, with about 37.9 million people living with HIV worldwide as of 2018. Sub-Saharan Africa (SSA) accounts... (Review)
Review
HIV has been a serious global health concern since its discovery, with about 37.9 million people living with HIV worldwide as of 2018. Sub-Saharan Africa (SSA) accounts for 68% of the infection and contributed 74% of the 1.5 million deaths in 2013 despite having only 12% of the total world population residing in the region. This systematic review has attempted to determine the association between heavy metal toxicity and the occurrence of non-communicable diseases in the HIV/AIDS population. Three databases were systematically searched: PubMed, Scopus, and Google Scholar for studies written in English and published between 1 April 2000 and 12 April 2020. Studies were excluded if the main outcomes were not measured or did not meet the inclusion criteria. All the six included studies are cross-sectional in design, and therefore were evaluated using the STROBE checklist. The data extraction was done using an extraction table; the ratio of female to male participants included in the study was 1.09:1. Qualitative analysis was used due to the heterogeneity in the heavy metal biomarkers and the outcome measured by the included studies. Two studies compared the concentration of heavy metals in HIV-positive and HIV-negative participants while one compared the levels between HAART-naïve and HAART-treated participants, and three determined the association between heavy metal toxicity and non-communicable diseases (liver fibrosis, anaemia, and reproductive parameters, respectively) in HIV-positive patients. Blood lead, cadmium, and mercury levels were higher in HIV-seropositive than -seronegative subjects, whereas serum zinc level was lower in HIV-seropositive than -seronegative subjects, but the causal association between heavy metals and non-communicable diseases in HIV subjects is largely unknown. Interdisciplinary research between nutrition, toxicology, and human health is envisaged for primary and secondary prevention and treatment.
Topics: Africa South of the Sahara; Cross-Sectional Studies; Female; HIV Infections; Humans; Male; Metals, Heavy; Noncommunicable Diseases
PubMed: 34068196
DOI: 10.3390/medicina57050492 -
Journal of Intellectual Disability... Aug 2023Down syndrome (DS) is the most common genetic disorder. To date, the scientific literature regarding micronutrient status in children and adolescents with DS has not... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Down syndrome (DS) is the most common genetic disorder. To date, the scientific literature regarding micronutrient status in children and adolescents with DS has not been systematically reviewed. Therefore, our aim was to provide a systematic review and meta-analysis on this topic.
METHODS
We identified all relevant case-control studies published by 1 January 2022, by searching the PubMed and Scopus databases for original English-language articles analysing the micronutrient status of individuals with DS. Forty studies were included in the systematic review and 31 in the meta-analysis.
RESULTS
Statistically significant differences between individuals with DS (cases) and non-DS (controls) (P ≤ 0.05) were obtained for zinc, selenium, copper, vitamin B12, sodium and calcium. Serum, plasma and whole blood analyses showed lower zinc levels in cases than controls {standardised mean difference [SMD] serum [95% confidence interval (CI)] = -2.32 [-3.22, -1.41], P < 0.00001; SMD plasma [95% CI] = -1.29 [-2.26, -0.31], P < 0.01; SMD blood [95% CI] = -1.59 [-2.29, -0.89], P < 0.00001}. Similarly, plasma and blood selenium concentrations were significantly lower in cases than controls (SMD plasma [95% CI] = -1.39 [-2.26, -0.51], P = 0.002; SMD blood [95% CI] = -1.86 [-2.59, -1.13], P < 0.00001). Intraerythrocytic copper and serum B12 were higher in cases than controls (SMD Cu [95% CI] = 3.33 [2.19, 4.46], P < 0.00001; SMD B12 [95% CI] = 0.89 [0.01, 1.77], P = 0.048). Blood calcium was lower in cases than controls (SMD Ca [95% CI] = -0.77 [-1.34, -0.21], P = 0.007).
CONCLUSIONS
This study provides the first systematic overview of micronutrient status in children and adolescents with DS and has shown that relatively little consistent research has been executed in this field. There is a clear need for more well-designed, clinical trials to study the micronutrient status and effects of dietary supplements in children and adolescents with DS.
Topics: Child; Humans; Adolescent; Micronutrients; Down Syndrome; Selenium; Copper; Calcium; Zinc
PubMed: 37218392
DOI: 10.1111/jir.13042 -
Environmental Health Perspectives Mar 2020Electronic cigarettes (e-cigarettes) have become popular, in part because they are perceived as a safer alternative to tobacco cigarettes. An increasing number of...
BACKGROUND
Electronic cigarettes (e-cigarettes) have become popular, in part because they are perceived as a safer alternative to tobacco cigarettes. An increasing number of studies, however, have found toxic metals/metalloids in e-cigarette emissions.
OBJECTIVE
We summarized the evidence on metal/metalloid levels in e-cigarette liquid (e-liquid), aerosols, and biosamples of e-cigarette users across e-cigarette device systems to evaluate metal/metalloid exposure levels for e-cigarette users and the potential implications on health outcomes.
METHODS
We searched PubMed/TOXLINE, Embase®, and Web of Science for studies on metals/metalloids in e-liquid, e-cigarette aerosols, and biosamples of e-cigarette users. For metal/metalloid levels in e-liquid and aerosol samples, we collected the mean and standard deviation (SD) if these values were reported, derived mean and SD by using automated software to infer them if data were reported in a figure, or calculated the overall mean (mean ± SD) if data were reported only for separate groups. Metal/metalloid levels in e-liquids and aerosols were converted and reported in micrograms per kilogram and nanograms per puff, respectively, for easy comparison.
RESULTS
We identified 24 studies on metals/metalloids in e-liquid, e-cigarette aerosols, and human biosamples of e-cigarette users. Metal/metalloid levels, including aluminum, antimony, arsenic, cadmium, cobalt, chromium, copper, iron, lead, manganese, nickel, selenium, tin, and zinc, were present in e-cigarette samples in the studies reviewed. Twelve studies reported metal/metalloid levels in e-liquids (bottles, cartridges, open wick, and tank), 12 studies reported metal/metalloid levels in e-cigarette aerosols (from cig-a-like and tank devices), and 4 studies reported metal/metalloid levels in human biosamples (urine, saliva, serum, and blood) of e-cigarette users. Metal/metalloid levels showed substantial heterogeneity depending on sample type, source of e-liquid, and device type. Metal/metalloid levels in e-liquid from cartridges or tank/open wicks were higher than those from bottles, possibly due to coil contact. Most metal/metalloid levels found in biosamples of e-cigarette users were similar or higher than levels found in biosamples of conventional cigarette users, and even higher than those found in biosamples of cigar users.
CONCLUSION
E-cigarettes are a potential source of exposure to metals/metalloids. Differences in collection methods and puffing regimes likely contribute to the variability in metal/metalloid levels across studies, making comparison across studies difficult. Standardized protocols for the quantification of metal/metalloid levels from e-cigarette samples are needed. https://doi.org/10.1289/EHP5686.
Topics: Aerosols; Electronic Nicotine Delivery Systems; Humans; Metalloids; Metals; Saliva
PubMed: 32186411
DOI: 10.1289/EHP5686 -
Biological Trace Element Research Sep 2020The relationship between thyroid hormones metabolism and trace element levels has biological plausibility; however, previous reports that compared trace element levels... (Meta-Analysis)
Meta-Analysis Review
The relationship between thyroid hormones metabolism and trace element levels has biological plausibility; however, previous reports that compared trace element levels in patients with hypothyroidism and healthy individuals yielded conflicting results. Therefore, the aim of this meta-analysis was to investigate the association between selected trace elements (i.e., selenium (Se), zinc (Zn), iron (Fe), manganese (Mn), copper (Cu), lead (Pb)), and magnesium (Mg) concentrations in patients with hypothyroidism and healthy controls. Electronic databases, including PubMed, Scopus, Embase, and Science Direct, were searched systematically until September 2019. Thirty-two observational studies were included in the final analyses. Hedges' g tests were used to estimate effect sizes, as trace element concentrations were reported using different measurement units across the studies. Selenium (Hedges' g = - 0.52; 95% CI = [- 1.05, - 0.002]; P = 0.049) and Zn (Hedges' g = - 0.86; 95% CI = [- 1.66, - 0.06]; P = 0.035) concentrations were significantly lower, whereas Pb concentrations were significantly higher (Hedges' g = 0.34; 95% CI = [0.10, 0.59]; P = 0.006) in patients with hypothyroidism compared with healthy controls. There were no differences in the concentrations of Fe, Cu, Mn, and Mg between the groups. Patients with hypothyroidism exhibited lower Se and Zn and increased Pb concentrations compared with healthy controls. High-quality studies with larger sample sizes are required to explicate the link between trace element status and hypothyroidism.
Topics: Copper; Humans; Hypothyroidism; Selenium; Trace Elements; Zinc
PubMed: 31820354
DOI: 10.1007/s12011-019-01963-5