Serum nickel is associated with craniosynostosis risk: Evidence from humans and mice

Association between urinary polycyclic aromatic hydrocarbons and risk of metabolic associated fatty liver disease

OBJECTIVE

To investigate the effect of urinary PAHs on MAFLD.

METHODS

The study included 3,136 adults from the National Health and Nutrition Examination Survey (NHANES) conducted between 2009 and 2016. Among them, 1,056 participants were diagnosed with MAFLD and were designated as the case group. The analysis of the relationship between monohydroxy metabolites of seven PAHs in urine and MAFLD was carried out using logistic regression and Bayesian kernel regression (BKMR) models.

RESULTS

In single-pollutant models, the concentration of 2-hydroxynaphthalene (2-OHNAP) was positively correlated with MAFLD (OR = 1.47, 95% CI 1.18, 1.84), whereas 3-hydroxyfluorene (3-OHFLU) and 1-hydroxypyrene (1-OHPYR) demonstrated a negative correlation with MAFLD (OR = 0.59, 95% CI 0.48 0.73; OR = 0.70, 95% CI 0.55, 0.89). Conversely, in multi-pollutant models, 2-OHNAP, 2-hydroxyfluorene (2-OHFLU), 2-hydroxyphenanthrene, and 3-hydroxyphenanthrene (2&3-OHPHE) displayed positive correlations with MAFLD (OR = 6.17, 95% CI 3.15, 12.07; OR = 2.59, 95% CI 1.37, 4.89). However, 3-OHFLU and 1-OHPYR continued to exhibit negative correlations with MAFLD (OR = 0.09, 95% CI 0.05, 0.15; OR = 0.62, 95% CI 0.43, 0.88). Notably, the BKMR analysis mixtures approach did not indicate a significant joint effect of multiple PAHs on MAFLD, but identified interactions between 3-OHFLU and 2-OHFLU, 1-OHPYR and 2-OHFLU, and 1-OHPYR and 3-OHFLU.

CONCLUSION

No significant association was found between mixed PAHs exposure and the risk of MAFLD. However, interactions were observed between 3-OHFLU and 2-OHFLU. Both 2-OHFLU and 2&3-OHPHE exposure are significant risk factors for MAFLD, whereas 3-OHFLU is a key protective factor for the disease.

Human Health Effects of Oral Exposure to Chromium: A Systematic Review of the Epidemiological Evidence

The toxicity and carcinogenicity of hexavalent chromium via the inhalation route is well established. However, a scientific debate has arisen about the potential effects of oral exposure to chromium on human health. Epidemiological studies evaluating the connection between ingested chromium and adverse health effects on the general population are limited. In recent years, a wealth of biomonitoring studies has emerged evaluating the associations between chromium levels in body fluids and tissues and health outcomes. This systematic review brings together epidemiological and biomonitoring evidence published over the past decade on the health effects of the general population related to oral exposure to chromium. In total, 65 studies were reviewed. There appears to be an inverse association between prenatal chromium exposure and normal fetal development. In adults, parameters of oxidative stress and biochemical alterations increase in response to chromium exposure, while effects on normal renal function are conflicting. Risks of urothelial carcinomas cannot be overlooked. However, findings regarding internal chromium concentrations and abnormalities in various tissues and systems are, in most cases, controversial. Environmental monitoring together with large cohort studies and biomonitoring with multiple biomarkers could fill the scientific gap.

Associations Between Individual and Combined Metal Exposures in Whole Blood and Kidney Function in U.S. Adults Aged 40 Years and Older

The effects of metal exposure on kidney function have been reported in previous literature. There is limited and inconsistent information on the associations between individual and combined exposures to metals and kidney function among the middle-aged and older population. The aim of this study was to clarify the associations of exposure to individual metals with kidney function while accounting for potential coexposure to metal mixtures and to evaluate the joint and interactive associations of blood metals with kidney function. A total of 1669 adults aged 40 years and older were enrolled in the present cross-sectional study using the 2015-2016 National Health and Nutrition Examination Survey (NHANES). Single-metal and multimetal multivariable logistic regression models, quantile G-computation, and Bayesian kernel machine regression models (BKMR) were fitted to explore the individual and joint associations of whole blood metals [lead (Pb), cadmium (Cd), mercury (Hg), cobalt (Co), manganese (Mn), and selenium (Se)] with the odds of decreased estimated glomerular filtration rate (eGFR) and albuminuria. A decreased eGFR was defined as an eGFR ≤ 60 mL/min per 1.73 m2, and albuminuria was categorized as a urinary albumin-creatinine ratio (UACR) of ≥ 30.0 mg/g. The results from quantile G-computation and BKMR indicated positive associations between exposure to the metal mixture and the prevalence of decreased eGFR and albuminuria (all P values < 0.05). These positive associations were mainly driven by blood Co, Cd, and Pb. Furthermore, blood Mn was identified as an influential element contributing to an inverse correlation with kidney dysfunction within metal mixtures. Increasing blood Se levels were negatively associated with the prevalence of decreased eGFR and positively associated with albuminuria. In addition, a potential pairwise interaction between Mn-Co on decreased eGFR was identified by BKMR analysis. Findings from our study suggested a positive association between exposure to the whole blood metal mixture and decreased kidney function, with blood Co, Pb, and Cd being the main contributors to this association, while Mn demonstrated an inverse relationship with renal dysfunction. However, as our study was cross-sectional in nature, further prospective studies are warranted to better understand the individual and combined effects of metals on kidney function.

Assessment of sources and health risks of heavy metals in metropolitan household dust among preschool children: The LEAPP-HIT study

The most common construction material used in Taiwan is concrete, potentially contaminated by geologic heavy metals (HMs). Younger children spend much time indoors, increasing HM exposure risks from household dust owing to their behaviors. We evaluated arsenic (As), cadmium (Cd), and lead (Pb) concentrations in fingernails among 280 preschoolers between 2017 and 2023. We also analyzed HM concentrations, including As, Cd, Pb, chromium (Cr), nickel (Ni), copper (Cu), zinc (Zn), iron (Fe), and manganese (Mn), in 90 household dust and 50 road dust samples from a residential area where children lived between 2019 and 2021 to deepen the understanding of sources and health risks of exposure to HMs from household dust. The average As, Cd, and Pb concentrations in fingernails were 0.12 ± 0.06, 0.05 ± 0.05, and 0.95 ± 0.77 μg/g, respectively. Soil parent materials, indoor construction activities, vehicle emissions, and mixed indoor combustion were the pollution sources of HMs in household dust. Higher Cr and Pb levels in household dust may pose non-carcinogenic risks to preschoolers. Addressing indoor construction and soil parent materials sources is vital for children's health. The finding of the present survey can be used for indoor environmental management to reduce the risks of HM exposure and avoid potential adverse health effects for younger children.

Sp1-activated FGFR2 is involved in early-life exposure to nickel-induced craniosynostosis by regulating the ERK1/2 signaling pathway

Nickel, a common environmental hazard, is a risk factor for craniosynostosis. However, the underlying biological mechanism remains unclear. Here, we found that early-life nickel exposure induced craniosynostosis in mice. In vitro, nickel promoted the osteogenic differentiation of human mesenchymal stem cells (hMSCs), and its osteogenic ability in vivo was confirmed by an ectopic osteogenesis model. Further mRNA sequencing showed that ERK1/2 signaling and FGFR2 were aberrantly activated. FGFR2 was identified as a key regulator of ERK1/2 signaling. By promoter methylation prediction and methylation-specific PCR (MSP) assays, we found that nickel induced hypomethylation in the promoter of FGFR2, which increased its binding affinity to the transcription factor Sp1. During pregnancy and postnatal stages, AZD4547 rescued nickel-induced craniosynostosis by inhibiting FGFR2 and ERK1/2. Compared with normal individuals, nickel levels were increased in the serum of individuals with craniosynostosis. Further logistic and RCS analyses showed that nickel was an independent risk factor for craniosynostosis with a nonlinear correlation. Mediated analysis showed that FGFR2 mediated 30.13% of the association between nickel and craniosynostosis risk. Collectively, we demonstrate that early-life nickel exposure triggers the hypomethylation of FGFR2 and its binding to Sp1, thereby promoting the osteogenic differentiation of hMSCs by ERK1/2 signaling, leading to craniosynostosis.

Associations between plasma metal/metalloid mixtures and the risk of central obesity: A prospective cohort study of Chinese adults

Central obesity has increased rapidly over the past decade and posed a substantial disease burden worldwide. Exposure to metals/metalloids has been acknowledged to be involved in the development of central obesity through regulation of cortisol, insulin resistance, and glucocorticoid receptor reduction. Despite the importance, it is lack of prospective study which comprehensively evaluate the relations between multiple metals exposure and central obesity. We explored the prospective associations of plasma metal concentrations with central obesity in a prospective study of the Dongfeng-Tongji cohort. The present study included 2127 participants with a 6.87-year mean follow-up duration. We measured 23 plasma metal/metalloid concentrations at baseline. The associations between metals and incident central obesity were examined utilizing the Cox proportional hazard regression in single and multiple metals models. Additionally, we applied elastic net (ENET), Bayesian kernel machine regression (BKMR), plasma metal score (PMS), and quantile-based g-computation (Qgcomp) models to explore the joint associations of metal mixtures with central obesity. After adjusting potential confounders, we found significant associations of plasma manganese (Mn) and thallium (Tl) concentrations with a higher risk of central obesity, whereas plasma rubidium (Rb) concentration was associated with a lower risk of central obesity both in single and multiple metals models (all FDR <0.05). The ENET and Qqcomp models verified similar metals (Mn, Rb, and Tl) as important predictors for central obesity. The results of both BKMR model and PMS suggested cumulative exposure to metal mixtures was associated with a higher risk of central obesity. Our findings suggested that co-exposure to metals was associated with a higher risk of central obesity. This study expands our knowledge that the management of metals/metalloids exposure may be beneficial for the prevention of new-onset central obesity, which may subsequently alleviate the disease burden of late-life health outcomes.

Mediation analysis of urinary metals and stroke risk by inflammatory markers

BACKGROUND

The association between metals and stroke has been reported, but the mediating role of inflammation between metals and stroke remains unclear.

METHODS

We included 9326 adults from the National Health and Nutrition Examination Survey in this study. Through least absolute selection and shrinkage operator (LASSO) regression, weighted quantile sum (WQS) regression, logistic regression, linear regression, restricted cubic spline analysis, and mediation analysis, we explored the association between metals and stroke, as well as the association between metals and inflammatory indicators, and further evaluated the mediating effect of inflammatory indicators on the association between selected metals and stroke risk.

RESULTS

The results of the present study suggested positive associations between mixed metals, cadmium and uranium and stroke risk. There is a positive correlation and dose‒response relationship between cadmium and C-reactive protein (CRP). Moreover, CRP mediates 10.1% of the association between cadmium and stroke.

CONCLUSIONS

At the epidemiological level, CRP mediates the association between cadmium and stroke risk, suggesting that inflammation may be a potential mechanism for metal-induced stroke.

Single and Joint Associations of Polycyclic Aromatic Hydrocarbon Exposure with Liver Function during Early Pregnancy

The individual and combined associations of polycyclic aromatic hydrocarbons (PAHs) metabolites on liver function during pregnancy are still lacking. We aimed to explore the connection between urinary PAH metabolites and liver function in early pregnant women in southwest China based on the Zunyi birth cohort. Ten urinary PAH metabolites and five liver function parameters during early pregnancy were measured. The associations of single PAHs with parameters of liver function were assessed using multiple linear regression. A Bayesian kernel machine regression (BKMR) model was used to evaluate the joint associations of the PAH mixture with outcomes. We found that each 1% increment of urinary 2-hydroxyphenanthrene (2-OH-PHE) was associated with 3.36% (95% CI: 0.40%, 6.40%) higher alanine aminotransferase (ALT) and 2.22% (95% CI: 0.80%, 3.67%) higher aspartate aminotransferase (AST). Each 1% increment in 1-hydroxy-phenanthrene (1-OH-PHE) was significantly associated with 7.04% (95% CI: 1.61%, 12.75%) increased total bile acid (TBA). Additionally, there was a significant positive linear trend between 2-OH-PHE and AST and 1-OH-PHE and TBA. BKMR also showed a significant positive association of PAH mixture with AST. Our results indicate that PAH metabolites were associated with increased parameters of liver function among early pregnant women. Early pregnant women should pay more attention to the adverse relationships between PAHs and liver function parameters to prevent environment-related adverse perinatal outcomes.

Comparative metabolomic analysis reveals Ni(II) stress response mechanism of Comamonas testosteroni ZG2

The focus on the toxicity of nickel (Ni(II)) in animal and human cells has increased recently. Ni(II) contamination hazards to animals and humans can be reduced by bioremediation methods. However, one of the limitation of bioremediation bacteria in soil remediation is that they cannot survive in moderate and heavy contamination Ni(II)-contaminated environments. Therefore, the Ni(II) response mechanism of Comamonas testosteroni ZG2 which has soil remediation ability in high-concentration Ni(II) environment must be elucidated. The results demonstrated that the ZG2 strain can survive at 350 mg/L concentration of Ni(II), but the growth of ZG2 was completely inhibited under the concentration of 400 mg/L Ni(II) with significant alterations in the membrane morphology, adhesion behavior, and functional groups and serious membrane damage. Furthermore, the metabolic analysis showed that Ni(II) may affect the adhesion behavior and biofilm formation of the ZG2 strain by affecting the abundance of metabolites in amino acid biosynthesis, aminoacyl-tRNA biosynthesis, ABC transporter, and cofactor biosynthesis pathways, and inhibiting its growth. This study provides new evidence clarifying the response mechanism of Ni(II) stress in the ZG2 strain, thus playing a significant role in designing the strategies of bioremediation.

Association between nickel exposure and body compositions in the United States: a population-based cross-sectional study

BACKGROUND

Increasing body fat or decreasing muscle and bone mass were associated with worse health outcomes in the adult population. The effects of nickel exposure on body composition are not known. The aim of the current study was to investigate the relationship between urinary nickel levels and body compositions.

MATERIALS AND METHODS

Two thousand seven hundred sixty-two participants were included in the analysis from the National Health and Nutrition Examination Surveys of 2017-2018 after excluding participants who have missing data on urinary nickel and those with missing all body mass component data. We used weighted generalized linear models to explore the relationship between urinary nickel and body mass components under interpolating missing covariable values. Simultaneously, sensitivity analyses and subgroup analysis were conducted to verify stability of analysis result. Curve fitting and saturation effect analysis were used to explore the possible nonlinear relationship between urine nickel and body compositions.

RESULTS

Among the 2,762 participants, the average urinary nickel level was 1.58 ug/L. The weighted generalized linear models, the sensitivity analyses and subgroup analyses found no significant linear relationship between urinary nickel and body compositions. For body weight, BMI, TLM, ALM, TRF, TOF and BMC, the urine nickel saturation effect values were 0.76, 0.74, 0.5, 0.67, 0.64, 0.48, and 0.45 ug/L, respectively. For each 1 ug/L rise in urinary nickel levels at levels below the turning point, body weight increases (β = 9.06, 95% CI = 2.75, 15.36, p = 0.01), BMI increases (β = 3.20, 95% CI = 1.36, 5.05, p =  < 0.001), TLM decreases (β = -47.39, 95% CI = -97.38, 2.59, p = 0.06), ALM decreases (β = -37.25, 95% CI = -63.25, -11.24, p = 0.01), TRF increases (β = 20.68, 95% CI = 1.50, 39.86, p = 0.03), TOF increases (β = 57.92, 95% CI = -0.12, 115.95, p = 0.05), and BMC decreases (β = -6.84, 95% CI = -12.64, -1.04, p = 0.02).

CONCLUSIONS

In summary, our study demonstrated that a dose-response relationship exists between urinary nickel and body compositions, with a low inflection point level of urinary nickel for the saturation effect.

Association Between Heavy Metals Exposure and Height in Chinese Preschoolers

OBJECTIVES

This study aimed to explore the association between multiple metals' exposure and children's height.

METHODS

We collected urine samples and physical measurement data of 1477 preschoolers in China. Children's actual height was measured, and whether reached target height was also assessed. Logistic regression analysis was performed to explore the association between heavy metals and height. The least absolute shrinkage and selection operator regression was used to select the urinary metals, which were highly correlated.

RESULTS

In the single-metal model after adjusting for potential confounders, urinary iron, aluminum, nickel, chrome, titanium, vanadium, selenium, rubidium, and thallium levels were negatively associated with actual height. Urinary iron, aluminum, nickel, and chrome concentrations were also negatively associated with target height.

CONCLUSIONS

The findings suggested that some urinary metal exposure might be associated with height in preschoolers.

Polystyrene microplastics arrest skeletal growth in puberty through accelerating osteoblast senescence

Polystyrene microplastics (PS-MPs) have attracted worldwide attention to their massive accumulation in terrestrial and aquatic ecosystems. It has been demonstrated that MPs are easily to accumulate in organs and exert toxic effects. However, their exposure risk to the skeleton remains unknown. In this study, we observed PS-MPs accumulation in both the long bones and axial bones, leading to reduced body length, as well as femur and tibia length. PS-MPs treated mice exhibited redundant skeletal growth and impaired trabecular bone micro-architecture, which is due to the suppressed osteogenic ability as the number of osteoblasts decreased significantly in PS-MPs treated mice. In histological analysis, we observed the accumulation of senescent osteoblasts in the bone trabecula of PS-MPs treated mice, as well as the impaired autophagy with decreased autophagosome and reduced autophagy-related proteins in the senescent osteoblasts. Re-establishing autophagy effectively reversed the senescent phenotype in osteoblasts and ameliorated PS-MPs induced skeletal growth arrest. Hence, our study reveals the detrimental role of PS-MPs in skeletal growth in puberty through accelerating osteoblast senescence, which may be alleviated by reactivating the autophagy. This study provides new evidence of the PS-MPs on health threats and the potential therapeutic targets to reverse it.

Associations of nickel exposure and kidney function in U.S. adults, NHANES 2017-2018

BACKGROUNDS

Nickel (Ni) is a ubiquitous heavy metal, but epidemiological studies on the association between Ni and kidney function are limited and controversial.

AIM

We aimed to explore the relationship between urinary Ni concentrations and kidney function in U.S. adults.

METHODS

This was a cross-sectional study based on the 2017-2018 National Health and Nutrition Examination Survey (NHANES) (n = 1588). Multiple linear regression models, logistic regression models, and restricted cubic spline models (RCS) were fitted to explore the associations between urinary Ni and estimated glomerular filtration rate (eGFR), urinary albumin-creatinine ratio (UACR), and the odds of impaired kidney function, which was defined as an eGFR ≤ 60 mL/min per 1.73 m², or UACR ≥ 30.0 mg/g. Bayesian kernel machine regression (BKMR) was used to account for joint-metal effects.

RESULTS

Compared with the lowest quartile, urinary Ni at the third quartile was associated with increased eGFR (β = 2.42, 95 % CI: 0.23-4.19); the highest quartile of urinary Ni was correlated with increased UACR (β = 0.10, 95 % CI: 0.02-0.18), as well as higher odds of impaired kidney function (OR=1.65, 95 % CI:1.08-2.54). Urinary Ni had a nonlinear inverted U-shape relationship with eGFR (P_nonlinear = 0.007), and linear J-shape associations with UACR (P_nonlinear = 0.063) and impaired kidney function (P_nonlinear= 0.215). Metal interaction of urinary Ni with cadmium (Cd) on eGFR was observed.

CONCLUSIONS

Our findings provided evidence that Ni exposure linked with declined kidney function and might interact with Cd exposure. Considering the cross-sectional design of the NHANES study, further prospective studies are necessary.

Embryonic Exposure to Cigarette Smoke Extract Impedes Skeletal Development and Evokes Craniofacial Defects in Zebrafish

Exposure to cigarette smoke represents the largest source of preventable death and disease in the United States. This may be in part due to the nature of the delayed harmful effects as well as the lack of awareness of the scope of harm presented by these products. The presence of “light” versions further clouds the harmful effects of tobacco products. While active smoking in expectant mothers may be reduced by educational and outreach campaigns, exposure to secondhand smoke is often involuntary yet may harm the developing embryo. In this study, we show that the main component of secondhand smoke, sidestream cigarette smoke, from several brands, including harm-reduction versions, triggered unsuccessful hatching at 3 dpf and reduced overall survival at 6 dpf in developing zebrafish. At non-lethal concentrations, craniofacial defects with different severity based on the cigarette smoke extract were noted by 6 dpf. All tested products, including harm-reduction products, significantly impacted cartilage formation and/or bone mineralization in zebrafish embryos, independent of whether the bones/cartilage formed from the mesoderm or neural crest. Together, these results in a model system often used to detect embryonic malformations imply that exposure of a woman to secondhand smoke while pregnant may lead to mineralization issues in the skeleton of her newborn, ultimately adding a direct in utero association to the increased fracture risk observed in children of mothers exposed to cigarette smoke.

Prenatal exposure to nickel and atopic dermatitis at age 3 years: a birth cohort study with cytokine profiles

BACKGROUND

Nickel, the fifth most common element on Earth, is the leading inducer of contact allergies in humans, with potent immunological effects. Nickel-induced contact allergies predominantly affect females. Maternal exposure to nickel has been associated with several developmental abnormalities. However, how a maternal nickel exposure affects the development of atopic diathesis and immune abnormalities in children has never been addressed.

OBJECTIVES

We aimed to determine whether maternal Ni exposure affects the development of atopic dermatitis and immune abnormalities in their children.

METHODS

Using a birth cohort study, we analysed 140 mother-child pairs recruited in 2012-2015 from central Taiwan. Maternal exposure to nickel was estimated using urinary nickel levels measured by inductively coupled plasma mass spectrometry (ICP-MS). The serum levels of 65 analytes and IgE in 3-year-old children were profiled with a multiplex ELISA. The correlation between the maternal urinary nickel concentration and serum analyte levels was assessed using Spearmen's correlation. Multivariant regression analysis was performed to evaluate the association between maternal urinary nickel levels and serum analyte concentrations in their children.

RESULTS

The geometric means of the maternal urinary nickel and the children's serum IgE levels were 2.27 μg/L and 69.71 IU/ml, respectively. The maternal nickel exposure was associated with increased serum levels of IL-1β, IL-2, TNF-α, and leukaemia inhibitory factor (LIF) but with decreased serum levels of matrix metalloproteinase-1 (MMP-1), IL-2R, and eotaxin-1 in the children. In addition, the development of childhood atopic dermatitis at 3 years old was significantly associated with the child's serum levels of IgE and IL-2R, but it was negatively associated with the maternal nickel exposure.

CONCLUSIONS

This is the first study showing the potential immunological effects of maternal nickel exposure in their children at an early developmental stage.

Joint association of polycyclic aromatic hydrocarbons and heavy metal exposure with pulmonary function in children and adolescents aged 6-19 years

Studies have reported associations between polycyclic aromatic hydrocarbon (PAH) or heavy metal (HM) exposure and respiratory diseases. However, evidence of their joint associations with pulmonary function, especially in children and adolescents aged 6-19 years, is lacking. We utilized cross-sectional data from 1,734 children and adolescents aged 6-19 years collected in the National Health and Nutrition Examination Survey 2007-2012 and analysed mixed PAH and mixed HM exposures and their joint association with pulmonary function by applying weighted quantile sum (WQS) regression and Bayesian kernel machine regression (BKMR). Multivariate linear regressions were carried out to determine the relationships between individual urinary PAH metabolites or blood HM levels and pulmonary function indices. We found that mixed PAHs and HMs were negatively related to forced expiratory volume in 1 s (FEV1) in subjects aged 6-12 years (all p values < 0.05). We found synergistic associations of PAH and HM exposure on pulmonary function impairment, mainly in children; lead (Pb) was the most damaging. In the analysis of individual PAH metabolites or HMs, Pb exposure was negatively associated with FEV1 values in all subgroups (all p values < 0.05). Thus, our findings indicate that increased PAH or HM exposure is associated with impairments to pulmonary function and that this association is more pronounced in children.

Genome-wide association and Mendelian randomization study of blood copper levels and 213 deep phenotypes in humans

Metal elements are present in the human body, and their levels in the blood have important impacts on health. In this study, 2488 Chinese individuals were included in a genome-wide association study of 21 serum metal levels, with approximately 179,000 East Asian individuals in a bidirectional two-sample Mendelian randomization (MR) analysis, and 628,000 Europeans in a two-sample MR analysis. We identified two single nucleotide polymorphisms (SNPs) rs35691438 and rs671 that were significantly associated with serum copper levels (SCLs). The bidirectional two-sample MR analysis in the East Asian population showed that gamma-glutamyl transpeptidase levels have a causal effect on SCLs. SCLs have causal effects on six outcomes, namely risks of esophageal varix, glaucoma, sleep apnea syndrome, and systemic lupus erythematosus, white blood cell count, and usage of drugs affecting bone structure and mineralization. The two-sample MR analyses in the European population showed causal effects of erythrocyte copper levels on risks of carpal tunnel syndrome and compression fracture. Our results provide original insights into the causal relationship between blood metal levels and multiple human phenotypes.

A genome-wide association study in a Chinese population identifies SNPs associated with serum copper levels. Mendelian randomization analysis reveals causal effects on multiple human phenotypes in East Asian and European populations.

Prenatal PFAS and psychosocial stress exposures in relation to fetal growth in two pregnancy cohorts: Applying environmental mixture methods to chemical and non-chemical stressors

BACKGROUND

Prenatal exposure to individual per‑ and poly‑fluoroalkyl substances (PFAS) and psychosocial stressors have been associated with reductions in fetal growth. Studies suggest cumulative or joint effects of chemical and non-chemical stressors on fetal growth. However, few studies have examined PFAS and non-chemical stressors together as a mixture, which better reflects real life exposure patterns. We examined joint associations between PFAS, perceived stress, and depression, and fetal growth using two approaches developed for exposure mixtures.

METHODS

Pregnant participants were enrolled in the Chemicals in Our Bodies cohort and Illinois Kids Development Study, which together make up the ECHO.CA.IL cohort. Seven PFAS were previously measured in 2nd trimester maternal serum samples and were natural log transformed for analyses. Perceived stress and depression were assessed using self-reported validated questionnaires, which were converted to t-scores using validated methods. Quantile g-computation and Bayesian kernel machine regression (BKMR) were used to assess joint associations between PFAS, perceived stress and depression t-scores and birthweight z-scores (N = 876).

RESULTS

Individual PFAS, depression and perceived stress t-scores were negatively correlated with birthweight z-scores. Using quantile g-computation, a simultaneous one quartile increase in all PFAS, perceived stress and depression t-scores was associated with a slight reduction in birthweight z-scores (mean change per quartile increase = -0.09, 95% confidence interval = -0.21,0.03). BKMR similarly indicated that cumulative PFAS and stress t-scores were modestly associated with lower birthweight z-scores. Across both methods, the joint association appeared to be distributed across multiple exposures rather than due to a single exposure.

CONCLUSIONS

Our study is one of the first to examine the joint effects of chemical and non-chemical stressors on fetal growth using mixture methods. We found that PFAS, perceived stress, and depression in combination were modestly associated were lower birthweight z-scores, which supports prior studies indicating that chemical and non-chemical stressors are jointly associated with adverse health outcomes.

Serum lipids mediate the relationship of multiple polyaromatic hydrocarbons on non-alcoholic fatty liver disease: A population-based study

Polyaromatic hydrocarbons (PAHs) are recognized as organic pollutants with liver toxicity. However, the relationship between PAHs and nonalcoholic fatty liver disease (NAFLD) is unclear in humans. The aim of this study was to investigate the levels of PAHs in the US population and their association with the risk of NAFLD. We investigated urinary levels of nine PAHs in 2436 participants from the National Health and Nutrition Examination Survey (NHANES) between 2005 and 2012, including 1-Hydroxynapthalene (1-OHN), 2-Hydroxynapthalene (2-OHN), 3-Hydroxyfluorene (3-OHF), 2-Hydroxyfluorene (2-OHF), 3-Hydroxyphenanthrene (3-OHPhe), 1-Hydroxyphenanthrene (1-OHPhe), 2-Hydroxyphenanthrene (2-OHPhe), 1-Hydroxypyrene (1-OHPyr), 9-Hydroxyfluorene (9-OHF). Logistic regression models were used to estimate the relationship between single PAH and NAFLD. Assessment of the overall effect of multiple PAH mixtures on NAFLD using Bayesian kernel machine regression (BKMR) model. There were 698 participants diagnosed with NAFLD in the study group. After adjusting for related covariates such as sex, age, race, education, marital status, poverty income ratio (PIR), body mass index (BMI), total energy intake, smoking, hypertension, and diabetes, logistic regression analysis showed that compared to the low tertile (T1), the odds ratio of the high tertile (T3) was 1.70 (95%CI: 1.26-2.29, p = 0.001) for total PAHs, 1.50 (95%CI: 1.11-2.03, p = 0.008) for 2-OHN, 1.75 (95%CI: 1.31-2.34, p < 0.001) for 2-OHPhe, 1.59 (95%CI: 1.18-2.14, p = 0.002) for 9-OHF and 0.63 (95%CI: 0.46-0.87, p = 0.004) for 3-OHF. In the BKMR model, we found that the overall effect of the nine PAH mixtures was positively associated with the risk of NAFLD. Mediation analysis showed that HDL and TG mediated the association between PAHs and NAFLD. Our study suggests that multiple PAHs mixtures exposure may induce NAFLD by mediating serum lipids in human metabolism.

Bioaccumulation of Toxic Metals in Children Exposed to Urban Pollution and to Cement Plant Emissions

Cement plants located in urban areas can increase health risk. Although children are particularly vulnerable, biomonitoring studies are lacking. Toenail concentration of 24 metals was measured in 366 children (6-10 years), who live and attend school in a city hosting a cement plant. Living addresses and schools were geocoded and attributed to exposed or control areas, according to modeled ground concentrations of PM₁₀ generated by the cement plant. Air levels of PM₁₀ and NO₂ were monitored. PM₁₀ levels were higher in the exposed, than in the control area. The highest mean PM₁₀ concentration was recorded close to the cement plant. Conversely, the highest NO₂ concentration was in the control area, where vehicular traffic and home heating were the prevalent sources of pollutants. Exposed children had higher concentrations of Nickel (Ni), Cadmium (Cd), Mercury (Hg), and Arsenic (As) than controls. These concentrations correlated each other, indicating a common source. Toenail Barium (Ba) concentration was higher in the control- than in the exposed area. The location of the attended school was a predictor of Cd, Hg, Ni, Ba concentrations, after adjusting for confounders. In conclusion, children living and attending school in an urban area exposed to cement plant emissions show a chronic bioaccumulation of toxic metals, and a significant exposure to PM₁₀ pollution. Cement plants located in populous urban areas seem therefore harmful, and primary prevention policies to protect children health are needed.