Cadmium exposure and risk of breast cancer: A meta-analysis

Cadmium exposure and health outcomes:An umbrella review of meta-analyses

OBJECTIVE

This umbrella review synthesizes evidence from meta-analyses to assess the health outcomes associated with cadmium (Cd) exposure.

METHODS

Literature search was conducted in four Databases: PubMed, Embase, APA PsycNe, and the Cochrane Databases. Evaluating evidence strength via Assess Systematic Reviews 2 (AMSTAR 2), umbrella review methodology and Grading of Recommendations, Assessment, Development, and Evaluation (GRADE).

RESULTS

Our review encompassed 79 non-overlapping studies, investigating 48 unique health outcomes through 113 independent effect sizes. Using the AMSTAR 2 tool, we found that 2 (3 %) meta-analyses were rated as high quality, 6 (8 %) as moderate quality, 38 as low quality, and 33 as very low quality. Applying the GRADE criteria, we observed that 1 (1 %) effect size was rated A (male fertility), 8 (7 %) were rated B (breast cancer, prostate cancer, hypertension, stroke, urolithiasis), 30 were rated C, and 74 were rated D. According to the umbrella review methodology, 5 (4 %) outcomes provided highly suggestive evidence, 13 (12 %) provided suggestive evidence, 51 provided weak evidence (class IV), and 44 had insufficient evidence for statistically significant results (class V). Meta-analyses on circulatory diseases, pregnancy outcomes, perinatal outcomes, skeletal and connective tissue diseases, neurological disorders, urinary system diseases, and male fertility had >80 % statistically significant results, while endocrine system diseases and mental and behavioral disorders had <33 %.

CONCLUSION

Cd exposure is significantly linked to various health outcomes, with implications for clinical practice and public health recommendations.

Non-occupational exposure to cadmium and breast cancer: A comprehensive and critical review

Breast cancer (BC) is a multifactorial disease with unresolved etiology. Environmental pollutants, primarily trace metals, play a pivotal role in the pathophysiological cascade of malignant tumors, including BC. In this up-to-date review, we comprehensively and critically examined the relationship between cadmium (Cd) and BC. For this purpose, peer-reviewed studies from relevant databases (PubMed, SCOPUS, and Cochrane Library) over the last 40 years were retrieved and analyzed. We found that in vitro and in vivo studies strongly support the view that Cd has harmful effects on breast health. According to the human studies, we found that Cd could be responsible for the development and progression of malignant breast tumors due to markedly higher levels in clinical matrices of cases (whole blood, urine, breast tissue, keratin materials) than in clinical matrices of controls. Cadmium does not appear to affect BC density. In contrast, Cd has been found to have a detrimental effect on sex hormones, disrupting the balance of estrogen and androgen. We found that studies looking at dietary Cd intake and BC risk generally (without measuring urine or blood Cd) do not support the association between dietary Cd intake and BC risk. In notable contrast, studies looking at dietary Cd intake and BC risk by measuring Cd in urine or blood generally support this association. The effect of airborne Cd on BC risk was weak, but in favor of specific histological forms, primarily ER-/PR- invasive tubular breast carcinomas. Regardless of the intake route of Cd into the body, it can be concluded that Cd has a harmful effect on breast health. However, well-designed longitudinal, mechanistic, meta-analytic, and other studies are urgently needed to confirm the exact role of environmental Cd in breast carcinogenesis.

The impact of cadmium exposure on breast cancer risk: Exploring dose-response relationships and mediating effects

Cadmium (Cd), an endocrine disruptor, has been linked to hormone-related cancers, including breast cancer (BC). However, previous studies investigating the association between Cd exposure and BC risk have yielded inconsistent results, and the effects of Cd on BC subtypes remain poorly understood. We employed logistic regression and restricted cubic splines (RCS) to examine the relationship between Cd exposure and BC. A meta-analysis was subsequently conducted to validate the association between Cd exposure and BC. Lastly, mediation analysis was applied to explore the underlying mechanisms linking Cd exposure to BC. Data from 5954 participants in the National Health and Nutrition Examination Survey (1999-2020) were analyzed. Elevated Cd levels in the fourth quartile were significantly associated with an increased BC risk (odds ratio (OR) = 3.74, 95 % confidence interval (CI): 1.45 - 9.62, Ptrend = 0.019), compared to the first quartile group. A linear dose-response relationship was seen between urinary Cd levels and BC risk (Pnon-linear = 0.532), with BC risk increasing 317 % (OR = 3.17, 95 % CI: 1.93 - 5.20, Ptrend < 0.001) for 1 μg/g creatinine increases in urinary Cd levels. The meta-analysis, which included 20 eligible studies, further observed a possible link between Cd exposure and BC risk (relative risk (RR) = 1.17, 95 % CI: 1.06 - 1.29, I2 = 83 %), particularly in estrogen receptor-positive (ER+) subtypes (RR = 1.08, 95 % CI: 1.01 - 1.16, I2 = 70 %). Mediation analysis further revealed that glycated hemoglobin (HbA1c) mediated 9.09 % of the Cd-BC risk association. In conclusion, the study results suggest a potential association between Cd levels and an increased BC risk, particularly in ER+ subtypes. Mechanistically, HbA1c was identified as a mediator in this association. These findings underscore the complex interplay between Cd exposure and metabolic dysregulation in the development of BC, highlighting the potential role of HbA1c in modulating BC risk among individuals exposed to Cd.

Association between urinary cadmium levels and increased gallstone disease in US adults

Heavy metal exposure is acknowledged as a risk factor for poor health. However, the effect of heavy metal exposure on the prevalence of gallstones is still unknown. Therefore, we investigated the relationship between heavy metal concentrations and the prevalence of gallstones among US adults. Multivariate logistic regression indicated that only urinary cadmium was an independent risk factor for gallstones. Compared to the low urine cadmium group, the high cadmium group had a elevated increased risk of gallstone formation. Furthermore, the weighted quantile sum model showed that heavy metal mixtures were not associated with gallstone prevalence. Additionally, urinary cadmium levels were associated with an increased risk of gallstone formation in young individuals, males, Mexican Americans, Non-Hispanic Whites, as well as smokers and drinkers. Moreover, nine machine learning methods were utilized to construct an interpretable predictive model for gallstone prevalence. Among these models, the XGBoost model exhibited the highest performance and was selected for further investigation. Subsequently, shapely additive explanations was used for model interpretation. The results also indicated that urinary cadmium concentrations were the most important variable for gallstones. Thus, our results indicated that long-term chronic cadmium exposure is a risk factor for gallstone prevalence.

Study of toxic and essential elemental imbalances at more advance stage of breast carcinoma patients

Delayed diagnosis and limited access to healthcare resources are leading to advanced stage breast carcinoma posing a formidable health challenge to modern medical science. Avoiding the occurrence of breast carcinoma is only possible by ascertaining the risk factors contributing to the progression of this fatal malignancy. Among other factors, exposure to trace elements plays a decisive role in progression of breast carcinoma development. The purpose of this investigation was to evaluate the harmful traces and vital components (Pb, Ca, Mn, Cd, Na, Cr, Cu, Mg, Sr, K, Fe, Zn, Co, Li, Se, Ag, Hg, As, Al and Ni) contents in the blood (n = 161), scalp hair (n = 149) and nails (n = 135) of stage IV breast carcinoma patients and female controls by atomic absorption spectrometry. The results revealed that mean Cr, Cu, Pb and Cd levels were elevated significantly (p < 0.05) in the nails and blood, while Ni, Co, Cr, Pb and Cd levels (p < 0.05) were elevated in the scalp hair of stage IV breast carcinoma patients than the female controls. Based on pathological breast cancer types, Pb and Cd were elevated in invasive ductal carcinoma, while Cu and Co were higher in invasive lobular carcinoma patients. Multivariate analysis was applied for the source of identification and apportionment of toxic trace elements in both donor groups. Most of the factors showed significant differences between the malignant and control groups' dietary, housing, and tobacco use/nonuse behaviors. The correlation analysis revealed significantly different association patterns for toxic trace elements in patients and controls and has an influential effect on cancer risk. Overall, the current study indicates a potential role of toxic trace elements in the development of breast carcinoma and these findings could be significant in the predicting diagnosis/prognosis of breast malignancy.

New insights into heavy metal cadmium-induced liver injury: Prominent role of programmed cell death mechanisms

The heavy metal cadmium (Cd) is an important environmental factor that induces liver injury and contributes to liver disease. Ongoing research aims to refine our understanding of the pathogenesis of cadmium-induced liver injury and the interactions between the various mechanisms. Oxidative stress, described as a pathophysiological basis of liver injury, is a process in which reactive oxygen species are generated, causing the destruction of hepatocyte structure and cellular dysfunction. Additionally, the activation of oxidative stress downstream signals regulates several forms of cell death, such as apoptosis, necroptosis, autophagy, ferroptosis, and pyroptosis, which significantly contributes to liver damage. Furthermore, the interplay between different types of programmed cell death highlights the complexity of liver injury mechanisms. This review summarizes the role of programmed cell death in Cd-induced liver injury and explores the relationships between different programmed cell death pathways, which is expected to provide new insights into the mechanisms of Cd-induced liver injury.

Associations between dietary exposure to profiles of metalloestrogens and estrogen-receptor positive breast cancer risk in the French E3N cohort

Metalloestrogens are ionic metals and metalloids that can activate estrogen receptor, and are suspected to play a role in breast cancer occurrence. This study explored the relationship between dietary exposure profiles to metalloestrogens and estrogen-receptor positive breast cancer (ERP-BC) risk among women in the French E3N cohort.A prospective study was conducted involving 66 722 women who completed a food frequency questionnaire in 1993. Food consumption data were combined with food contamination data obtained from the Second French Total Diet Study, to estimate the dietary intake of 14 metalloestrogens. A principal component analysis was performed to identify the main dietary exposure profiles to metalloestrogens. The retained principal components were included in Cox regression models, used to estimate Hazard Ratios (HR) and their 95% confidence intervals (95% CI) for the associations between the adherence to the identified profiles and ERP-BC risk identified until 2014, adjusted for confounding factors selected using a directed acyclic graph.After an average follow-up of 17.7 years, 3 739 incident cases of ERP-BC were identified. Four principal components were retained, explaining 80.5% of the variance. A statistically significant positive association between the third principal component, mainly characterized by dietary intake of inorganic arsenic and vanadium, and ERP-BC risk was estimated (HR: 1.04, 95% CI: 1.00-1.07, p-value: 0.03). No statistically significant association was found when evaluating the effect of each metalloestrogen individually.The results suggests that even relatively low levels of exposure to inorganic arsenic and vanadium, when combined, could increase the risk of ERP-BC.

Water sources and educational attainment in Colombian adults: evidence from the national nutritional survey

BACKGROUND

Academic achievement is essential to people's individual and social development by enhancing opportunities for significant personal achievement throughout life. Exposure to toxic agents due to poor water quality may negatively influence neurodevelopment in children and adolescents into adulthood.

OBJECTIVE

We aimed to estimate the association between the type of water for drinking purposes and academic achievements in Colombian adults.

METHODS

We designed a cross-sectional study based on the National Survey of Nutritional Situation in Colombia (Encuesta Nacional de la Situación Nutricional en Colombia -ENSIN-) 2015. Academic achievement in our study was classified as less than complete primary school (0-4 years), between complete primary and incomplete secondary (5-10 years), between complete secondary and incomplete higher education (11-15 years), and complete higher education and more (16-24 years). We utilized adjusted ordinal logistic regression to estimate betas (β's) and Odds Ratio [OR] with 95% confidence intervals [95%CI].

RESULTS

After adjusting for potential confounders, we report an inverse association between consumption of untreated water and academic attainments, where individuals who drink surface water [β: -0.625; 95%CI: -0.629, -0.620], or groundwater [β: -0.368; 95%CI: -0.372, -0.364] were less likely to achieve higher educational levels compared to those consuming treated water. This pattern was similar across the country when disaggregated by region.

CONCLUSION

We found that people with lower levels of education are more likely to consume untreated water in Colombia. Our results encourage improving access to treated water to the population with an emphasis on rural communities and the Atlantic region.

The gut microbiota: A key player in cadmium toxicity - implications for disease, interventions, and combined toxicant exposures

Cadmium (Cd) is a highly toxic heavy metal contaminant found in soil and water due to human activities such as mining and industrial discharge. Cd can accumulate in the body, leading to various health risks such as organ injuries, osteoporosis, renal dysfunction, Type 2 diabetes (T2DM), reproductive diseases, hypertension, cardiovascular diseases, and cancers. The gut is particularly sensitive to Cd toxicity as it acts as the primary barrier against orally ingested Cd. Even at low concentrations, Cd can cause oxidative stress, inflammation, and intestinal bleeding. Cd also disrupts the gut microbiota, affecting its structure, taxonomic composition, and metabolic functions. Cd exposure alters the structure of the gut microbial community, reducing diversity and upregulating certain phyla and genera. This disturbance can lead to physiological and metabolic imbalances, including disruptions in energy homeostasis, amino acid, lipid, nucleotide, and short-chain fatty acid (SCFAs) metabolism. The effects of Cd on the gut microbiota depend on the duration of exposure, the dose of Cd, and can vary based on sex and age. Cd-induced gut dysbiosis has been linked to various diseases, including diabetes, adiposity, atherosclerosis, liver damage, infections, cancer, and neurodegenerative diseases. Interventions targeting the gut microbiota, such as probiotics, specific diets, melatonin, selenium, vitamin D3, and certain compounds, have shown potential in reducing the health risks associated with Cd exposure. However, combined exposure to Cd and other toxicants, such as microplastics (MPs), heavy metals, and antibiotics, can amplify the toxicity and dysbiosis in the gut microbiota.

Association of cadmium and lead exposure with mortality in cancer survivors: A prospective cohort study

Lead and cadmium are well-documented for their carcinogenic properties and their potential to induce cellular malignancy. Nevertheless, there is a paucity of research examining the correlation between blood cadmium and lead levels and the prognostic outcomes of cancer survivors. This study aims to investigate the relationship between blood concentrations of these heavy metals and both overall and site-specific cancer mortality risks among cancer survivors. We identified mortality rates and specific causes of death among cancer survivors by using National Health and Nutrition Examination Survey mortality data. To assess mortality outcomes, we employed multivariable Cox regression analyses, generating hazard ratios (HR) and 95 % confidence intervals (CI). We used Kaplan-Meier survival curves and restricted cubic spline models to further examine these associations. We conducted subgroup analyses to observe the prognostic risks associated with high concentrations of these metals across various tumor categories. This study revealed a significant positive correlation between whole blood cadmium concentration and all-cause mortality in cancer survivors, yielding a hazard ratio (HR) of 1.73 (95 % CI: 1.39-2.16). Elevated blood cadmium levels were significantly linked to increased cancer-specific mortality, with an HR of 2.72 (95 % CI: 1.73-4.26). A notable positive association was found between blood lead and cancer-specific mortality (HR = 1.83, 95 % CI: 1.13-2.97). Subgroup analyses indicated that elevated blood cadmium levels were significantly correlated with increased mortality risk in patients with skin and soft tissue cancers, whereas high blood lead levels were significantly associated with greater mortality risk in patients with reproductive system cancers. Additionally, elevated levels of both blood lead and cadmium were significantly related to a marked increase in mortality risk among patients with lung and mediastinal malignancies. In conclusion, our study indicates a positive correlation between increased whole blood cadmium concentrations and both all-cause and cancer-specific mortality among cancer survivors.

Plumbagin Inhibits Cadmium-Induced Interleukin-6/STAT3 Signaling in the Triple-Negative Breast Cancer Cell Line

INTRODUCTION

Plumbagin has been found to reduce proinflammatory cytokine expression in activated macrophages and carrageenan-induced paw edema. Cadmium triggers the release of interleukin-6 (IL-6), a key mediator of inflammation and carcinogenesis in many cell types. The effects of plumbagin on cadmium-induced inflammation in triple-negative breast cancer cells are unknown.

METHOD

We investigated the effects of plumbagin on cadmium-induced IL-6 expression and signal transducer and activator of transcription 3 (STAT3) activation in MDA-MB-231, a triple-negative breast cancer cell line, using real-time PCR, ELISA, and Western blotting.

RESULT

Non-cytotoxic concentrations of cadmium chloride at 1 and 10 μM upregulated the IL-6 mRNA expression after 3 h of exposure and increased the IL-6 release after 24 h. Plumbagin at 4 μM or more was toxic to cells after 24 h. Plumbagin at 1 μM co-treated with cadmium reduced the expression and secretion of IL-6. At 24-h post-exposure, plumbagin decreased the levels of phosphorylated STAT3 induced by cadmium.

CONCLUSION

Plumbagin inhibits cadmium-induced IL-6/STAT3 signaling in a triple-negative breast cancer cell and further in vivo studies are required to elucidate the potential use of plumbagin on cancer progression.

Mechanisms of Heavy Metal Cadmium (Cd)-Induced Malignancy

The environmental pollution of cadmium is worsening, and its significant carcinogenic effects on humans have been confirmed. Cadmium can induce cancer through various signaling pathways, including the ERK/JNK/p38MAPK, PI3K/AKT/mTOR, NF-κB, and Wnt. It can also cause cancer by directly damaging DNA and inhibiting DNA repair systems, or through epigenetic mechanisms such as abnormal DNA methylation, LncRNA, and microRNA. However, the detailed mechanisms of Cd-induced cancer are still not fully understood and require further investigation.

Modification Effects of Homologous Recombination Repair Gene Polymorphisms on the Associations Between Urinary Metals and Breast Cancer Risk

Metals are recognized as important factors related to breast cancer (BC) risk. Homologous recombination repair (HRR) genes might modify the toxicity of metals by influencing the distribution and metabolism of metal compounds. This study aims to investigate the modification effects of single nucleotide polymorphisms (SNPs) in HRR genes on the associations between urinary metals and BC risk. A total of 685 BC cases and 741 controls were recruited from October 2009 to December 2012. Twenty-one metals were analyzed in urine samples using inductively coupled plasma mass spectrometry (ICP-MS), and three SNPs (LIG3 rs1052536, RFC1 rs6829064, and RAD54L rs17102086) were genotyped. We identified significant interactions between four metals and two SNPs on the risk of BC. For LIG3 rs1052536 C/T variant, participants with CT/TT genotypes exposed to higher cobalt (Co) levels had higher BC risk compared to those with CC genotype (Pinteraction = 0.048). For RAD54L rs17102086 T/C variant, participants with TT genotype who were exposed to higher levels of zinc (Zn), Co, arsenic (As), and strontium (Sr) had more pronounced BC risk than the CC/TC genotypes (all Pinteraction < 0.05). This study showed compelling evidence for the interaction between genetic variants within the HRR system and urinary metals on BC risk. Our findings highlight the need to consider genetic makeup when evaluating the carcinogenic or protective potential of metals.

Detrimental effects of cadmium on male infertility: A review

Infertility has become a serious health and socio-economic-psychological problem globally. The harmful role of trace metals in male infertility is recognized but still not sufficiently explained. Herein, a comprehensive review was conducted to elucidate the detrimental role of cadmium (Cd) on male infertility, particularly on infertility with unknown (idiopathic) causes. Peer-reviewed studies from 2000 to 2024 dealing with seminal plasma and blood Cd levels of fertile and infertile men were retrieved were interrogated with regard to strict inclusion/exclusion criteria, and then were thoroughly reviewed and analyzed. Another aim of this review was to indicate the potential effects of Cd on changes in seminogram findings. A median range of seminal plasma Cd levels from 0.2 to 1.5 µg/L can be considered safe for men's fertility. This review strongly implies that Cd levels were notably higher in seminal plasma of infertile cases than controls. The review's data also indicate that exposure to tobacco smoke is a major source of elevated seminal and blood Cd levels in infertile men. Newer research points to the importance of Cd in lower levels from the environment on changes in seminogram findings, primarily count, motility of spermatozoa, and their morphology. Overall, this review implies that seminal plasma Cd levels could be a good indicator of semen quality. However, new, in-depth studies are needed to confirm or reject the causal relationship of Cd with male infertility.

Relationships between blood cadmium concentration and risk of nine cancers: evidence from the NHANES 1999-2018 and Mendelian randomization analyses

BACKGROUND

Previous observational studies examining the relationship between cadmium exposure and various cancers have yielded conflicting results. This study aims to comprehensively clarify the relationship between blood cadmium concentration (BCC) and nine specific cancers.

METHODS

A retrospective analysis of National Health and Nutrition Examination Survey (NHANES) 1999-2018 identified 36,991 participants. Multivariable logistic regression was used to assess the association between BCC and the risk of nine specific cancers. Additionally, Mendelian randomization (MR) analyses were conducted to investigate potential causal relationships.

RESULTS

Multivariable logistic regression analysis of the NHANES data indicated a positive association between BCC and the risk of bladder and lung cancers (P < 0.05) and a negative association with the risk of kidney and prostate cancers (P < 0.05). The MR analyses demonstrated a causal relationship between BCC and kidney cancer (P < 0.05). Additionally, it uncovered causal associations with breast, cervical, and colon cancers (P < 0.05).

CONCLUSION

Elevated BCC was associated with an increased risk of bladder and lung cancers while demonstrating an inverse relationship with kidney and prostate cancers. MR analysis revealed that cadmium exposure may act as a protective factor against breast, cervical, colon, and kidney cancers, that must be confirmed with new studies.

Serum and urinary cadmium and zinc profiles in breast cancer patients and their association with estrogen and HER-2 receptors, and redox status

BACKGROUND

Cadmium, a metal implicated in environmental toxicity, is linked to tumor growth and cancer. On the other hand, zinc plays an essential function in oxidative stress and can counteract cadmium toxicity and carcinogenicity. This research aims to evaluate the urine and serum values of cadmium and zinc in breast cancer (BC) patients and their association with estrogen (ER) and HER-2 receptors, and redox status.

METHODS

Forty BC patients and thirty healthy subjects participated in this study. Cadmium and zinc levels were measured in serum and urine samples by atomic absorption spectrophotometer. Redox status markers were determined by colorimetric methods.

RESULTS

The amount of cadmium in the BC patients was substantially greater than in the healthy subjects. Zinc levels were significantly lower in patients with BC compared to controls. Breast cancer patients with ER-positive tumors had significantly higher urinary cadmium concentrations (U-Cd) compared to patients with ER-negative tumors. There was no significant difference between the parameters of redox status and the value of cadmium and zinc between patients with BC in the HER-2 subgroup. Malondialdehyde levels in the serum were substantially greater in BC patients than in healthy subjects. Total thiol level and catalase and superoxide dismutase activity in serum were considerably lower in BC patients than in healthy subjects.

CONCLUSIONS

The etiology of BC may be due to a disturbance in redox status and levels of elements. Increasing U-Cd and lowering zinc levels in the serum could be the risk factors for BC.

Experimental study on the adsorption and interaction of P and Cd in polluted sediment from Dongting Lake

A series of experiments was performed to elucidate the effects of the adsorption and interaction of different concentrations of P and Cd on the availability of P and Cd. First, the sediments before and after maturation were subjected to X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and Fourier transform infrared (FTIR) spectroscopy. The results revealed that the composition and main components of the sediment were unchanged by maturation. The adsorption results fitted by the Freundlich equation revealed that the maximum concentration of Cd in the sediment changed from 979.12 mg/L to 980.92 mg/L and 1215 mg/L after the addition of 1 mg/L and 2 mg/L P, respectively. The maximum concentration of P in the sediments increased from 397.57 mg/L to 403.19 mg/L and 422.89 mg/L after the addition of Cd concentrations of 5 mg/L and 50 mg/L, respectively. A batch experiment was subsequently performed with multiple groups of P and Cd at the same concentration. The results revealed that the content of available Cd was the highest when the content of P was 180 mg/kg and that the content of available P was the highest when the content of Cd was 1 mg/kg. However, when the concentrations of P and Cd exceeded a certain level, Cd3(PO4)2 precipitated. Finally, the experimental results were reverified by XPS, and the results revealed that the contents of P and Cd in the sediments increased through adsorption and precipitation between P and Cd.

Cadmium in biological samples and site-specific cancer risk and mortality: A systematic review of original articles and meta-analyses

BACKGROUND

Cadmium (Cd) is classified as a class 1 carcinogen by the IARC, yet uncertainty persists regarding the total burden of cancer (incidence and mortality) caused by exposure to it, due to the still limited evidence with regard to its aetiological role in cancer at several body sites.

OBJECTIVES AND METHODS

We searched PubMed and EMBASE for meta-analyses and original articles published by February 1st, 2024, that focused on the link between cadmium measured in biological samples (blood, urine, finger-/toe-nails, and hair) and site-specific cancer risk and mortality.

RESULTS

We included 9 meta-analyses and 57 original articles (of these, the design was retrospective in 38 and prospective in 19, and Cd levels were quantified in blood, n=33, urine, n=19, both blood and urine, n=2, or finger-/toenail, n=3). Current data consistently suggest a causal role of exposure to cadmium in pancreas, lung, and bladder carcinogenesis. Total cancer risk and mortality are also positively correlated with Cd levels in biological samples. The evidence is weak or inconclusive for the remaining cancer sites (including breast and prostate), mostly due to the limited number of studies available to date and/or methodological limitations.

DISCUSSION

Exposure to cadmium poses a risk for increased cancer incidence and mortality. Cadmium-related cancer burden might indeed be currently underestimated, as the amount of available evidence for most cancer sites and types is currently limited, and more research in the field is warranted. Continuing efforts to contain Cd pollution and mitigate associated health risk are also needed.

Mammary gland, skin and soft tissue tumors in pet cats: findings of the feline tumors collected from 2002 to 2022

Introduction

Cancer is a leading cause of death in cats, and the rate of such disease has been increasing recently. Nonetheless, feline oncology represents an important area of study not only for the health and wellbeing of cats but also for human health since various types of cancer in cats share similarities to those found in humans. Therefore, epidemiological studies on feline oncology may suggest environmental and genetic factors contributing to cancer in cats, which can eventually be translated to improve human cancer care.

Method

To provide an initial understanding of the epidemiology of feline neoplasms, a descriptive study was undertaken using a dataset documenting cases of feline cancer gathered from the Liguria region (northwest Italy) spanning from 2002 to 2022. The database includes tumor location, morphological codes of the International Classification of Diseases for Oncology, 3rd Edition (ICD-O-3), feline's breed, sex, neuter status, date of birth, date of diagnosis, national territorial unit code of the town of the owner's residence, and an alphanumeric string uniquely identifying the owner's surname.

Results and discussion

The dataset involves a population of 4,399 cats, including 3,195 females (1,425 neutered) and 1,204 males (750 neutered). Our results indicate that mammary gland tumors are the most represented tumors in the female population, while soft tissue and skin cancers appear to have a higher abundance in the male population during the periods investigated (2002-2022). Moreover, Poisson regression analysis showed that not neutered female cats have a significantly increased risk of developing mammary gland tumors compared to the neutered female population [proportional morbidity ratio (PMR) neutered vs. not neutered = 0.58, 95% CI: 0.47-0.72]; meanwhile, for both sexes, for soft tissue and skin tumors, being neutered appears to be a risk factor (PMR neutered vs. not neutered = 2.26, 95% CI: 1.86-2.73; PMR neutered vs. not neutered = 1.16, 95% CI: 0.89-1.51). Finally, the evaluation of the Ligurian municipalities pollution, based on wild boars data (i.e., biomonitors), which coexisted with cats, was correlated to cancer development for all the tumors investigated (in polluted areas, estimated PMRs ranged from 42.61 to 80.13, 95% CI: 29.94-105.11). Overall, the data presented here suggest the use of the feline population as a possible animal model for human health, i.e., sentinel.

Multi-pollutant exposure profiles associated with breast cancer risk: A Bayesian profile regression analysis in the French E3N cohort

BACKGROUND

Human exposure to air pollution involves complex mixtures of multiple correlated air pollutants. To date, very few studies have assessed the combined effects of exposure to multiple air pollutants on breast cancer (BC) risk.

OBJECTIVES

We aimed to assess the association between combined exposures to multiple air pollutants and breast cancer risk.

METHODS

The study was based on a case-control study nested within the French E3N cohort (5222 incident BC cases/5222 matched controls). For each woman, the average of the mean annual exposure to eight pollutants (benzo(a)oyrene, cadmium, dioxins, polychlorinated biphenyls (PCB153), nitrogen dioxide (NO2), ozone, particulate matter and fine particles (PMs)) was estimated from cohort inclusion in 1990 to the index date. We used the Bayesian Profile Regression (BPR) model, which groups individuals according to their exposure and risk levels, and assigns a risk to each cluster identified. The model was adjusted on a combination of matching variables and confounders to better consider the design of the nested case-control study. Odds ratios (OR) and their 95 % credible intervals (CrI) were estimated.

RESULTS

Among the 21 clusters identified, the cluster characterised by low exposures to all pollutants, except ozone, was taken as reference. A consistent increase in BC risk compared to the reference cluster was observed for 3 clusters: cluster 9 (OR=1.61; CrI=1.13,2.26), cluster 16 (OR=1.59; CrI=1.10,2.30) and cluster 15 (OR=1.38; CrI=1.00,1.88) characterised by high levels of NO2, PMs and PCB153. The other clusters showed no consistent association with BC.

DISCUSSION

This is the first study assessing the effect of exposure to a mixture of eight air pollutants on BC risk, using the BPR approach. Overall, results showed evidence of a positive joint effect of exposure to high levels to most pollutants, particularly high for NO2, PMs and PCB153, on the risk of BC.

Metals on the Menu-Analyzing the Presence, Importance, and Consequences

Metals are integral components of the natural environment, and their presence in the food supply is inevitable and complex. While essential metals such as sodium, potassium, magnesium, calcium, iron, zinc, and copper are crucial for various physiological functions and must be consumed through the diet, others, like lead, mercury, and cadmium, are toxic even at low concentrations and pose serious health risks. This study comprehensively analyzes the presence, importance, and consequences of metals in the food chain. We explore the pathways through which metals enter the food supply, their distribution across different food types, and the associated health implications. By examining current regulatory standards for maximum allowable levels of various metals, we highlight the importance of ensuring food safety and protecting public health. Furthermore, this research underscores the need for continuous monitoring and management of metal content in food, especially as global agricultural and food production practices evolve. Our findings aim to inform dietary recommendations, food fortification strategies, and regulatory policies, ultimately contributing to safer and more nutritionally balanced diets.

Multiple xenoestrogen air pollutants and breast cancer risk: Statistical approaches to investigate combined exposures effect

Studies suggested that exposure to air pollutants, with endocrine disrupting (ED) properties, have a key role in breast cancer (BC) development. Although the population is exposed simultaneously to a mixture of multiple pollutants and ED pollutants may act via common biological mechanisms leading to synergic effects, epidemiological studies generally evaluate the effect of each pollutant separately. We aimed to assess the complex effect of exposure to a mixture of four xenoestrogen air pollutants (benzo-[a]-pyrene (BaP), cadmium, dioxin (2,3,7,8-Tétrachlorodibenzo-p-dioxin TCDD)), and polychlorinated biphenyl 153 (PCB153)) on the risk of BC, using three recent statistical methods, namely weighted quantile sum (WQS), quantile g-computation (QGC) and Bayesian kernel machine regression (BKMR). The study was conducted on 5222 cases and 5222 matched controls nested within the French prospective E3N cohort initiated in 1990. Annual average exposure estimates to the pollutants were assessed using a chemistry transport model, at the participants' residence address between 1990 and 2011. We found a positive association between the WQS index of the joint effect and the risk of overall BC (adjusted odds ratio (OR) = 1.10, 95% confidence intervals (CI): 1.03-1.19). Similar results were found for QGC (OR = 1.11, 95%CI: 1.03-1.19). Despite the association did not reach statistical significance in the BKMR model, we observed an increasing trend between the joint effect of the four pollutants and the risk of BC, when fixing other chemicals at their median concentrations. BaP, cadmium and PCB153 also showed positive trends in the multi-pollutant mixture, while dioxin showed a modest inverse trend. Despite we found a clear evidence of a positive association between the joint exposure to pollutants and BC risk only from WQS and QGC regression, we observed a similar suggestive trend using BKMR. This study makes a major contribution to the understanding of the joint effects of air pollution.

The dynamic face of cadmium-induced Carcinogenesis: Mechanisms, emerging trends, and future directions

Cadmium (Cd) is a malleable element with odorless, tasteless characteristics that occurs naturally in the earth's crust, underground water, and soil. The most common reasons for the anthropological release of Cd to the environment include industrial metal mining, smelting, battery manufacturing, fertilizer production, and cigarette smoking. Cadmium-containing products may enter the environment as soluble salts, vapor, or particle forms that accumulate in food, soil, water, and air. Several epidemiological studies have highlighted the association between Cd exposure and adverse health outcomes, especially renal toxicity, and the impact of Cd exposure on the development and progression of carcinogenesis. Also highlighted is the evidence for early-life and even maternal exposure to Cd leading to devastating health outcomes, especially the risk of cancer development in adulthood. Several mechanisms have been proposed to explain how Cd mediates carcinogenic transformation, including epigenetic alteration, DNA methylation, histone posttranslational modification, dysregulated non-coding RNA, DNA damage in the form of DNA mutation, strand breaks, and chromosomal abnormalities with double-strand break representing the most common DNA form of damage. Cd induces an indirect genotoxic effect by reducing p53's DNA binding activity, eventually impairing DNA repair, inducing downregulation in the expression of DNA repair genes, which might result in carcinogenic transformation, enhancing lipid peroxidation or evasion of antioxidant interference such as catalase, superoxide dismutase, and glutathione. Moreover, Cd mediates apoptosis evasion, autophagy activation, and survival mechanisms. In this review, we decipher the role of Cd mediating carcinogenic transformation in different models and highlight the interaction between various mechanisms. We also discuss diagnostic markers, therapeutic interventions, and future perspectives.

Involvement of ERK and Oxidative Stress in Airway Exposure to Cadmium Chloride Aggravates Airway Inflammation in Ovalbumin-Induced Asthmatic Mice

Inhalation represents a significant route of cadmium (Cd) exposure, which is associated with an elevated risk of lung diseases. This research study aims to evaluate the impact of repeated low-dose cadmium inhalation on exacerbating airway inflammation induced by ovalbumin (OVA) in asthma-afflicted mice. Mice were grouped into four categories: control (Ctrl), OVA, cadmium chloride (CdCl2), and OVA + cadmium chloride (OVA + CdCl2). Mice in the OVA group displayed increased airway mucus secretion and peribronchial and airway inflammation characterized by eosinophil cell infiltration, along with elevated levels of Th2 cytokines (IL-4, IL-5, IL-13) in bronchoalveolar lavage fluids (BALFs). These parameters were further exacerbated in the OVA + CdCl2 group. Additionally, the OVA + CdCl2 group exhibited higher levels of the oxidative stress marker malondialdehyde (MDA), greater activity of glutathione peroxidase (GSH-Px), and higher phosphorylation of extracellular regulated kinase (ERK) in lung tissue. Treatment with U0126 (an ERK inhibitor) and α-tocopherol (an antioxidant) in the OVA + CdCl2 group resulted in reduced peribronchial and airway inflammation as well as decreased airway mucus secretion. These findings indicate that CdCl2 exacerbates airway inflammation in OVA-induced allergic asthma mice following airway exposure. ERK and oxidative stress are integral to this process, and the inhibition of these pathways significantly alleviates the adverse effects of CdCl2 on asthma exacerbation.

The endocrine disruptor cadmium modulates the androgen-estrogen receptors ratio and induces inflammatory cytokines in luminal (A) cell models of breast cancer

PURPOSE

Breast cancer (BC) is the most common malignancy that affects women, and it is, to date, their leading cause of death. Luminal A molecular subtype accounts for 40% of BC and is characterized by hormone receptors positive/human epidermal growth factor 2 expression and current treatment consists of surgery plus aromatase inhibitor therapy. Interestingly, several studies demonstrated that the heavy metal cadmium (Cd), classified as a group 1 human carcinogen and widely spread in the environment, exerts estrogen-like activities in several tissues and suggested an intriguing relationship between increased Cd exposure and BC incidence. Thus, aim of this study was to evaluate effects of Cd on Luminal A BC estrogen receptor (ER) positive/progesterone receptor positive cell models in vitro to characterize the mechanism(s) involved in breast cell homeostasis disruption.

METHODS

T47D and MCF7 were exposed to Cd (0.5-1 µM) for 6-24 h to evaluate potential alterations in: cells viability, steroid receptors and intracellular signaling by western blot. Moreover, we evaluated the expression of inflammatory cytokines interleukin by RT-PCR.

RESULTS

Our results showed a significant induction of androgen receptor (AR) and an increased AR/ER ratio. Further, Cd exposure increased pro-inflammatory cytokines interleukin (IL)6, IL8 and tumor necrosis factor α levels. Finally, as previously demonstrated by our group, Cd alters pathways such as mitogen-activated protein kinase family and protein kinase B.

CONCLUSION

In conclusion, our study demonstrates that Cd modifies the expression and pattern of ERs and AR in BC cell lines, suggesting an alteration of BC cells homeostasis, likely predisposing to a carcinogenetic microenvironment.

Differential effect of the duration of exposure on the carcinogenicity of cadmium in MCF10A mammary epithelial cells

The carcinogenic role of cadmium (Cd2+) in breast cancer is still debatable. Current data points to duration of exposure as the most important element. In our study, we designed an in vitro model to investigate the effects of 3 weeks versus 6 weeks of low-level CdCl2 exposure on MCF10A cells. Our results demonstrated that after 3 weeks of CdCl2 exposure the cells displayed significant changes in the DNA integrity, but there was no development of malignant features. Interestingly, after 6 weeks of exposure, the cells significantly increased their invasion, migration and colony formation capacities. Additionally, MCF10A cells exposed for 6 weeks to CdCl2 had many dysregulated genes (4905 up-regulated and 4262 down-regulated). As follows, Cd-induced phenotypical changes are accompanied by a profound modification of the transcriptomic landscape. Furthermore, the molecular alterations driving carcinogenesis in MCF10A cells exposed to CdCl2 were found to be influenced by the duration of exposure, as in the case of MEG8. This long non-coding RNA was down-regulated at 3 weeks, but up-regulated at 6 weeks of exposure. In conclusion, even very low levels of Cd (0.5 μM) can have significant carcinogenic effects on breast cells in the case of subchronic exposure.

Toxicity Tolerance in the Carcinogenesis of Environmental Cadmium

Cadmium (Cd) is an environmental toxicant of worldwide public health significance. Diet is the main non-workplace Cd exposure source other than passive and active smoking. The intestinal absorption of Cd involves transporters for essential metals, notably iron and zinc. These transporters determine the Cd body burden because only a minuscule amount of Cd can be excreted each day. The International Agency for Research on Cancer listed Cd as a human lung carcinogen, but the current evidence suggests that the effects of Cd on cancer risk extend beyond the lung. A two-year bioassay demonstrated that Cd caused neoplasms in multiple tissues of mice. Also, several non-tumorigenic human cells transformed to malignant cells when they were exposed to a sublethal dose of Cd for a prolonged time. Cd does not directly damage DNA, but it influences gene expression through interactions with essential metals and various proteins. The present review highlights the epidemiological studies that connect an enhanced risk of various neoplastic diseases to chronic exposure to environmental Cd. Special emphasis is given to the impact of body iron stores on the absorption of Cd, and its implications for breast cancer prevention in highly susceptible groups of women. Resistance to cell death and other cancer phenotypes acquired during Cd-induced cancer cell transformation, under in vitro conditions, are briefly discussed. The potential role for the ZnT1 efflux transporter in the cellular acquisition of tolerance to Cd cytotoxicity is highlighted.

Novel pyrazoline and pyrazole "turn on" fluorescent sensors selective for Zn2+/Cd2+ at λem 480 nm and Fe3+/Fe2+ at λem 465 nm in MeCN

A small series of simple pyrazoline and pyrazole based sensors, all derived from the same chalcone precursors, were synthesised, characterised and screened for their fluorescence "turn on" properties in the presence of multiple metals. Pyrazole 8 displayed an excellent fluorescence profile with approx. 20× fold increase in λem 480 nm with Zn2+ compared to a 2.5× fold increase with Cd2+. Pyrazole 9 displayed a 30× fold increase at λem 465 nm for Fe3+ compared to Fe2+ with a Fe3+ limit of detection of 0.025 μM. The corresponding pyrazolines displayed contrasting properties with important implications for future pyrazoline and pyrazole sensor design.

Mortality and heavy metals environmental exposure: a study in dogs

Introduction

Dogs are human companions and share environmental conditions with their owners. Epidemiological studies have shown that dogs seem to be good sentinel animals for the association of diseases and/or mortality provoked by chronic exposure to heavy metals (Cd, Pb).

Methods

In the present work, we analyze the registered death cases and population from the National Canine Registry from 2020 to 2022, involving a dog population of 582,564 and 17,507 deaths. The mortality rate in male and not-purebred dogs is higher than in female and purebred dogs, respectively. The mortality cases were cross-referenced with the environmental pollution data relating to the concentration of Cd and Pb detected, between 2012 and 2022, in the various municipalities of the Liguria region. We then calculated SMR (Standardized Mortality Rate) throughout the region and found that mortality increases from the eastern to the western Ligurian coast.

Results and discussion

We observed that the most polluted areas present the highest SMRs (IRR = 1.36, 95%CI: from 1.31 to 1.41). Considering dog ages, we found that mortality in young dogs is not affected by pollution, while mortality in old dogs (10-20 years old) is heavily affected by it (IRR = 8.97, 95%CI from 8.09 to 9.93). In conclusion, the data suggest the importance of canine health and biomonitor studies and provide a basis for future research involving both animal and human health.

Molybdenum and cadmium cause blood-testis barrier dysfunction through ROS-mediated NLRP3 inflammasome activation in sheep

In this study, 24 healthy male sheep were divided into four groups: the control group, Mo group (45 mg Mo·kg-1·BW), Cd group (1 mg Cd·kg-1·BW), and Mo + Cd group (45 mg Mo·kg-1·BW + 1 mg Cd·kg-1·BW). The experiment was last for 50 d. The results showed that Mo and Cd co-exposure induced histopathological changes and ultrastructural damage, decreased the mRNA and protein expression levels of BTB (blood-testis barrier)-related factors (CX-43, ZO-1, OCLN) (P < 0.05) and the T-SOD and CAT activity (P < 0.05), increased the MDA content (P < 0.05) and the proinflammatory factors levels (P < 0.05) in sheep testes. Moreover, the results showed that a sharp decline in BTB-related factors and antioxidase activity, and a significant increase in reactive oxygen species (ROS) levels (P < 0.05) and the expression levels of NLRP3 inflammasome-related factors (P < 0.05) in primary Sertoli cells (SCs) under Mo and Cd co-exposure. However, treatment with a ROS scavenger or NLRP3 inflammasome inhibitors could relieve BTB damage and oxidative injury, reduce the production of ROS (P < 0.05) and decrease the level of inflammatory factors (P < 0.05). Overall, these results indicated that Mo and Cd co-exposure reduced BTB-related protein levels and promoted ROS production and inflammatory reactions by activating the ROS/NLRP3 inflammasome pathway in sheep testes, which eventually induced reproductive toxicity.

Assessment of salivary cadmium levels and breast density in the Marin Women's Study

BACKGROUND

We aimed to determine if salivary cadmium (Cd) levels had any association with breast density, hoping to establish a less invasive cost-effective method of stratifying Cd burden as an environmental breast cancer risk factor.

METHODS

Salivary Cd levels were quantified from the Marin Women's Study, a Marin County, California population composite. Volumetric compositional breast density (BDsxa ) data were measured by single x-ray absorptiometry techniques. Digital screening mammography was performed by the San Francisco Mammography Registry. Radiologists reviewed mammograms and assigned a Breast Imaging-Reporting and Data System score. Early morning salivary Cd samples were assayed. Association analyses were then performed.

RESULTS

Cd was quantifiable in over 90% of saliva samples (mean = 55.7 pg/L, SD = 29). Women with higher saliva Cd levels had a non-significant odds ratio of 1.34 with BI-RAD scores (3 or 4) (95% CI 0.75-2.39, p = 0.329). Cd levels were higher in current smokers (mean = 61.4 pg/L, SD = 34.8) than former smokers or non-smokers. These results were non-significant. Pilot data revealed that higher age and higher BMI were associated with higher BI-RAD scores (p < 0.001).

CONCLUSION

Salivary Cd is a viable quantification source in large epidemiologic studies. Association analyses between Cd levels and breast density may provide additional information for breast cancer risk assessment, risk reduction plans, and future research directions. Further work is needed to demonstrate a more robust testing protocol before the extent of its usefulness can be established.

Exploring the adsorption efficacy of Cassia fistula seed carbon for Cd (II) ion removal: Comparative study of isotherm models

The current study demonstrates the potential of Cassia fistula seed carbon (CFSC), a waste lignocellulosic biomass, to eliminate Cd (II) ion-from saturated liquid samples. The efficient removal of about 93.2% (w/v) of Cd (II) ions from 10 mg/L concentration was achieved within 80 min of treatment. The CFSC dosage of 100 mg/50 mL accounted as optimal for enhanced Cd (II) removal. Cd (II) adsorption onto CFSC was observed to be maximum at pH 6. The investigational trials were assessed with three isotherm models such Dubinin-Radushkevich, Freundlich, and Langmuir. The specifications obtained from this experimental study align well with the Langmuir isotherm model, which describes the maximal adsorption capacity of 68.02 mg/g. Cd (II) adsorption data from this study exhibited the R2 of 0.9 under pseudo-second-order. Maximum desorption (76.3% w/v) was obtained with 0.3 M HCL. This study revealed that thermally activated C. fistula seed carbon (CFSC) can be tuned to be lucrative adsorbent for Cd (II) elimination from water and waste-water.

Exposure to environmental chemicals and cancer risk: epidemiological evidence from Japanese studies

Exposure to certain chemicals in the environment may contribute to the risk of developing cancer. Although cancer risk from environmental chemical exposure among general populations is considered low compared to that in occupational settings, many people may nevertheless be chronically exposed to relatively low levels of environmental chemicals which vary by such various factors as residential area, lifestyle, and dietary habits. It is therefore necessary to assess population-specific exposure levels and examine their association with cancer risk. Here, we reviewed epidemiological evidence on cancer risk and exposure to dichlorodiphenyltrichloroethane (DDT), hexachlorocyclohexane (HCH), polychlorinated biphenyls (PCBs), per- and polyfluoroalkyl substances (PFASs), cadmium, arsenic, and acrylamide. Japanese are widely exposed to these chemicals, mainly through the diet, and an association with increased cancer risk is suspected. Epidemiological evidence from Japanese studies to date does not support a positive association between blood concentrations of DDT, HCH, PCBs, and PFASs and risk of breast or prostate cancer. We established assessment methods for dietary intake of cadmium, arsenic, and acrylamide using a food frequency questionnaire. Overall, dietary intakes of cadmium, arsenic, and acrylamide were not significantly associated with increased risk of total cancer and major cancer sites in the Japan Public Health Center-based Prospective Study. However, statistically significant positive associations were observed between dietary cadmium intake and risk of estrogen receptor-positive breast cancer among postmenopausal women, and dietary arsenic intake and risk of lung cancer among male smokers. In addition, studies using biomarkers as exposure assessment revealed statistically significant positive associations between urinary cadmium concentration and risk of breast cancer, and between ratio of hemoglobin adducts of acrylamide and glycidamide and risk of breast cancer. Epidemiological studies of general populations in Japan are limited and further evidence is required. In particular, studies of the association of organochlorine and organofluorine compounds with risk of cancer sites other than breast and prostate cancer are warranted, as are large prospective studies of the association between biomarkers of exposure and risk of cancer.