Blood Metal Research Articles

Cross-sectional and prospective associations of early childhood circulating metals with early and mid-childhood cognition in the Project Viva cohort

BackgroundRelatively little is known about the immediate and prospective neurodevelopmental impacts of joint exposure to multiple metals (i.e., metal mixtures) in early childhood. ObjectivesTo estimate associations of early childhood (∼3 years of age) blood metal concentrations with cognitive test scores at early and mid-childhood (∼8 years of age). MethodsWe studied children from the Project Viva cohort. We measured erythrocyte concentrations of seven essential (Co, Cu, Mg, Mn, Mo, Se, and Zn) and eight non-essential metals (As, Ba, Cd, Cs, Hg, Pb, Sn, and Sr) in early childhood blood samples. Trained research assistants administered cognitive tests assessing vocabulary, visual-motor ability, memory, and general intelligence (standard deviations: ∼10 points), in early and mid-childhood. We employed multivariable linear regression to examine associations of individual metals with test scores adjusting for confounders, other concurrently measured metals, and first-trimester maternal blood metals. We also estimated joint associations and explored interaction between metals in mixture analyses. ResultsWe analyzed 349 children (median whole blood Pb ∼1 μg/dL). In cross-sectional analyses, each doubling of Pb was associated with lower visual-motor function (mean difference: −2.43 points, 95% confidence interval (CI): −4.01, −0.86) and receptive vocabulary, i.e., words understood (−1.45 points, 95% CI: −3.26, 0.36). Associations of Pb with mid-childhood cognition were weaker and less precise by comparison. Mg was positively associated with cognition in cross-sectional but not prospective analyses, and cross-sectional associations were attenuated in a sensitivity analysis removing adjustment for concurrent metals. We did not observe joint associations nor interactions. DiscussionIn this cohort with low blood Pb levels, increased blood Pb was robustly associated with lower cognitive ability in cross-sectional analyses, even after adjustment for prenatal Pb exposure, and regardless of adjustment for metal co-exposures. However, associations with mid-childhood cognition were attenuated and imprecise, suggesting some buffering of Pb neurotoxicity in early life. What this study addsRelatively few studies have comprehensively separated the effects of neurotoxic metals such as lead (Pb) from pre- and postnatal co-occurring metals, nor examined persistence of associations across childhood. In a cohort of middle-class children, we found higher early childhood (∼3 y) blood Pb was associated with lower scores on cognitive tests, independent of other metals and prenatal blood Pb. However, early childhood Pb was only weakly associated with cognition in mid-childhood (∼8 y). Our results suggest the effects of low-level Pb exposure may attenuate over time in some populations, implying the presence of factors that may buffer Pb neurotoxicity in early life.

Association of blood metal exposure with age at menarche in Korean women: KNHANES (2008–2017)

Humans are exposed to metals in their daily lives and this metal exposure is responsible for various adverse health effects. Delayed pubertal development has been suggested as an adverse outcome of metal exposure; however, evidence in nationally representative populations, especially in Asia, is limited. We evaluated the association of blood cadmium (Cd), lead (Pb), and mercury (Hg) levels with the age at menarche in Korean females whose blood heavy metals were measured as part of the Korean National Health and Nutrition Examination Survey (KNHANES) 2008–2017. Among the females 16 years of age or older, all measured heavy metals in blood, i.e., Cd, Pb, and Hg, were positively associated with age at menarche. These associations remained significant in a model adjusted for age, survey year, income, education, body mass index, smoking history, and menopausal status as covariates (β: 0.10, 95% confidence interval (CI): 0.03–0.18 for Cd; β: 0.17, 95%CI: 0.06–0.27 for Pb; β: 0.12, 95%CI: 0.05–0.19 for Hg). When the population was separated by age group at the time of the survey, the significance between heavy metal levels and age at menarche became inconsistent, but the general trends were similar. Among those in their 20s and 40s, blood Cd showed a significant association, while Pb was significant among those in their 40s and 50s. A similar trend was observed in the sensitivity analysis in the girls aged 10–15 years at the time of the survey. Blood Cd levels were associated with decreased odds of precocious menarche (OR: 0.57, 95%CI: 0.31–1.03). Delayed menarche is a risk factor for cardiovascular and chronic kidney diseases in later life; hence, public health implication of heavy metal exposure warrants a public health attention.

Blood metal analysis of plasmas from donors with and without SARS-CoV-2 using laser-induced breakdown spectroscopy and logistic regression.

Research on the correlation between metal levels in blood and Covid-19 infection has been conducted primarily by assessing how each individual blood metal is linked to different aspects of the disease using samples from donors with various levels of severity to Covid-19 infection. Using logistics regression on LIBS spectra of plasma samples collected pre- and post- Covid-19 pandemic from donors known to have developed various levels of antibodies to the SARS-Cov-2 virus, we show that relying on the levels of Na, K, and Mg together is more efficient at differentiating the two types of plasma samples than any single blood alone.

Association of multiple blood metals and systemic atherosclerosis: A cross-sectional study in the CAD population

BackgroundCoronary atherosclerotic disease (CAD) is often accompanied by peripheral atherosclerosis, resulting in a higher risk of ischemia and cardiovascular death. Exposure to metals is associated with atherosclerotic plaques at specific sites. However, less is known about the effects of mixed metals on systemic atherosclerotic burden in CAD patients. ObjectivesTo investigate the association of metal mixtures with systemic atherosclerotic burden in a CAD population. MethodsA cross-sectional study including 1562 CAD patients from Southwest China was conducted. The levels of 10 blood metals were measured via inductively coupled plasma spectrometry. More than one vessel with a stenosis ≥50% vessel diameter was defined as CAD. Carotid and lower limb atherosclerosis was assessed by using ultrasound, and coronary atherosclerosis was quantified via arterial angiography. Systemic atherosclerosis was scored according to the presence or absence of lesions at the three sites and the total number of lesions. To investigate the combined impacts and interaction effects of metals, Bayesian kernel machine regression was used. Weighted quantile regression was used to identify the contributions of the metals. ResultsSignificant overall associations of mixed metals with systemic atherosclerotic burden were found. These positive overall associations were mainly driven by Cd, Cu and Pb in systemic atherosclerosis. The main contributing factors were As and Cu for coronary atherosclerosis as well as Cd, Cu and Pb for carotid and lower limb atherosclerosis. Cd and Pb or Cr can interact, and Pb interacts with age, sex and alcohol. ConclusionsIn CAD patients, exposure to combinations of metals was highly positively associated with systemic atherosclerotic burden. These significant trends were more pronounced in the peripheral arteries and carotid arteries. Controlling environmental metal exposure can contribute to reducing systemic atherosclerosis in CAD patients.

Associations Between Prenatal Blood Metals and Vitamins and Cord Blood Peptide Hormone Concentrations.

Nonessential metals have endocrine disrupting properties, interfere with cellular processes, generate reactive oxygen and deplete antioxidants, while essential metals and vitamins act as antioxidants. The extent to which prenatal metals and vitamins are associated with cord blood hormones involved in maternal and fetal metabolic and growth processes is unknown. We measured six nonessential (arsenic, barium, cadmium, cesium, lead, mercury) and four essential (magnesium, manganese, selenium, zinc) metals and trace elements, and two vitamins (B12 and folate) in first trimester blood from participants in the longitudinal pre-birth Project Viva cohort, who were recruited between 1999-2002 in eastern Massachusetts. We measured adiponectin, C-peptide, IGF-1, IGF-2, IGFBP-3, insulin, and leptin concentrations in cord blood (~n=695). We used covariate-adjusted quantile g-computation for mixtures and linear regression for individual exposures to estimate associations with cord blood peptide hormones. The essential metal mixture (magnesium, manganese, selenium, zinc) was associated with higher IGF-1 (β=3.20 ng/ml per quartile, 95% CI: 0.39, 6.01), IGF-2 (β=10.93 ng/ml, 95% CI: 0.08, 21.79), and leptin (β=1.03 ng/ml, 95% CI: 0.25, 1.80). Magnesium was associated with higher leptin (β=2.90 ng/ml, 95% CI: 0.89, 4.91), while B12 was associated with lower adiponectin, IGF-2, and leptin, but higher C-peptide. Other individual nonessential metals were associated with cord blood hormones. Our findings suggest that some prenatal metals and vitamins are associated with cord blood hormones, which may influence growth and development.

Blood lead concentrations in exposed forecourt attendants and taxi drivers in parts of South Africa

BackgroundLeaded fuel was banned in South Africa in 2006, in order to improve human health and reduce environmental pollution. Lead (Pb) has been suggested to contribute to the development of neurodegenerative disorders, and the role of respiratory exposure to Pb from petrol fumes should not be neglected in this context. In addition to Pb, petrol contains various harmful chemicals including other neurotoxic metals and hydrocarbons. Objectives and MethodsHere, we investigated concentrations of Pb and other metals in blood from petrol station forecourt attendants (n = 38), taxi drivers (n = 21), and unexposed controls (n = 36). Taxi drivers and forecourt attendants were divided into three groups each, based on number of years worked. A questionnaire was designed to investigate the health status of the participants. Blood samples were collected by medical professionals and analyzed for metal concentrations by ICP-MS. ResultsA positive correlation between number of years worked and Pb blood concentrations was found. The highest Pb concentration (60.2 µg/L) was observed in a forecourt attendant who had worked 11–20 years, and the average Pb concentration in this group (24.5 µg/L) was significantly (p < 0.05) higher than in forecourt attendants who had worked 2–5 years (10.4 µg/L). Some individuals had elevated concentrations of manganese, arsenic, cadmium, chromium and cobalt, yet not significantly elevated at the group level. The blood levels of arsenic appeared to be related to smoking. Mood swings, dizziness, headaches and tiredness were reported by the workers. ConclusionBlood Pb concentrations in petrol station forecourt attendants and taxi drivers exposed to leaded petrol are elevated and correlate to exposure time. A health monitoring program should be erected for all individuals working in these industries, and preventive measures should be implemented to eliminate metal exposure from petrol.

Mediating role of systemic inflammation in the association between heavy metals exposure and periodontitis risk.

This study evaluated the mediating role of systemic inflammation in the association between exposure to heavy metals and periodontitis in a nationwide sample of adults. Pooled cross-sectional data from the National Health and Nutrition Examination Survey (NHANES 2009-2014) were used (n=8993). Periodontitis was defined by a full-mouth examination and classified as no/mild and moderate/severe (mod/sev) groups. Blood and urinary heavy metal levels were investigated, including cadmium (Cd), lead (Pb), and mercury (Hg). In addition, systemic inflammation was assessed using circulatory leukocytecounts and C-reactive protein (CRP) levels. Multivariable logistic regression analysis revealed the positive associations of blood and urinary levels of Cd and Pb with mod/sev periodontitis. In contrast,blood Hg levels did not show a significant association. The odds of having periodontitis were 1.233 and 1.311 times higher for each one-unit increment in Ln-transformed blood Cd (95% confidence interval [CI]: 1.109-1.371) and Pb (95% CI: 1.170-1.470), respectively. Mediation analysis suggested a 6.3% to 11.5% contribution of leucocyte counts in the association of blood Cd and Pb levels with periodontitis. Sensitivity analyses for urinary Cd levels yielded consistent mediating effects. However, no significant mediating effect of CRP was detected. Higher exposures to Cd and Pb were positively associated with periodontitis risk. These associations might be partially mediated by the elevated levels of leukocytes rather than CRP. Further longitudinal studies are needed to elucidate the discordant results of the systemic inflammatory biomarkers.

Hepato-renal toxicity of low dose metal(oid)s mixture in real-life risk simulation in rats: Effects on Nrf2/HO-1 signalling and redox status

The understanding that humans are exposed to a low level of toxic metals and metalloids in their lifetime has resulted in a shift in scientific and regulatory perspectives from the traditional evaluation of single metal toxicity to complex mixtures, relevant to real-life exposure. Therefore, the aim of this study was to examine the impact of real-life, 90-days exposure to mixture of toxic metal(oid)s, Cd, Pb, Ni, Cr, As and Hg, on the nuclear factor erythroid 2–related factor 2 and hemoxygenase-1 (Nrf2/HO-1) signalling and redox status by assessing total sulfhydryl groups (SH), glutathione (GSH), superoxide dismutase activity (SOD), malondialdehyde (MDA), and ischemia modified albumin (IMA) in the liver and kidney of Wistar rats. Animals (20 males and 20 females) were randomized in 2 control and 6 treated groups that received by oral gavage mixture of metal(oid)s solutions in doses that reflect blood metal(oid) levels determined in previous human biomonitoring study as benchmark dose (F/M _BMD), median (F/M _MED), and 95th percentile (F/M _95). Our results have shown that metal(oid)s mixture impaired the activation of the Nrf2/HO-1 pathway in the kidney and liver of male rats and kidney of female rats, followed by depletion of GSH levels in males. Additionally, in males elevated levels of IMA in the liver were observed, while in both genders increased MDA levels were observed in the kidney. Interestingly, the effects were more pronounced in male than in female rats. This study is among the first that examined hepato-renal toxic mechanisms of real-life metal mixture exposure, while our results might be of immense importance for assessing the risk of exposure to mixtures of toxic substances.

Heavy Metals in Follicular Fluid Affect the Ultrastructure of the Human Mature Cumulus-Oocyte Complex.

It is known that exposure to heavy metal such as lead (Pb) and cadmium (Cd) has several adverse effects, particularly on the human reproductive system. Pb and Cd have been associated with infertility in both men and women. In pregnant women, they have been associated with spontaneous abortion, preterm birth, and impairment of the development of the fetus. Since these heavy metals come from both natural and anthropogenic activities and their harmful effects have been observed even at low levels of exposure, exposure to them remains a public health issue, especially for the reproductive system. Given this, the present study aimed to investigate the potential reproductive effects of Pb and Cd levels in the follicular fluid (FF) of infertile women and non-smokers exposed to heavy metals for professional reasons or as a result of living in rural areas near landfills and waste disposal areas in order to correlate the intrafollicular presence of these metals with possible alterations in the ultrastructure of human cumulus-oocyte complexes (COCs), which are probably responsible for infertility. Blood and FF metals were measured using atomic absorption spectrometry. COCs corresponding to each FF analyzed were subjected to ultrastructural analyses using transmission electron microscopy. We demonstrated for the first time that intrafollicular levels of Pb (0.66 µg/dL-0.85 µg/dL) and Cd (0.26 µg/L-0.41 µg/L) could be associated with morphological alterations of both the oocyte and cumulus cells' (CCs) ultrastructure. Since blood Cd levels (0.54 µg/L-1.87 µg/L) were above the current reference values established by the guidelines of the Agency for Toxic Substances and Disease Registry (ATSDR) and the Environmental Protection Agency (EPA) (0.4 µg/L), whereas blood Pb levels (1.28 µg/dL-3.98 µg/dL) were below the ATSDR reference values (≤5 µg/dL), we believe that these alterations could be due especially to Cd, even if we cannot exclude a possible additional effect of Pb. Our results highlighted that oocytes were affected in maturation and quality, whereas CCs showed scarcely active steroidogenic elements. Regressing CCs, with cytoplasmic alterations, were also numerous. According to Cd's endocrine-disrupting activity, the poor steroidogenic activity of CCs might correlate with delayed oocyte cytoplasmic maturation. So, we conclude that levels of heavy metals in the blood and the FF might negatively affect fertilization, embryo development, and pregnancy, compromising oocyte competence in fertilization both directly and indirectly, impairing CC steroidogenic activity, and inducing CC apoptosis.

The association of blood metals with latent tuberculosis infection among adults and adolescents.

We aimed to investigate the relationship of metal exposure and latent tuberculosis infection (LTBI) among US adults and adolescents. Participants from the National Health and Nutrition Examination Surveys (NHANES 2011 ~ 2012) were included. Multiple logistic regression models were used to explore the associations between metal exposure and LTBI. A total of 5,248 adults and 1,860 adolescents were included in the present analysis. For adults, we only found a positive association between total mercury and LTBI (OR: 1.411; 95% CI: 1.164 ~ 1.710) when used as a continuous variable. Compared with Q1, Q4 increased the prevalence of LTBI (2.303; 1.455 ~ 3.644) when used as a quartile. The OR of total mercury and LTBI was higher among females (1.517; 1.009 ~ 2.279), individuals aged 45 ~ 64 (1.457; 1.060 ~ 2.002), and non-Hispanic White individuals (1.773; 1.316 ~ 2.388). A relationship was observed among only participants with obesity (1.553; 1.040 ~ 2.319) or underweight (1.380; 1.076 ~ 1.771), with college or above (1.645; 1.184 ~ 2.286), with PIR > 3.0 (1.701; 1.217 ~ 2.376), reported smoking (1.535; 1.235 ~ 1.907) and drinking (1.464; 1.232 ~ 1.739). For adolescents, blood manganese was positively associated with LTBI. The OR and 95% CIs for each one-unit increase in the log-transformed level of blood manganese with LTBI were 9.954 (1.389 ~ 71.344). Significant associations were observed in girls, aged ≥12 years and in the non-Hispanic white population. In conclusion, total mercury is associated with an increased prevalence of LTBI among adults and positive association between blood manganese and LTBI was observed among adolescents. Further studies should be conducted to verify the results and explore potential biological mechanisms.

4 Urinary Fluoride Levels and Metal Co-Exposures Among Pregnant Women in Los Angeles, California

Objective:Approximately 73% of the United States (US) population on public water systems receives fluoridated water for tooth decay prevention. In Los Angeles (LA) County, 89% of cities are at least partially fluoridated. Drinking water is the primary source of fluoride exposure in the US. Studies conducted in Mexico and Canada suggest that prenatal fluoride exposure, at levels relevant to the US, may contribute to poorer neurodevelopment in offspring. However, data on biomarkers and patterns of fluoride exposure among US pregnant women are scarce. This study examined urinary fluoride levels according to sociodemographic factors and metal co-exposures among pregnant women in the US.Participants and Methods:Participants were from the Maternal and Developmental Risks from Environmental and Social Stressors (MADRES) cohort based in Los Angeles, California. There were 293 and 490 women with urine fluoride measured during the first and third trimesters of pregnancy, respectively. An intra-class correlation coefficient examined consistency of specific gravity-adjusted maternal urinary fluoride (MUFsg) between trimesters. Kruskal-Wallis and Mann-Whitney U tests examined associations of MUFsg with sociodemographic variables. Spearman correlations examined associations of MUFsg with blood and urine metals within and between trimesters. A False Discovery Rate (FDR) correction accounted for multiple comparisons. The criterion for statistical significance was an alpha of 0.05.Results:Participants were approximately 29 years old on average, and 80% were Hispanic or Latina. Median (IQR) MUFsg during trimesters one and three was 0.65 (0.5) mg/L and 0.8 (0.59) mg/L, respectively. MUFsg levels were moderately consistent between trimesters (N=292, ICC = 0.46, 95%CI: 0.32,0.57). Maternal age was positively associated with MUFsg during first (p = 0.16, p = 0.006) and third (p = 0.18, p &lt; 0.001) trimesters. MUFsg differed by race/ethnicity during first and third trimesters (N = 293, H (3) = 7.99, p = 0.046; N = 486, H (3) = 25.31, p &lt; 0.001, respectively). Specifically, MUFsg was higher for White, Non-Hispanic participants (first trimester Median (IQR) =1.03 (1.31) mg/L; third trimester Median (IQR) = 1.32 (1.24) mg/L) than for Hispanic participants in both trimesters (first trimester Median (IQR) =0.64 (0.48) mg/L; third trimester Median (IQR) = 0.76 (0.55) mg/L). Additionally, during trimester three, MUFsg was higher for White, Non-Hispanic participants than for Black Non-Hispanic participants (Median (IQR) = 0.82 (0.49) mg/L). MUFsg also differed by education during trimester one (N = 293, H (4) = 10.61, p = 0.031), and was higher for participants with some graduate training than for those with high school or some college/technical school education (ps = 0.03 and 0.04, respectively). After FDR correction, MUFsg was associated with blood lead (N =91, p = 0.29, p = 0.024) and urinary cadmium (N =279, p = 0.19, p = 0.042), copper (N=279, p = 0.16, p = 0.042), and tungsten (N=279, p = 0.16, p = 0.049) during trimester three.Conclusions:Consistent with studies conducted in Canada and Mexico, MUFsg increased across pregnancy. Lower MUFsg among Hispanic and Non-Hispanic Black participants may reflect lower tap water consumption. Metal co-exposures are important to consider when examining potential neurodevelopmental impacts of fluoride.

Urinary fluoride levels and metal co-exposures among pregnant women in Los Angeles, California

BackgroundFluoride is ubiquitous in the United States (US); however, data on biomarkers and patterns of fluoride exposure among US pregnant women are scarce. We examined specific gravity adjusted maternal urinary fluoride (MUFsg) in relation to sociodemographic variables and metal co-exposures among pregnant women in Los Angeles, California.MethodsParticipants were from the Maternal and Developmental Risks from Environmental and Social Stressors (MADRES) cohort. There were 293 and 490 women with MUFsg measured during first and third trimesters, respectively. An intra-class correlation coefficient examined consistency of MUFsg between trimesters. Kruskal–Wallis and Mann-Whitney U tests examined associations of MUFsg with sociodemographic variables. Covariate adjusted linear regression examined associations of MUFsg with blood metals and specific gravity adjusted urine metals among a subsample of participants within and between trimesters. A False Discovery Rate (FDR) correction accounted for multiple comparisons.ResultsMedian (IQR) MUFsg was 0.65 (0.5) mg/L and 0.8 (0.59) mg/L, during trimesters one and three respectively. During both trimesters, MUFsg was higher among older participants, those with higher income, and White, non-Hispanic participants than Hispanic participants. MUFsg was also higher for White, non-Hispanic participants than for Black, non-Hispanic participants in trimester three, and for those with graduate training in trimester one. MUFsg was negatively associated with blood mercury in trimester one and positively associated with blood lead in trimester three. MUFsg was positively associated with various urinary metals, including antimony, barium, cadmium, cobalt, copper, lead, nickel, tin, and zinc in trimesters one and/or three.ConclusionsMUFsg levels observed were comparable to those found in pregnant women in Mexico and Canada that have been associated with poorer neurodevelopmental outcomes. Lower urinary fluoride levels among Hispanic and non-Hispanic Black participants in MADRES compared to non-Hispanic White participants may reflect lower tap water consumption or lower fluoride exposure from other sources. Additional research is needed to examine whether MUFsg levels observed among pregnant women in the US are associated with neurodevelopmental outcomes.

The mediating role of accelerated biological aging in the association between blood metals and cognitive function

Aging is a key risk factor in cognitive diseases. Recently, metal exposures were found associated with both biological aging and cognitive function. Here, we aim to evaluate the associations of blood metals with cognitive function and the mediated effect of biological aging. Fourteen metals were detected and biological age was calculated through Klemera and Doubal method among 514 adults in Beijing, China. The generalized linear models indicated that the copper (Cu), molybdenum (Mo), and strontium (Sr) were positively associated with biological aging [βCu (95% CI): 12.76 (9.26, 16.27); βMo (95% CI): 1.50 (0.15, 2.85)], and βSr (95% CI): 1.86 (0.68, 3.03)], while vanadium (V) was inversely related to biological aging [βV (95% CI): −0.76 (−1.48, −0.05)]. Subsequently, Cu, lead (Pb), selenium (Se), and biological aging were associated with cognitive function and further mediation analyses confirmed that biological aging partially mediated (33.98%, P = 0.019) the association of Cu and cognitive function. Additionally, we constructed a lifestyle index that implied the modifiable healthy lifestyle could slow aging to attenuate the detrimental effect of metals on cognition. Our findings provide insights into the potential pathways linking multiple metals exposure to aging and cognition and underscore the importance of adopting healthy lifestyles.

Effects of long-term metal exposure on the structure and co-occurrence patterns of the oral microbiota of residents around a mining area.

The aim of our study was to investigate the impact of long-term exposure to heavy metals on the microbiome of the buccal mucosa, to unveil the link between environmental contamination and the oral microbial ecosystem, and to comprehend its potential health implications. Subjects were divided into two groups: the exposure group and the control group. We collected samples of buccal mucosa, soil, and blood, and conducted microbial diversity analysis on both groups of oral samples using 16S rRNA gene sequencing. The concentrations of heavy metals in blood and soil samples were also determined. Additionally, microbial networks were constructed for the purpose of topological analysis. Due to long-term exposure to heavy metals, the relative abundance of Rhodococcus, Delftia, Fusobacterium, and Peptostreptococcus increased, while the abundance of Streptococcus, Gemella, Prevotella, Granulicatella, and Porphyromonas decreased. The concentrations of heavy metals in the blood (Pb, Cd, Hg, and Mo) were associated with the growth of Rhodococcus, Delftia, Porphyromonas, and Gemella. In addition, the relative abundances of some pathogenic bacteria, such as Streptococcus anginosus, S. gordonii, and S. mutans, were found to be enriched in the exposure group. Compared to the exposure group network, the control group network had a greater number of nodes, modules, interactive species, and keystone taxa. Module hubs and connectors in the control group converted into peripherals in the exposure group, indicating that keystone taxa changed. Metals in the blood (Pb, Cd, Hg, and Mo) were drivers of the microbial network of the buccal mucosa, which can have adverse effects on the network, thus providing conditions for the occurrence of certain diseases. Long-term exposure to multiple metals perturbs normal bacterial communities in the buccal mucosa of residents in contaminated areas. This exposure reduces the complexity and stability of the microbial network and increases the risk of developing various diseases.

Synergistic impact of co-exposures to whole blood metals on chronic kidney disease in general US adults: a cross‑sectional study of the National Health and Nutrition Examination Survey 2011-2020.

The impact of exposure to metals on chronic kidney disease (CKD) has only been investigated in two-way or single metal interactions in previous studies. We investigated the associations between five single metals in blood and their mixed exposure and CKD by using the machine learning approach. Relevant data were extracted from the National Health and Nutrition Examination Survey (NHANES 2011-2020), and the level of five metals in blood detected by inductively coupled plasma mass spectrometry was considered as exposures, namely, cadmium (Cd), lead (Pb), total mercury (Hg), manganese (Mn), and selenium (Se). The correlations between individual metal and metal mixtures and CKD were then evaluated by survey-multivariable logistic regression (SMLR), generalized weighted quantile sum (WQS), and Bayesian kernel machine regression (BKMR). Altogether, our study included 12,412 participants representing 572.6 million non-institutionalized US adults. Several single metals with the high quartile of exposure showed a positive association with the CKD ratio including Cd [(AOR = 1.873, 95% CI: 1.537, 2.284), Q4], Pb [(AOR = 1.559, 95% CI: 1.295, 1.880), Q4], and total Hg [(AOR = 1.169, 95% CI: 1.018, 1.343), Q2], while Mn [(AOR = 0.796, 95% CI: 0.684, 0.927), Q2] and Se [(AOR = 0.805, 95% CI: 0.664, 0.976), Q4] were negatively associated with the CKD ratio. In light of the positive fit of the WQS regression model, a significantly positive correlation was found between mixed metals and CKD (AOR = 1.373, 95% CI: 1.224, 1.539) after full covariate adjustment, and a similar finding was also detected in the BKMR model. Our study revealed that each single metal including Cd, Pb, and total Hg might have a positive association with CKD while this association was negative for both Mn and Se. The five metals might have a positive joint effect on CKD.

Prenatal metal concentrations and physical abnormalities in the Japan Environment and Children's Study.

The association between prenatal metal exposure and congenital anomalies is unclear. We aimed to examine the association between exposure to cadmium, lead, mercury, selenium, and manganese and physical abnormalities. Data from 89,887 pregnant women with singleton pregnancies who participated in the Japan Environment and Children's Study (JECS) were used. The correlation between maternal blood metal concentrations and physical abnormalities during the second or third trimester was investigated using logistic regression models. Physical anomalies included those observed at birth or at 1 month, primarily from ICD-10 Chapter 17, particularly congenital anomalies associated with environmental factors (e.g., hypospadias, cryptorchidism, cleft lip and palate, digestive tract atresia, congenital heart disease, and chromosomal abnormalities) and minor abnormalities. After adjusting for covariates, the OR (95% CIs) of physical abnormalities for a one-unit rise in Mn concentrations in all individuals were 1.26 (1.08, 1.48). The OR (95% CIs) of physical abnormalities in the 4th quartile (≥18.7 ng/g) were 1.06 (1.01, 1.13) (p-value for the trend = 0.034) compared with those in the 1st quartile (≤12.5 ng/g). In Japan, maternal blood Mn concentrations above threshold during pregnancy may slightly increase the incidence of physical abnormalities. Physical abnormalities (including minor anomalies and congenital anomalies) are associated with prenatal manganese concentrations. They are not associated with cadmium, lead, mercury, and selenium concentrations.

Investigation of the relationship between heavy metals in the blood and depression in people with different body mass indices using the NHANES database: A cross-sectional study

BackgroundExposure to heavy metals considered a major risk factor for mental health. ObjectiveExamining how heavy metals in blood are associated with depression in individuals of various body mass indexes. MethodsA total sample of 15,560 individuals was screened, with 4355 participants finally enrolled to study. The PHQ-9 was used to assess participants' depressive symptoms. ResultsA logistic regression analysis was used to investigate the relationship between the levels of heavy metals in the blood and the depression. Serum cadmium levels were found to be associated with risk of depression, with an odds ratio of 2.247 (95 % CI: 1.584–3.244). However, no significant correlations were observed between depression and blood levels of lead, selenium, and manganese. Subgroup analysis was performed and found that higher Cd concentrations were associated with a greater risk of depression at the same BMI. With the same Cd concentration, the risk of depression was lowest when participants' BMI was ≥30 kg/m2 and increased with increasing BMI when participants' BMI was <30 kg/m2. LimitationsIt is not possible to analyze the effect of external exposure to Cd. ConclusionCd in blood may be positively correlated with depression in American adults, and the effect of this trend is different in people with different body mass indices. With the increase in BMI, the risk gradually rises. However, it is lowest among obese people.

Correction: Potential Factors Associated with the Blood Metal Concentrations of Reproductive-Age Women in Taiwan

Correction: Potential Factors Associated with the Blood Metal Concentrations of Reproductive-Age Women in Taiwan

Erectile dysfunction in copper and cobalt miners: a cross-sectional study in the former Katanga province, Democratic Republic of the Congo.

The African Copperbelt is a site of intense artisanal and industrial mining and refining of copper and cobalt. We aimed to investigate factors that are possibly associated with erectile dysfunction (ED) in metal miners in the former Katanga province of the Democratic Republic of the Congo. In a cross-sectional study of 138 miners and 139 controls (bakers), we administered questionnaires to obtain sociodemographic and occupational data and to assess male sexual function (International Index of Erectile Function [IIEF]) and marital relation quality (Revised Dyadic Adjustment Scale). Furthermore, we measured trace metals in blood and urine, as well as testosterone and thyroid hormones in serum. Outcomes included the prevalence of questionnaire-derived ED and the relation of ED with individual characteristics, serum testosterone, and environmental factors. Miners were on average 4years older than bakers (mean ± SD, 37.5 ± 6.9 vs 33.3 ± 5.7 years). Miners had significantly lower scores than bakers on the IIEF (median [IQR], 66 [49-73] vs 73 [66-74]) and the 3 domains of the Revised Dyadic Adjustment Scale (consensus, satisfaction, cohesion). Free testosterone was significantly lower in miners than bakers (ng/dL; 8.11 [6.90-10.10] vs 10.52 [8.83-12.58]; P ˂ .001). In miners, sex hormone-binding globulin correlated positively with blood Pb and urinary Cd. In a multivariable analysis, mild to moderate ED or moderate ED (IIEF-erectile function score ≤18) was significantly associated with having a mining-related job (adjusted odds ratio [aOR], 2.6; 95% CI, 1.3-5.3), work seniority ˃5years (aOR, 2.3; 95% CI, 1.1-4.6), alcohol consumption (aOR, 2.8; 95% CI, 1.2-6.7), and aphrodisiacs use (aOR, 4.2; 95% CI, 2.2-8.0). Mediation analysis showed that marital relationship partially mediated the relation between work seniority >5years in mining and ED. The high prevalence of ED found in artisanal mine workers indicates that work-related factors should be considered as possibly contributing, directly or indirectly, to sexual dysfunction in men. Strengths include being the first epidemiologic study documenting ED with validated questionnaires and its possible determinants, including exposure to toxic metals, among young artisanal miners vs a suitable control group. Limitations are the cross-sectional design with convenience sampling and absence of objective confirmation of ED. As compared with controls, miners reported poorer sexual function and lower quality of their marital relationship, and they had lower free testosterone levels, which may be due to their high exposure to trace metals.

Individual, sociodemographic, and lifestyle influence on blood chromium, cobalt, and nickel levels in healthy population living in Belgrade, Serbia.

The rapid trend of industrialization and urbanization can lead to greater exposure of the general population to chromium, cobalt, and nickel. Their total body burden from all routes of recent exposure, as well as interindividual variability in exposure levels, metabolism, and excretion rates, are reflected in the blood metal concentrations. The main goals in this study were as follows: observing the reference levels of chromium, cobalt, and nickel in the blood of the population living in Belgrade, identification of individual and sociodemographic factors that most affect their blood levels, and comprehension of recent exposure to chromium, cobalt, and nickel. Blood was sampled from 984 participants, voluntary blood donors, who agreed to participate in this study. Individual and sociodemographic data were collected using questionnaire adapted for different subpopulations. Blood metal analyses were measured using ICP-MS method (7700×, Agilent, USA). Our study provided reference values of chromium, cobalt, and nickel in blood for adult population (18-65 years) and confirmed that blood cobalt and nickel levels were mostly influenced by age and gender, and age, respectively. Furthermore, weight status affected blood chromium and cobalt levels, while national origin affected blood chromium levels. The present study highlighted the importance of human biomonitoring studies to monitor exposure status and identify subpopulations with increased exposure to chromium, cobalt, and nickel.