Relationship between heavy metal exposure and type 2 diabetes: a large-scale retrospective cohort study using occupational health examinations

Concurrent Lead and Cadmium Exposure Among Diabetics: A Case-Control Study of Socio-Demographic and Consumption Behaviors

Introduction/Objectives: Type 2 diabetes (T2D) continues to pose a substantial global public health challenge. Current evidence has linked an increase in the risk of T2D to chronic exposure to the heavy metals cadmium (Cd) and lead (Pb). The present study aimed to examine whether the reported links existed in an area of southern Thailand with known Pb contamination. Materials and Methods: A case-control study design was used to recruit 88 diagnosed T2D cases and 90 age-, gender- and locality-matched non-diabetic controls. Blood levels of Cd and Pb were used as exposure indicators. Exposure-related risk factors and socio-demographic data were collected through questionnaires. Results: A significant association was found between blood Pb and T2D diagnosis, but the association between blood Cd and T2D was not statistically significant. Factors related to high Pb exposure were education, occupation, income, smoking habits, alcohol consumption, and dietary patterns, particularly the consumption of sweet and fatty foods. Participants with higher blood Pb levels had poorer glycemic control, thereby suggesting potential interference of Pb with oral hypoglycemic agents. Conclusions: This study confirms the connection between Pb exposure and increased risk of having T2D. Additionally, it identified socio-demographic factors, and consumption habits that contributed to such an enhanced T2D risk. The role of Cd exposure requires further studies, using urinary Cd excretion, which reflects long-term exposure conditions. These findings suggest the need to incorporate environmental and occupational exposure in diabetes care strategies. From the clinical and public health perspectives, targeted interventions should focus on reducing heavy metal exposure, improving risk awareness, and strengthening occupational safety measures to prevent disease progression.

[Heavy metals and derangement in carbohydrate metabolism in eye diseases: a systematic review]

PURPOSE

To uncover the negative impacts of heavy metals on carbohydrate metabolism, their mechanisms and contributory factors, as well as their role on the etiopathogenesis, pathophysiology, and progression of eye diseases.

MATERIAL AND METHODS

Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA), various databases were searched (e.g., Scopus, PubMed, etc.) to collect evidence on the link and role of heavy metals in carbohydrate metabolism and pathogenesis of eye diseases. Included studies were appraised for quality using the Critical Appraisal Skills Programme checklists and extracted data were analyzed using the narrative synthesis method.

RESULTS

Of the 128 papers retrieved, 24 papers met the inclusion criteria. Heavy metals are associated with the onset and progression of diabetes and eye diseases secondary to diabetes (age-related macular degeneration, cataract, and diabetic retinopathy) majorly via toxic interference (induction, inhibition and/or deactivation) of glucose metabolizing enzymes and oxidative stress. The etiology of DR is intricate and includes the simultaneous disruption of several metabolic and signaling mechanisms within the retinal neurovascular unit. The retina is more susceptible to metal-induced toxicities due to the high affinity of heavy metals to melanin content of the retinal epithelium.

CONCLUSION

This study emphasizes the harmful effects of chronic and intermittent exposure to heavy metals, suggesting no safe exposure levels. To prevent eye diseases secondary to heavy metals-induced altered carbohydrate metabolism, metal chelators, low glycemic diets, and lifestyle modifications should be exploited among vulnerable populations.

Vitamin E Intake Attenuated the Association Between Elevated Blood Heavy Metal (Pb, Cd, and Hg) Concentrations and Diabetes Risk in Adults Aged 18-65 Years: Findings from 2007-2018 NHANES

The association between heavy metal exposure and diabetes is controversial and vitamin E (VE) may reduce diabetes risk. We aimed to examine the associations between blood heavy metals (BHMs) and diabetes risk and VE's role in the relationship. From the 2007-2018 NHANES, 10,721 participants aged ≥ 18 were included for multiple statistical analyses, which revealed that BHMs and dietary VE intake were negatively associated with diabetes and fasting plasma glucose (FPG). The diabetes prevalence in each quartile (Q) of heavy metal exposure increased with age, but within age Q4, it generally decreased with exposure quartiles. Moreover, BHMs were positively associated with all-cause and diabetes-related mortalities with aging, which induced an age breakpoint of 65 years for age-stratified analyses on the associations between BHMs and diabetes risk. In those aged > 65, BHMs were negatively correlated with diabetes risk and its biomarkers; however, in adults aged 18-65, the correlation was positive. At higher VE intake levels, blood lead was associated with a lower diabetes risk and all three BHMs demonstrated lower FPG levels than those at lower VE intake levels. In conclusion, consuming sufficient VE and avoiding heavy metal exposure are highly recommended to reduce diabetes risk.

Biochemical study of the risk of diabetes, prediabetic and insulin resistance in car painters and its association with mercury exposure: a retrospective case-control study

Purpose

There is controversy about the effect of mercury (Hg) exposure on developing diabetes and insulin resistance. This study aimed to assess the risk of diabetes and insulin resistance in car painters using biochemical markers and serum Hg levels.

Methods

A retrospective case-control study involving 210 male participants aged between 25 and 50 years. The participants were divided into two groups: Car painters for at least one year and healthy people who had not worked as car painters and had no health concerns or chronic diseases.

Results

The serum levels of Hg, MDA (malondialdehyde), interleukin (IL)-1β, visfatin, fasting insulin, and fasting blood glucose (FBG) were evaluated. Serum Hg levels were significantly higher in car painters compared to the control group (19.00 ± 7.20 vs. 8.339 ± 3.916 μg/L, P-value < 0.001). Serum levels of visfatin, MDA, insulin, FBG, and IL-1β were significantly higher in the car painter compared to the control (P-value < 0.001). There was a significantly higher proportion of people with diabetes in car painters compared to control (8.6% vs. 0%) and higher prediabetic (30.5% vs. 13.3%, P-value < 0.001). In car painter workers, levels of Hg were significantly higher in DM compared to prediabetic and normoglycemic car painter workers (27.01 ± 1.59, 23.98 ± 4.31, and 15.39 ± 6.41 μg/mL, respectively, P-value < 0.001); additionally, levels of Hg were significantly higher car painter with insulin resistance compared to non-insulin resistance workers (21.18 ± 7.29 vs. 16.79 ± 16.7 μg/mL, P-value < 0.001).

Conclusions

Increased serum Hg in car painters increases the risk of insulin resistance and diabetes/prediabetes status.

Toxic Metals Impact Gut Microbiota and Metabolic Risk in Five African-Origin Populations

Exposure to toxic metals impacts obesity and type 2 diabetes (T2DM) risk. Yet, the underlying mechanisms remain largely unknown. Gut microbiota has been strongly associated with progression of cardiometabolic risk. To determine whether high metal exposures and gut dysbiosis interact to promote metabolic dysregulation and cardiometabolic risk, we assessed relationships between these factors. We analyzed cross-sectional associations between arsenic, lead, mercury, cadmium, and cardiometabolic health markers in 178 randomly selected African-origin adults (52% female, 51% obese, mean age=43.0±6.4 years) from Ghana, South Africa, Seychelles, Jamaica, and USA. Metal levels were dichotomized to high or low at the median level of each metal. We analyzed associations between gut microbiome taxa, metal levels, clinical measures (BMI, fasting blood glucose, and blood pressure) and diagnoses (hypertension, obesity, and diabetes status). High vs. low lead and arsenic exposures had a significant effect on beta diversity (p <0.05). 71 taxa were associated with high lead levels: 30 with elevated BMI, 22 with T2DM, and 23 with elevated fasting blood glucose (p<0.05). 115 taxa were associated with high arsenic levels: 32 with elevated BMI, 33 with T2DM, and 26 with elevated blood glucose (p<0.05). Of the taxa associated with high lead and arsenic exposure and either elevated BMI or fasting blood glucose, porphyrin metabolism was the most enriched metabolic pathway. These data collectively provide the first findings in a human study that the gut microbiome may drive the association between lead and arsenic exposure and obesity and T2DM risk.

Evaluation of the cognitive, physiological, and biomarker effects of heavy metal exposure in Wistar rats

Background and Aim

Individuals exposed to heavy metals are known to experience physiological and biochemical changes, which raise questions regarding possible health effects. In our earlier research, significant concentrations of vanadium (V), mercury (Hg), cadmium (Cd), and arsenic (As) were found in food and medical packaging materials. This study aimed to evaluate the cognitive, physiological, and biomarker effects of select heavy metal exposure in Wistar rats.

Materials and Methods

Over a 13-week period, five groups of rats (six rats per group, with both males and females) were assessed to study the effects of oral exposure to V, Hg, Cd, and As. The study focused on evaluating physiological, cognitive, and biochemical markers, with the results compared to those of a control group.

Results

Comparing all groups of rats treated with heavy metals, the study revealed significant deficits in learning and spatial orientation (water maze test); rats treated with V, Cd, and Hg showed signs of depression. Rats treated with As also showed signs of hyperactivity, which may indicate a connection to attention-deficit hyperactivity disorder (rat tail suspension test). The groups exposed to different heavy metals varied in their physiological (water and food intake, urine and feces output) and biochemical responses (enzyme-linked immunosorbent assay, prostate-specific antigen, T3, T4, thyroid-stimulating hormone, carcinoembryonic antigen, and blood glucose analysis), with Hg exhibiting the strongest impacts. Rats given Hg showed signs of hypothyroidism, such as increased food intake and weight gain.

Conclusion

This study clarifies the complex relationships between exposure to heavy metals and various biological systems, shedding light on their potential health impacts. The findings provide insight into the effects of heavy metals on neural and thyroid tissues, as well as their propensity to cause cellular dedifferentiation. However, the study has certain limitations, such as the relatively short duration of exposure and the use of only a few selected biomarkers. Future research should focus on long-term exposure studies, incorporate a broader range of biomarkers, and explore the underlying mechanisms at a molecular level to better understand the full spectrum of health risks associated with heavy metal exposure.

Associations of insulin sensitivity and immune inflammatory responses with child blood lead (Pb) and PM2.5 exposure at an e-waste recycling area during the COVID-19 lockdown

Fine particular matter (PM2.5) and lead (Pb) exposure can induce insulin resistance, elevating the likelihood of diabetes onset. Nonetheless, the underlying mechanism remains ambiguous. Consequently, we assessed the association of PM2.5 and Pb exposure with insulin resistance and inflammation biomarkers in children. A total of 235 children aged 3-7 years in a kindergarten in e-waste recycling areas were enrolled before and during the Corona Virus Disease 2019 (COVID-19) lockdown. Daily PM2.5 data was collected and used to calculate the individual PM2.5 daily exposure dose (DED-PM2.5). Concentrations of whole blood Pb, fasting blood glucose, serum insulin, and high mobility group box 1 (HMGB1) in serum were measured. Compared with that before COVID-19, the COVID-19 lockdown group had lower DED-PM2.5 and blood Pb, higher serum HMGB1, and lower blood glucose and homeostasis model assessment of insulin resistance (HOMA-IR) index. Decreased DED-PM2.5 and blood Pb levels were linked to decreased levels of fasting blood glucose and increased serum HMGB1 in all children. Increased serum HMGB1 levels were linked to reduced levels of blood glucose and HOMA-IR. Due to the implementation of COVID-19 prevention and control measures, e-waste dismantling activities and exposure levels of PM2.5 and Pb declined, which probably reduced the association of PM2.5 and Pb on insulin sensitivity and diabetes risk, but a high level of risk of chronic low-grade inflammation remained. Our findings add new evidence for the associations among PM2.5 and Pb exposure, systemic inflammation and insulin resistance, which could be a possible explanation for diabetes related to environmental exposure.

Association of serum metal levels with type 2 diabetes: A prospective cohort and mediating effects of metabolites analysis in Chinese population

Several studies have suggested an association between exposure to various metals and the onset of type 2 diabetes (T2D). However, the results vary across different studies. We aimed to investigate the associations between serum metal concentrations and the risk of developing T2D among 8734 participants using a prospective cohort study design. We utilized inductively coupled plasmamass spectrometry (ICP-MS) to assess the serum concentrations of 27 metals. Cox regression was applied to calculate the hazard ratios (HRs) for the associations between serum metal concentrations on the risk of developing T2D. Additionally, 196 incident T2D cases and 208 healthy control participants were randomly selected for serum metabolite measurement using an untargeted metabolomics approach to evaluate the mediating role of serum metabolite in the relationship between serum metal concentrations and the risk of developing T2D with a nested casecontrol study design. In the cohort study, after Bonferroni correction, the serum concentrations of zinc (Zn), mercury (Hg), and thallium (Tl) were positively associated with the risk of developing T2D, whereas the serum concentrations of manganese (Mn), molybdenum (Mo), barium (Ba), lutetium (Lu), and lead (Pb) were negatively associated with the risk of developing T2D. After adding these eight metals, the predictive ability increased significantly compared with that of the traditional clinical model (AUC: 0.791 vs. 0.772, P=8.85×10-5). In the nested casecontrol study, a machine learning analysis revealed that the serum concentrations of 14 out of 1579 detected metabolites were associated with the risk of developing T2D. According to generalized linear regression models, 7 of these metabolites were significantly associated with the serum concentrations of the identified metals. The mediation analysis showed that two metabolites (2-methyl-1,2-dihydrophthalazin-1-one and mestranol) mediated 46.81% and 58.70%, respectively, of the association between the serum Pb concentration and the risk of developing T2D. Our study suggested that serum Mn, Zn, Mo, Ba, Lu, Hg, Tl, and Pb were associated with T2D risk. Two metabolites mediated the associations between the serum Pb concentration and the risk of developing T2D.

Multimetal exposure: Challenges in diagnostics, prevention, and treatment

Extensive use of heavy metals has posed a serious concern for ecosystem and human too. Heavy metals are toxic in nature and their accumulation in human body causes serious disorders such as neurological disease, cardiac disease, gastrointestinal problems, skin disorders, reproductive disease, lungs diseases, and so on. Furthermore, heavy metals not only affect the human health but also have a negative impact on the economy. In the current review, we have elaborated the impact of heavy metal exposure on human health and socioeconomics. We have discussed the molecular mechanism involved in the heavy metal-induced human disorders such as oxidative stress, neuroinflammation, and protein misfolding. Finally, we discussed the preventive measure and treatment strategy that could counter the negative effects of heavy metal intoxications. In conclusion, there is a substantial correlation between heavy metals and the onset and advancement of several health issues. Chelation treatment could be a useful tactic to lessen the toxic metal load and the difficulties that come with it.

Associations of metals and metal mixtures with glucose homeostasis: A combined bibliometric and epidemiological study

This study employs a combination of bibliometric and epidemiological methodologies to investigate the relationship between metal exposure and glucose homeostasis. The bibliometric analysis quantitatively assessed this field, focusing on study design, predominant metals, analytical techniques, and citation trends. Furthermore, we analyzed cross-sectional data from Beijing, examining the associations between 14 blood metals and 6 glucose homeostasis markers using generalized linear models (GLM). Key metals were identified using LASSO-PIPs criteria, and Bayesian kernel machine regression (BKMR) was applied to assess metal mixtures, introducing an "Overall Positive/Negative Effect" concept for deeper analysis. Our findings reveal an increasing research interest, particularly in selenium, zinc, cadmium, lead, and manganese. Urine (27.6%), serum (19.0%), and whole blood (19.0%) were the primary sample types, with cross-sectional studies (49.5%) as the dominant design. Epidemiologically, significant associations were found between 9 metals-cobalt, copper, lithium, manganese, nickel, lead, selenium, vanadium, zinc-and glucose homeostasis. Notably, positive-metal mixtures exhibited a significant overall positive effect on insulin levels, and notable interactions involving nickel were identified. These finding not only map the knowledge landscape of research in this domain but also introduces a novel perspective on the analysis strategies for metal mixtures.

Capturing of neurotoxins causing diabetes stress and nervous breakdown in the aqueous medium by naphthazarin esters

The fear of an increase in blood sugar can be very traumatic. Being diabetic either type I or type II leads to a disorder called diabetes distress having traits of stress, depression, and anxiety. Among risk factors of diabetes mellitus heavy and trace metal toxicity emerges as new risk factors reported in many studies. In this study we target toxic metals, viz., Ni2+, Zn2+, and Cu2+, involved in the pathogenesis of diabetes and diabetic stress with naphthazarin esters. The compounds C1-C3 isolated from the leaves and roots of Arnebia guttata were tested for their metal-binding ability in an aqueous medium in UV-Visible and nuclear magnetic resonance (NMR) studies. These probes are well-known naphthoquinones present in the Arnebia species. In the UV-Visible titrations of compounds C1-C3 with Na2+, K2+, Zn2+, Ca2+, Cu2+, Mg2+, Co2+, and Ni2+ ions, significant binding was observed with Ni2+, Cu2+, and Zn2+ ions in MeOH/H2O. There occurs a beautiful formation of red-shifted bands between the 520 to 620 nm range with a synergistic increase in absorbance. Also, the disappearance of proton peaks in the 1H NMR spectrum on addition of metal ions confirmed binding. Compounds C1-C3 isolated from A. guttata came out as potent Ni2+, Zn2+, and Cu2+ sensors that are reportedly involved in islet function and induction of diabetes.

Relationship between blood lead (Pb) concentration with risk of diabetes mellitus in women living in mining area

Diabetes is a global health concern with significant implications for individuals and societies. Diabetes results from a complex interaction between genes and environmental factors, including metal exposure. Lead or plumbum (Pb) is a heavy metal pollutant and is predicted to be associated with the morbidity of diabetes. The aim of this study was to assess the relationship between blood Pb level and possible risk factors (body mass index insulin resistance, carbohydrate intake, sugar intake, and physical activity) with fasting blood sugar (FBS) level in women living in the mining area. A cross-sectional study was conducted in a mining area of Indonesia located in Pemali District, Bangka Belitung Regency, involving women aged 30-49, selected through purposive sampling. Logistic regression was used to assess the relationship between the risk factors and FBS level, while the Spearman correlation was used to analyze the correlations between the risk factors and FBS level. Our data indicated that blood Pb concentration and other risk factors (carbohydrate intake, sugar intake and physical activity) were neither associated nor correlated with FBS level. However, as predicted, insulin resistance was associated with FBS level with OR: 9.66; 95%CI: 1.13-82.29; p=0.038. In addition, the Homeostatic Model Assessment Insulin Resistance (HOMA-IR) score was also correlated with FBS level (r=0.316, p=0.002). This study highlights the level of Pb is not associated with the risk of diabetes in women living in mining area.

Association Between Arsenic Toxicity, AS3MT Gene Polymorphism and Onset of Type 2 Diabetes

Arsenic (As) exposure in drinking water has become a serious public health issue. AS3MT gene is involved in the metabolism of arsenic, so a single nucleotide polymorphism in this gene may lead to the development of type 2 diabetes in arsenic-exposed areas. This study aimed to evaluate the association of the AS3MT gene with the development of type 2 diabetes in highly arsenic-exposed areas of Punjab, Pakistan. Total 200 samples equal in number from high arsenic exposed-areas of Lahore (Nishtar) and Kasur (Mustafa Abad) were collected. rs11191439 was utilized as an influential variable to evaluate the association between arsenic metabolism and diabetes status to find a single nucleotide polymorphism in the AS3MT gene. We observed the arsenic level in drinking water of the arsenic-exposed selected areas 115.54 ± 1.23 µg/L and 96.88 ± 0.48 µg/L, respectively. The As level in the urine of diabetics (98.54 ± 2.63 µg/L and 56.38 ± 12.66 µg/L) was higher as compared to non-diabetics (77.58 ± 1.8 µg/L and 46.9 ± 8.95 µg/L) of both affected areas, respectively. Correspondingly, the As level in the blood of diabetics (6.48 ± 0.08 µg/L and 5.49 ± 1.43 µg/L) and non-diabetics (6.22 ± 0.12 µg/L and 5.26 ± 0.24 µg/L) in the affected areas. Genotyping showed significant differences in the frequencies of alleles among cases and controls. Nevertheless, notable disparities in genotype distribution were observed in SNPs rs11191439 (T/C) (P < 0.05) and when comparing T2D patients and non-diabetic control subjects. The AS3MT gene and clinical parameters show a significant association with the affected people with diabetes living in arsenic-exposed areas.

The Role of Endocrine Disruption Chemical-Regulated Aryl Hydrocarbon Receptor Activity in the Pathogenesis of Pancreatic Diseases and Cancer

The aryl hydrocarbon receptor (AHR) serves as a ligand-activated transcription factor crucial for regulating fundamental cellular and molecular processes, such as xenobiotic metabolism, immune responses, and cancer development. Notably, a spectrum of endocrine-disrupting chemicals (EDCs) act as agonists or antagonists of AHR, leading to the dysregulation of pivotal cellular and molecular processes and endocrine system disruption. Accumulating evidence suggests a correlation between EDC exposure and the onset of diverse pancreatic diseases, including diabetes, pancreatitis, and pancreatic cancer. Despite this association, the mechanistic role of AHR as a linchpin molecule in EDC exposure-related pathogenesis of pancreatic diseases and cancer remains unexplored. This review comprehensively examines the involvement of AHR in EDC exposure-mediated regulation of pancreatic pathogenesis, emphasizing AHR as a potential therapeutic target for the pathogenesis of pancreatic diseases and cancer.

Associations between metals and metabolomic profiles related to diabetes among adults in a rural region

INTRODUCTION

Exposure to metals is associated with increased risk of type 2 diabetes (T2D). Potential mechanisms for metals-T2D associations involve biological processes including oxidative stress and disruption of insulin-regulated glucose uptake. In this study, we assessed whether associations between metal exposure and metabolite profiles relate to biological pathways linked to T2D.

MATERIALS AND METHODS

We used data from 29 adults rural Colorado residents enrolled in the San Luis Valley Diabetes Study. Urinary concentrations of arsenic, cadmium, cobalt, lead, manganese, and tungsten were measured. Metabolic effects were evaluated using untargeted metabolic profiling, which included 61,851 metabolite signals detected in serum. We evaluated cross-sectional associations between metals and metabolites present in at least 50% of samples. Primary analyses adjusted urinary heavy metal concentrations for creatinine. Metabolite outcomes associated with each metal exposure were evaluated using pathway enrichment to investigate potential mechanisms underlying the relationship between metals and T2D.

RESULTS

Participants had a mean age of 58.5 years (standard deviation = 9.2), 48.3% were female, 48.3% identified as Hispanic/Latino, 13.8% were current smokers, and 65.5% had T2D. Of the detected metabolites, 455 were associated with at least one metal, including 42 associated with arsenic, 22 with cadmium, 10 with cobalt, 313 with lead, 66 with manganese, and two with tungsten. The metabolic features were linked to 24 pathways including linoleate metabolism, butanoate metabolism, and arginine and proline metabolism. Several of these pathways have been previously associated with T2D, and our results were similar when including only participants with T2D.

CONCLUSIONS

Our results support the hypothesis that metals exposure may be associated with biological processes related to T2D, including amino acid, co-enzyme, and sugar and fatty acid metabolism. Insight into biological pathways could influence interventions to prevent adverse health outcomes due to metal exposure.

The associations of non-essential metal mixture with fasting plasma glucose among Chinese older adults without diabetes

The evidence about the effect of non-essential metal mixture on fasting plasma glucose (FPG) levels among older adults without diabetes is limited. This study aims to estimate the individual and joint relationship between five non-essential metals and FPG levels in Chinese older adults without diabetes. This study included 2362 older adults without diabetes. Urinary concentrations of five non-essential metals, i.e., cesium (Cs), aluminum (Al), thallium (Tl), cadmium (Cd), and arsenic (As), were detected by inductively coupled plasma mass spectrometry (ICP-MS). The associations of single metals and the metal mixture with FPG levels were assessed using linear regression and Bayesian kernel machine regression (BKMR) models, respectively. Adjusted single-metal linear regression models showed positive associations of urinary Al (β = 0.016, 95%CI: 0.001-0.030) and Cs (β = 0.018, 95%CI: 0.006-0.031) with FPG levels. When comparing the 2th, 3th, and 4th quartiles of urine Cs to its 1th quartile, the significant associations between Cs and FPG levels were found and presented as an "inverted U" trend (βQ2 vs. Q1: 0.034; βQ3 vs. Q1:0.054; βQ4 vs. Q1: 0.040; all P<0.05). BKMR analyses showed urinary level of Cs exhibited an "inverted U" shape association with FPG levels. Moreover, the FPG levels increased linearly with the raised levels of the non-essential metal mixture, and the posterior inclusion probability (PIP) of Cs was the highest (0.92). Potential positive interaction of As and Cs on FPG levels was found in BKMR model. Stratified analysis displayed significant interactions of hyperlipidemia and urine Cs or Tl on FPG levels. An inverse U-shaped association between Cs and FPG was found, individually and as mixture. The FPG levels increased with the raised levels of the non-essential metal mixture, and Cs was the most contributor to FPG levels. Further research is required to confirm the correlation between non-essential metals and FPG levels and to clarify the underlying mechanisms.

Identification of the regulatory network and potential markers for type 2 diabetes mellitus related to internal exposure to metals in Chinese adults

People intake metals from their environment. This study investigated type 2 diabetes mellitus (T2DM) related to internal exposure to metals and attempted to identify possible biomarkers. A total of 734 Chinese adults were enrolled, and urinary levels of ten metals were measured. Multinomial logistic regression model was used to assess the association between metals and impaired fasting glucose (IFG) and T2DM. Gene ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and protein-protein interaction were used to explore the pathogenesis of T2DM related to metals. After adjustment, lead (Pb) was positively associated with IFG (odds ratio [OR] 1.31, 95% confidence interval [CI] 1.06-1.61) and T2DM (OR 1.41, 95% CI 1.01-1.98), but cobalt was negatively associated with IFG (OR 0.57, 95% CI 0.34-0.95). Transcriptome analysis showed 69 target genes involved in the Pb-target network of T2DM. GO enrichment indicated that the target genes are enriched mainly in the biological process category. KEGG enrichment indicated that Pb exposure leads to non-alcoholic fatty liver disease, lipid and atherosclerosis, and insulin resistance. Moreover, there is alteration of four key pathways, and six algorithms were used to identify 12 possible genes in T2DM related to Pb. SOD2 and ICAM1 show strong similarity in expression, suggesting a functional correlation between these key genes. This study reveals that SOD2 and ICAM1 may be potential targets of Pb exposure-induced T2DM and provides novel insight into the biological effects and underlying mechanism of T2DM related to internal exposure to metals in the Chinese population.

An evaluation of the effects of mixed heavy metals on prediabetes and type 2 diabetes: epidemiological and toxicogenomic analysis

The link between mixed heavy metals (mercury, lead, and cadmium), prediabetes, and type 2 diabetes mellitus (T2DM), especially molecular mechanisms, is poorly understood. Thus, we aimed to identify the association between mixed heavy metals and T2DM and its components using a data set from the Korean National Health and Nutrition Examination Survey. We further analyzed the main molecular mechanisms implicated in T2DM development induced by mixed heavy metals using in-silico analysis. Our findings observed that serum mercury was associated with prediabetes, elevated glucose, and ln2-transformed glucose when using different statistical methods. "AGE-RAGE signaling pathway in diabetic complications", "non-alcoholic fatty liver disease", "metabolic Syndrome X", and three miRNAs (hsa-miR-98-5p, hsa-let-7a-5p, and hsa-miR-34a-5p) were listed as the most important molecular mechanisms related to T2DM development caused by mixed heavy metals. These miRNA sponge structures were created and examined, and they may be beneficial in the treatment of T2DM. The predicted cutoff values for three heavy metal levels linked to T2DM and its components were specifically identified. Our results imply that chronic exposure to heavy metals, particularly mercury, may contribute to the development of T2DM. To understand the changes in the pathophysiology of T2DM brought on by a combination of heavy metals, more research is required.

Exposure to multiple metals and diabetes mellitus risk in dong ethnicity in China: from the China multi-ethnic cohort study

Metals play an important role in the development of diabetes mellitus (DM). The association of metals with diabetes among the Dong ethnicity in China remains poorly understood. The current study aimed to evaluate the association of single metal exposure and multi-metal co-exposure with DM risk. Urinary concentrations of arsenic, cadmium, chromium, copper, iron, lead, manganese, mercury, molybdenum, nickel, strontium, vanadium, and zinc were measured using inductively coupled plasma-mass spectrometry (ICP-MS) among 4479 Dong ethnic participants aged 30-79 years from the China Multi-Ethnic Cohort (CMEC) study. Based on tertiles, the metal exposure can be divided into three groups: low, middle, and high exposure. Multivariate logistic regression models and principal component analysis were performed to determine exposure to single-metal and multi-metal co-exposure in relation to DM. A decrease in risk of DM was associated with iron (OR = 0.78, 95% CI: 0.61-1.00 and 0.68, 0.53-0.88 for the middle and high vs. low) and strontium (OR = 0.87, 95% CI: 0.69-1.12 and 0.67, 0.51-0.86 for the middle and high vs. low), respectively. A principal component 3 (PC3) characterized by iron and strontium showed an inverse association with DM. A principal component 4 (PC4) characterized by manganese and lead positively associated with DM. Exposure to high concentrations of urinary iron and strontium may reduce the risk of diabetes mellitus. This study revealed an increase in the risk of diabetes mellitus by co-exposure to high concentrations of urinary manganese and lead.

Association of SLC11A1 polymorphisms with anthropometric and biochemical parameters describing Type 2 Diabetes Mellitus

Diabetes, a leading cause of death globally, has different types, with Type 2 Diabetes Mellitus (T2DM) being the most prevalent one. It has been established that variations in the SLC11A1 gene impact risk of developing infectious, inflammatory, and endocrine disorders. This study is aimed to investigate the association between the SLC11A1 gene polymorphisms (rs3731864 G/A, rs3731865 C/G, and rs17235416 + TGTG/- TGTG) and anthropometric and biochemical parameters describing T2DM. Eight hundred participants (400 in each case and control group) were genotyped using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and amplification-refractory mutation system-PCR (ARMS-PCR) methods. Lipid profile, fasting blood sugar (FBS), hemoglobin A1c level, and anthropometric indices were also recorded for each subject. Findings revealed that SLC11A1-rs3731864 G/A, -rs17235416 (+ TGTG/- TGTG) were associated with T2DM susceptibility, providing protection against the disease. In contrast, SLC11A1-rs3731865 G/C conferred an increased risk of T2DM. We also noticed a significant association between SLC11A1-rs3731864 G/A and triglyceride levels in patients with T2DM. In silico evaluations demonstrated that the SLC11A2 and ATP7A proteins also interact directly with the SLC11A1 protein in Homo sapiens. In addition, allelic substitutions for both intronic variants disrupt or create binding sites for splicing factors and serve a functional effect. Overall, our findings highlighted the role of SLC11A1 gene variations might have positive (rs3731865 G/C) or negative (rs3731864 G/A and rs17235416 + TGTG/- TGTG) associations with a predisposition to T2DM.

Relationship between Metal Exposures, Dietary Macronutrient Intake, and Blood Glucose Levels of Informal Electronic Waste Recyclers in Ghana

While metal exposures are generally high among informal electronic waste (e-waste) recyclers, the joint effect of metals and dietary macronutrients on their metabolic health is unknown. Therefore, we investigated the relationship between metal exposures, dietary macronutrients intake, and blood glucose levels of e-waste recyclers at Agbogbloshie using dietary information (48-h recall survey), blood metals (Pb & Cd), and HbA1C levels of 151 participants (100 e-waste recyclers and 51 controls from the Accra, Ghana) in March 2017. A linear regression model was used to estimate the joint relationship between metal exposures, dietary macronutrient intake, and blood glucose levels. Except for dietary proteins, both groups had macronutrient deficiencies. Diabetes prevalence was significantly higher among controls. Saturated fat, OMEGA-3, and cholesterol intake were associated with significant increases in blood glucose levels of recyclers. In a joint model, while 1 mg of cholesterol consumed was associated with a 0.7% increase in blood glucose, 1 g/L of Pb was found to significantly increase blood glucose levels by 0.9% among recyclers. Although the dietary consumption of cholesterol and fat was not high, it is still possible that exposure to Pb and Cd may still increase the risk of diabetes among both e-waste recyclers and the general population.

Effects of multi-metal exposure on the risk of diabetes mellitus among people aged 40-75 years in rural areas in southwest China

AIMS/INTRODUCTION

Metals play an important role in diabetes mellitus. This cross-sectional study aimed to evaluate the overall, individual and interactive effects of multi-metal exposure on the prevalence of diabetes mellitus, impaired fasting glucose (IFG) rate and fasting blood glucose (FBG) levels.

MATERIALS AND METHODS

The FBG levels of a study population from a cadmium (Cd)-polluted area (n = 250) and an unpolluted area (n = 204), and the metal levels, including magnesium, calcium (Ca), iron (Fe), zinc (Zn), arsenic (As), Cd, copper and lead (Pb) in blood and urine were detected. The study population was divided into a normal fasting glucose group, an IFG group and a diabetes mellitus group on the basis of FBG levels.

RESULTS

The IFG rate and diabetes mellitus prevalence were negatively associated with blood Cd and urine Zn levels (IFG rate: odds ratio [OR] 0.780, 95% confidence interval [CI] 0.655-0.928; OR 0.622, 95% CI 0.465-0.831. Diabetes mellitus prevalence: OR 0.506, 95% CI 0.288-0.888; OR 0.609, 95% CI 0.395-0.939), the IFG rate was positively associated with urine Fe levels (OR 1.876, 95% CI 1.290-2.778), and diabetes mellitus prevalence was positively associated with urine Pb and blood Fe levels (OR 1.185, 95% CI 1.022-1.376; OR 1.008, 95% CI 1.001-1.014). A linear negative correlation was observed between FBG levels and blood Cd, and non-linear inverted U-shaped associations were found between FBG levels and Zn, Pb and copper in urine.

CONCLUSIONS

This research suggests that multi-metal exposure, especially Cd, Fe, Zn, copper and Pb, is linked to diabetes mellitus, and the interactive effects of multiple metals require further exploration.

Cadmium exposure and risk of diabetes and prediabetes: A systematic review and dose-response meta-analysis

BACKGROUND

Cadmium exposure has been associated with increased diabetes risk in several studies, though there is still considerable debate about the magnitude and shape of the association.

OBJECTIVE

To perform a systematic review and meta-analysis of observational studies investigating the relation between cadmium exposure and risk of type 2 diabetes and prediabetes, and to summarize data on the magnitude and shape of the association.

DATA SOURCE

After conducting an online literature search through October 1, 2021, we identified 42 eligible studies investigating the association between cadmium exposure and risk of diabetes and prediabetes.

STUDY ELIGIBILITY CRITERIA

We included studies that assessed cadmium exposure through biomarker levels; examined type 2 diabetes or prediabetes among outcomes; and reported effect estimates for cadmium exposure for meta-analysis only.

STUDY APPRAISAL AND SYNTHESIS METHODS

Studies were evaluated using ROBINS-E risk of bias tool. We quantitively assessed the relation between exposure and study outcomes using one-stage dose-response meta-analysis with a random effects meta-analytical model.

RESULTS

In the meta-analysis, comparing highest-versus-lowest cadmium exposure levels, summary relative risks (RRs) for type 2 diabetes were 1.24 (95% confidence interval 0.96-1.59), 1.21 (1.00-1.45), and 1.47 (1.01-2.13) for blood, urinary, and toenail matrices, respectively. Similarly, there was an increased risk of prediabetes for cadmium concentrations in both urine (RR = 1.41, 95% CI: 1.15-1.73) and blood (RR = 1.38, 95% CI: 1.16-1.63). In the dose-response meta-analysis, we observed a consistent linear positive association between cadmium exposure and diabetes risk, with RRs of 1.25 (0.90-1.72) at 2.0 µg/g of creatinine. Conversely for blood cadmium, diabetes risk appeared to increase only above 1 µg/L. Prediabetes risk increased up to approximately 2 µg/g creatinine above which it reached a plateau with RR of 1.42 (1.12-1.76) at 2 µg/g creatinine.

LIMITATIONS AND CONCLUSIONS

This analysis provides moderate-certainty evidence for a positive association between cadmium exposure (measured in multiple matrices) and risk of both diabetes and prediabetes.

A review of environmental metabolism disrupting chemicals and effect biomarkers associating disease risks: Where exposomics meets metabolomics

Humans are exposed to an ever-increasing number of environmental toxicants, some of which have gradually been elucidated to be important risk factors for metabolic diseases, such as diabetes and obesity. These metabolism-sensitive diseases typically occur when key metabolic and signaling pathways were disrupted, which can be influenced by the exposure to contaminants such as endocrine disrupting chemicals (EDCs), along with genetic and lifestyle factors. This promotes the concept and research on environmental metabolism disrupting chemicals (MDCs). In addition, identifying endogenous biochemical markers of effect linked to disease states is becoming an important tool to screen the biological targets following environmental contaminant exposure, as well as to provide an overview of toxicity risk assessment. As such, the current review aims to contribute to the further understanding of exposome and human health and disease by characterizing environmental exposure and effect metabolic biomarkers. We summarized MDC-associated metabolic biomarkers in laboratory animal and human cohort studies using high throughput targeted and nontargeted metabolomics techniques. Contaminants including heavy metals and organohalogen compounds, especially EDCs, have been repetitively associated with metabolic disorders, whereas emerging contaminants such as perfluoroalkyl substances and microplastics have also been found to disrupt metabolism. In addition, we found major limitations in the effective identification of metabolic biomarkers especially in human studies, toxicological research on the mixed effect of environmental exposure has also been insufficient compared to the research on single chemicals. Thus, it is timely to call for research efforts dedicated to the study of combined effect and metabolic alterations for the better assessment of exposomic toxicology and health risks. Moreover, advanced computational and prediction tools, further validation of metabolic biomarkers, as well as systematic and integrative investigations are also needed in order to reliably identify novel biomarkers and elucidate toxicity mechanisms, and to further utilize exposome and metabolome profiling in public health and safety management.