Detection rates, trends in and factors affecting observed levels of selected volatile organic compounds in blood among US adolescents and adults

The association between exposure to volatile organic chemicals and serum α-Klotho in USA middle to old aged population: A cross-sectional study from NHANES 2011-2016

BACKGROUND

Volatile Organic Compounds (VOCs) constitute an omnipresent category of environmental contaminants. Numerous studies have identified associations between various VOCs and human diseases. The anti-aging protein α-Klotho has been shown to exert protective influences across a variety of disease origins and progressions. This study aims to explore the relationship between serum α-Klotho levels and exposure to VOCs in humans.

METHODS

This analysis utilized data from 1672 participants aged from 40 to 79 years in 2011-2016 NHANES. Exposure to VOCs was assessed through measurements of urinary VOC metabolites (mVOCs), with 16 mVOCs selected for analysis. Multivariate generalized linear models (GLM), restricted cubic splines (RCS), weighted quantile sum (WQS) regression models, and Bayesian kernel machine regression (BKMR) models were employed to examine the connection between serum α-Klotho and individual mVOCs and mVOCs mixtures, as well as to identify the primary monomeric mVOCs responsible for these associations.

RESULTS

Our research revealed that 8 mVOCs exhibited inverse associations with serum α-Klotho levels in GLM and RCS models. Particularly noteworthy, N-Acetyl-S-(2-cyanoethyl)-L-cysteine (CYMA), a metabolite of acrylonitrile, emerged as the most influential mVOC in both WQS and BKMR models. Furthermore, the mVOCs mixture was found to be negatively correlated with serum α-Klotho. The detrimental effects of mVOCs on serum α-Klotho were observed to significantly diminish in individuals with elevated serum vitamin D levels.

CONCLUSION

Our study highlights a significant inverse relationship between serum α-Klotho and the mixture of mVOCs, indicating that exposure to VOCs may impact the molecular pathways of aging and related diseases by influencing α-Klotho concentrations. Remarkably, the attenuation of this association by high serum vitamin D levels implies potential therapeutic strategies. Our study underscores the importance of minimizing VOCs exposure to mitigate the adverse effects on α-Klotho. Further research is warranted to elucidate the underlying mechanisms of these relationships.

Chloroform associated with bone mineral density and bone mineral content in adults: A population-based cross-sectional research

BACKGROUND

Bone mineral density is an important indicator of osteoporosis, and its variation with volatile organic compounds exposure has rarely been studied. However, the relationship between chloroform (an essential volatile organic compounds component) and bone mineral density remains unclear. Consequently, we aimed to explore the relationship between chloroform alone and bone mineral density or bone mineral content.

METHODS

Herein, 2,553 individuals aged 18 and above from the National Health and Nutrition Examination Surveys (NHANES) in 2009-2010, 2013-2014, and 2017-2020, were included. We employed two independent t-tests and multi-linear regression models to statistically assess the relationship between chloroform exposure and BMD/BMC in the spine and femoral area.

RESULTS

A "V"-shaped correlation between chloroform exposure and bone mineral density or bone mineral content (BMD/BMC) was observed in the unadjusted model, particularly in the Ward's triangle and femoral neck as a whole. A negative correlation was specifically observed for the Ward's triangle BMD/BMC and L4 BMD/BMC. On the other hand, in the adjusted model, a dominantly negative correlation between the L4 BMC and chloroform exposure was observed over a range of exposure levels. The subgroup analysis revealed a negative correlation between chloroform concentrations and BMC in the femur and spine, especially in women and the 65-80 age population.

CONCLUSION

Our study revealed a "V" shaped correlation between chloroform and BMD/BMC of the femur and spine in U.S. adults. This finding highlights the fact that prolonged exposure to chloroform may cause the changes in BMD/BMC.

Low-dose blood BTEX are associated with pulmonary function through changes in inflammatory markers among US adults: NHANES 2007-2012

The effects of blood benzene, toluene, ethylbenzene, and xylenes (BTEX) on lung function among general adults remain unknown. We enrolled 5519 adults with measured blood BTEX concentrations and lung function from the US National Health and Nutrition Examination Survey 2007-2012. Weighted linear models were fitted to assess the associations of BTEX with lung function and inflammation parameters (white blood cell five-part differential count and C-reactive protein). The mediating effect of inflammation between BTEX and lung function was also examined. Blood BTEX concentrations decreased yearly from 1999 and were extremely low from 2007 to 2012. Benzene and toluene exerted the greatest influence on lung function in terms of forced vital capacity (FVC), forced expiratory volume in the first second (FEV1), calculated FEV1:FVC ratio, peak expiratory flow rate (PEFR), and forced mid expiratory flow (FEF_25-75%). Both ethylbenzene and all xylene isomers had no effects on FVC but reduced FEV1, FEV1:FVC ratio, PEFR, and FEF_25-75%. Weighted quantile analyses demonstrated that BTEX mixture was associated with decreases in FVC, FEV1, FEV1:FVC ratio, PEFR, and FEF_25-75%, with benzene weighted most heavily for all lung function parameters. BTEX also increased the levels of inflammation indicated by white blood cell five-part differential count and C-reactive protein, and increased levels of inflammation also reduced lung function. From multiple mediation analysis, inflammation mediated the effects of benzene on FEV1 and PEFR, the effects of toluene on FEV1, and the effects of ethylbenzene on FEV1 and PEFR. Low-dose exposure to BTEX was associated with reduced pulmonary function both in large and small airways. Inflammation could be involved in this pathogenesis.

Smoking is associated with elevated blood level of volatile organic compounds: a population-based analysis of NHANES 2017-2018

BACKGROUND

The study aims to explore the association between cigarette smoking with blood exposure to volatile organic compounds using population data from the National Health and Nutrition Examination Survey (NHANES) 2017-2018.

METHODS

Based on the data of NHANES 2017-2018, we identified 1117 participants aged 18 to 65 years, who had complete VOCs testing data and filled out the Smoking-Cigarette Use and Volatile Toxicant questionnaires. The participants consisted of 214 dual-smoking persons, 41 E-cigarette smokers, 293 combustible-cigarette smokers and 569 non-smokers. We used One-way ANOVA and Welch's ANOVA to compare differences of VOCs concentration among 4 groups and multivariable regression model to confirm the factors associated with VOCs concentration.

RESULTS

In dual-smoking and combustible-cigarette smokers, blood concentration of 2,5-Dimethylfuran, Benzene, Benzonitrile, Furan, Isobutyronitrile were higher than non-smokers. When compared with people who never smoked, E-cigarette smokers had similar blood concentrations of VOCs. Blood concentrations of Benzene, Furan, and Isobutyronitrile were significant higher in combustible-cigarette smokers than in E-cigarette smokers. In the multivariable regression model, dual-smoking and combustible-cigarette smoking were associated with elevated blood concentrations of several VOCs except 1,4-Dichlorobenzene, while E-cigarette smoking was only associated with elevated 2,5-Dimethylfuran concentration.

CONCLUSIONS

Smoking, mainly dual-smoking and combustible-cigarette smoking, is associated with elevated blood concentration of VOCs, while the effect is weak in E-cigarette smoking.

Assessing volatile organic compounds exposure and prostate-specific antigen: National Health and Nutrition Examination Survey, 2001–2010

Background

Volatile organic compounds (VOCs) are a large group of chemicals widely used in people's daily routines. Increasing evidence revealed the VOCs' accumulating toxicity. However, the VOCs toxicity in male prostate has not been reported previously. Thus, we comprehensively evaluated the association between VOCs and prostate-specific antigen (PSA).

Methods

A total of 2016 subjects were included in our study from the National Health and Nutrition Examination Survey with VOCs, PSA, and other variables among U.S. average population. We constructed XGBoost Algorithm Model, Regression Model, and Generalized linear Model (GAM) to analyze the potential association. Stratified analysis was used to identify high-risk populations.

Results

XGBoost Algorithm model identified blood chloroform as the most critical variable in the PSA concentration. Regression analysis suggested that blood chloroform was a positive association with PSA, which showed that environmental chloroform exposure is an independent risk factor that may cause prostate gland changes [β, (95% CI), P = 0.007, (0.003, 0.011), 0.00019]. GAM observed the linear relationship between blood chloroform and PSA concentration. Meanwhile, blood chloroform linear correlated with water chloroform in the lower dose range, indicating that the absorption of water may be the primary origin of chloroform. Stratified associations analysis identified the high-risk group on the chloroform exposures.

Conclusion

This study revealed that blood chloroform was positively and independently associated with total PSA level, suggesting that long-term environmental chloroform exposure may cause changes in the prostate gland.

Associations between select blood VOCs and hematological measures in NHANES 2005-2010

Exposure to VOCs is linked to health effects ranging from asthma to cancer and to negative impacts on the hematopoietic system. We examined the association between select blood VOC concentrations and hematological measures in a representative sample of the U.S. population from NHANES cycles spanning the years 2005 to 2010. We used Cox regression to assess the association between complete blood count with five-part differential (CBC) parameters and seven select blood VOCs, while addressing low detection rates among VOCs. Tobacco smoke exposure was classified using serum cotinine levels. The not-smoke-exposed group had lower VOC levels for most analytes compared with the smoke-exposed. Correlations between benzene, toluene, ethylbenzene, and xylenes (BTEX) were moderate to strong. Statistical associations were found between benzene, toluene, ethylbenzene, xylene, and styrene (BTEXS) and hematocrit, hemoglobin, and white blood cell count among the smoke-exposed. Among the not-smoke-exposed, there was an association between BTEX and platelet count. We considered benzene most likely to be associated with higher levels of CBC concentrations. Our findings suggest VOC levels currently found in the general U.S. population are associated with changes in hematological measures, and smoking could be a contributor.

National secular trends in ambient air volatile organic compound levels and biomarkers of exposure in the United States

BACKGROUND

Exposure to air pollution is a leading cause of global mortality. Volatile organic compounds (VOCs) are constituents of ambient air that could exert adverse health effects.

OBJECTIVE

To examine the relationship between VOC levels in ambient air and individual-level exposure to VOCs, as assessed by urinary VOC metabolites.

METHODS

Secular trends in 11 ambient air VOCs (2005-2013) and individual-level metabolites of 14 VOCs (2005-2014) were assessed using National Monitoring Programs (NMP) and National Health and Nutrition Examination Survey (NHANES) data, respectively. To isolate environmental exposure, individuals reporting exposure to tobacco smoke were excluded. Quantile regression models were used to assess secular trends in VOC exposure, and survey-weighted regression models were built to identify factors associated with VOC exposure.

RESULTS

All annual levels of ambient VOCs decreased from 2005 to 2013 (Range: 12.5%-77.2%). However, 11 of the corresponding VOC metabolites increased during the same time (Range: 0.3%-53.6%). There was a proportional change in patterns of VOC exposure across NHANES waves, with the middle quantiles of exposure showing the largest increase. VOC exposures were significantly associated with age, sex, race, education, and physical inactivity, but not with secular VOC trends.

DISCUSSION

In the United States, individual-level exposure to several VOCs increased between 2005 and 2014 despite a decline in ambient air VOC levels. This inverse relationship suggests that ambient VOCs are not the primary source of VOC exposure, therefore, decreasing ambient VOCs alone may not be sufficient to protect against the adverse health effects associated with VOC exposure.

Evaluation of potential health effects associated with occupational and environmental exposure to styrene - an update

The potential chronic health risks of occupational and environmental exposure to styrene were evaluated to update health hazard and exposure information developed since the Harvard Center for Risk Analysis risk assessment for styrene was performed in 2002. The updated hazard assessment of styrene's health effects indicates human cancers and ototoxicity remain potential concerns. However, mechanistic research on mouse lung tumors demonstrates these tumors are mouse-specific and of low relevance to human cancer risk. The updated toxicity database supports toxicity reference levels of 20 ppm (equates to 400 mg urinary metabolites mandelic acid + phenylglyoxylic acid/g creatinine) for worker inhalation exposure and 3.7 ppm and 2.5 mg/kg bw/day, respectively, for general population inhalation and oral exposure. No cancer risk value estimates are proposed given the established lack of relevance of mouse lung tumors and inconsistent epidemiology evidence. The updated exposure assessment supports inhalation and ingestion routes as important. The updated risk assessment found estimated risks within acceptable ranges for all age groups of the general population and workers with occupational exposures in non-fiber-reinforced polymer composites industries and fiber-reinforced polymer composites (FRP) workers using closed-mold operations or open-mold operations with respiratory protection. Only FRP workers using open-mold operations not using respiratory protection have risk exceedances for styrene and should be considered for risk management measures. In addition, given the reported interaction of styrene exposure with noise, noise reduction to sustain levels below 85 dB(A) needs be in place.