Acrylamide Exposure and Oxidative DNA Damage, Lipid Peroxidation, and Fasting Plasma Glucose Alteration: Association and Mediation Analyses in Chinese Urban Adults

Selenium reduces acrylamide-induced testicular toxicity in rats by regulating HSD17B1, StAR, and CYP17A1 expression, oxidative stress, inflammation, apoptosis, autophagy, and DNA damage

This study investigated the effects of Selenium (Se) on testis toxicity induced by Acrylamide (ACR) in rats. In our study, 50 male adult rats were used, and the rats were divided into five groups; control, ACR, Se0.5 + ACR, Se1 + ACR, and Se1. Se and ACR treatments were applied for 10 days. On the 11th day of the experimental study, intracardiac blood samples from the rats were taken under anesthesia and euthanized. Sperm motility and morphology were evaluated. Dihydrotestosterone, FSH, and LH levels in sera were analyzed with commercial ELISA kits. MDA, GSH, TNF-α, IL-6, and IL-1β levels and SOD, GPx, and CAT, activities were measured to detect the level of oxidative stress and inflammation in rat testis tissues. Expression analysis of HSD17B1, StAR, CYP17A1, MAPk14, and P-53 as target mRNA levels were performed with Real Time-PCR System technology for each cDNA sample synthesized from rat testis RNA. Testicular tissues were evaluated by histopathological, immunohistochemical, and immunofluorescent examinations. Serum dihydrotestosterone and FSH levels decreased significantly in the ACR group compared to the control group, while LH levels increased and a high dose of Se prevented these changes caused by ACR. A high dose of Se prevented these changes caused by ACR. ACR-induced testicular oxidative stress, inflammation, apoptosis, changes in the expression of reproductive enzymes, some changes in sperm motility and morphology, DNA, and tissue damage, and Se administration prevented these pathologies caused by ACR. As a result of this study, it was determined that Se prevents oxidative stress, inflammation, apoptosis, autophagy, and DNA damage in testicular toxicity induced by ACR in rats.

Acrylamide, an air pollutant, enhances allergen-induced eosinophilic lung inflammation via group 2 innate lymphoid cells

Air pollution significantly impacts the aggravation of asthma. Exposure to acrylamide, a volatile organic compound in tobacco smoke, is associated with elevated risks of allergy-related outcomes among active smokers. As group 2 innate lymphoid cells (ILC2s) can act as an environmental sensor and significantly contribute to protease allergen-induced lung inflammation, we aimed to elucidate the causal relationship and how inhaled acrylamide worsens allergic lung inflammation via ILC2s. Intranasal acrylamide exposure at nanomolar levels significantly enhanced allergen-induced or recombinant mouse interleukin-33-induced lung inflammation in C57BL/6 mice or Rag1-/- mice, respectively. The cardinal features of lung inflammation included accumulated infiltration of ILC2s and eosinophils. Transcriptomic analysis revealed a gene expression pattern associated with proliferation-related pathways in acrylamide-treated ILC2s. Western blotting revealed significantly higher expression of Ras and phospho-Erk in acrylamide-treated ILC2s than the control, suggesting Ras-Erk signaling pathway involvement. Ex vivo and in vitro analysis showed that acrylamide treatment mainly increased Ki-67+ ILC2s and the cell number of ILC2s whereas PD98059, a highly selective Erk inhibitor, effectively counteracted the acrylamide effect. Intratracheal administration of acrylamide-treated ILC2s significantly enhanced eosinophil infiltration in Rag1-/- mice. This study suggests that airborne acrylamide may enhance the severity of allergen-induced airway eosinophilic inflammation, partly via altering ILC2 proliferative activity.

Increased Levels of Urine Volatile Organic Compounds Are Associated With Diabetes Risk and Impaired Glucose Homeostasis

CONTEXT

Volatile organic compounds (VOCs) are pervasive environmental pollutants that have been linked to various adverse health effects. However, the effect of ambient VOCs, whether individually or in mixtures, on diabetes remains uncertain and requires further investigation.

OBJECTIVE

This study investigates the effects of ambient VOCs exposure, whether single or mixed, on diabetes mellitus and glucose homeostasis in the general population.

METHODS

Urinary concentrations of VOC metabolites were obtained from the National Health and Nutrition Examination Survey. Survey-weighted logistic regression and generalized linear regression were used to explore the associations between individual VOC exposure and diabetes risk and glucose homeostasis indicators, respectively. Weighted quantile sum (WQS) regression models were applied to assess the combined effects of VOC mixtures.

RESULTS

Out of 8468 participants, 1504 had diabetes mellitus. Eight VOC metabolites showed positive associations with diabetes mellitus (OR, 1.15-1.43; all P < .05), insulin resistance (IR) (OR, 1.02-1.06; P < .05), and other glucose homeostasis indicators (β, 0.04-2.32; all P < .05). Mixed VOC models revealed positive correlations between the WQS indices and diabetes risk (OR = 1.52; 95% CI, 1.29-1.81), IR (OR = 1.36; 95% CI, 1.14-1.62), and other glucose homeostasis indicators (β, 0.17-2.22; all P < .05).

CONCLUSION

Urinary metabolites of ambient VOCs are significantly associated with an increased diabetes risk and impaired glucose homeostasis. Thus, primary prevention policies aimed at reducing ambient VOCs could attenuate diabetes burden.

Ultra-processed Food Intake and Risk of Type 2 Diabetes in Korean Adults

BACKGROUND

Several studies from the United States and European countries reported a positive association between ultra-processed food intake and diabetes risk. However, little is known about the association in Asian populations. It is also unknown about the individual ultra-processed food items that are most unfavorably associated with diabetes risk.

OBJECTIVE

We examined the associations of ultra-processed food intake (combined, as well as individual ultra-processed food items) with the risk of type 2 diabetes.

METHODS

This prospective analysis included 7438 participants aged 40-69 y from the Korean Genome and Epidemiology Study Ansan-Ansung cohort. Dietary intake was assessed at baseline using a 103-item semiquantitative food-frequency questionnaire. Ultra-processed foods were classified using the Nova definition. Incident type 2 diabetes cases were identified via follow-up interviews and health examination. Multivariable Cox proportional hazard models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs), adjusting for potential confounders.

RESULTS

During the follow-up (2001-2019; median: 15 y), a total of 1187 type 2 diabetes cases were identified. Compared with the lowest quartile of ultra-processed food intake, the highest quartile was positively associated with diabetes risk [HR (95% CI) = 1.34 (1.13, 1.59), P-trend = 0.002]. The association did not change after additional adjustment for diet quality or BMI. Among individual ultra-processed food items, a higher consumption of ham/sausage [per 1% increase in the weight ratio: HR (95% CI) = 1.40 (1.05, 1.86)], instant noodles [1.07 (1.02, 1.11)], ice cream [1.08 (1.03, 1.13)], and carbonated beverages [1.02 (1.00, 1.04)] were associated with an increased risk of type 2 diabetes, whereas a higher intake of candy/chocolate was associated with a decreased risk [0.78 (0.62, 0.99)].

CONCLUSIONS

Our data suggest that the high intake of ultra-processed foods, particularly ham/sausage, instant noodles, ice cream, and carbonated beverages, is associated with an increased risk of type 2 diabetes in Korean adults.

Association of urinary arsenic metabolism with type 2 diabetes and glucose homeostasis: Cross-sectional and longitudinal associations

BACKGROUND

Previous researches have assessed the relationships of urinary arsenic metabolism with type 2 diabetes (T2D) and glucose-insulin homeostasis, but the results were controversial, and potential mechanisms remain largely unclear.

OBJECTIVES

This study aimed to investigate the cross-sectional and longitudinal associations of urinary arsenic metabolism with T2D prevalence and glucose changes in relatively higher arsenic exposure, and further to evaluate the underlying roles of oxidative damage in these relationships.

METHODS

We included 796 participants at baseline, among them 509 participants were followed up after 2 years. Logistic regression model and leave-one-out approach were applied to evaluate the associations of arsenic metabolism with T2D prevalence. Linear mixed model was conducted to estimate the relationship of arsenic metabolism with glycemic changes over two years. The associations between arsenic metabolism and indicators of oxidative stress were assessed with a linear regression model. We further performed mediation analysis to investigate the role of oxidative stress in the associations of arsenic metabolism with 2-year change of glucose levels.

RESULTS

Higher urinary MMA% increased T2D prevalence and baseline glucose levels. MMA% was positively associated with 2-year change of glucose levels. Moreover, we observed significant dose-response relationship between MMA% and 8-hydroxy-2-deoxyguanosine (8-OHdG). However, the mediating role of 8-OHdG in the association of MMA% and 2-year change of glucose levels was not observed in this population.

CONCLUSIONS

In this population exposure to relatively higher arsenic levels, higher MMA% contributed to increased T2D prevalence and glucose homeostasis disorder. Arsenic metabolism also affected oxidative stress levels, especially 8-OHdG. Further studies are required to investigate the potential mechanisms.

From a toxin to an obesogen: a review of potential obesogenic roles of acrylamide with a mechanistic approach

Obesity and obesity-related disorders such as cancer, type 2 diabetes, and fatty liver have become a global health problem. It is well known that the primary cause of obesity is positive energy balance. In addition, obesity is the consequence of complex gene and environment interactions that result in excess calorie intake being stored as fat. However, it has been revealed that there are other factors contributing to the worsening of obesity. The presence of nontraditional risk factors, such as environmental endocrine-disrupting chemicals, has recently been associated with obesity and comorbidities caused by obesity. The aim of this review was to examine the evidence and potential mechanisms for acrylamide having endocrine-disrupting properties contributing to obesity and obesity-related comorbidities. Recent studies have suggested that exposure to environmental endocrine-disrupting obesogens may be a risk factor contributing to the current obesity epidemic, and that one of these obesogens is acrylamide, an environmental and industrial compound produced by food processing, particularly the processing of foods such as potato chips, and coffee. In addition to the known harmful effects of acrylamide in humans and experimental animals, such as neurotoxicity, genotoxicity, and carcinogenicity, acrylamide also has an obesogenic effect. It has been shown in the literature to a limited extent that acrylamide may disrupt energy metabolism, lipid metabolism, adipogenesis, adipocyte differentiation, and various signaling pathways, and may exacerbate the disturbances in metabolic and biochemical parameters observed as a result of obesity. Acrylamide exerts its main potential obesogenic effects through body weight increase, worsening of the levels of obesity-related blood biomarkers, and induction of adipocyte differentiation and adipogenesis. Additional mechanisms may be discovered. Further experimental studies and prospective cohorts are needed, both to supplement existing knowledge about acrylamide and its effects, and to clarify its established relationship with obesity and its comorbidities.

DNA damage resulting from human endocrine disrupting chemical exposure: Genotoxicity, detection and dietary phytochemical intervention

In recent years, exposure to endocrine disrupting chemicals (EDCs) has posed an increasing threat to human health. EDCs are major risk factors in the occurrence and development of many diseases. Continuous DNA damage triggers severe pathogenic consequences, such as cancer. Beyond their effects on the endocrine system, EDCs genotoxicity is also worthy of attention, owing to the high accessibility and bioavailability of EDCs. This review investigates and summarizes nearly a decade of DNA damage studies on EDC exposure, including DNA damage mechanisms, detection methods, population marker analysis, and the application of dietary phytochemicals. The aims of this review are (1) to systematically summarize the genotoxic effects of environmental EDCs (2) to comprehensively summarize cutting-edge measurement methods, thus providing analytical solutions for studies on EDC exposure; and (3) to highlight critical data on the detoxification and repair effects of dietary phytochemicals. Dietary phytochemicals decrease genotoxicity by playing a major role in the detoxification system, and show potential therapeutic effects on human diseases caused by EDC exposure. This review may support research on environmental toxicology and alternative chemo-prevention for human EDC exposure.

Single-chemical and mixture effects of multiple volatile organic compounds exposure on liver injury and risk of non-alcoholic fatty liver disease in a representative general adult population

Evidence on liver injury and non-alcoholic fatty liver disease (NAFLD) from volatile organic compounds (VOCs) exposure is insufficient. A cross-sectional study including 3011 US adults from the National Health and Nutrition Examination Survey was conducted to explore the associations of urinary exposure biomarkers (EBs) for 13 VOCs (toluene, xylene, ethylbenzene, styrene, acrylamide, N,N-dimethylformamide, acrolein, crotonaldehyde, 1,3-butadiene, acrylonitrile, cyanide, propylene oxide, and 1-bromopropane) with liver injury biomarkers and the risk of NAFLD by performing single-chemical (survey weight regression) and mixture (Bayesian kernel machine regression [BKMR] and weighted quantile sum [WQS]) analyses. We found significant positive associations of EBs for toluene and 1-bromopropane with alanine aminotransferase (ALT), EBs for toluene, crotonaldehyde, and 1,3-butadiene with asparate aminotransferase (AST), EBs for 1,3-butadiene and cyanide with alkaline phosphatase (ALP), EBs for xylene and cyanide with hepamet fibrosis score (HFS), EBs for the total 13 VOCs (except propylene oxide) with United States fatty liver index (USFLI), and EBs for xylene, N,N-dimethylformamide, acrolein, crotonaldehyde, and acrylonitrile with NALFD; and significant inverse associations of EBs for ethylbenzene, styrene, acrylamide, acrolein, crotonaldehyde, 1,3-butadiene, acrylonitrile, cyanide, and propylene oxide with total bilirubin, EBs for ethylbenzene, styrene, acrylamide, acrolein, 1,3-butadiene, acrylonitrile, and cyanide with albumin (ALB), EBs for ethylbenzene, styrene, acrylamide, N,N-dimethylformamide, acrolein, crotonaldehyde, 1,3-butadiene, acrylonitrile, cyanide, and propylene oxide with total protein (TP), and EB for 1-bromopropane with AST/ALT (all P-FDR<0.05). In BKMR and WQS, the mixture of VOC-EBs was significantly positively associated with ALT, AST, ALP, HFS, USFLI, and the risk of NAFLD, while significantly inversely associated with TBIL, ALB, TP, and AST/ALT. VOCs exposure was associated with liver injury and increased risk of NAFLD in US adults. These findings highlight that great attention should be paid to the potential risk of liver health damage from VOCs exposure.

A systematic review: on the mercaptoacid metabolites of acrylamide, N-acetyl-S-(2-carbamoylethyl)-L-cysteine

Acrylamide is widely found in a variety of fried foods and cigarettes and is not only neurotoxic and carcinogenic, but also has many potential toxic effects. The current assessment of acrylamide intake through dietary questionnaires is confounded by a variety of factors, which poses limitations to safety assessment. In this review, we focus on the levels of AAMA, the urinary metabolite of acrylamide in humans, and its association with other diseases, and discuss the current research gaps in AAMA and the future needs. We reviewed a total of 25 studies from eight countries. In the general population, urinary AAMA levels were higher in smokers than in non-smokers, and higher in children than in adults; the highest levels of AAMA were found in the population from Spain, compared with the general population from other countries. In addition, AAMA is associated with several diseases, especially cardiovascular system diseases. Therefore, AAMA, as a biomarker of internal human exposure, can reflect acrylamide intake in the short term, which is of great significance for tracing acrylamide-containing foods and setting the allowable intake of acrylamide in foods.

Cross-sectional and longitudinal relationships between ozone exposure and glucose homeostasis: Exploring the role of systemic inflammation and oxidative stress in a general Chinese urban population

The adverse health effects of ozone pollution have been a globally concerned public health issue. Herein we aim to investigate the association between ozone exposure and glucose homeostasis, and to explore the potential role of systemic inflammation and oxidative stress in this association. A total of 6578 observations from the Wuhan-Zhuhai cohort (baseline and two follow-ups) were included in this study. Fasting plasma glucose (FPG) and insulin (FPI), plasma C-reactive protein (CRP, biomarker for systemic inflammation), urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG, biomarker for oxidative DNA damage), and urinary 8-isoprostane (biomarker for lipid peroxidation) were repeatedly measured. After adjusting for potential confounders, ozone exposure was positively associated with FPG, FPI, and homeostasis model assessment of insulin resistance (HOMA-IR), and negatively associated with HOMA of beta cell function (HOMA-β) in cross-sectional analyses. Each 10 ppb increase in cumulative 7-days moving average ozone was associated with a 13.19%, 8.31%, and 12.77% increase in FPG, FPI, and HOMA-IR, respectively, whereas a 6.63% decrease in HOMA-β (all P < 0.05). BMI modified the associations of 7-days ozone exposure with FPI and HOMA-IR, and the effects were stronger in subgroup whose BMI ≥24 kg/m². Consistently high exposure to annual average ozone was associated with increased FPG and FPI in longitudinal analyses. Furthermore, ozone exposure was positively related to CRP, 8-OHdG, and 8-isoprostane in dose-response manner. Increased CRP, 8-OHdG, and 8-isoprostane could dose-dependently aggravate glucose homeostasis indices elevations related to ozone exposure. Increased CRP and 8-isoprostane mediated 2.11-14.96% of ozone-associated glucose homeostasis indices increment. Our findings suggested that ozone exposure could cause glucose homeostasis damage and obese people were more susceptible. Systemic inflammation and oxidative stress might be potential pathways in glucose homeostasis damage induced by ozone exposure.

Carbon disulfide exposure induced lung function reduction partly through oxidative protein damage: A cross-sectional and longitudinal analysis

Carbon disulfide (CS₂) exposure has been associated with lung function reduction in occupational population. However, evidence on the general population with relatively low CS₂ exposure is lacking and the mechanism involved remains largely unknown. Urinary CS₂ metabolite (2-mercaptothiazolidine-4-carboxylic acid, TTCA) and lung function were determined in the urban adults from the Wuhan-Zhuhai cohort at baseline in 2011-2012 and were repeated every 3 years. Cross-sectional and longitudinal associations between TTCA and lung function were estimated using linear mixed models. Inflammation and oxidative damage biomarkers in blood/urine were measured to evaluate their potential mediating roles involved. Cross-sectionally, participants in the highest quartile of TTCA level showed a 0.64% reduction in FEV₁/FVC and a -308.22 mL/s reduction in PEF, compared to those in the lowest quartile. Longitudinally, participants with consistently high TTCA level had annually -90.27 mL/s decline in PEF, compared to those with consistently low TTCA level. Mediation analysis revealed that plasma protein carbonyl mediated 49.89% and 22.10% of TTCA-associated FEV₁/FVC and PEF reductions, respectively. Conclusively, there was a cross-sectional and longitudinal association between CS₂ exposure and lung function reduction in the general urban adults, and protein carbonylation (oxidative protein damage) partly mediated lung function reduction from CS₂ exposure.

Temporal trend and global burden of type 2 diabetes attributable to non-optimal temperature, 1990-2019: an analysis for the Global Burden of Disease Study 2019

Exposure to hot or cold temperatures was reported to be associated with increased mortality and morbidity of type 2 diabetes, but few studies have estimated the temporal trend and global burden of type 2 diabetes attributable to non-optimal temperature. Based on the Global Burden of Disease Study 2019, we collected data on the numbers and rates of deaths and disability-adjusted life years (DALYs) of type 2 diabetes attributed to non-optimal temperature. The joinpoint regression analysis was used to estimate the temporal trends of the age-standardized rate of mortality and DALYs from 1990 to 2019 by average annual percentage change (AAPC). From 1990 to 2019, globally, the numbers of deaths and DALYs of type 2 diabetes attributable to non-optimal temperature increased by 136.13% (95% (uncertainty interval) UI: 87.04% to 277.76%) and 122.26% (95% UI: 68.77% to 275.59%), with the number from 0.05 (95% UI: 0.02 to 0.07) million and 0.96 (95% UI: 0.37 to 1.51) million in 1990 to 0. 11 (95% UI: 0.07 to 0.15) million and 2.14 (95% UI: 1.35 to 3.13) million in 2019. The age-standardized mortality rate (ASMR) and DALYs rate (ASDR) of type 2 diabetes attributable to non-optimal temperature showed an increasing trend in the high temperature effect and lower (low, low-middle and middle) socio-demographic index (SDI) region, with AAPCs of 3.17%, 1.24%, 1.61%, and 0.79% (all P < 0.05), respectively. The greatest increased ASMR and ASDR were observed in Central Asia, followed by Western Sub-Saharan Africa and South Asia. Meanwhile, the contribution of type 2 diabetes burden attributable to high temperature gradually increased globally and in five SDI regions. In addition, the global age-specific rate of mortality and DALYs of type 2 diabetes attributable to non-optimal temperature for both men and women almost increased with age in 2019. The global burden of type 2 diabetes attributable to non-optimal temperature increased from 1990 to 2019, particularly in high temperature, regions with lower SDI, and the older population. Appropriate temperature interventions are necessary to curb climate change and increasing diabetes.

The potential role of plasma miR-4301 in PM2.5 exposure-associated lung function reduction

The effect of PM_2.5 exposure on lung function reduction has been well-documented, but the underlying mechanism remains unclear. MiR-4301 may be involved in regulating pathways related to lung injury/repairment, and this study aimed to explore the potential role of miR-4301 in PM_2.5 exposure-associated lung function reduction. A total of 167 Wuhan community nonsmokers were included in this study. Lung function was measured and personal PM_2.5 exposure moving averages were evaluated for each participant. Plasma miRNA was determined by real-time polymerase chain reaction. A generalized linear model was conducted to assess the relationships among personal PM_2.5 moving average concentrations, lung function, and plasma miRNA. The mediation effect of miRNA on the association of personal PM_2.5 exposure with lung function reduction was estimated. Finally, we performed pathway enrichment analysis to predict the underlying pathways of miRNA in lung function reduction from PM_2.5 exposure. We found that each 10 μg/m³ increase in the 7-day personal PM_2.5 moving average concentration (Lag0-7) was related to a 46.71 mL, 1.15%, 157.06 mL/s, and 188.13 mL/s reductions in FEV₁, FEV₁/FVC, PEF, and MMF, respectively. PM_2.5 exposure was negatively associated with plasma miR-4301 expression levels in a dose‒response manner. Additionally, each 1% increase in miR-4301 expression level was significantly associated with a 0.36 mL, 0.01%, 1.14 mL/s, and 1.28 mL/s increases in FEV₁, FEV₁/FVC, MMF, and PEF, respectively. Mediation analysis further revealed that decreased miR-4301 mediated 15.6% and 16.8% of PM_2.5 exposure-associated reductions in FEV₁/FVC and MMF, respectively. Pathway enrichment analyses suggested that the wingless related-integration site (Wnt) signaling pathway might be one of the pathways regulated by miR-4301 in the reduction of lung function from PM_2.5 exposure. In brief, personal PM_2.5 exposure was negatively associated with plasma miR-4301 or lung function in a dose‒response manner. Moreover, miR-4301 partially mediated the lung function reduction associated with PM_2.5 exposure.

Long-term effect of styrene and ethylbenzene exposure on fasting plasma glucose: A gene-environment interaction study

Styrene and ethylbenzene (S/EB) are hazardous pollutants that have attracted worldwide concern. In this prospective cohort study, S/EB exposure biomarker (the sum of mandelic acid and phenylglyoxylic acid [MA+PGA]) and fasting plasma glucose (FPG) were repeatedly measured three times. The polygenic risk score (PRS) based on 137 single nucleotide polymorphisms for type 2 diabetes mellitus (T2DM) was calculated to evaluate cumulative genetic effect. In repeated-measures cross-sectional analyses, MA+PGA (β [95% confidence interval]: 0.106 [0.022, 0.189]) and PRS (0.111 [0.047, 0.176]) were significantly related to FPG. For long-term effect assessment, participants with sustained high MA+PGA or with high PRS had 0.021 (95% CI: -0.398, 0.441) or 0.465 (0.064, 0.866) mmol/L increase in FPG, respectively, over 3 years follow-up, and had 0.256 (0.017, 0.494) or 0.265 (0.004, 0.527) mmol/L increase in FPG, respectively, over 6 years follow-up. We further detected a significant interaction effect between MA+PGA and PRS on FPG change, compared with participants with sustained low MA+PGA and low PRS, those with sustained high MA+PGA and high PRS had 0.778 (0.319, 1.258) mmol/L increase in FPG (P for interaction=0.028) over 6 years follow-up. Our study provides the first evidence that long-term exposure to S/EB potentially increases FPG, which might be aggravated by genetic susceptibility.

Food contaminants and potential risk of diabetes development: A narrative review

The number of people diagnosed with diabetes continues to increase, especially among younger populations. Apart from genetic predisposition and lifestyle, there is increasing scientific and public concern that environmental agents may also contribute to diabetes. Food contamination by chemical substances that originate from packaging materials, or are the result of chemical reactions during food processing, is generally recognized as a worldwide problem with potential health hazards. Phthalates, bisphenol A (BPA) and acrylamide (AA) have been the focus of attention in recent years, due to the numerous adverse health effects associated with their exposure. This paper summarizes the available data about the association between phthalates, BPA and AA exposure and diabetes. Although their mechanism of action has not been fully clarified, in vitro, in vivo and epidemiological studies have made significant progress toward identifying the potential roles of phthalates, BPA and AA in diabetes development and progression. These chemicals interfere with multiple signaling pathways involved in glucose and lipid homeostasis and can aggravate the symptoms of diabetes. Especially concerning are the effects of exposure during early stages and the gestational period. Well-designed prospective studies are needed in order to better establish prevention strategies against the harmful effects of these food contaminants.

Urinary metabolites of multiple volatile organic compounds, oxidative stress biomarkers, and gestational diabetes mellitus: Association analyses

Volatile organic compounds are ubiquitous in the environment, which may cause various adverse health effects. The objectives of this study were to investigate associations of single and mixture of urinary metabolites of volatile organic compounds (mVOCs) with gestational diabetes mellitus (GDM) risk, and examine the possible role of oxidative stress in the associations. This nested case-control study included 454 GDM cases and 454 healthy controls matched by maternal age and infant sex. Urinary concentrations of twenty-one mVOCs and three oxidative stress biomarkers (including 8-OHdG, 8-OHG, and HNEMA), in early pregnancy were measured. Analyses using logistic regression model showed that an interquartile range increase in urinary concentrations of six individual mVOCs (ATCA, BPMA, CEMA, 3HPMA, MU, and TGA) were significantly associated with increased odds of GDM by 19-27%. Weighted quantile sum regression analyses showed that in each quartile increment of the mixture of mVOCs, the odds of GDM increased by 39% (95% CI: 16%, 67%), with 2-aminothiazoline-4-carboxylic acid weighted the most in the associations (weight: 25%). Furthermore, significant associations of the oxidative stress biomarkers with both GDM and certain mVOCs were observed. These results suggested that certain urinary mVOCs (correspondingly, the parent VOCs such as 1-bromopropane, cyanide, and benzene should be concerned as priority ones for regulation and policy making) in early pregnancy were significantly associated with elevated GDM incidence, and the associations were potentially related with oxidative stress biomarkers.

Cross-sectional and Longitudinal Associations Between Propylene Oxide Exposure and Lung Function Among Chinese Community Residents: Roles of Oxidative DNA Damage, Lipid Peroxidation, and Protein Carbonylation

BACKGROUND

Toxicologic studies have reported propylene oxide (PO) exposure may harm the respiratory system, but the association between PO exposure and lung function and potential mechanism remains unclear.

RESEARCH QUESTION

What is the association between PO exposure and lung function and potential mediating mechanism?

STUDY DESIGN AND METHODS

Urinary PO metabolite [N-Acetyl-S-(2-hydroxypropyl)-L-cysteine (2HPMA)] as PO internal exposure biomarker and lung function were measured for 3,692 community residents at baseline and repeated at 3-year follow up. Cross-sectional and longitudinal associations between urinary 2HPMA and lung function were assessed by linear mixed model. Urinary 8-hydroxy-deoxyguanosine, urinary 8-iso-prostaglandin-F2α, and plasma protein carbonyls as biomarkers of oxidative DNA damage, lipid peroxidation, and protein carbonylation, respectively, were measured for all participants to explore their potential roles in 2HPMA-associated lung function decline by mediation analysis.

RESULTS

After adjustment for potential covariates, each threefold increase in urinary 2HPMA was cross sectionally associated with a 26.18 mL (95% CI, -50.55 to -1.81) and a 21.83 mL (95% CI, -42.71 to -0.95) decrease in FVC and FEV1, respectively, at baseline (all P < .05). After 3 years of follow up, 2HPMA was observed to be longitudinally associated with FEV1/FVC decline. No significant interaction effect of smoking or passive smoking was observed (Pinteraction > .05), and the associations between 2HPMA and lung function indexes were persistent among participants who were not smoking and those who were not passive smoking in both baseline and follow-up evaluations. We observed urinary 8-hydroxy-deoxyguanosine partially mediated the associations of 2HPMA with FVC (mediation proportion, 5.48%) and FEV1 (mediation proportion, 6.81%), and plasma protein carbonyl partially mediated the association between 2HPMA and FEV1 (mediation proportion, 3.44%).

INTERPRETATION

PO exposure was associated with lung function decline among community residents, and oxidative DNA damage and protein carbonylation partially mediated PO exposure-associated lung function decline. Further attention on respiratory damage caused by PO exposure is warranted.

Assessment of acrylamide exposure in Spain by human biomonitoring: Risk and predictors of exposure

Acrylamide (AA), a chemical compound currently classified as "reasonably anticipated to be a human carcinogen", is formed through the Maillard reaction in processed carbohydrate-rich foods and is also present in tobacco smoke. The primary sources of AA exposure in the general population are dietary intake and inhalation. Within a 24-h period, humans eliminate approximately 50% of AA in the urine, predominantly in the form of mercapturic acid conjugates such as N-acetyl-S-(2-carbamoylethyl)-L-cysteine (AAMA), N-acetyl-S-(2-carbamoyl-2- hydroxyethyl)-L-cysteine (GAMA3), and N-acetyl-3-[(3-amino-3-oxopropyl)sulfinyl]-L-alanine (AAMA-Sul). These metabolites serve as short-term biomarkers for AA exposure in human biomonitoring studies. In this study, we analysed first-morning urine samples from the adult population (aged 18-65 years) residing in the Valencian Region, Spain, (n = 505). AAMA, GAMA-3 and AAMA-Sul were quantified in 100% of the analysed samples, with geometric means (GM) of 84, 11 and 26 μg L^-1, respectively, while the estimated daily intake of AA in the studied population ranged from 1.33 to 2.13 μg·kg-bw^-1·day^-1 (GM). Statistical analysis of the data indicated that the most significant predictors of AA exposure were smoking and the amount of potato fried products and, biscuits and pastries consumed last 24 h. Based on risk assessment approaches conducted, the findings suggest that exposure to AA could pose a potential health risk. Therefore, it is crucial to closely monitor and continuously evaluate AA exposure to ensure the well-being of the population.

The association between dietary acrylamide intake and the risk of type 2 diabetes incidence in the Tehran lipid and glucose study

This study aimed at investigating the association of acrylamide consumption with the incidence of type 2 diabetes (T2D) in adults. The 6022 subjects of the Tehran lipid and glucose study participants were selected. The acrylamide content of food items were summed and computed cumulatively across follow up surveys. Multivariable Cox proportional hazard regression analyses were performed to estimate the hazards ratio (HR) and 95% confidence interval (CI) of incident T2D. This study was done on men and women, respectively aged 41.5 ± 14.1 and 39.2 ± 13.0 years. The mean ± SD of dietary acrylamide intake was 57.0 ± 46.8 µg/day. Acrylamide intake was not associated with the incidence of T2D after adjusting for confounding variables. In women, a higher acrylamide intake was positively associated with T2D [HR (CI) for Q4: 1.13 (1.01-1.27), P trend: 0.03] after adjusting for confounding factors. Our results demonstrated that dietary intake of acrylamide was associated with an increased risk of T2D in women.

Acrolein Exposure Impaired Glucose Homeostasis and Increased Risk of Type 2 Diabetes: An Urban Adult Population-Based Cohort Study with Repeated Measures

Acrolein is an identified high-priority hazardous air pollutant ubiquitous in daily life and associated with cardiometabolic risk that attracts worldwide attention. However, the etiology role of acrolein exposure in glucose dyshomeostasis and type 2 diabetes (T2D) is unclear. This repeated-measurement prospective cohort study included 3522 urban adults. Urine/blood samples were repeatedly collected for determinations of acrolein metabolites (N-acetyl-S-(3-hydroxypropyl)-l-cysteine, N-acetyl-S-(2-carboxyethyl)-l-cysteine; acrolein exposure biomarkers), glucose homeostasis, and T2D at baseline and a three-year follow-up. We found that each 3-fold increment in acrolein metabolites was cross-sectionally associated with 5.91-6.52% decrement in homeostasis model assessment-insulin sensitivity (HOMA-IS) and 0.07-0.14 mmol/L, 4.02-4.57, 5.91-6.52, 19-20, 18-19, and 23-31% increments in fasting glucose (FPG), fasting insulin (FPI), HOMA-insulin resistance (HOMA-IR), risks of prevalent IR, impaired fasting glucose (IFG), and T2D, respectively; longitudinally, participants with sustained-high acrolein metabolite levels had increased risks of incident IR, IFG, and T2D by 63-80, 87-99, and 120-154%, respectively (P < 0.05). In addition, biomarkers of heme oxygenase-1 activity (exhaled carbon monoxide), lipid peroxidation (8-iso-prostaglandin-F2α), protein carbonylation (protein carbonyls), and oxidative DNA damage (8-hydroxy-deoxyguanosine) mediated 5.00-38.96% of these associations. Our study revealed that acrolein exposure may impair glucose homeostasis and increase T2D risk via mediating mechanisms of heme oxygenase-1 activation, lipid peroxidation, protein carbonylation, and oxidative DNA damage.

Lipid peroxidation mediates the association between iron overload and liver injury: cross-sectional and longitudinal analyses in general Chinese urban adults

Iron overload has been associated with acute/chronic organ failure, but whether iron overload induces liver injury remains unclear. The objectives of this study were to assess the relationship between urinary iron and serum alanine aminotransferase (ALT, a biomarker for liver injury), and investigate the potential mediating roles of lipid peroxidation and oxidative DNA damage in such association. Levels of urinary iron, serum ALT, and urinary biomarkers of lipid peroxidation (8-iso-prostaglandin-F_2α [8-iso-PGF_2α]) and oxidative DNA damage (8-hydroxy-deoxyguano-sine [8-OHdG]) were measured among 5386 observations of 4220 participants from the Wuhan-Zhuhai cohort. The relationships of urinary iron with serum ALT and risk of hyperALT were evaluated by linear mixed model and logistic regression model, respectively. The mediating roles of 8-iso-PGF_2α and 8-OHdG were assessed by mediation analyses. This cross-sectional analysis found that urinary iron was positively associated with ALT (β = 0.032; 95% CI: 0.020, 0.044) and hyperALT prevalence (OR = 1.127; 95% CI: 1.065, 1.192). After 3 years of follow-up, participants with persistent high iron levels had increased risk of developing hyperALT (RR = 3.800; 95% CI: 1.464, 9.972) when compared with those with persistent low iron levels. In addition, each 1% increase in urinary iron was associated with a 0.146% (95% CI: 0.128%, 0.164%) increase and a 0.192% (95% CI: 0.154%, 0.229%) increase in 8-iso-PGF_2α and 8-OHdG, respectively. Urinary 8-iso-PGF_2α (β = 0.056; 95% CI: 0.039, 0.074) was positively associated with ALT, while the association between 8-OHdG and ALT was insignificant. Furthermore, increased 8-iso-PGF_2α significantly mediated 22.48% of the urinary iron-associated ALT increment. Our study demonstrated that iron overload was significantly associated with liver injury, which was partly mediated by lipid peroxidation. Controlling iron intake and regulating lipid peroxidation may help in preventing liver injury.

Arsenic exposure incurs hyperglycemia mediated by oxidative damage in urban adult population: A prospective cohort study with three repeated measures

The associations and potential mechanisms of low to moderate arsenic exposure with fasting plasma glucose (FPG) and type 2 diabetes mellitus (T2DM) are still unclear. To assess the effects of short-term and long-term arsenic exposure on hyperglycemia and the mediating effect of oxidative damage on such association, three repeated-measures studies with 9938 observations were conducted in the Wuhan-Zhuhai cohort. The levels of urinary total arsenic, FPG, urinary 8-iso-prostaglandin F2alpha (8-iso-PGF2α), urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG), and plasma protein carbonyls (PCO) were measured. Generalized linear mixed models were used to evaluate the exposure-response relationships of urinary total arsenic with FPG and the prevalent risks of impaired fasting glucose (IFG), T2DM, and abnormal glucose regulation (AGR). Cox regression models were applied to assess the associations of arsenic exposure with incident risks of IFG, T2DM, and AGR. Mediation analyses were performed to assess the mediating effects of 8-iso-PGF2α, 8-OHdG, and PCO. In cross-sectional analyses, each one-unit increase in natural log-transformed urinary total arsenic was associated with a 0.082 (95% CI: 0.047 to 0.118) mmol/L increase in FPG, as well as a 10.3% (95% CI: 1.4%-20.0%), 4.4% (95% CI: 5.3%-15.2%), and 8.7% (95% CI: 1.2%-16.6%) increase in prevalent risks of IFG, T2DM, and AGR, respectively. In longitudinal analyses, arsenic exposure was further associated with the annual increased rate of FPG with a β (95% CI) of 0.021 (95% CI: 0.010 to 0.033). The incident risks of IFG, T2DM, and AGR were increased without statistical significance when arsenic levels increased. Mediation analyses showed that 8-iso-PGF2α and PCO mediated 30.04% and 10.02% of the urinary total arsenic-associated FPG elevation, respectively. Our study indicated that arsenic exposure was associated with elevated level and progression rate of FPG among general Chinese adults, where lipid peroxidation and oxidative protein damage might be the potential mechanisms.

Daily folate consumption is associated with reduced all-cause and cardiovascular disease mortality among US adults with diabetes, prediabetes, or insulin resistance

We hypothesized that daily folate consumption may have a beneficial effect on mortality among adults with dysglycemia. This prospective cohort study was conducted on 9266, 12,601, and 16,025 US adults with diabetes, prediabetes, and insulin resistance (IR; homeostasis model assessment of IR >2.6), respectively, from the National Health and Nutrition Examination Survey Ⅲ and 1999-2018. Daily folate consumption was obtained from dietary recall. All-cause, cardiovascular disease (CVD), and cancer mortality were obtained by linking to the National Death Index Mortality Data. During 117,746.00, 158,129.30, and 210,896.80 person-years of follow-up, 3356 (1053 CVD and 672 cancer), 3796 (1117 CVD and 854 cancer), and 4340 (1286 CVD and 928 cancer) deaths occurred among participants with diabetes, prediabetes, and IR, respectively. After multivariate adjustment, each 1-unit increase in ln-transformed daily folate consumption was linearly associated with 7.1% (hazard ratio [HR], 0.929; 95% confidence interval [CI], 0.914-0.945), 12.4% (HR, 0.886; 95% CI, 0.860-0.912), and 6.4% (HR, 0.936; 95% CI, 0.903-0.972) decreases in risk of all-cause, CVD, and cancer mortality, respectively, among participants with diabetes. Among participants with prediabetes, each 1-unit increase in ln-transformed daily folate consumption was linearly associated with 3.6% (HR, 0.964; 95% CI, 0.949-0.980), 7.8% (HR, 0.922; 95% CI, 0.895-0.949), and 3.6% (HR, 0.964; 95% CI, 0.932-0.997) decreases in risk of all-cause, CVD, and cancer mortality, respectively. Among participants with IR, each 1-unit increase in ln-transformed daily folate consumption was linearly associated with 5.7% (HR, 0.943; 95% CI, 0.929-0.956) and 9.0% (HR, 0.910; 95% CI, 0.885-0.933) decreases in risk of all-cause and CVD mortality, respectively. Increased daily folate consumption may be beneficial in reducing all-cause and CVD mortality of adults with dysglycemia. More research is needed to explore the underlying mechanisms.

Obesity modifies the association of environmental pyrethroid exposure with glucose homeostasis in the US general adults

Environmental pyrethroids are concerning due to their widespread residues and potential implications on human health. We aimed to assess the association of pyrethroid exposure with glucose homeostasis and examine the interaction between obesity and pyrethroid exposure. A total of 4233 US general adults from the National Health and Nutrition Examination Survey with measured urinary pyrethroid metabolites, fasting plasma glucose (FPG), fasting insulin (FINS), and glycated hemoglobin A1c (HbA1c) were included in the study. The homeostasis model assessment (HOMA2) calculator was utilized to assess insulin resistance (HOMA2-IR), insulin sensitivity (HOMA2-IS), and beta-cell function (HOMA2-β). We estimated the associations of pyrethroid metabolites with glucose homeostasis parameters (FPG, FINS, HbA1c, HOMA2-IR, HOMA2-IS, and HOMA2-β) using multivariate linear regression models and restricted cubic spline models and further assessed the interaction between obesity and pyrethroid metabolites on glucose dyshomeostasis. Urinary 3-phenoxybenzoic acid (3-PBA) was the most detected pyrethroid metabolite (81%) with a median concentration of 0.43 (interquartile range 0.20-1.01) μg/g urinary creatinine. Compared with the participants in the lowest quartile, those in the highest quartile of 3-PBA had a 1.93% (95% confidence interval: 0.46%, 3.42%), 6.69% (1.96%, 11.64%), 1.60% (0.64%, 2.57%), 7.06% (2.33%, 12.01%), -6.59% (-10.72%, -2.28%), and 1.10% (-2.69%, 5.04%) alteration in FPG, FINS, HbA1c, HOMA2-IR, HOMA2-IS, and HOMA2-β, respectively. The restricted cubic spline model displayed a linear positive association between 3-PBA and FPG, FINS, HbA1c, and HOMA2-IR, and a negative association with HOMA2-IS (all P for overall <0.05 and P for non-linear >0.05). Additionally, the association between urinary 3-PBA and FPG was modified by general obesity (P for interaction <0.05), with a more pronounced association observed in obese participants than in non-obese participants. Our findings suggested that pyrethroid exposure was associated with glucose dyshomeostasis. General obesity significantly heightened the association between pyrethroid exposure and increased FPG level.

Associations of urinary 1,3-butadiene metabolite with glucose homeostasis, prediabetes, and diabetes in the US general population: Role of alkaline phosphatase

The chemical - 1,3-butadiene (BD) is a volatile organic compound ubiquitous in the environment. However, the relationships and underlying mechanisms between BD exposure and glucose dyshomeostasis and diabetes in the general population remain unclear. We sought to explore the associations of BD exposure with glucose homeostasis, prediabetes, and diabetes, as well as the role of serum alkaline phosphatase (ALP) in these associations. This study included 5092 US general residents from the National Health and Nutrition Examination Survey with measurements of urinary BD metabolite (N-Acetyl-S-(3,4-dihydroxybutyl)-L-cysteine, DHBMA) and serum ALP. Glucose homeostasis was evaluated by fasting plasma glucose (FPG), fasting serum insulin (FINS), glycohemoglobin (HbA1c), and homeostasis model assessment of insulin resistance (HOMA-IR). HOMA-IR>2.6 was considered as insulin resistance (IR). Prediabetes and diabetes were determined according to the recommendations of the American Diabetes Association. The associations of DHBMA with glucose homeostasis, prediabetes, and diabetes were assessed by linear regression models and logistic regression models. The mediating role of ALP was evaluated by mediation analysis. We observed positive dose-response relationships of DHBMA level with glucose homeostasis indices and ALP levels, as well as with the risks of prediabetes and diabetes (all P < 0.05 and/or P for trend <0.05). Each 2-fold increase in DHBMA was associated with a 1.32%, 9.20%, 0.72%, and 10.64% increase in FPG, FINS, HbA1c, and HOMA-IR, respectively (all P < 0.05). And the corresponding odds ratios (ORs) and 95% confidence intervals (CIs) for IR, prediabetes, and diabetes were 1.36 (1.14, 1.61), 1.51 (1.26, 1.83), and 1.20 (0.90, 1.61), respectively. Furthermore, increased ALP significantly mediated 15.29%-41.12% of the associations of DHBMA with glucose dyshomeostasis and increased risks of prediabetes and diabetes. Our findings indicated that BD exposure was associated with glucose dyshomeostasis and increased risks of prediabetes and diabetes. The upregulation of ALP might play a significant role in these associations.

Urinary metabolites of multiple volatile organic compounds among pregnant women across pregnancy: Variability, exposure characteristics, and associations with selected oxidative stress biomarkers

Volatile organic compounds (VOCs) are a group of pollutants pervasive in daily life with identified adverse health effects. However, no study has investigated the variability in VOC metabolites during pregnancy and their relationships with oxidative stress biomarkers in pregnant women. In the present study, the variability of 21 selected VOC metabolites was examined and their relationships with three selected oxidative stress biomarkers measured in spot urine samples at three trimesters of 1094 pregnant women were analyzed. Nineteen VOC metabolites were ubiquitous in the urine samples with detection rates ranging from 75.9% to 100%. Monohydroxybutenyl mercapturic acid (MHBMA) and s-phenyl mercapturic acid (PMA) had detection rates lower than 1.00%. Intraclass correlation coefficients (ICCs) of the detected analytes at three trimesters ranged 0.07-0.24, and the concentrations were highest in the first trimester. Higher concentrations of some VOC metabolites were related with participant characteristics including higher pre-pregnancy body mass index (BMI), lower education level, unemployment during pregnancy, multiparity, and sampling season of summer or winter. In repeated cross-sectional analyses, interquartile range (IQR) increases in the 19 detected VOC metabolites were positively related with 8-hydroxy-2'-deoxyguanosine (8-OHdG), 8-hydroxyguanosine (8-OHG), and 4-hydroxy nonenal mercapturic acid (HNEMA) with the estimates ranging from 9.00% to 204%. The mixture effect of the VOC metabolites on the oxidative stress biomarkers was further assessed using weighted quantile sum regression (WQS) models and the results showed that the WQS index of VOC metabolite mixture was significantly associated with 8-OHdG (β: 0.37, 0,32, and 0.39 at the 1st, 2nd, and 3rd trimester, respectively), 8-OHG (0.38, 0.32, and 0.39) and HNEMA (1.21, 1.08, and 1.10). Glycidamide mercapturic acid (GAMA), and trans,trans-muconic acid (MU) were the strongest contributors of the mixture effect on 8-OHdG, 8-OHG, and HNEMA, respectively. Overall, urinary concentrations of the VOC metabolites during pregnancy were strongly associated with the oxidative stress biomarkers.

Associations of co-exposure to polycyclic aromatic hydrocarbons and metals with hyperuricemia risk in Chinese coke oven workers: Mediating roles of oxidative damage

Ubiquitous polycyclic aromatic hydrocarbons (PAHs) and metals could induce hyperuricemia and oxidative damage individually, while their co-exposure effects on hyperuricemia risk and the potential roles of oxidative damage in these health outcomes remain poorly understood. We conducted a cross-sectional study in 1379 coke oven workers. We evaluated the levels of PAH-metal exposure and oxidative damage by urinary monohydroxy-PAHs, plasma benzo [a]pyrene-7,8-diol-9,10-epoxide-albumin (BPDE-Alb) adducts, urinary metals, urinary 8-iso-prostaglandin-F2α, and urinary 8-hydroxydeoxyguanosine (8-OH-dG). The subjects were classified into cases of hyperuricemia and controls by the levels of blood uric acid. We found that the sum of multiple hydroxyphenanthrene (ΣOH-Phe) was robustly associated with the increase in hyperuricemia risk, while rubidium and strontium had robust protective associations with hyperuricemia risk (P_trend<0.05). The risk association of ΣOH-Phe was weaker in workers with high levels of rubidium and strontium [P for modifying effect (P_ME) < 0.030]. The protective association of strontium was more pronounced in workers with higher ΣOH-Phe (P_ME = 0.014). We also found that 8-OH-dG was a risk factor for hyperuricemia (P_trend = 0.006) and mediated 10.13% of the elevated hyperuricemia risk associated with ΣOH-Phe. Our findings suggested that individual PAHs and metals, as well as their co-exposure, may influence hyperuricemia risk among coke oven workers, with oxidative DNA damage playing a potential mediating role in their associations.

Associations between urinary biomarkers of oxidative stress and biomarkers of tobacco smoke exposure in smokers

Oxidative stress can contribute to the development of diseases, and may originate from exposures to toxicants commonly found in air pollution and cigarette smoke such as polycyclic aromatic hydrocarbons (PAHs) and volatile organic compounds (VOCs). Yet, associations between these exposures and oxidative stress biomarkers are poorly characterized. We report here novel associations between 14 exposure biomarkers of PAHs and VOCs, and two oxidative stress biomarkers; 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) and 8-isoprostaglandin F_2α (8-isoprostane) in urine obtained from smokers participating in an ongoing clinical study (ESTxENDS, NCT03589989). We also assessed associations between six biomarkers of tobacco smoke exposure (metabolites of nicotine and tobacco-specific nitrosamines (TSNAs)) and both oxidative stress biomarkers. We then quantified the relative importance of each family of the 20 exposure biomarkers on oxidative stress. Participating smokers (153 men and 117 women, median age 44 years) had on average smoked 25 [2-62] years and smoked about 17 [5-40] cigarettes per day at the time of the study. Multiple linear regression results showed an association between 8-oxodG concentrations and the following metabolites in decreasing relative importance: PAHs (beta coefficient β = 0.105, p-value <0.001, partial R² = 0.15) > VOCs (β = 0.028, p < 0.001, partial R² = 0.09) > nicotine (β = 0.226, p < 0.001, partial R² = 0.08); and between 8-isoprostane concentrations and metabolites of PAHs (β = 0.117, p < 0.001, partial R² = 0.14) > VOCs (β = 0.040, p < 0.001, partial R² = 0.14) > TSNAs (β = 0.202, p = 0.003, partial R² = 0.09) > nicotine (β = 0.266, p < 0.001, partial R² = 0.08). Behavioral factors known to contribute to oxidative stress, including sleep quality, physical activity, and alcohol consumption, did not play a significant role. Exposures to PAHs and VOCs among smokers were significantly associated with oxidative stress.

Cross-sectional and longitudinal relationships between urinary 1-bromopropane metabolite and pulmonary function and underlying role of oxidative damage among urban adults in the Wuhan-Zhuhai cohort in China

1-bromopropane is a US Environmental Protection Agency-identified significant hazardous air pollutant with concerned adverse respiratory effect. We aimed to investigate the relationship between 1-bromopropane exposure and pulmonary function and the underlying role of oxidative damage, which all remain unknown. Pulmonary function and urinary biomarkers of 1-bromopropane exposure (N-Acetyl-S-(n-propyl)-L-cysteine, BPMA) and oxidative damage to DNA (8-hydroxy-deoxyguanosine, 8-OHdG) and lipid (8-iso-prostaglandin-F2α, 8-iso-PGF2α) were measured for 3259 Chinese urban adults from the Wuhan-Zhuhai cohort. The cross-sectional relationship of BPMA with pulmonary function and the joint relationship of BPMA and 8-OHdG or 8-iso-PGF2α with pulmonary function were investigated by linear mixed models. The mediating roles of 8-OHdG and 8-iso-PGF2α were evaluated by mediation analysis. Additionally, a panel of 138 subjects was randomly convened from the same cohort to evaluate the stability of BPMA repeatedly measured in urine samples collected over consecutive three days and intervals of one, two, and three years, and to estimate the longitudinal relationship of BPMA with pulmonary function change in three years. We found each 3-fold increase in BPMA was cross-sectionally related to FVC and FEV₁ reductions by 29.88-mL and 25.67-mL, respectively (all P < 0.05). Joint relationship of BPMA and 8-OHdG rather than 8-iso-PGF2α with reduced pulmonary function was observed. Moreover, 8-OHdG significantly mediated 9.44% of the BPMA-related FVC reduction. Findings from the panel revealed a fair to excellent stability (intraclass correlation coefficient: 0.43-0.79) of BPMA in repeated urines collected over a period of three years. Besides, BPMA was longitudinally related to pulmonary function reduction in three years: compared with subjects with persistently low BPMA level, those with persistently high BPMA level had 79.08-mL/year and 49.80-mL/year declines in FVC and FEV₁, respectively (all P < 0.05). Conclusively, 1-bromopropane exposure might impair pulmonary function of urban adult population, and oxidative DNA damage might be a potential mechanism underlying 1-bromopropane impairing pulmonary function especially FVC.

Cross-sectional and longitudinal associations of styrene and ethylbenzene exposure with heart rate variability alternation among urban adult population in China

Styrene and ethylbenzene (S/EB) are the monomers of polystyrene (PS) and polyethylene (PE), respectively, and have been identified as significant hazardous air pollutants by the U.S. Environmental Protection Agency. However, the adverse effects of S/EB on human health, especially cardiovascular health, have not been well established. Urinary biomarker of S/EB exposure and heart rate variability (HRV) were measured in urban adults from the Wuhan-Zhuhai cohort and were repeated after 3-year and 6-year follow-ups. Linear mixed models were used to estimate associations of S/EB exposure biomarker with HRV and longitudinal additional annual change of HRV. The mediating role of transforming growth factor (TGF)-β1 was tested by using mediation analysis. A total of 2842 general adults were included at baseline analysis, and 4748 observations were included in the repeated measurement study. In the cross-sectional analysis, each 1% increment in urinary S/EB exposure biomarker was significantly associated with a 0.106 % (95 % CI: -0.160, -0.052), 0.109 % (-0.169, -0.049), 0.099 % (-0.145, -0.053), 0.040 % (-0.060, -0.020), and 0.031 % (-0.054, -0.007) decrement in low frequency (LF), high frequency (HF), total power (TP), standard deviation of all normal-to-normal intervals (SDNN), and square root of the mean squared difference between adjacent normal-to-normal interval, respectively. Smoking status modified the relationships of urinary S/EB exposure biomarker with TP and SDNN. TGF-β1 mediated 3.09-5.16 % of the association between urinary S/EB biomarker and lower HRV. The follow-up analyses detected a negative association between urinary S/EB exposure biomarker and the additional annual change of LF (β: -0.016; 95 % CI: -0.028, -0.004), HF (-0.014; -0.026, -0.001), and TP (-0.011; -0.021, -0.001). Our findings demonstrated that S/EB exposure was associated with HRV reduction among the general urban adults and the TGF-β pathway may play a part of the mediating role in this association.

The association between biomarkers of acrylamide and cancer mortality in U.S. adult population: Evidence from NHANES 2003-2014

The association between acrylamide (AA) and the development of cancer has been extensively discussed but the results remained controversial, especially in population studies. Large prospective epidemiological studies on the relationship of AA exposure with cancer mortality were still lacking. Therefore, we aimed to assess the association between AA biomarkers and cancer mortality in adult population from National Health and Nutrition Examination Survey (NHANES) 2003-2014. We followed 3717 participants for an average of 10.3 years. Cox regression models with multivariable adjustments were performed to determine the relationship of acrylamide hemoglobin adduct (HbAA) and glycidamide hemoglobin adduct (HbGA) with cancer mortality. Mediation analysis was conducted to demonstrate the mediated role of low-grade inflammation score (INFLA-score) in this correlation. Compared with the lowest quintile, participants with the highest quintile of HbAA, HbGA and HbAA+HbGA had increased cancer mortality risk, and the hazard ratios(HRs) were 2.07 (95%CI:1.04-4.14) for HbAA, 2.39 (95%CI:1.29-4.43) for HbGA and 2.48 (95%CI:1.28-4.80) for HbAA+HbGA, respectively. And there was a considerable non-linearity association between HbAA and cancer mortality (pfor non-linearity = 0.0139). We further found that increased INFLA-score significantly mediated 71.67% in the effect of HbGA exposure on increased cancer mortality risk. This study demonstrates that hemoglobin biomarkers of AA are positively associated with cancer mortality in adult American population and INFLA-score plays a mediated role in this process. Our findings can raise public awareness of environmental and dietary exposure to acrylamide and remind people to refrain from smoking or having acrylamide-rich foods.

Cross-sectional and longitudinal associations of acrolein exposure with pulmonary function alteration: Assessing the potential roles of oxidative DNA damage, inflammation, and pulmonary epithelium injury in a general adult population

BACKGROUND

Acrolein is a significant high priority hazardous air pollutant with pulmonary toxicity and the leading cause of most noncancer adverse respiratory effects among air toxics that draws great attention. Whether and how acrolein exposure impacts pulmonary function remain inconclusive.

OBJECTIVES

To assess the association of acrolein exposure with pulmonary function and the underlying roles of oxidative DNA damage, inflammation, and pulmonary epithelium integrity.

METHODS

Among 3,279 Chinese adults from the Wuhan-Zhuhai cohort, associations of urinary acrolein metabolites (N-Acetyl-S-(2-carboxyethyl)-L-cysteine, CEMA; N-Acetyl-S-(3-hydroxypropyl)-L-cysteine, 3HPMA) as credible biomarkers of acrolein exposure with pulmonary function were analyzed by linear mixed models. Joint effects of biomarkers of oxidative DNA damage (8-hydroxy-deoxyguanosine), inflammation (C-reactive protein, CRP), and pulmonary epithelium integrity (Club cell secretory protein, CC16) with acrolein metabolites on pulmonary function and the mediating roles of these biomarkers were assessed. Besides, a subgroup (N = 138) was randomly recruited from the cohort to assess the stabilities of acrolein metabolites and their longitudinal associations with pulmonary function change in three years.

RESULTS

Significant inverse dose-response relationships between acrolein metabolites and pulmonary function were found. Each 10-fold increment in CEMA, 3HPMA, or ΣUACLM (CEMA + 3HPMA) was cross-sectionally related to a 68.56-, 40.98-, or 46.02-ml reduction in FVC and a 61.54-, 43.10-, or 50.14-ml reduction in FEV₁, respectively (P < 0.05). Furthermore, acrolein metabolites with fair to excellent stabilities were found to be longitudinally associated with pulmonary function decline in three years. Joint effects of acrolein metabolites with 8-hydroxy-deoxyguanosine, CRP, and CC16 on pulmonary function were identified. CRP significantly mediated 5.97% and 5.51% of CEMA-associated FVC and FEV₁ reductions, respectively. 8-hydroxy-deoxyguanosine significantly mediated 6.78%, 6.88%, and 7.61% of CEMA-, 3HPMA-, and ΣUACLM-associated FVC reductions, respectively.

CONCLUSIONS

Acrolein exposure of general adults was cross-sectionally and longitudinally related to pulmonary function decline, which was aggravated and/or partly mediated by oxidative DNA damage, inflammation, and pulmonary epithelium injury.

A review of practical statistical methods used in epidemiological studies to estimate the health effects of multi-pollutant mixture

Environmental risk factors have been implicated in adverse health effects. Previous epidemiological studies on environmental risk factors mainly analyzed the impact of single pollutant exposure on health, while in fact, humans are constantly exposed to a complex mixture consisted of multiple pollutants/chemicals. In recent years, environmental epidemiologists have sought to assess adverse health effects of exposure to multi-pollutant mixtures based on the diversity of real-world environmental pollutants. However, the statistical challenges are considerable, for instance, multicollinearity and interaction among components of the mixture complicate the statistical analysis. There is currently no consensus on appropriate statistical methods. Here we summarized the practical statistical methods used in environmental epidemiology to estimate health effects of exposure to multi-pollutant mixture, such as Bayesian kernel machine regression (BKMR), weighted quantile sum (WQS) regressions, shrinkage methods (least absolute shrinkage and selection operator, elastic network model, adaptive elastic-net model, and principal component analysis), environment-wide association study (EWAS), etc. We sought to review these statistical methods and determine the application conditions, strengths, weaknesses, and result interpretability of each method, providing crucial insight and assistance for addressing epidemiological statistical issues regarding health effects from multi-pollutant mixture.

Associations of Hemoglobin Adducts of Acrylamide and Glycidamide with Prevalent Metabolic Syndrome in a Nationwide Population-Based Study

Environmental and dietary exposures to acrylamide (AA) have been linked with various metabolic-related outcomes, but the results are mixed. However, the association between long-term exposure to AA and the prevalence of metabolic syndrome (MetS) remains unknown. In this study, we aimed to assess the relationship between hemoglobin adducts of AA, biomarkers of internal exposure to AA, and MetS prevalence among a U.S. nationwide population. MetS patients were defined by meeting three or more of the following five characteristics: elevated blood pressure, high fasting glucose, abdominal obesity, hypertriglyceridemia, and lower high-density lipoprotein cholesterol (HDL-C). Multivariate-adjusted logistic regression models and restricted cubic spline models were used to analyze the associations between AA hemoglobin biomarkers and MetS prevalence. A total of 1552 MetS cases were documented. After adjustment for the potential confounders, the odds ratios (95% confidence intervals) of MetS prevalence in the highest quartile of AA hemoglobin biomarkers were 0.60 (0.40-0.89), 1.26 (0.84-1.89), 0.93 (0.71-1.21), and 1.61 (1.18-2.20) for HbAA, HbGA, the sum of HbAA and HbGA (HbAA + HbGA), and the ratio of HbGA to HbAA (HbGA/HbAA), compared with the lowest quartile, respectively. HbAA was significantly and inversely associated with blood pressure, fasting glucose, abdominal obesity, hypertriglyceridemia, and low HDL-C, while the HbGA/HbAA ratio was also positively associated with abdominal obesity, hypertriglyceridemia, and low HDL-C. The restricted cubic spline models revealed a positive relationship between the HbGA/HbAA ratio and the prevalence of MetS, while the HbAA level was inversely associated with MetS prevalence. Our current findings provided epidemiological evidence that HbAA and the HbGA/HbAA ratio were significantly associated with MetS prevalence among general U.S. adults. Further studies should be conducted to examine the association between internal exposure to AA and MetS prevalence.

The Association Between Exposure to Acrylamide and Mortalities of Cardiovascular Disease and All-Cause Among People With Hyperglycemia

Background

Acrylamide is a common environmental volatile organic compound that humans are frequently exposed to in their daily lives. However, whether exposure to acrylamide is associated with long-term survival in patients with hyperglycemia remains largely unknown.

Methods and Results

A total of 3,601 hyperglycemic people were recruited in this study, including 1,247 people with diabetes and 2,354 people with pre-diabetes, who enrolled in the National Health and Nutrition Examination survey (2003–2004, 2005–2006, and 2013–2014). The acrylamide exposure was measured by the serum hemoglobin adduct of acrylamide (HbAA) and glycidamide (HbGA), and the ratio of HbAA and HbGA (HbAA/HbGA) was calculated, which were all categorized into quintiles. The National Death Index was used to identify the participants' death information until 2015. Cox proportional hazards (CPHs) regression models were performed to examine the survival relationship between these biomarkers and mortality. During the 28,652 person-year follow-up, 268 deaths due to the cardiovascular disease (CVD) were documented. After adjustment for multiple confounders, compared with participants in the lowest quintile of HbAA/HbGA, the participants in the highest quintile were more likely to die due to CVD (hazard ratio [HR] = 1.61, 95% CI: 1.09–2.39) and all-cause (HR = 1.59, 95% CI: 1.25–2.01). Moreover, subgroup analysis showed that the highest quintile of HbAA/HbGA in the people with diabetes or pre-diabetes was related to mortalities risk of CVD (HRdiabetes = 1.92, 95% CI: 1.11–3.31; HRpre−diabetes = 1.78, 95% CI: 1.01–3.14) and all-cause mortality (HRdiabetes = 1.81, 95% CI: 1.27–2.58; HRpre−diabetes = 1.59, 95% CI: 1.14–2.20). Additionally, no significant association between the levels of HbAA or HbGA and CVD mortality was observed among people with diabetes or pre-diabetes.

Conclusion

Higher levels of HbAA/HbGA are associated with greater mortalities of CVD and all-cause among hyperglycemic people.

Blood ethylene oxide, systemic inflammation, and serum lipid profiles: Results from NHANES 2013-2016

BACKGROUND

Using data from the National Health and Nutrition Examination Survey (NHANES), this study aimed to explore the relationship between ethylene oxide (EO) exposure and serum lipid profiles as well as the mediation effect of systemic inflammation among the general adult population.

METHODS

This cross-sectional study analyzed NHANES data from 2013 to 2016, examining a total of 2721 participants. The EO biomarker (hemoglobin adduct of EO [HbEO]) was quantified in blood using a high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method. The association among HbEO levels, inflammatory biomarkers, and four serum lipids was evaluated using a multivariable linear regression model. Mediating analysis was performed to examine the effect of inflammatory biomarkers on the relationship between HbEO levels and serum lipid profiles.

RESULTS

As the quartiles of HbEO increased, high-density lipoprotein cholesterol (HDL-C) monotonically decreased (p for trend <0.001). Using the lowest quartile of HbEO as a reference, the percent change for HDL-C was 6.30% (95% CI: 3.89%, 8.71%) in the highest quartile of HbEO. HbEO levels were dose-dependently associated with triglycerides (TG) (p for trend = 0.001). The percent change in TG in the fourth quartile of HbEO was 17.24% (95% CI: 2.01%, 32.48%) compared to the first quartile. Overall, inflammatory biomarkers (hs-CRP, alkaline phosphatase, white blood cell count, neutrophil count, and lymphocyte count) increased monotonically in correlation with increasing HbEO levels (all p for trend <0.01); were positively correlated with total cholesterol (TC), TG, and low-density lipoprotein cholesterol (LDL-C); and were negatively associated with HDL-C. Additionally, inflammatory biomarkers strongly mediated the relationships between HbEO and HDL-C and TG with maximum mediated proportions of 21.40% and 33.40%, respectively.

CONCLUSIONS

These findings suggest that HbEO is closely linked to serum lipid profiles and that systemic inflammation may be a key mediator of this association.

Acrylamide exposure increases cardiovascular risk of general adult population probably by inducing oxidative stress, inflammation, and TGF-β1: A prospective cohort study

Acrylamide (ACR) exposure and consequent health hazards are alarming public health issues that attract worldwide concern. The World Health Organization urges more researches into health hazards from ACR exposure. However, whether and how ACR exposure increases cardiovascular risk remain unclear, and we sought to address these issues in this prospective cohort study conducted on 3024 general adults with 3-year follow-up (N = 871 at follow-up). Individual urinary ACR metabolites (N-Acetyl-S-(2-carbamoylethyl)-L-cysteine [AAMA] and N-Acetyl-S-(2-carbamoyl-2-hydroxyethyl)-L-cysteine [GAMA]) as credible biomarkers of ACR exposure were detected to assess their cross-sectional and longitudinal relationships with 10-year cardiovascular disease (CVD) risk, a well measure of overall cardiovascular risk. Besides, biomarkers of oxidative stress (urinary 8-hydroxy-deoxyguanosine [8-OHdG] and 8-iso-prostaglandin-F2α [8-iso-PGF2α]) and inflammation (circulating mean platelet volume [MPV] and plasma C-reactive protein [CRP]) as well as plasma transforming growth factor-β1 (TGF-β1) were measured to assess their mediating/mechanistic roles in the relationships of ACR metabolites with 10-year CVD risk. We found AAMA, GAMA, and ΣUAAM (AAMA + GAMA) were cross-sectionally and longitudinally related to increased 10-year CVD risk with odds ratios (95% confidence intervals [CIs]) of 1.32 (1.04, 1.70), 1.81 (1.36, 2.40), and 1.40 (1.07, 1.82), respectively, and risk ratios (95% CIs) of 1.99 (1.10, 3.60), 2.48 (1.27, 4.86), and 2.13 (1.15, 3.94), respectively. Furthermore, 8-OHdG, 8-iso-PGF2α, MPV, CRP, and TGF-β1 were found to significantly mediate 8.06-48.92% of the ACR metabolites-associated 10-year CVD risk increment. In summary, daily ACR exposure of general adults was cross-sectionally and longitudinally associated with increased cardiovascular risk, which was partly mediated by oxidative stress, inflammation, and TGF-β1, suggesting for the first time that ACR exposure may well increase cardiovascular risk of general adult population partly by mechanisms of inducing oxidative stress, inflammation, and TGF-β1. Our findings have important public health implications that provide potent epidemiological evidence and vital mechanistic insight into cardiovascular risk increment from ACR exposure.

Acrylamide and Potential Risk of Diabetes Mellitus: Effects on Human Population, Glucose Metabolism and Beta-Cell Toxicity

Diabetes mellitus is a frequent endocrine disorder characterized by hyperglycemia. Acrylamide (AA) is food contaminant formed during the high-temperature processing of food rich in carbohydrates and low in proteins. Recent human epidemiological studies have shown a potential association between AA exposure and the prevalence of diabetes in the general population. In male rats, AA treatment promoted pancreatic islet remodeling, which was determined by alpha-cell expansion and beta-cell reduction, while in female rats AA caused hyperglycemia and histopathological changes in pancreatic islets. In vitro and in vivo rodent model systems have revealed that AA induces oxidative stress in beta cells and that AA impairs glucose metabolism and the insulin signaling pathway. Animal studies have shown that diabetic rodents are more sensitive to acrylamide and that AA aggravates the diabetic state. In this review, we provide an overview of human epidemiological studies that examined the relation between AA exposure and glucose disorders. In addition, the effects of AA treatment on pancreatic islet structure, beta-cell function and glucose metabolism in animal models are comprehensively analyzed with an emphasis on sex-related responses. Furthermore, oxidative stress as a putative mechanism of AA-induced toxicity in beta cells is explored. Finally, we discuss the effects of AA on diabetics in a rodent model system.

Acrylamide in widely consumed foods - a review

Acrylamide (AA) is considered genotoxic, neurotoxic and a 'probable human carcinogen'. It is included in group 2 A of the International Agency for Research on Cancer (IARC). The formation of AA occurs when starch-based foods are subjected to temperatures higher than 120 °C in an atmosphere with very low water content. The aim of this review is to shed light on the toxicological aspects of AA, showing its regulatory evolution, and describing the most interesting mitigation techniques for each food category involved, with a focus on compliance with EU legislation in the various classes of consumer products of industrial origin in Europe.

Assessment of the genotoxicity of acrylamide

EFSA was requested to deliver a statement on a recent publication revisiting the evidence for genotoxicity of acrylamide (AA). The statement was prepared by a Working Group and was endorsed by the CONTAM Panel before its final approval. In interpreting the Terms of Reference, the statement considered the modes of action underlying the carcinogenicity of AA including genotoxic and non‐genotoxic effects. Relevant publications since the 2015 CONTAM Panel Opinion on AA in food were reviewed. Several new studies reported positive results on the clastogenic and mutagenic properties of AA and its active metabolite glycidamide (GA). DNA adducts of GA were induced by AA exposure in experimental animals and have also been observed in humans. In addition to the genotoxicity of AA, there is evidence for both secondary DNA oxidation via generation of reactive oxygen species and for non‐genotoxic effects which may contribute to carcinogenesis by AA. These studies extend the information assessed by the CONTAM Panel in its 2015 Opinion, and support its conclusions. That Opinion applied the margin of exposure (MOE) approach, as recommended in the EFSA Guidance for substances that are both genotoxic and carcinogenic, for risk characterisation of the neoplastic effects of AA. Based on the new data evaluated, the MOE approach is still considered appropriate, and an update of the 2015 Opinion is not required at the present time.

MiR-27a-5p regulates acrylamide-induced mitochondrial dysfunction and intrinsic apoptosis via targeting Btf3 in rats

Acrylamide (AA), a potential carcinogen, is commonly formed in foods rich in carbohydrates at high heat. It is known that AA-induced mitochondrial dysfunction is responsible for its toxicity. Previously we found AA exposure increased miR-27a-5p expression in livers of SD rats. Here, the regulation mechanism of miR-27a-5p in mitochondrial dysfunction was investigated in rat liver cell lines (IAR20) and SD rats. The results showed that the overexpressed miR-27a-5p contributes to modulating mitochondrial dysfunction and Btf3 is identified as its target gene. The knockdown of Btf3 increases the cleaved PARP1 level and the phosphorylation of ATM and p53, which results in mitochondria-dependent apoptosis. Therefore, the miR-27a-5p-Btf3-ATM-p53 axis might play a vital role in the promotion of AA-induced cell apoptosis through disrupting mitochondrial structure and function. This would provide a potential target for the assessment and intervention of AA toxicity.

Repeated measurements of 21 urinary metabolites of volatile organic compounds and their associations with three selected oxidative stress biomarkers in 0-7-year-old healthy children from south and central China

Human beings are extensively and concurrently exposed to multiple volatile organic compounds (VOCs, including some Class I human carcinogens), which may induce oxidative stress in human body. Data on urinary metabolites of VOCs (mVOCs) among young children are limited. No studies have examined their inter-day variability of mVOCs and their associations with oxidative stress biomarkers (OSBs) using repeated urine samples from children. In this study, we measured twenty one mVOCs and three OSBs [8-hydroxy-2'-deoxyguanosine (8-OHdG; for DNA), 8-hydroxyguanosine (8-OHG; for RNA], and 4-hydroxy nonenal mercapturic acid (HNEMA; for lipid)] in 390 urine samples of 130 children (three samples on three consecutive days provided by each participant) aged 0-7 years from September 2018 to January 2019 in Shenzhen, south China, and Wuhan, central China. HPMMA (3-hydroxypropyl-1-methyl mercapturic acid/N-Acetyl-S-(3-hydroxypropyl-1-methyl)-l-cysteine), 3HPMA (3-hydroxypropyl mercapturic acid/N-Acetyl-S-(3-hydroxypropyl)-l-cysteine), and ATCA (2-aminothiazoline-4-carboxylic acid) had higher specific gravity-adjusted median concentrations (1 383, 286, and 273 μg/L, respectively) than the others. Intraclass correlation coefficients of mVOCs ranged from 0.29 to 0.71. After false-discovery rate (FDR, defined as FDR q-value < 0.05) adjustment, linear mixed-effects models revealed that 14 mVOCs were positively associated with 8-OHdG (β range: 0.09-0.37), 11 mVOCs were positively associated with 8-OHG (β range: 0.08-0.30), and 11 mVOCs were positively associated with HNEMA (β range: 0.21-0.70) in urine. Considering the weight of the mVOC index accounted for the associations, based on the weighted quantile sum regression model, parent compounds of DHBMA (3,4-dihydroxybutyl mercapturic acid/N-Acetyl-S-(3,4-dihydroxybutyl)-l-cysteine) and t,t-MA (trans,trans-muconic acid) should be listed as priority VOCs for management to mitigate health risks. For the first time, this study characterized the inter-day variability of urinary mVOCs and their associations with selected OSBs (8-OHdG, 8-OHG, and NHEMA) in young, healthy Chinese children.

Associations of propylene oxide exposure with fasting plasma glucose and diabetes: Roles of oxidative DNA damage and lipid peroxidation

Whether propylene oxide (PO) exposure is associated with hyperglycemia were rarely explored. We aimed to determine the relationship between PO exposure and glucose metabolism, and potential role of oxidative stress. Among 3294 Chinese urban adults, urinary PO metabolite (N-Acetyl-S-(2-hydroxypropyl)-L-cysteine, 2HPMA), biomarkers of oxidative DNA damage (8-oxo-7,8-dihydro-20-deoxyguanosine, 8-OHdG) and lipid peroxidation (8-isoprostane, 8-iso-PGF_2α) in urine were determined. The associations of 2HPMA with 8-OHdG, 8-iso-PGF_2α, fasting plasma glucose (FPG), and risk of diabetes were explored. The roles of 8-OHdG and 8-iso-PGF_2α on association of 2HPMA with FPG and risk of diabetes were detected. After adjusted for potential confounders, each 1-unit increase in log-transformed concentration of 2HPMA was associated with a 0.15-mmol/L increase in FPG level, and the adjusted OR (95% CI) of diabetes by the associations of log-transformed urinary 2HPMA concentrations was 1.47 (95% CI: 1.03-2.11). Combination effects of 2HPMA with 8-OHdG or 8-iso-PGF_2α on risk of diabetes were detected, and elevated 8-iso-PGF_2α significantly mediated 34.5% of the urinary 2HPMA-associated FPG elevation. PO exposure was positively associated with FPG levels and risk of diabetes. PO exposure combined with DNA oxidative damage or lipid peroxidation may increase the risk of diabetes, and lipid peroxidation may partially mediate the PO exposure-induced FPG elevation.

Exposure assessment of Spanish lactating mothers to acrylamide via human biomonitoring

Acrylamide (AA) is an organic compound classified as "Probably carcinogenic to humans" (Group 2 A) that can be found principally in processed carbohydrate-rich foods and tobacco smoke. In humans, after exposure, AA is rapidly metabolized and excreted in urine, predominantly as N-acetyl-S-(2-carbamoylethyl)-l-cysteine (AAMA), N-acetyl-S-(2-carbamoyl-2-hydroxyethyl)-l-cysteine (GAMA3) and N-Acetyl-3-[(3-amino-3-oxopropyl)sulfinyl]-L-alanine (AAMA-Sul), which can be used as short-term biomarkers of exposure to AA. In this study, the presence of AA metabolites in urine samples of lactating mothers living in Spain (n = 114) was analyzed by "dilute and shoot" and liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). All urinary metabolites were detected in 100% of the analyzed samples, with geometric means of 70, 33 and 15 ng ml^-1, for AAMA, AAMA-Sul and GAMA3, respectively. The consumption of coffee, bread and precooked food products were found to be significant predictors of internal exposure to AA. An estimated daily intake (EDI) of AA based on its urinary metabolites was calculated, obtaining mean values between 1.2 and 1.9 μg AA·kg bw^-1·day^-1 in the target population. The risk assessment was evaluated using both reverse and forward dosimetry, showing an average margin of exposure (MOE) of 349 and a hazard quotient (HQ) of 5.5. Therefore, AA exposure should be considered a medium priority for risk assessment follow-up in the Spanish population, since a health concern with respect to non-neoplastic toxicity could not be discarded.

Urinary metabolites of multiple volatile organic compounds among general population in Wuhan, central China: Inter-day reproducibility, seasonal difference, and their associations with oxidative stress biomarkers

General population are concurrently and extensively exposed to many volatile organic compounds (VOCs), including some Group 1 human carcinogens, such as 1,3-butadiene. However, only a few studies assessed internal exposure levels of VOCs; particularly, very limited studies have examined associations between the urinary concentrations of multiple VOC metabolites (mVOCs) and oxidative stress biomarkers (OSBs) among the general population. In this study, 21 mVOCs and three OSBs including 8-hydroxy-2'-deoxyguanosine (8-OHdG; for DNA), 8-hydroxyguanosine (8-OHG; for RNA), and 4-hydroxy nonenal mercapturic acid (HNEMA; for lipid) were measured in 406 urine samples collected from 128 healthy adults during autumn and winter of 2018 in Wuhan, central China, including repeated samples taken in 3 d from 75 volunteers. Inter-day reproducibility for most mVOCs was good to excellent; urinary concentrations of mVOCs in winter were generally higher than those in autumn. Risk assessment was conducted by calculating hazard quotients for the parent compounds, and the results suggested that acrolein, 1,3-butadiene, and cyanide should be considered as high-priority hazardous ones for management. After false-discovery adjustment, 16 of the studied mVOCs were positively associated with 8-OHdG and 8-OHG (β values ranged from 0.04 to 0.48), and four mVOCs were positively associated with HNEMA (β values ranged from 0.21 to 0.78). Weighted quantile sum regression analyses were used to assess associations of mVOC mixture and OSBs, and we found significantly positive associations between the mixture index and OSBs, among which the strongest mVOC contributors for the associations were 2-methylhippuric acid for both DNA (20%) and RNA (17%) oxidative damage, and trans,trans-muconic acid (50%) for lipid peroxidation. This study firstly reported good to excellent short-term reproducibility, seasonal difference in autumn and winter, and possible health risk in urinary concentrations of multiple mVOCs among the general population.

Negative Association between Acrylamide Exposure and Metabolic Syndrome Markers in Adult Population

Metabolic syndrome encompasses multiple conditions that increase the risk of cardiovascular disease, and exposure to environmental chemicals can cause metabolic syndrome. This cross-sectional study analyzed data from the US National Health and Nutrition Examination Survey (2003-2006) on 4318 adult participants to assess the association between acrylamide (AA) exposure and metabolic syndrome. Concentrations of hemoglobin-adducted AA (HbAA) and hemoglobin-adducted glycidamide (HbGA) were evaluated. Metabolic syndrome markers related to HbAA and HbGA and the effect of exposure to AA and GA on the prevalence of metabolic syndrome were studied by ANOVA and multivariate logistic regression analyses, respectively. HbAA concentration inversely correlated with the number of metabolic syndrome markers (p < 0.05). An increased HbAA concentration was noted with reduced high triglyceride and low high-density lipoprotein cholesterol levels in the adjusted model (p < 0.05). High fasting plasma glucose level significantly correlated with HbGA concentration in the adjusted model. In conclusion, AA exposure alters metabolic syndrome markers in adults. Additional clinical and animal studies will clarify the role of AA exposure at different stages in the progression of metabolic syndrome-related diseases.

Acrylamide exposure and pulmonary function reduction in general population: The mediating effect of systemic inflammation

Acrylamide exposure along with resultant potential adverse health effects have attracted global concern, and the World Health Organization calls for more and urgent studies on the health risks from acrylamide. However, the association and mechanism between acrylamide exposure and pulmonary dysfunction remain unclear. Our goals were to investigate the relationship of internal acrylamide exposure with lung function reduction, and the potential mediating role of systematic inflammation in that relationship. Our study was conducted within the Wuhan-Zhuhai cohort. Urinary biomarkers of acrylamide exposure (N-acetyl-S-(2-carbamoylethyl)-l-cysteine, AAMA; N-acetyl-S-(2-carbamoyl-2-hydroxyethyl)-l-cysteine, GAMA) and lung function were determined among 3271 general adults, of whom 2595 had test results of systemic inflammatory marker plasma C-reactive protein (CRP). We employed linear mixed models to assess the relations among urinary acrylamide metabolites, pulmonary function and plasma CRP, and PRODCLIN program to evaluate the mediating role of CRP. We observed that urinary acrylamide metabolites were inversely and dose-dependently related to lung function (P trend<0.05). Each 1-unit increment in log-transformed level of AAMA, GAMA, or AAMA+GAMA (ΣUAAM) was significantly (P < 0.05) related to a 59.9-, 64.2-, or 64.3-mL reduction in FVC, and a 53.9-, 59.7-, or 58.5-mL reduction in FEV₁, respectively. Such relationships were independent of smoking, and were significant in physically inactive rather than physically active participants. AAMA (β = 0.10), GAMA (β = 0.16) and ΣUAAM (β = 0.12) were significantly (P < 0.05) related to increased CRP, which was significantly (P < 0.05) related to reduced FVC (β = -55.3) and FEV₁ (β = -40.6). We further found that increased CRP significantly (P < 0.05) mediated 6.34-11.1% of the urinary acrylamide metabolites-associated lung function reductions. For the first time, our findings suggested that exposure to acrylamide in daily life was related to reduced lung function and increased systemic inflammation in general population, and systemic inflammation further mediated acrylamide-associated lung function reduction, indicating a potential mechanistic role of systemic inflammation underlying pulmonary dysfunction from acrylamide exposure.

Association of acrylamide and glycidamide haemoglobin adduct levels with diabetes mellitus in the general population

The frequency and duration of exposure to acrylamide (AA) from the environment and diet are associated with a range of adverse health effects. However, whether long-term AA exposure is related to diabetes mellitus (DM) remains unknown. Data from 3577 adults in the National Health and Nutrition Examination Survey (NHANES) 2005-2006 and 2013-2016 aged ≥ 20 years was analysed. The main analyses applied multivariate logistic regression and restricted cubic spline models to investigate the associations between DM and AA haemoglobin biomarkers, including haemoglobin adducts of acrylamide and glycidamide (HbAA and HbGA), the sum of HbAA and HbGA (HbAA + HbGA), and the ratio of HbGA to HbAA (HbGA/HbAA) levels. After multivariable adjustment, the odds ratios (95% confidence intervals) for DM comparing the highest with the lowest AA haemoglobin biomarker quartiles were 0.71 (0.55, 0.93), 0.92 (0.71, 1.18), 0.80 (0.62, 1.03) and 1.95 (1.51, 2.51) for HbAA, HbGA, HbAA + HbGA and HbGA/HbAA, respectively. The restricted cubic spline model demonstrated that HbAA was linearly and inversely associated with risk of DM (P for trend = 0.013), while HbGA/HbAA was nonlinearly and positively associated with the prevalence of DM (P for trend <0.001). These results support for epidemiological evidence that the HbAA and HbGA/HbAA are significantly associated with DM. Further studies are warranted to infer the causal role of AA exposure in the prevalence of DM.

Rosmarinic acid attenuates acrylamide induced apoptosis of BRL-3A cells by inhibiting oxidative stress and endoplasmic reticulum stress

Acrylamide (AA) is a common endogenous contaminant in food, with a complex toxicity mechanism. The study on liver damage to experimental animals caused by AA has aroused a great attention. Rosmarinic acid (RosA) as a natural antioxidant shows excellent protective effects against AA-induced hepatotoxicity, but the potential mechanism is still unclear. In the current study, the protective effect of RosA on BRL-3A cell damage induced by AA was explored. RosA increased the activity of SOD and GSH, reduced the content of ROS and MDA, and significantly reduced the oxidative stress (OS) damage of BRL-3A cells induced by AA. RosA pretreatment inhibited the MAPK signaling pathway activated by AA, and down-regulated the phosphorylation of JNK, ERK and p38. RosA pretreatment also reduced the production of calcium ions caused by AA. In addition, the key proteins p-IRE1α, XBP-1s, TRAF2 of the IRE1 pathway, and the expression of endoplasmic reticulum stress (ERS) characteristic proteins GRP78, p-ASK1, Caspase-12 and CHOP were also down-regulated by RosA. NAC blocked the activation of the MAPK signaling pathway and inhibited the ERS pathway. RosA reduced the rate of apoptosis and down-regulated the expression of Bax/Bcl-2 and Caspase-3, thereby inhibiting AA-induced apoptosis. In conclusion, RosA reduced the OS and ERS induced by AA in BRL-3A cells, thereby inhibiting cell apoptosis, and it could be used as a potential protective agent against AA toxicity.