Association between urinary metabolites of volatile organic compounds and cardiovascular disease in the general population from NHANES 2011-2018

Association of volatile organic compound metabolites with hearing loss: unveiling their potential mechanism and intervention target

Hearing loss (HL) is an otolaryngology disease susceptible to environmental pollutants. Volatile organic compounds (VOCs), as a class of chemical pollutants with evaporation propensity, pose a great threat to human health. However, the association between VOCs and HL remains unclear. This study aimed to explore the association between urinary-specific VOC metabolites and HL. It included 1048 participants from the National Health and Nutrition Examination Survey (NHANES) from 2011 to 2012. Multivariate linear regression models, smooth curve analysis, and stratified analysis were employed to investigate the relationship between urinary-specific VOC metabolite concentrations and pure tone audiometry (PTA) across three different frequencies. A two-piecewise linear regression model was employed to analyze the threshold effects of urinary-specific VOC metabolites on hearing threshold changes. Furthermore, a comparative toxicogenomics database (CTD) and functional gene enrichment were constructed. An interaction network of transcription factors, genes, and non-coding RNA was constructed to further confirm the upstream and downstream regulatory relationships. Molecular docking analyses were conducted to explore the potential binding modes and critical docking sites. Additionally, a moderation analysis was conducted to investigate the role of oxidative stress in moderating the influence of VOC metabolites on hearing. Multivariate linear regression model discerned a significant correlation between cyanide 2-aminothiazoline-4-carboxylic acid (ATCA) with speech-frequency PTA and N-acetyl-S-(3,4-dihydroxybutyl)-L-cysteine (DHBMA) with high-frequency PTA. The smoothed curve and threshold effect analysis corroborated a positive linear relationship between cyanide ATCA and speech-frequency PTA without a threshold effect only in the 20-34 age group. Additionally, the bioinformatics analysis discovered pathogenic genes related to cyanide-induced HL and suggested that oxidative stress responses play a critical role in this biological process. Furthermore, the moderation effect of total bilirubin (TB), an oxidative stress-associated molecule, was ascertained on the effects of ATCA on hearing. Our findings suggest a potential link between VOC metabolites and hearing and indicate the crucial role of oxidative stress responses in this association.

Exposure to Volatile Organic Compounds in Relation to Visceral Adiposity Index and Lipid Accumulation Product Among U.S. Adults: NHANES 2011-2018

Volatile organic compounds (VOCs) are associated with obesity health risks, while the association of mixed VOCs with visceral adiposity indicators remains unclear. In this study, a total of 2015 adults from the National Health and Nutrition Examination Survey (NHANES) were included. Weighted generalized linear models, restricted cubic spline (RCS), weighted quantile sum (WQS), and Bayesian kernel machine regression (BKMR) were adopted to assess the association of VOC metabolites (mVOCs) with the visceral adiposity index (VAI) and lipid accumulation product (LAP). Multiple mVOCs were positively associated with the VAI and LAP in the single-exposure model, especially N-acetyl-S-(2-carboxyethyl)-L-cysteine (CEMA) and N-acetyl-S-(N-methylcarbamoyl)-L-cysteine (AMCC). The associations of mVOCs with VAI and LAP were more significant in <60-year-old and non-obese individuals, with interactions of CEMA with age and AMCC with obesity status. Nonlinear relationships between certain mVOCs and the VAI or the LAP were also observed. In the WQS model, co-exposure to mVOCs was positively correlated with the VAI [β (95%CI): 0.084 (0.022, 0.147)]; CEMA (25.24%) was the major contributor. The result of the BKMR revealed a positive trend of the association between mixed mVOCs and the VAI. Our findings suggest that VOC exposure is strongly associated with visceral obesity indicators. Further large prospective investigations are necessary to support our findings.

Association between urinary volatile organic compounds metabolites and rheumatoid arthritis among the adults from NHANES 2011-2018

Rheumatoid arthritis (RA) is closely associated with environmental factors. Volatile organic compounds (VOCs) are a common environment pollutant which can induce autoimmune diseases. However, studies on the relationship between VOCs and RA are still unclear. This study aimed to evaluate the potential associations between exposure to urinary VOCs and RA risk among adults. Data was analyzed from the National Health and Nutrition Examination Survey (NHANES) 2011-2018. We used logistics regression, restricted cubic splines (RCS) model, (Weighted Quantile Sum) WQS, qgcomp and (Bayesian Kernel Machine Regression) BKMR models to assess single and mixed relationships between VOCs and RA. A total of 3390 participants and 15 urinary VOCs included in this study. The results showed that AMCC, CEMC, DHBC, MB3C, PHGA, and PMMC were significantly higher than in RA compare to the participants without RA. Logistic regression model reveals that AAMC, AMCC, CEMC, CYMC, DHBC, HPMC, and MB3C were positive correlation with RA which age between 20 and 50. Then the WQS, qgcomp, and BKMR model suggest a positive association between mixed urinary VOCs and RA, with WQS and qgcomp model highlighting CYMC and CEMC as the major contributors in age 20-59 group. In BKMR analysis, the overall effects of co-exposure displayed CYMC, CEMC, and AMCC has significant positive with RA in age 20-59. Furthermore, RCS regression proved the positive linear relationship between CYMC, AMCC, and CEMC with RA. According to our study results, we demonstrated that exposure to certain urinary VOCs (CYMC, CEMC, and AMCC) is associated with an increased prevalence of RA among adults that age 20-59.

Acrylamide Exposure and Cardiovascular Risk: A Systematic Review

Background/Objectives: Acrylamide is a food contaminant formed during high-temperature cooking processes, leading to unintentional human exposure. Diet is the primary source for non-smokers, with potatoes, cereals, and coffee being the main contributors. While animal studies have demonstrated that acrylamide is neurotoxic, genotoxic, mutagenic, and cardiotoxic, its effects on human cardiovascular health remain poorly understood. This study aimed to evaluate the association between acrylamide exposure and cardiovascular risk. Methods: A comprehensive literature search was conducted across four databases without restrictions on publication year or language (last search: 1 July 2024). The risk of bias was assessed using the Joanna Briggs Institute critical appraisal tools. Results: In total, 28 studies were included, predominantly from the US NHANES sample and with cross-sectional designs. Higher acrylamide exposure was associated with an increased risk of cardiovascular mortality but was inversely associated with glucose and lipid levels, as well as key cardiovascular risk factors such as diabetes, obesity, and metabolic syndrome. Conversely, glycidamide-acrylamide's most reactive metabolite-was positively associated with elevated glucose and lipid levels, higher systolic blood pressure, and increased obesity prevalence. Conclusions: These findings suggest that the adverse cardiovascular effects of acrylamide may be mediated by its conversion to glycidamide. Further research is necessary to fully elucidate the impact of acrylamide on cardiovascular health. Meanwhile, public health efforts should continue to focus on mitigation strategies within the food industry and raising public awareness about exposure.

Volatile organic compounds (VOC) metabolites in urine are associated with increased systemic inflammation levels, and smokers are identified as a vulnerable population

BACKGROUND

Previous studies indicated that exposure to VOCs was linked to increased systemic inflammation levels. However, the dose-response relationships between urine VOCs metabolites and systemic inflammation have not been established, and the key metabolite of the toxic compounds has not been identified.

METHODS

We used data in 7007 US adults in the NHANES cycles (2011-2018) across 8 years. Urinary VOC metabolites were measured using ultra-performance liquid chromatography and electrospray tandem mass spectrometry (UPLC-ESI/MSMS). VOC metabolites were adjusted by urinary creatinine level before analysis. Systemic inflammation was assessed by systemic immune-inflammation index (SII) and systemic inflammation response index (SIRI) indices. Generalized linear models, restricted cubic splines (RCS), and weighted quantile sum (WQS) regression were applied to evaluate the associations, exposure-response (E-R) curve and identify the key contributor compound, adjusting for gender, age, race, BMI, marital condition, education level, smoking level, alcohol consumption and physical activity. Smoking status was assessed as an effect modifier.

RESULTS

Significant and robust positive correlations were found between 8 VOC metabolites and both SII and SIRI. They were N-Acetyl-S-(2-carboxyethyl)-L-cysteine (CEMA), N-Acetyl-S-(2-cyanoethyl)-L-cysteine (CYMA), N-Acetyl-S-(3,4-dihydroxybutyl)-L-cysteine (DHBMA), N-Acetyl-S-(3-hydroxypropyl)-L-cysteine (3HPMA), mandelic acid (MA), N-Acetyl-S-(4-hydroxy-2-butenyl)-L-cysteine (MHBMA3), phenylglyoxylic acid (PGA), and N-Acetyl-S-(3-hydroxypropyl-1-methyl)-L-cysteine (HPMMA). The RCS curves showed J-shaped or exponential shaped E-R relationships for most VOC metabolites. WQS regression found that exposure to the mixture of VOC metabolites was related to increased systemic inflammation, and MA was the key VOC metabolite contributing most to systemic inflammation levels. Smokers exhibited higher levels of urinary VOCs and larger susceptibility to VOC-related increases in SII and SIRI compared to non-smokers.

CONCLUSION

This study demonstrated a strong link between urinary VOC metabolites and increased systemic inflammation, and smokers were more susceptible. Our findings highlighted the significance of reducing VOC exposure to mitigate the inflammation levels, particularly for smokers.

Association of urinary volatile organic compounds and chronic kidney disease in patients with diabetes: real-world evidence from the NHANES

BACKGROUND

Chronic kidney disease (CKD) is common in patients with diabetes mellitus (DM). Volatile organic compounds (VOCs) are widespread pollutants that may impact DM development.

OBJECTIVE

This study aims to explore the association between urinary VOC metabolites and CKD in patients with DM.

METHODS

Adult National Health and Nutrition Examination Survey (NHANES) 2011 to 2018 participants with DM were included in this study. CKD was defined as an estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73 m2 or urine albumin-to-creatinine ratio (UACR) ≥ 30 mg/g. Multivariable regression models were used to analyze the associations between urinary VOC metabolites and CKD.

RESULTS

A total of 1,295 participants with DM and a mean age of 59 years were included. After adjustment for demographic and clinical characteristics, elevated levels of N-acetyl-S-(2-carbamoylethyl)-L-cysteine (AAMA) (tertile 2: adjusted odds ratio (aOR)  =   1.81, 95% confidence interval (CI): 1.15-2.85, p  =  0.012), N-acetyl-S-(N-methylcarbamoyl)-L-cysteine (AMCC) (tertile 2: aOR   =  1.84, 95% CI: 1.10-3.08, p  =  0.021), DHBMA (tertile 3: aOR  =  1.93, 95% CI: 1.12-3.35, p  =   0.020), and phenylglyoxylic acid (PGA) (tertile 3: aOR   =  1.71, 95% CI: 1.11-2.63, p  =  0.017) were significantly associated with increased likelihood of CKD.

CONCLUSION

Specific urinary VOC metabolite levels are positively associated with an increased risk of CKD in patients with DM. These findings suggest that monitoring urinary VOC metabolites could be important for the prevention and management of CKD in this population. Future longitudinal studies should focus on establishing causality and elucidating the underlying mechanisms of these associations.

Associations of urinary volatile organic compounds with cardiovascular disease among the general adult population

This study was to estimate the associations of volatile organic compounds (VOCs) exposure with the prevalence of total and specific cardiovascular disease (CVD) among the general adult population. This cross-sectional study analyzed 15 urinary VOC metabolites in the general population using the 2011-2016 National Health and Nutrition Examination Survey (n = 5,213). The weighted study population with 47.0 years median age, was primarily female (51.2%). The prevalence of total CVD in the overall population was 7.9%. The single-exposure analyzes of AAMA, ATCA, CEMA, CYMA, DHBMA, 3HPMA, and 3MHA +4MHA were significantly associated with increased prevalence of total CVD. Qgcomp regression consistently showed that urinary VOCs-mixed exposure was positively correlated with the prevalence of total and specific CVDs (chronic heart failure, angina, and stroke), and highlighted each VOCs metabolite weights and direction. The similar results were observed for the WQS regression using mixed analysis methods. In conclusion, exposure to VOCs increases CVD prevalence and advances the identification of risk factors for CVD for environmental study.

Identifying cardiovascular disease risk in the U.S. population using environmental volatile organic compounds exposure: A machine learning predictive model based on the SHAP methodology

BACKGROUND

Cardiovascular disease (CVD) remains a leading cause of mortality globally. Environmental pollutants, specifically volatile organic compounds (VOCs), have been identified as significant risk factors. This study aims to develop a machine learning (ML) model to predict CVD risk based on VOC exposure and demographic data using SHapley Additive exPlanations (SHAP) for interpretability.

METHODS

We utilized data from the National Health and Nutrition Examination Survey (NHANES) from 2011 to 2018, comprising 5098 participants. VOC exposure was assessed through 15 urinary metabolite metrics. The dataset was split into a training set (70 %) and a test set (30 %). Six ML models were developed, including Random Forest (RF), Light Gradient Boosting Machine (LightGBM), Decision Tree (DT), Extreme Gradient Boosting (XGBoost), Multi-Layer Perceptron (MLP), and Support Vector Machines (SVM). Model performance was evaluated using the Area Under the Receiver Operating Characteristic Curve (AUROC), accuracy, balanced accuracy, F1 score, J-index, kappa, Matthew's correlation coefficient (MCC), positive predictive value (PPV), negative predictive value (NPV), sensitivity (sens), specificity (spec) and SHAP was applied to interpret the best-performing model.

RESULTS

The RF model exhibited the highest predictive performance with an ROC of 0.8143. SHAP analysis identified age and ATCA as the most significant predictors, with ATCA showing a protective effect against CVD, particularly in older adults and those with hypertension. The study found a significant interaction between ATCA levels and age, indicating that the protective effect of ATCA is more pronounced in older individuals due to increased oxidative stress and inflammatory responses associated with aging. E-values analysis suggested robustness to unmeasured confounders.

CONCLUSIONS

This study is the first to utilize VOC exposure data to construct an ML model for predicting CVD risk. The findings highlight the potential of combining environmental exposure data with demographic information to enhance CVD risk prediction, supporting the development of personalized prevention and intervention strategies.

Mediating role of systemic inflammation in the association between volatile organic compounds exposure and periodontitis: NHANES 2011-2014

BACKGROUND

Volatile organic compounds (VOCs) are ubiquitous environmental pollutants which have been suggested to have adverse effects on human health. While the influence of environmental pollutant exposures on periodontitis has attracted elevating attention in recent years, the epidemiological evidence on the association between VOCs exposure and periodontitis was scarce. This study aimed to investigate the potential mediating role of systemic inflammation factors in the complex association between VOCs exposure and periodontitis.

METHODS

Utilizing data from the National Health and Nutrition Examination Survey (NHANES) 2011-2014, we examined the impacts of VOCs exposure on periodontitis. Concentrations of urinary metabolites of VOCs (mVOCs) were measured using electrospray tandem mass spectrometry to evaluate internal VOCs exposure. Multivariable logistic regression, restricted cubic spline regression (RCS), Bayesian kernel machine regression (BKMR) and Quantile g-computation (QGC) models were performed to investigate the impacts of VOCs exposure on periodontitis. Mediation models were applied to assess the mediated effects of systemic inflammation on the association between mixed VOCs exposure and periodontitis. Besides, we analyzed the association between mixed VOCs exposure and periodontitis in stratified age, gender, and smoking status subgroups.

RESULTS

1,551 participants were ultimately included for further analyses, of whom 45.20% suffering from periodontitis. Multivariable logistic regression and RCS identified positive associations between single urinary mVOCs and periodontitis (P < 0.05). Notably, BKMR and QGC models suggested that mixed VOCs exposure was significantly associated with periodontitis, with 2-Aminothiazoline-4-carboxylic acid (ATCA) contributing the most (conditional posterior inclusion probability = 0.997). Moreover, systemic inflammation markers (leukocyte and lymphocyte counts) were found to partly mediate the association between VOCs exposure and periodontitis (P < 0.05). No interaction effect was identified between mixed VOCs exposure and periodontitis in age, gender and smoking status subgroups (P > 0.05).

CONCLUSION

This study demonstrated a positive association between VOCs exposure and periodontitis, which was potentially mediated by systemic inflammation factors. Further longitudinal researches are demanded to clarify the underlying mechanisms.

Biological aging mediates the association between volatile organic compounds and cardiovascular disease

BACKGROUND

Evidence for the relationship between individual and combined volatile organic compounds (VOCs) and cardiovascular disease (CVD) is limited. Besides, the mediating role of biological aging (BA) has not been studied. Therefore, this study aimed to examine the association between VOCs and CVD risk and to explore the mediating effects of BA.

METHODS

Logistic regression models were used to investigate the relationships of metabolites of volatile organic compounds (mVOCs) and BA with CVD. In addition, weighted quantile sum (WQS) regression, adaptive elastic networks, and Environmental Risk Score (AENET-ERS) were utilized to assess overall associations of mixed VOCs co-exposure with CVD. Mediation analyses were used to identify potential mediating effects of BA.

RESULTS

In the single-pollutant model, CYMA was shown to be associated with an increased risk of CVD. Additionally, we identified significantly positive associations between the WQS index and CVD (odds ratio (OR) = 1.292, 95% confidence interval (CI): 1.006, 1.660), and DHBMA had the greatest contribution for CVD (0.246). Furthermore, the AENET-ERS results showed that 8 mVOCs were significantly associated with CVD, and ERS was related to an elevated risk of CVD (OR = 1.538, 95%CI: 1.255, 1.884). Three BA indicators mediated the association of the mVOCs mixture with CVD, with mediating effect proportions of 11.32%, 34.34%, and 7.92%, respectively.

CONCLUSION

The risk of CVD was found to increase with both individual and combined exposure to VOCs. BA mediates the positive effects of VOCs on CVD, suggesting that this pathway may be one of the mechanisms of CVD.

Exposure to volatile organic compounds and mortality in US adults: A population-based prospective cohort study

Volatile organic compounds (VOCs) are ubiquitous in both indoor and outdoor environments. Evidence on the associations of individual and joint VOC exposure with all-cause and cause-specific mortality is limited. Measurements of 15 urinary VOC metabolites were available to estimate exposure to 12 VOCs in the National Health and Nutritional Examination Survey (NHANES) 2005-2006 and 2011-2018. The environment risk score (ERS) was calculated using LASSO regression to reflect joint exposure to VOCs. Follow-up data on death were obtained from the NHANES Public-Use Linked Mortality File through December 31, 2019. Cox proportional hazard models and restricted cubic spline models were applied to evaluate the associations of individual and joint VOC exposures with all-cause and cause-specific mortality. Population attributable fractions were calculated to assess the death burden attributable to VOC exposure. During a median follow-up of 6.17 years, 734 (8.34 %) deaths occurred among 8799 adults. Urinary metabolites of acrolein, acrylonitrile, 1,3-butadiene, and ethylbenzene/styrene were significantly associated with all-cause, cardiovascular disease (CVD), respiratory disease (RD), and cancer mortality in a linear dose-response manner. Linear and robust dose-response relationships were also observed between ERS and all-cause and cause-specific mortality. Each 1-unit increase in ERS was associated with a 33.6 %, 39.1 %, 109.8 %, and 67.8 % increase for all-cause, CVD, RD, and cancer mortality risk, respectively. Moreover, joint exposure to VOCs contributed to 17.95 % of all-cause deaths, 13.49 % of CVD deaths, 35.65 % of RD deaths, and 33.85 % of cancer deaths. Individual and joint exposure to VOCs may enhance the risk of all-cause and cause-specific mortality. Reducing exposure to VOCs may alleviate the all-cause and cause-specific death burden.

Single and mixed effects of multiple volatile organic compounds exposure on hematological parameters in the U.S. adult population

BACKGROUND

Most research exploring the correlation between volatile organic compounds (VOCs) and hematological parameters have focused on single VOCs. Our study aimed to explore the single and combined effects of VOCs on hematological parameters through three statistical models.

METHODS

Data from 4 cycles of the National Health and Nutrition Examination Survey (NHANES) were used in this study. The correlations between single exposure to 16 VOCs and hematological parameters in the general population were assessed by weighted multiple linear regression. Weighted quantile sum (WQS) and Bayesian kernel machine regression (BKMR) models were used to explore the relationship between the combined important VOCs selected by the least absolute shrinkage and selection operator (LASSO) and hematological parameters, as well as the effects of smoking status on them.

RESULTS

A total of 4089 adults were included in the study. We found that a variety of VOCs were significantly associated with hematological parameters. Among them, N-acetyl-S-(benzyl)-l-cysteine (BMA) was significantly negatively correlated with white blood cell (WBC), red blood cell (RBC), lymphocyte, and neutrophil counts. N-acetyl-S-(3-hydroxypropyl-1-methyl)-l-cysteine (HPMMA) was significantly positively correlated with WBC, monocyte, lymphocyte, and neutrophil counts. In the WQS analysis, the WQS index of the VOCs mixtures was positively correlated with WBC (β: 0.031; P < 0.001), monocyte (0.023; P = 0.021), and neutrophil (0.040; P = 0.001) counts, while negatively associated with RBC (-0.013; P < 0.001) counts. The BKMR model revealed that combined exposure to VOCs levels ≥70th percentile was significantly associated with lower RBC counts, and BMA was identified as the dominant contributor. Smoking significantly influenced the relationship between VOCs and hematological parameters.

CONCLUSIONS

Our study indicated the effects of single and overall VOCs exposure on hematological parameters and suggested the hematotoxicity as well as pro-inflammatory effects of VOCs, which had strong public health implications for reducing the potential health hazards of VOCs exposure to the hematologic system.

Baseline data and associations between urinary biomarkers of polycyclic aromatic hydrocarbons, blood pressure, hemogram, and lifestyle among wildland firefighters

Introduction

Available literature has found an association between firefighting and pathologic pathways leading to cardiorespiratory diseases, which have been linked with exposure to polycyclic aromatic hydrocarbons (PAHs). PAHs are highlighted as priority pollutants by the European Human Biomonitoring Initiative in occupational and non-occupational contexts.

Methods

This cross-sectional study is the first to simultaneously characterize six creatinine-adjusted PAHs metabolites (OHPAHs) in urine, blood pressure, cardiac frequency, and hemogram parameters among wildland firefighters without occupational exposure to fire emissions (> 7 days), while exploring several variables retrieved via questionnaires.

Results

Overall, baseline levels for total OHPAHs levels were 2 to 23-times superior to the general population, whereas individual metabolites remained below the general population median range (except for 1-hydroxynaphthalene+1-hydroxyacenaphtene). Exposure to gaseous pollutants and/or particulate matter during work-shift was associated with a 3.5-fold increase in total OHPAHs levels. Firefighters who smoke presented 3-times higher total concentration of OHPAHs than non-smokers (p < 0.001); non-smoker females presented 2-fold lower total OHPAHs (p = 0.049) than males. 1-hydroxypyrene was below the recommended occupational biological exposure value (2.5 μg/L), and the metabolite of carcinogenic PAH (benzo(a)pyrene) was not detected. Blood pressure was above 120/80 mmHg in 71% of subjects. Firefighters from the permanent intervention team presented significantly increased systolic pressure than those who performed other functions (p = 0.034). Tobacco consumption was significantly associated with higher basophils (p = 0.01-0.02) and hematocrit (p = 0.03). No association between OHPAHs and blood pressure was found. OHPAHs concentrations were positively correlated with monocyte, basophils, large immune cells, atypical lymphocytes, and mean corpuscular volume, which were stronger among smokers. Nevertheless, inverse associations were observed between fluorene and pyrene metabolites with neutrophils and eosinophils, respectively, in non-smokers. Hemogram was negatively affected by overworking and lower physical activity.

Conclusion

This study suggests possible associations between urinary PAHs metabolites and health parameters in firefighters, that should be further assessed in larger groups.