Prenatal exposure to metal mixtures and lung function in children from the New Hampshire birth cohort study

Prenatal exposure to metals/metalloids, even at common US population levels, may pose risks to fetal health, and affect children's lung function. Yet, the combined effects of simultaneous prenatal exposures on children's lung function remain largely unexplored. This study analyzed 11 metals (As speciation, Cd, Co, Cu, Mo, Ni, Pb, Sb, Se, Sn, Zn) in maternal urine during weeks 24-28 of gestation and evaluated lung function, including forced vital capacity (FVC) and forced expiratory volume in the first second of expiration (FEV1), in 316 US mother-child pairs at around age 7. We used Bayesian Kernel Machine Regression (BKMR), weighted quantile sum regression (WQSR), and multiple linear regression to examine the association between metal mixture exposure and children's lung function, adjusting for maternal smoking, child age, sex, and height. In BKMR models assessing combined exposure effects, limited evidence of metal non-linearity or interactions was found. Nevertheless, Co, As species, and Pb showed a negative association, while Mo exhibited a positive association with children's FVC and FEV1, with other metals held constant at their medians. The weighted index, from WQSR analysis assessing the cumulative impact of all metals, highlighted prenatal Mo with the highest positive weight, and Co, As, and Sb with the most substantial negative weights on children's FVC and FEV1. Urinary Co and Pb were negatively associated with FVC (β = -0.09, 95% confidence interval (CI) (-0.18; -0.01) and β = -0.07, 95% CI (-0.13; 0.00), respectively). Co was also negatively associated with FEV1 (β = -0.09, 95% CI (-0.18; 0.00). There was a negative association between As and FVC, and a positive association between Mo and both FVC and FEV1, though with wide confidence intervals. Our findings suggest that prenatal trace element exposures may impact children's lung function, emphasizing the importance of reducing toxic exposures and maintaining adequate nutrient levels.

Biomarkers of exposure and potential harm in exclusive users of electronic cigarettes and current, former, and never smokers

Electronic cigarette (EC) aerosol emissions generally contain fewer and lower concentrations of harmful and potentially harmful constituents, compared with cigarette smoke. Further studies are needed to establish whether decreased emissions translate to reduced health risks for EC users. In a cross-sectional study, biomarkers of exposure (BoE) to certain tobacco smoke toxicants and biomarkers of potential harm (BoPH), associated with biological processes linked to the potential development of smoking-related diseases and oxidative stress, were assessed in solus Vuse ECs users and current, former, and never smokers. In total, 213 participants were enrolled, and smoking status was confirmed by urinary cotinine, exhaled carbon monoxide, and N-(2-cyanoethyl)valine levels (EC users and former smokers only). During confinement participants used their usual product (EC or cigarette) as normal and BoE and BoPHs were assessed via blood, 24-h urine, and physiological assessment. Significantly lower levels of all urinary BoE; MHBMA, HMPMA, 3-HPMA, NNN, 3-OH-B[a]P, S-PMA, NNAL (all p < 0.0001), and TNeq (p = 0.0074) were observed in EC users when compared with smokers. Moreover, significantly lower levels were observed in EC users for 3 of the 7 BoPH measured, carboxyhaemoglobin (p < 0.0001), soluble intercellular adhesion molecule-1 (p = 0.0028), and 11-dehydrothromboxane B2 (p = 0.0012), when compared with smokers. As compared with smokers, solus Vuse EC users have significantly lower exposure to tobacco toxicants for the BoE, and 3 BoPH measured. These results add to the weight of evidence supporting EC as part of a tobacco harm reduction strategy.

Assessment of biomarkers of exposure and potential harm, and physiological and subjective health measures in exclusive users of nicotine pouches and current, former and never smokers

Background: Oral nicotine pouches (NPs) are smokeless, tobacco-free products that have a potential role in tobacco harm reduction strategies.Methods: In a cross-sectional study in Sweden/Denmark, several recognised biomarkers of potential harm (BoPHs) linked to smoking-related diseases/their initiating biological processes, and biomarkers of exposure (BoEs) to tobacco/tobacco smoke toxicants were compared among exclusive adult users of Velo NPs and current/former/never smokers. Over 24 h, participants used their usual product (Velo NP or cigarette) as normal, and BoEs/BoPHs were assessed via blood/24-h urine/exhaled breath/physiological assessments.Results: Among the primary endpoints, total NNAL (16.9 ± 29.47 vs 187.4 ± 228.93 pg/24 h), white blood cell count (5.59 ± 1.223 vs 6.90 ± 1.758 × 10⁹/L), and COHb (4.36 ± 0.525 vs 8.03 ± 2.173% saturation) were significantly lower among Velo users than among smokers (91%, 19% and 46% lower, respectively, all P < 0.0001), while fractional exhaled NO, previously shown to be lower in smokers, was significantly higher (23.18 ± 17.909 vs 11.20 ± 6.980 ppb) among Velo users (107% higher, P < 0.0001). Furthermore, sICAM-1 tended to be lower (185.9 ± 42.88 vs 204.5 ± 64.85 ng/mL) among Velo users than smokers (9% lower). Several secondary endpoints, including six BoEs (3-HPMA (246.7 ± 91.07 vs 1165.7 ± 718.35 μg/24 h), 3-OH-B[a]P (82.4 ± 217.58 vs 258.3 ± 190.20 pg/24 h), HMPMA (135.1 ± 77.85 vs 368.8 ± 183.15 μg/24 h), MHBMA (0.22 ± 0.166 vs 3.39 ± 2.943 μg/24 h), S-PMA (0.10 ± 0.059 vs 3.53 ± 2.736 µg/24 h) and total NNN (7.5 ± 24.84 vs 9.7 ± 5.93 ng/24 h)), were significantly lower among Velo users (78.8%, 68.1%, 63.4%, 93.5%, 97.2% and 22.7% lower, respectively, P < 0.0001-0.0011), while total nicotine equivalents was significantly higher among Velo users (22.6 ± 12.69 vs 12.1 ± 7.92 mg/24 h, P < 0.0001), although Velo user levels are comparable to those previously reported among oral tobacco users, and Velo user and smoker mean levels were similar in Denmark.Conclusion: As compared with smokers, exclusive users of Velo NPs have significantly less exposure to tobacco toxicants and more favourable BoPHs associated with initiating biological processes of smoking-related diseases.International Standard Registered Clinical Trial number: ISRCTN16988167.

Investigation of exposure biomarkers in human plasma following differing levels of tobacco-specific N-nitrosamines and nicotine in cigarette smoke

Tobacco-specific N-nitrosamines (TSNAs) are strong carcinogens widely found in tobacco products, environmental tobacco smoke, lake, and wastewater. The main objective of this study was to investigate the effects of cigarette smoke with different yields of TSNAs (NNK, NNN, NAT, NAB) and nicotine on the levels of biomarkers of exposure in smokers' plasma. Three hundred healthy volunteers were recruited comprising 60 smokers of each of 3 mg, 8 mg and 10 mg ISO tar yield cigarettes and 60 smokers who smoked 10 mg, 8 mg, and 3 mg for 14 days sequentially and 60 non-smokers. All study participants were male, aged from 21 to 45 years old, and were recruited from a same unit in Hebei, China. We measured the levels of NNAL, NAT, NNN, NAB and cotinine in plasma from 240 smokers and 60 non-smokers using a novel method established by online two-dimensional solid phase extraction-liquid chromatography-tandem mass spectrometry. The results showed that NNAL, NAT, NNN, NAB and cotinine in the plasma of smokers smoking cigarette with low TSNAs and nicotine were lower than that with high TSNAs and nicotine. When smokers switched from higher to lower TSNA yields of cigarettes, their plasma NNAL, NAT, NNN, NAB levels significantly decreased. The plasma concentrations of NNAL were significantly correlated with those of cotinine, NNN, NAT and NAB for smokers (p < 0.001). Similarly, the plasma concentrations of cotinine were significantly correlated with those of NNN, NAT and NAB for smokers (p < 0.001). The plasma NNAL, NAT, NNN, NAB and cotinine levels for smokers were significantly higher than those for non-smokers. These findings suggested that the total NNAL, NNN, NAT, NAB and cotinine in plasma were valid and reliable biomarkers for human exposure to TSNAs and nicotine.

Changes in biomarkers of exposure and biomarkers of potential harm after 360 days in smokers who either continue to smoke, switch to a tobacco heating product or quit smoking

The aim of this study was to investigate whether biomarkers of exposure (BoE) and potential harm (BoPH) are modified when smokers either continue to smoke or switch from smoking cigarettes to exclusive use of a tobacco heating product (THP) in an ambulatory setting over the period of a year, and to compare any changes with smokers who quit tobacco use completely and with never smokers' biomarker levels. Participants in this year-long ambulatory study were healthy smokers with a self-reported low intent to quit assigned either to continue smoking or switch to a THP; a group of smokers with a self-reported high intent to quit who abstained from tobacco use; and a group of never smokers. Various BoE and BoPH related to oxidative stress, cardiovascular and respiratory diseases and cancer were assessed at baseline and up to 360 days. Substantial and sustained reductions in BoE levels were found at 360 days for both participants who switched from smoking to THP use and participants who quit smoking, in many cases the reductions being of a similar order for both groups. The never smoker group typically had lower levels of the measured BoEs than either of these groups, and much lower levels than participants who continued to smoke. Several BoPHs were found to change in a favourable direction (towards never smoker levels) over the year study for participants who completely switched to THP or quit, while BoPHs such as soluble intercellular adhesion molecule-1 were found to change in an unfavourable direction (away from never smoker levels) in participants who continued to smoke. Our findings, alongside chemical and toxicological studies undertaken on the THP used in this study, lead to the conclusion that smokers who would have otherwise continued to smoke and instead switch entirely to the use of this THP, will reduce their exposure to tobacco smoke toxicants and as a consequence are reasonably likely to reduce disease risks compared to those continuing to smoke.

Understanding heterogeneity among individuals who smoke cigarettes and vape: assessment of biomarkers of exposure and potential harm among subpopulations from the PATH Wave 1 Data

Introduction

People who both smoke cigarettes and vape are often considered as a homogenous group even though multiple subgroups may exist. We examined biomarkers of exposure (BOE) and biomarkers of potential harm (BOPH) to differentiate between subgroups of people who smoke and vape based on PATH Study Wave 1 (2013–2014) data.

Methods

We compared people who only smoke cigarettes everyday (Group A, n = 2442) and people who only vape everyday (Group C, n = 169) against people who smoke and vape segmented into subgroups of people who frequently smoke and vape (Group B1, n = 169), frequently smoke and infrequently vape (Group B2, n = 678), frequently vape and infrequently smoke (Group B3, n = 57), and infrequently smoke and vape (Group B4, n = 66). Eighteen BOEs (representing exposure to TSNAs, nicotine, heavy metals, PAHs, and volatile organic compounds) and four BOPHs (representing inflammation and oxidative stress) were compared within the subgroups.

Results

Levels of many BOEs/BOPHs were higher among Group B2 relative to Groups B1, B3, and B4. Compared to Group A, many BOEs were significantly lower in Groups B3 (15/18) and B4 (17/18), and some BOEs were higher among B2 (4/18). Compared to Group C, significantly lower BOEs were observed for Group B4 (2/18).

Conclusions

Overall, the levels of BOEs and BOPHs in people who smoke and vape are associated with frequency of cigarette smoking. Our findings indicate that not all people who smoke and vape are the same, and tobacco product use frequency should be considered when categorizing people who smoke and vape.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12954-022-00673-x.

Associations of urinary and dietary cadmium with urinary 8-oxo-7,8-dihydro-2'-deoxyguanosine and blood biochemical parameters

Cadmium is a heavy metal with established adverse effects on human health, namely on bone, liver and kidney function and the cardiovascular system. We assessed cadmium exposure and its correlation with biomarkers of toxicity. We recruited 137 non-smoking blood donors without a history of chronic disease or cancer who resided in the Northern Italy province of Reggio Emilia (mean age 47 years, range 30-60 years) in the 2017-2019 period. We used a semi-quantitative food frequency questionnaire to estimate dietary cadmium intake and urine samples to assess concentrations of urinary cadmium and 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG). Median urinary cadmium and 8-oxodG concentrations were 0.21 μg/L (interquartile range (IQR): 0.11-0.34 μg/L) and 3.21 μg/g creatinine (IQR: 2.21-4.80 μg/g creatinine), respectively, while median dietary cadmium intake was 6.16 μg/day (IQR: 5.22-7.93 μg/day). We used multivariable linear and spline regression models to estimate mean differences exposure concentrations. Dietary and urinary cadmium were positively correlated, and both were positively and linearly correlated with 8-oxodG. We found a positive association of urinary cadmium with blood alanine aminotransferase (ALT), total cholesterol, low-density lipoprotein (LDL)-cholesterol and thyroid-stimulating hormone (TSH) concentrations. We also observed a positive association with triglycerides, in both linear (beta regression coefficient = 77.03, 95% confidence interval 32.27-121.78) and non-linear spline regression analyses. Despite the positive correlation between dietary and urinary cadmium estimates, dietary cadmium intake showed inconsistent results with the study endpoints and generally weaker associations, suggesting a decreased capacity to reflect actual cadmium exposure. Overall, these findings suggest that even low levels of cadmium exposure may adversely alter hematological and biochemical variables and induce oxidative stress.

Dietary Exposure to Essential and Non-essential Elements During Infants' First Year of Life in the New Hampshire Birth Cohort Study

Even the low levels of non-essential elements exposure common in the US may have health consequences especially early in life. However, little is known about the infant's dynamic exposure to essential and non-essential elements. This study aims to evaluate exposure to essential and non-essential elements during infants' first year of life and to explore the association between the exposure and rice consumption. Paired urine samples from infants enrolled in the New Hampshire Birth Cohort Study (NHBCS) were collected at approximately 6 weeks (exclusively breastfed) and at 1 year of age after weaning (n = 187). A further independent subgroup of NHBCS infants with details about rice consumption at 1 year of age also was included (n = 147). Urinary concentrations of 8 essential (Co, Cr, Cu, Fe, Mn, Mo, Ni, and Se) and 9 non-essential (Al, As, Cd, Hg, Pb, Sb, Sn, V, and U) elements were determined as a measure of exposure. Several essential (Co, Fe, Mo, Ni, and Se) and non-essential (Al, As, Cd, Hg, Pb, Sb, Sn, and V) elements had higher concentrations at 1 year than at 6 weeks of age. The highest increases were for urinary As and Mo with median concentrations of 0.20 and 1.02 µg/L at 6 weeks and 2.31 and 45.36 µg/L at 1 year of age, respectively. At 1 year of age, As and Mo urine concentrations were related to rice consumption. Further efforts are necessary to minimize exposure to non-essential elements while retaining essential elements to protect and promote children's health.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12403-022-00489-x.

Reductions in biomarkers of exposure to selected harmful and potentially harmful constituents following exclusive and partial switching from combustible cigarettes to myblu™ electronic nicotine delivery systems (ENDS)

Electronic nicotine delivery systems (ENDS) offer adult combustible cigarette smokers an alternative, potentially reduced harm, mode of nicotine delivery, attributed to fewer and reduced levels of harmful and potentially harmful constituents (HPHCs) in their aerosols compared to cigarette smoke. These two identical, randomised, open label, two-part studies aimed to compare levels of 15 biomarkers of exposure (BoE) to selected HPHCs associated with tobacco smoking in healthy US adult smoker subjects (n = 72). Following 9 days of exclusive use of a range of allocated myblu™ ENDS variants, subjects' levels of 14 non-nicotine BoE were substantially reduced compared to baseline values (combustible cigarette use), in the range of 46-97%. BoE reductions were sustained in subjects who continued myblu use exclusively (n = 25) for a further 5 days, and returned to near baseline levels in subjects who returned to exclusive combustible cigarette use (n = 21). Dual users (n = 24) demonstrated reductions in BoE to a lesser extent than with exclusive myblu use. Measured nicotine equivalents did not significantly change throughout the study. These data suggest exclusive use of ENDS provides adult smokers seeking an alternative to combustible cigarettes with substantial reductions in HPHC exposures whilst achieving satisfying levels of nicotine delivery. Dual use involving substitution of cigarettes may also provide some of this advantage, but to lesser extent. Overall, the data contribute to the weight of evidence that ENDS are an important tool in tobacco harm reduction for adult smokers unwilling to or uninterested in quitting smoking. Study 1: NCT04430634, study 2: NCT04429932, clinicaltrials.gov (10-06-2020).

Carcinogenic biomarkers of exposure in the urine of heated tobacco product users associated with bladder cancer: A systematic review

To identify biomarkers of exposure present in Heated Tobacco Products (HTPs) users' urine which are associated with bladder cancer and to compare quantitative biomarker levels to those seen in combustible cigarette users. A systematic literature review was conducted in December 2020 with no date limits. Relevant studies that reported quantitative urinary biomarker of exposure in HTP users were included. Biomarkers and their parent compounds were classified by carcinogenicity according to the International Agency for Research on Cancer Monographs and were cross-referenced with the Collaborative on Health and the Environment Toxicant and Disease Database to determine associations with bladder cancer. Our literature search identified 561 articles and 30 clinical trial reports. 11 studies met inclusion criteria. These studies identified 29 biomarkers of exposure present in HTP users' urine, which reflect exposure to 21 unique parent compounds. Of these parent compounds, 14 are carcinogens and 10 have a known link to bladder cancer. HTP users' biomarkers of exposure were present at lower levels than combustible cigarette users but higher than never-smokers. Biomarkers of exposure to bladder carcinogens are present in the urine of HTP users. While levels of these biomarkers appear to be lower than combustible cigarette users, chronic urothelial exposure to bladder carcinogens is concerning and degree of bladder cancer risk remains unknown. Further long-term study is needed to elucidate the bladder cancer risk of HTP use.

Urinary biohazard markers in firefighters

Firefighters are the professional force at high risk of suffering potential health consequences due to their chronic exposure to numerous hazardous pollutants during firefighting activities. Unfortunately, determination of fire emission exposure is very challenging. As such, the identification and development of appropriate biomarkers is critical in meeting this need. This chapter presents a critical review of current information related with the use of different urinary biomarkers of effect and exposure in occupationally exposed firefighters over the last 25 years. Evidence suggests that urinary isoprostanes and mutagenicity testing are promising biomarkers of early oxidative stress. Data indicate that firefighters participating in firefighting activities present with increased urinary biomarkers of exposure. These include polycyclic aromatic hydrocarbons, heavy metals and metalloids, organo-chlorine and -phosphorus compounds, environmental phenols, phthalates, benzene and toluene. More studies are urgently needed to better evaluate firefighter occupational safety and health and to support the implementation of preventive measures and mitigation strategies to promote the protection of this chronically exposed group of workers.

Changes in biomarkers after 180 days of tobacco heating product use: a randomised trial

The aim of this study was to investigate whether biomarkers of exposure (BoE) and potential harm (BoPH) are modified when smokers switch from smoking cigarettes to exclusive use of a tobacco heating product (THP) in an ambulatory setting. Participants in this randomised, controlled study were healthy volunteer smokers assigned either to continue smoking or switch to a THP, and a control group of smokers who abstained from cigarette smoking. Various BoE and BoPH related to oxidative stress, cardiovascular and respiratory diseases, and cancer were assessed at baseline and up to 180 days. In continuing smokers, BoE and BoPH remained stable between baseline and day 180, while THP users' levels of most BoE reduced significantly, becoming similar to those in controls abstaining from cigarette smoking. Also at 180 days, significant changes in numerous BoPH, including total 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol, 8-epi-prostaglandin F2α type III, fractional concentration of exhaled nitric oxide and white blood cell count, were directionally consistent with lessened health impact. Our findings support the notion that the deleterious health impacts of cigarette smoking may be reduced in smokers who completely switch to using THPs.

Sexual identity differences in biomarkers of tobacco exposure among women in a national sample

BACKGROUND

Sexual minority women are consistently at increased risk for tobacco use compared to heterosexual women. Neither biomarkers of nicotine exposure nor biomarkers of tobacco toxicant exposure have been examined by sexual identity.

METHODS

This study used interview and biomarker data from women in the biomarker core sample of Wave 1 of the Population Assessment of Tobacco and Health (PATH) study (2013-2014; n = 4930). We examined associations of sexual identity with nicotine exposure (measured with urinary cotinine and TNE-2) and with tobacco-specific nitrosamines (measured with urinary NNAL). Multivariable regression modeling was used to examine these associations among the full biomarker core sample, among past 30-day tobacco users, and among exclusive established cigarette users before and after controlling for tobacco use quantity and intensity.

RESULTS

In the full biomarker sample of women, prior to adjusting for tobacco use quantity and intensity, bisexual women had significantly higher cotinine, TNE-2, and NNAL levels compared to heterosexual women. Among exclusive established cigarette users, gay/lesbian women had significantly higher NNAL compared to heterosexual women prior to adjusting for tobacco quantity and intensity. No differences by sexual identity were found after adjusting for tobacco use quantity and intensity.

CONCLUSIONS

This is the first study to demonstrate differences in biological markers of tobacco exposure by sexual identity among women in the U.S. This has important public health implications as greater exposure to both nicotine and to tobacco-specific nitrosamines are strongly linked to cancer risk.

Biomonitoring of fast-elimination endocrine disruptors - Results from a 6-month follow up on human volunteers with repeated urine and hair collection

BACKGROUND

The assessment of human exposure to fast-elimination endocrine disruptors (ED) such as phthalates, bisphenols or pesticides is usually based on urinary biomarkers. The variability of biomarkers concentration, due to rapid elimination from the body combined with frequent exposure is however pointed out as a major limitation to exposure assessment. Other matrices such as hair, less sensitive to short-term variations in the exposure, have been proposed as possible alternatives. Nevertheless, no study compared the information obtained from hair and urine respectively in a follow-up allowing to assess biomarkers variability over time in these two matrices, and to compare the correlation between them.

METHODS

In the present study, hair and urine samples were collected from 16 volunteers over a 6 months follow-up. All in all, 92 hair samples and 805 urines samples were collected and analyzed for the presence of 16 phthalate metabolites, 4 bisphenols and 8 pesticides/metabolites.

RESULTS

All the biomarkers analyzed were detected in at least one of the two matrices. 21 biomarkers were more frequently detected in hair, 6 in urine, and 1 was equivalent. Biomarkers intraclass correlation coefficients (ICC) ranged from 0.1 to 0.8 (ten above 0.4) in hair, and from 0.09 to 0.51 in urine (two above 0.4). The concentrations of biomarkers in hair and urine were significantly correlated for only one compound.

CONCLUSION

This study highlights the complexity of assessing exposure to fast-elimination ED and suggests considering with caution the specificity of the matrix in data interpretation. The results document the respective advantages and limitations of urine and hair, and provide new insight in the understanding of the information provided by these biological matrices and their relevance for the assessment of human exposure to fast elimination contaminants.

CAPSULE

92 hair and 805 urine samples collected from 16 volunteers over 6 months, tested for phthalate metabolites, bisphenols and pesticides. 19 biomarkers (in hair) and 24 (in urine) were detected in >50% of the samples.

Assessment of the potential vaping-related exposure to carbonyls and epoxides using stable isotope-labeled precursors in the e-liquid

The formation of carbonyls and epoxides in e-cigarette (EC) aerosol is possible due to heating of the liquid constituents. However, high background levels of these compounds have inhibited a clear assessment of exposure during use of ECs. An EC containing an e-liquid replaced with 10% of ¹³C-labeled propylene glycol and glycerol was used in a controlled use clinical study with 20 EC users. In addition, five smokers smoked cigarettes spiked with the described e-liquid. Seven carbonyls (formaldehyde, acetaldehyde, acrolein, acetone, crotonaldehyde, methacrolein, propionaldehyde) were measured in the aerosol and the mainstream smoke. Corresponding biomarkers of exposure were determined in the user’s urine samples. ¹³C-labeled formaldehyde, acetaldehyde and acrolein were found in EC aerosol, while all seven labeled carbonyls were detected in smoke. The labeled biomarkers of exposure to formaldehyde (¹³C-thiazolidine carboxylic acid and ¹³C-N-(1,3-thiazolidine-4-carbonyl)glycine), acrolein (¹³C₃-3-hydroxypropylmercapturic acid) and glycidol (¹³C₃-dihydroxypropylmercapturic acid) were present in the urine of vapers indicating an EC use-specific exposure to these toxicants. However, other sources than vaping contribute to a much higher extent by several orders of magnitude to the overall exposure of these toxicants. Comparing data for the native (unlabeled) and the labeled (exposure-specific) biomarkers revealed vaping as a minor source of user’s exposure to these toxicants while other carbonyls and epoxides were not detectable in the EC aerosol.

Identification of biomarkers specific to five different nicotine product user groups: Study protocol of a controlled clinical trial

Background

Assessing biomarker profiles in various body fluids is of large value to discern between the sole use of nicotine products. In particular, the assessment of the product compliance is required for long-term clinical studies. The objective of this study was the identification of biomarkers and biomarker patterns in body fluids, to distinguish between combustibles, heated tobacco products, electronic cigarettes, oral tobacco and oral/dermal nicotine products used for nicotine replacement therapy (NRT), as well as a control group of non-users.

Methods

A controlled, single-center study was conducted with 60 healthy subjects, divided into 6 groups (5 nicotine product user groups and one non-user group) based on their sole use of the products of choice. The subjects were confined for 76 h, during which, free and uncontrolled use of the products was provided. Sample collections were performed according to the study time schedule provided in Table 2. The primary outcome will be validated through analysis of the collected biospecimens (urine, blood, saliva, exhaled breath and exhaled breath condensate) by means of untargeted omics approaches (i.e. exposomics, breathomics and adductomics). Secondary outcome will include established biomarker quantification methods to allow for the identification of typical biomarker patterns. Statistical analysis tools will be used to specifically discriminate different product use categories.

Results/Conclusions

The clinical trial was successfully completed in May 2020, resulting in sample management and preparations for the quantitative and qualitative analyses. This work will serve as a solid basis to discern between biomarker profiles of different nicotine product user groups. The knowledge collected during this research will be required to develop prototype diagnostic tools that can reliably assess the differences and evaluate possible health risks of various nicotine products.

Development of a multi-mycotoxin LC-MS/MS method for the determination of biomarkers in pig urine

An LC-MS/MS method has been developed for the sensitive and selective determination of 35 mycotoxins (biomarkers of exposure) in pig urine samples. Sample preparation includes creatinine adjustment (with the developed LC-UV method) with enzymatic hydrolysis of pig urine samples followed by liquid-liquid (LLE) extraction. The LLE protocol, as well as enzymatic hydrolysis for indirect mycotoxin glucuronides determination, was optimized in this study. Additionally, two other sample preparation protocols were compared with the developed LLE method: immunoaffinity columns and solid-phase extraction cartridges (Oasis HLB). The detection and quantification of the biomarkers were performed using triple quadrupole mass spectrometry.The method was validated with regard to the guidelines specified by the EMEA (European Medicines Agency). The extraction recoveries were higher than 60% for 77% of the analytes studied, with the intra- and inter-day relative standard deviation being lower than 20% for most of the compounds at four different concentration levels. The limits of quantification ranged from 0.1 ng/mL for zearalenone and sterigmatocystin to 8 ng/mL for nivalenol. To the best knowledge of the authors, the matrix effect was evaluated for the first time in this study for six different urine samples, and the coefficient of variation was found to be lower than 15% for most analytes studied. Finally, the developed method was applied to analyse 56 pig urine samples. Deoxynivalenol (1-20 ng/mL), zearalenone (0.1-1.5 ng/mL) and ochratoxin A (1.5-15 ng/mL) were the main analytes detected in these samples. Moreover, the co-occurrence of alternariol monomethyl ether and alternariol in pig urine is reported herein for the first time.

Derivation of Biomonitoring Equivalents for aluminium for the interpretation of population-level biomonitoring data

Aluminium is widely used in many consumer products, however the primary source of aluminium exposure to the Canadian general population is through food. Aluminium can cause neurotoxicity and reproductive toxicity at elevated exposure levels. Health-based exposure guidance values have been established for oral exposure to aluminium, including a Minimal Risk Level (MRL) by the Agency for Toxic Substances and Disease Registry (ATSDR), a Provincial Tolerable Weekly Intake (PTWI) by the Joint FAO/WHO Expert Committee on Food Additives (JECFA) and a Tolerable Weekly Intake (TWI) by the European Food Safety Authority (EFSA). Aluminium concentration in blood and urine can be used as a tool for exposure characterization in a population. A pharmacokinetic (PK) model was developed based on human dosing data to derive blood Biomonitoring Equivalents (BEs), whereas a mass balance approach was used to derive urine BEs for the above guidance values. The BEs for blood for daily intake consistent with the MRL, PTWI and TWI were 18, 16 and 8 μg/L, respectively. BEs for urine for the same guidance values were 137, 123 and 57 μg/L, respectively. The derived BEs may be useful in interpreting population-level biomonitoring data in a health risk context and thereby screening and prioritizing substances for human health risk assessment and risk management.

Challenges associated with quantification of selected urinary biomarkers of exposure to tobacco products

Tobacco use, of which cigarette smoking is the most common, is a global health concern and is directly linked to over 7 million premature deaths annually. Measurement of the levels of tobacco-related biomarkers in biological matrices reflects human exposure to the chemicals in tobacco products. Nicotine, nicotine metabolites, anatabine, and anabasine are specific to tobacco and nicotine containing products. However, as nicotine and its metabolites are ubiquitous in the environment, background contamination during sample preparation can occur, making the quantification of target analytes challenging. The main purpose of the present study was to examine quality control measures needed in the determination of urinary nicotine, nicotine metabolites, anatabine, and anabasine. Urine samples (n = 75) and NIST standard reference materials SRM 3671 and SRM 3672 were analysed. A one-step extraction procedure using cold acetone was used in this study, which involved no additional clean up. The blank matrices investigated included synthetic urine prepared with HPLC-grade water, synthetic urine prepared with Milli-Q water, and bovine urine. By adopting strategies for minimizing the background levels, very low detection limits for all the target analytes ranging from 0.025 ng/mL for 3-hydroxycotinine to 0.634 ng/mL for nicotine, were achieved. Recoveries ranged between 67% and 118% with RSD values below 20%. Intra-day and inter-day precisions were in the range of 1.1-11.7% and 4.8-25.2%, respectively. The levels of all target analytes were higher in daily smokers than in non-smokers, with the largest difference observed for 3-hydroxycotinine. No difference was observed in the levels of target analytes between individuals who were former smokers, who never smoked or who were exposed to environmental tobacco smoke (ETS), except for total nicotine equivalents (TNE), which was significantly higher in non-smokers exposed to environmental tobacco smoke compared with study participants who never smoked. The results obtained from SRM 3671 and SRM 3672 could inform a potential certification of additional biomarkers of exposure to tobacco products in those standard reference materials.

Exposure of nursing mothers to polycyclic aromatic hydrocarbons: Levels of un-metabolized and metabolized compounds in breast milk, major sources of exposure and infants' health risks

In this study, biomonitoring of nursing Portuguese mothers to polycyclic aromatic hydrocarbons (PAHs) exposure and assessment of potential health risks of their infants were performed through determination of 18 PAHs and 6 major metabolites (OH-PAHs) in breast milk. Concentrations of total PAHs ranged between 55.2 and 1119 ng/g fat, being naphthalene, dibenz(a,h)anthracene, benzo(g,h,i)perylene, and phenanthrene the most abundant compounds (68.4% of ∑PAHs). Benzo(a)pyrene, known carcinogenic, was not detected. Total levels of OH-PAHs ranged from 6.66 to 455 ng/g fat with 1-hydroxyphenanthrene, 1-hydroxynaphthalene and 1-hydroxyacenaphthene as major compounds (96% of ∑OH-PAHs). Concentrations of ∑PAHs and ∑OH-PAHs were strongly correlated between each other (r = 0.692; p ≤ 0.001) and moderately-to-strongly associated with individual compounds (0.203 < r < 0.841; p ≤ 0.001). The attained data suggest increased levels of PAHs in older nursing mothers (>30 years) and in those whose child had lower weight (up to 3.0 kg). Breast-fed infant presented a median PAHs daily intake of 1.41 μg/kg body weight (total benzo(a)pyrene equivalents of 0.0679 μg/kg) and were exposed to 0.024 μg/kg body weight of ∑PAH4 [benz(a)anthracene, benzo(b)fluoranthene, benzo(j)fluoranthene, and chrysene]. Although breast milk is a secure food for newborns, un-metabolized and metabolized PAHs should be included in biomonitoring surveillance studies during breastfeeding to prevent potential health risks for infants.

Derivation of biomonitoring equivalents (BE values) for bismuth

Bismuth (Bi) is a natural element present in the environmental media. Bismuth has been used medicinally for centuries, specifically for the treatment of gastrointestinal (GI) disorders. Although bismuth toxicity is rare in humans, an outbreak of bismuth-induced neurotoxicity was reported in France and Australia in the mid-1970s. The primary source of bismuth exposure in the general population is via food. US FDA (2019) estimated recommended daily intake (RDI) for bismuth as 848 mg bismuth/day (12.1 mg Bi/kg-d assuming a body weight of 70 kg) for GI tract disorders. Exposures to bismuth can be quantified by measuring concentrations in blood and urine. Biomonitoring equivalents (BEs) were derived based on US FDA's RDI as a tool for interpretation of population-level biomonitoring data. A regression between steady state plasma concentrations and oral intakes was used to derive plasma BEs. A whole blood: plasma partitioning coefficient of 0.6 was used to convert plasma BE into whole blood BE. A mass balance equation with a urinary excretion fraction of 0.0003 was used to derive urinary BE. The BE values associated with US FDA's RDI for plasma, whole blood and urine were 8.0, 4.8 and 0.18 μg/L, respectively. These BE values together with bismuth biomonitoring data may be used in screening and prioritization of health risk assessment of bismuth in the general population.

Toxicokinetics of bisphenol-S and its glucuronide in plasma and urine following oral and dermal exposure in volunteers for the interpretation of biomonitoring data

The measurement of bisphenol-S (BPS) and its glucurono-conjugate (BPSG) in urine may be used for the biomonitoring of exposure in populations. However, this requires a thorough knowledge of their toxicokinetics. The time courses of BPS and BPSG were assessed in accessible biological matrices of orally and dermally exposed volunteers. Under the approval of the Research Ethics Committee of the University of Montreal, six volunteers were orally exposed to a BPS-d8 deuterated dose of 0.1 mg/kg body weight (bw). One month later, 1 mg/kg bw of BPS-d8 were applied on 40 cm² of the forearm and then washed 6 h after application. Blood samples were taken prior to dosing and at fixed time periods over 48 h after treatment; complete urine voids were collected pre-exposure and at pre-established intervals over 72 h postdosing. Following oral exposure, the plasma concentration-time courses of BPS-d8 and BPSG-d8 over 48 h evolved in parallel, and showed a rapid appearance and elimination. Average peak values (±SD) were reached at 0.7 ± 0.1 and 1.1 ± 0.4 h postdosing and mean (±SD) apparent elimination half-lives (t_½) of 7.9 ± 1.1 and 9.3 ± 7.0 h were calculated from the terminal phase of BPS-d8 and BPSG-d8 in plasma, respectively. The fraction of BPS-d8 reaching the systemic circulation unchanged (i.e. bioavailability) was further estimated at 62 ± 5% on average (±SD) and the systemic plasma clearance at 0.57 ± 0.07 L/kg bw/h. Plasma concentration-time courses and urinary excretion rate profiles roughly evolved in parallel for both substances, as expected. The average percent (±SD) of the administered dose recovered in urine as BPS-d8 and BPSG-d8 over the 0-72 h period postdosing was 1.72 ± 1.3 and 54 ± 10%. Following dermal application, plasma levels were under the lower limit of quantification (LLOQ) at most time points. However, peak values were reached between 5 and 8 h depending on individuals, suggesting a slower absorption rate compared to oral exposure. Similarly, limited amounts of BPS-d8 and its conjugate were recovered in urine and peak excretion rates were reached between 5 and 11 h postdosing. The average percent (±SD) of the administered dose recovered in urine as BPS-d8 and BPSG-d8 was about 0.004 ± 0.003 and 0.09 ± 0.07%, respectively. This study provided greater precision on the kinetics of this contaminant in humans and, in particular, evidenced major differences between BPA and BPS kinetics with much higher systemic levels of active BPS than BPA, an observation explained by a higher oral bioavailability of BPS than BPA. These data should also be useful in developing a toxicokinetic model for a better interpretation of biomonitoring data.

Burden of disease associated with dietary exposure to carcinogenic aflatoxins in Portugal using human biomonitoring approach

Human biomonitoring is an important tool to assess human exposure to chemicals, contributing to describe trends of exposure over time and to identify population groups that could be under risk. Aflatoxins are genotoxic and carcinogenic food contaminants causing hepatocellular carcinoma, the third leading cause of cancer deaths worldwide. In Portugal, scarce data are available regarding exposure to aflatoxins and no previous study used human biomonitoring data to comprehensively characterize the associated burden of disease. 24 h urine and first-morning urine paired samples were collected by 94 participants and were analyzed by liquid chromatography-tandem mass spectrometry for the quantitative determination of aflatoxins (B₁, B₂, G₁, G₂ and M₁). Deterministic and probabilistic models were developed to assess the Portuguese exposure to aflatoxins and to estimate the health impact of this exposure, estimating the attributed Disability-Adjusted Life Years (DALYs). Aflatoxins were detected in a maximum of 13% (AFB₁), 16% (AFB₂), 1% (AFG₁), 2% (AFG₂) and 19% (AFM₁) of the urine samples. Data obtained through the probabilistic approach revealed an estimated mean probable daily intake of 13.43 ng/kg body weight per day resulting in 0.13 extra cases of hepatocellular carcinoma, corresponding to mean annual DALYs of 172.8 for the Portuguese population (10291027 inhabitants). The present study generated for the first time and within a human biomonitoring study, reliable and crucial data to characterize the burden associated to the exposure to aflatoxins of the Portuguese population. The obtained results constitute an imperative support to risk managers in the establishment of preventive policy measures that contribute to ensure public health protection.

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.

Estimation of time to compromised tenability in fires: is it time to change paradigms?

The ISO standard 13571 estimates the time to the compromised tenability of people in enclosed fires. This is understood as the time which must be available for the structural design to pass an evacuation, or an escape paradigm for the evacuation of burning buildings. As with all emergency response planning values, such once-in-a-lifetime events cannot readily be validated side-by-side. Consequently, risk assessors must refer to animal-based reference data fitting the scenario of concern closely. The analysis detailed in this paper used the concentration × time (Cxt)-matrix of point of departures (PODs) from rats acutely exposed to carbon monoxide (CO), which is amongst the most abundant toxic fire gases. The objective of the analysis was to clarify whether the time- and effect-adjusted nonlethal threshold concentration LCt₀₁ × 1/3 from acute rat inhalation studies is suited to model thresholds characterizing any 'impairment of escape' in humans. Modeled outcomes are compared with published reference data from human volunteers exposed at the similar C × t's of CO at 800 ppm × 1-h and 100 ppm × 8-h. These exposure durations match the maximum escape duration of 1-h considered in the ISO standard 13571 and standards enforcing occupational exposure limits of 8-h duration. The reference PODs indicative of 'impairment of escape' in healthy adults relied on C × t's below those eliciting any loss of motor function or psychoneurological functions. The comparison of the LCt₀₁ × 1/3 based modeled outcomes from rats match favorably with the effect-based PODs from humans. Consistent with published evidence from humans, carboxyhemoglobin (COHb) saturation-a biomarker of exposure rather than of effect-failed to reliably predict effect-based outcomes. Unlike the LCt₀₁ × 1/3 threshold approach, the COHb-based median approach used by ISO TS 13571 is inconsistent with human evidence and both over- and under-estimates the CO-related potency for causing incapacitation at non-toxic and critically-toxic C × 's, respectively. In summary, it seems timely that the ISO TS 13571 standard pays attention to scientific progress in relevant toxicity information and refinements to scientific methods shown to adequately predict human risks.

Individual exposure level following indoor and outdoor air pollution exposure in Dakar (Senegal)

The consequences of indoor and outdoor air pollution on human health are of great concern nowadays. In this study, we firstly evaluated indoor and outdoor air pollution levels (CO, CO₂, NO, NO₂, PM₁₀) at an urban site in Dakar city center and at a rural site. Then, the individual exposure levels to selected pollutants and the variations in the levels of biomarkers of exposure were investigated in different groups of persons (bus drivers, traders working along the main roads and housemaids). Benzene exposure levels were higher for housemaids than for bus drivers and traders. High indoor exposure to benzene is probably due to cooking habits (cooking with charcoal), local practices (burning of incense), the use of cleaning products or solvent products which are important emitters of this compound. These results are confirmed by the values of S-PMA, which were higher in housemaids group compared to the others. Urinary 1-HOP levels were significantly higher for urban site housemaids compared to semirural district ones. Moreover, urinary levels of DNA oxidative stress damage (8-OHdG) and inflammatory (interleukin-6 and -8) biomarkers were higher in urban subjects in comparison to rural ones. The air quality measurement campaign showed that the bus interior was more polluted with PM₁₀, CO, CO₂ and NO than the market and urban or rural households. However, the interior of households showed higher concentration of VOCs than outdoor sites confirming previous observations of higher indoor individual exposure level to specific classes of pollutants.

Kinetic time courses of lambda-cyhalothrin metabolites after dermal application of Matador EC 120 in volunteers

A controlled kinetic study was conducted in volunteers dermally exposed to the widely used lambda-cyhalothrin pyrethroid pesticide to document the time courses of relevant biomarkers of exposure, in order to better assess biomonitoring data in workers. Matador^® EC120 formulation (120 g/l) was applied on 40 cm² of the forearm at a 0.25 mg/kg dose of lambda-cyhalothrin and left without occlusion or washing for 6 h. The application site was then washed thoroughly with soap and water. The kinetic time courses of cis-3-(2-chloro-3,3,3-trifluoroprop-1-en-1-yl)-2,2-dimethylcyclopropane carboxylic acid (CFMP) and 3-phenoxybenzoic acid (3-PBA) metabolites were determined in plasma and urine up to 84 h post-application. Results show that the fraction of lambda-cyhalothrin absorbed in the body was rapidly cleared following dermal contact. According to CFMP and 3-PBA plasma profiles, calculated mean apparent absorption half-lives (t_1/2) were 3 and 7.3 h, respectively, and corresponding mean apparent elimination t_1/2 were 11.2 and 7.6 h. These differences suggest some metabolism at the site-of-entry and storage of metabolites by the dermal route. Toxicokinetic parameters calculated from urinary profiles confirm the values of absorption and elimination rates. Metabolites were almost completely excreted over the 84-h period post-application and, on average, 0.12 and 0.08% of the applied lambda-cyhalothrin dose was recovered in the urine as CFMP and 3-PBA, respectively, indicating a low dermal absorption fraction of this pyrethroid. This study showed the potential use of CFMP and 3-PBA biomarkers for the assessment of dermal exposure to lambda-cyhalothrin pyrethroid.

Biomarkers of exposure in environment-wide association studies - Opportunities to decode the exposome using human biomonitoring data

BACKGROUND

The European Union's 7th Framework Programme (EU's FP7) project HEALS - Health and Environment-wide Associations based on Large Population Surveys - aims a refinement of the methodology to elucidate the human exposome. Human biomonitoring (HBM) provides a valuable tool for understanding the magnitude of human exposure from all pathways and sources. However, availability of specific biomarkers of exposure (BoE) is limited.

OBJECTIVES

The objective was to summarize the availability of BoEs for a broad range of environmental stressors and exposure determinants and corresponding reference and exposure limit values and biomonitoring equivalents useful for unraveling the exposome using the framework of environment-wide association studies (EWAS).

METHODS

In a face-to-face group discussion, scope, content, and structure of the HEALS deliverable "Guidelines for appropriate BoE selection for EWAS studies" were determined. An expert-driven, distributed, narrative review process involving around 30 individuals of the HEALS consortium made it possible to include extensive information targeted towards the specific characteristics of various environmental stressors and exposure determinants. From the resulting 265 page report, targeted information about BoE, corresponding reference values (e.g., 95th percentile or measures of central tendency), exposure limit values (e.g., the German HBM I and II values) and biomonitoring equivalents (BEs) were summarized and updated.

RESULTS

64 individual biological, chemical, physical, psychological and social environmental stressors or exposure determinants were included to fulfil the requirements of EWAS. The list of available BoEs is extensive with a number of 135; however, 12 of the stressors and exposure determinants considered do not leave any measurable specific substance in accessible body specimens. Opportunities to estimate the internal exposure stressors not (yet) detectable in human specimens were discussed.

CONCLUSIONS

Data about internal exposures are useful to decode the exposome. The paper provides extensive information for EWAS. Information included serves as a guideline - snapshot in time without any claim to comprehensiveness - to interpret HBM data and offers opportunities to collect information about the internal exposure of stressors if no specific BoE is available.

Assessment of the exposure to harmful and potentially harmful constituents in healthy Japanese smokers using a novel tobacco vapor product compared with conventional cigarettes and smoking abstinence

The objectives of this clinical study were to demonstrate a reduction in exposure to selected harmful and potentially harmful constituents (HPHCs), and to assess product use behavior, in Japanese healthy adult smokers who switched to a novel tobacco vapor product (NTV). 60 smokers were randomly assigned for 5 days to either (a) a group who switched to an NTV (n = 20), (b) a group who continued to smoke their own brand of conventional cigarettes (CC, n = 20) or (c) a smoking abstinence group (SA, n = 20). Fifteen biomarkers of exposure (BoEs) to 14 HPHCs and pyrene were measured at baseline, day 3 and 5. Product use behavior was assessed by measuring product consumption, nicotine uptake and puffing topography. During investigations, increases were observed in product consumption and total puff volume in NTV group subjects as compared to baseline. Additionally, nicotine uptake in the NTV group was approximately half that observed in the CC group. BoE values were significantly reduced in the NTV group as compared to those in the CC group. Significantly, the magnitude of the reduction in exposure to HPHCs observed in the NTV group (49-94%) was close to that observed for the SA group (39-95%).

Integrating chemical, toxicological and clinical research to assess the potential of reducing health risks associated with cigarette smoking through reducing toxicant emissions

The concept of a risk continuum for tobacco and nicotine products has been proposed, which differentiates products according to their propensity to reduce toxicant exposure and risk. Cigarettes are deemed the most risky and medicinal nicotine the least. We assessed whether a Reduced-Toxicant Prototype (RTP) cigarette could sufficiently reduce exposure to toxicants versus conventional cigarettes to be considered a distinct category in the risk continuum. We present findings from both pre-clinical and clinical studies in order to examine the potential for reduced smoke toxicant emissions to lower health risks associated with cigarette smoking. We conclude that current toxicant reducing technologies are unable to reduce toxicant emissions sufficiently to manifest beneficial disease-relevant changes in smokers. These findings point to a minimum toxicant exposure standard that future potentially reduced risk products would need to meet to be considered for full biological assessment. The RTP met WHO TobReg proposed limits on cigarette toxicant emissions, however the absence of beneficial disease relevant changes in smokers after six months reduced toxicant cigarette use, does not provide evidence that these regulatory proposals will positively impact risks of smoking related diseases. Greater toxicant reductions, such as those that can be achieved in next generation products e.g. tobacco heating products and electronic cigarettes are likely to be necessary to clearly reduce risks compared with conventional cigarettes.

Associations of urinary polycyclic aromatic hydrocarbon metabolites with fractional exhaled nitric oxide and exhaled carbon monoxide: A cross-sectional study

Exposure to Polycyclic aromatic hydrocarbons (PAHs) has been associated with inflammatory responses. Fractional exhaled nitric oxide (FeNO) and exhaled carbon monoxide (eCO) are both important inflammatory mediators especially in airways. However, few studies have investigated associations of PAH exposures with FeNO or eCO. Therefore, we aimed to quantify the associations of urinary PAH metabolites with FeNO and eCO levels, and investigate their potential effect modifiers by linear mixed models among 4133 participants from the Wuhan-Zhuhai cohort in China. We further performed stratified analyses to estimate effect modification. We found significant associations of increased urinary PAH metabolites with elevated eCO and FeNO. Among all participants, each 1% increase of 1-hydroxynaphthalene, 2-hydroxynaphthalene, 2-hydroxyfluorene, 4-hydroxyphenanthrene, 3-hydroxyphenanthrene, and total PAH metabolites was significantly associated with a 12.6% (95% confidence interval: 9.3%, 15.9%), 9.7% (6.5%, 12.9%), 7.5% (4.1%, 10.9%), 3.2% (0.2%, 6.2%), 2.7% (0.1%, 5.3%), and 6.5% (2.7%, 10.4%) increased eCO level, respectively; while each 1% increase of urinary 1-hydroxynaphthalene, 9-hydroxyphenanthrene, 3-hydroxyphenanthrene, and 2-hydroxyphenanthrene was associated with a -3.0% (-5.8%, -0.2%), 2.9% (0.3%, 5.6%), 3.2% (1.0%, 5.4%), and 4.5% (2.2%, 6.9%) change of FeNO level, respectively. Positive associations between certain urinary PAH metabolites and eCO were observed among both ever-smokers and non-smokers, and the associations were stronger among ever-smokers than that among non-smokers. Increased urinary PAH metabolites were associated with decreased FeNO among ever-smokers and elevated FeNO levels among non-smokers. Our findings suggest that PAH exposures may impair airway through inducing inflammatory response, especially among ever-smokers.

Evaluation of the safety profile of an electronic vapour product used for two years by smokers in a real-life setting

The safety profile of Puritane™, a closed system electronic vapour product (EVP), was evaluated when used by smokers of conventional cigarettes (CCs) for 24 months in a real-life setting. The study was a two-centre ambulatory clinical study with 209 healthy volunteers. Outcome measures included adverse events (AEs), vital signs, electrocardiogram, lung function tests, exposure to nicotine and selected smoke constituents, nicotine withdrawal effects and smoking desire. No serious AEs related to EVP use were observed. The most frequently reported AEs were headache, nasopharyngitis, sore throat and cough, reported by 28.7%, 28.7%, 19.6% and 16.7% of subjects, respectively, which dissipated over time. Small decreases in lung function were not considered clinically relevant. No clinically relevant findings were observed in the other safety parameters. From Month 2, nicotine withdrawal symptoms decreased. Smoking desire and CC consumption steadily decreased over time in all subjects. EVP use was associated with reduced exposure to cigarette smoke constituents, whereas urinary nicotine levels remained close to baseline. Body weight did not increase in CC subjects switching to the EVP. In conclusion, the aerosol of the EVP at study was well tolerated and not associated with any clinically relevant health concerns after usage for up to 24 months.

Fatal sarin poisoning in Syria 2013: forensic verification within an international laboratory network

During the United Nations fact-finding mission to investigate the alleged use of chemical warfare agents in the Syrian Arab Republic in 2013, numerous tissues from a deceased female victim, who had displayed symptoms of cholinergic crisis, were collected. The Organisation for the Prohibition of Chemical Weapons (OPCW) authorized two specialized laboratories in the Netherlands and Germany for forensic analysis of these samples. Diverse modern mass spectrometry (MS)-based procedures in combination with either liquid chromatography (LC) or gas chromatography (GC) separation were applied. A variety of biotransformation products of the nerve agent sarin was detected, including the hydrolysis product O-isopropyl methylphosphonic acid (IMPA) as well as covalent protein adducts with e.g., albumin and human butyrylcholinesterase (hBChE). IMPA was extracted after sample acidification by solid-phase extraction and directly analyzed by LC-tandem-MS with negative electrospray ionization (ESI). Protein adducts were found, either by fluoride-induced reactivation applying GC-MS techniques or by LC-MS-based detection after positive ESI for proteolyzed proteins yielding phosphonylated tyrosine residues or a specific phosphonylated hBChE-derived nonapeptide. These experimental results provided unambiguous evidence for a systemic intoxication and were the first proving the use of sarin in the ongoing bellicose conflict. This scenario underlines the requirement for qualified and specialized analytical laboratories to face repeated violation of the Chemical Weapons Convention.

Application of cDNA-AFLP to biomarker exploration in a non-model species Grandidierella japonica

Biomarkers of exposure can be used to identify specific contaminants that are adversely affecting aquatic organisms. However, it remains prohibitively costly to investigate multiple novel biomarkers of exposure in a non-model species, despite the development of next-generation sequencing technology. In this study, we focused on the use of cDNA-amplified fragment length polymorphism (AFLP) as a cost-effective biomarker discovery tool to test whether it could identify biomarkers of exposure in the non-model amphipod species Grandidierella japonica. Loci were identified that were differentially expressed in amphipods exposed to reference chemicals (Cu, Zn, and nicotine) and to an environmental sample (road dust) at sublethal concentrations. Eight loci were shown to respond consistently to nicotine at different concentrations, but not to Cu or Zn. Some of the loci also responded to an environmental road dust sample containing nicotine. These findings suggest that loci identified using cDNA-AFLP could be used as biomarkers of nicotine exposure in environmental samples with complex matrices. Further studies with other organisms and toxicants are needed, but we have demonstrated that the use of cDNA-AFLP to identify biomarkers for ecotoxicological studies of non-model species is at least feasible.

Time-matched analysis of DNA adduct formation and early gene expression as predictive tool for renal carcinogenesis in methylazoxymethanol acetate treated Eker rats

Genotoxic carcinogens pose great hazard to human health. Uncertainty of current risk assessment strategies and long latency periods between first carcinogen exposure and diagnosis of tumors have raised interest in predictive biomarkers. Initial DNA adduct formation is a necessary step for genotoxin induced carcinogenesis. However, as DNA adducts not always translate into tumorigenesis, their predictive value is limited. Here we hypothesize that the combined analysis of pro-mutagenic DNA adducts along with time-matched gene expression changes could serve as a superior prediction tool for genotoxic carcinogenesis. Eker rats, heterozygous for the tuberous sclerosis (Tsc2) tumor suppressor gene and thus highly susceptible towards genotoxic renal carcinogens, were continuously treated with the DNA alkylating carcinogen methylazoxymethanol acetate (MAMAc). Two weeks of MAMAc treatment resulted in a time-dependent increase of O⁶-methylguanine and N7-methylguanine adducts in the kidney cortex, which was however not reflected by significant expression changes of cyto-protective genes involved in DNA repair, cell cycle arrest or apoptosis. Instead, we found a transcriptional regulation of genes involved in the tumor-related MAPK, FoxO and TGF-beta pathways. Continuous MAMAc treatment for up to 6 months resulted in a mild but significant increase of cancerous lesions. In summary, the combined analysis of DNA adducts and early gene expression changes could serve as a suitable predictive tool for genotoxicant-induced carcinogenesis.

Recent advances in simultaneous analysis of bisphenol A and its conjugates in human matrices: Exposure biomarker perspectives

Human exposures to bisphenol A (BPA) has attained considerable global health attention and represents one of the leading environmental contaminants with potential adverse health effects including endocrine disruption. Current practice of measuring of exposure to BPA includes the measurement of unconjugated BPA (aglycone) and total (both conjugated and unconjugated) BPA; the difference between the two measurements leads to estimation of conjugated forms. However, the measurement of BPA as the end analyte leads to inaccurate estimates from potential interferences from background sources during sample collection and analysis. BPA glucuronides (BPAG) and sulfates (BPAS) represent better candidates for biomarkers of BPA exposure, since they require in vivo metabolism and are not prone to external contamination. In this work, the primary focus was to review the current state of the art in analytical methods available to quantitate BPA conjugates. The entire analytical procedure for the simultaneous extraction and detection of aglycone BPA and conjugates is covered, from sample pre-treatment, extraction, separation, ionization, and detection. Solid phase extraction coupled with liquid chromatograph and tandem mass spectrometer analysis provides the most sensitive detection and quantification of BPA conjugates. Discussed herein are the applications of BPA conjugates analysis in human exposure assessment studies. Measuring these potential biomarkers of BPA exposure has only recently become analytically feasible and there are limitations and challenges to overcome in biomonitoring studies.

Assessment of the reduction in levels of exposure to harmful and potentially harmful constituents in Japanese subjects using a novel tobacco heating system compared with conventional cigarettes and smoking abstinence: A randomized controlled study in confinement

Smoking conventional cigarettes (CCs) exposes smokers to harmful and potentially harmful constituents (HPHCs). The Tobacco Heating System 2.2 (THS 2.2), a candidate modified risk tobacco product, was developed to reduce or eliminate the formation of HPHCs, while preserving as much as possible the taste, sensory experience, nicotine delivery profile and ritual characteristics of CC. This randomized, controlled, open-label study in confinement for 5 day exposure aimed to demonstrate the reduction in exposure to selected HPHCs, to assess nicotine uptake and subjective effects, in participants switching to THS 2.2 (n = 80) compared to participants continuing smoking CCs (n = 40) and abstaining from smoking (n = 40). The subjects were randomized according to sex and daily CC consumption. The levels of biomarkers of exposure to HPHCs were significantly reduced in participants switching to THS 2.2, compared to CC use. More importantly, the magnitude of exposure reduction observed was close to that which was seen in participants who abstained from smoking for 5 days, while nicotine uptake was maintained. Reduction in urge-to-smoke was comparable between THS and CC groups, however THS 2.2 was slightly less satisfactory than CCs. The new, alternative tobacco product THS 2.2 was well tolerated.

A randomised, parallel group study to evaluate the safety profile of an electronic vapour product over 12 weeks

A randomised, parallel group clinical study was performed to evaluate the safety profile of an e-vapour product (EVP; 2.0% nicotine) in smokers of conventional cigarettes (CCs) switching to use the EVP for 12 weeks. During the study, no clinically significant product-related findings were observed in terms of vital signs, electrocardiogram, lung function tests and standard clinical laboratory parameters. Adverse events (AEs) reported by EVP subjects were more frequent during the first week after switching to the EVP. The frequency of AEs reduced thereafter and out of a total of 1515 reported AEs, 495 were judged as being related to nicotine withdrawal symptoms. The most frequently stated AEs were headache, sore throat, desire to smoke and cough reported by 47.4, 27.8, 27.5 and 17.0% of subjects, respectively. Only 6% of AEs were judged as probably or definitely related to the EVP. Additional observations in EVP subjects included a decrease in the level of urine nicotine equivalents by up to 33.8%, and decreases in the level of three biomarkers of exposure to toxicants known to be present in CC smoke (benzene, acrolein and 4-[methylnitrosamino]-1-[3-pyridyl]-1-butanone). The decrease in nicotine equivalents coincided with an increase in nicotine withdrawal symptoms, measured by a questionnaire, which subsided after two weeks. The data presented here shows the potential EVPs may offer smokers looking for an alternative to CCs.

Evaluating the relationship between biomarkers of potential harm and biomarkers of tobacco exposure among current, past, and nonsmokers: data from the National Health and Nutrition Examination Survey 2007-2012

Potential long-term health effects from tobacco products can be estimated by measuring changes in biochemical indicators of disease mechanisms like inflammation. This study assesses the potential relationships between biomarkers of potential harm (BOPH) and biomarkers of cigarette smoke exposure (BOE) based on data from the NHANES (2007-2012, n = 17,293 respondents). Statistically significant relationships were observed between white blood cells (WBC) and high-density lipoprotein (HDL) and BOE; between WBC and high-sensitivity C-reactive protein and smoking status; and between WBC and HDL and smoking intensity. This analysis suggests that WBC and HDL are useful BOPH in studies assessing the health risks of cigarette smoking.

Reductions in biomarkers of exposure, impacts on smoking urge and assessment of product use and tolerability in adult smokers following partial or complete substitution of cigarettes with electronic cigarettes

Background

Electronic cigarettes (e-cigarettes) are popular alternatives to conventional cigarettes among adult smokers wishing to reduce their exposure to harmful smoke constituents. However, little information exists on the relative internal exposures resulting from the exclusive or dual use of e-cigarettes.

Methods

Measurements of product use; adverse events; changes in smoking urge; and blood, urine and exhaled breath biomarkers of exposure (BoE) representing toxicants believed to contribute to smoking related diseases were made at baseline and after five days of product use in 105 clinically-confined smokers randomized into groups that partially or completely substituted their usual brand combustible cigarette with commercial e-cigarettes, or discontinued all nicotine and tobacco products.

Results

Subjects switching to e-cigarettes had significantly lower levels (29 %–95 %) of urinary BoEs after 5 days. Nicotine equivalents declined by 25 %–40 %. Dual users who substituted half of their self-reported daily cigarette consumption with e-cigarettes experienced 7 %–38 % reductions, but had increases (1 %–20 %) in nicotine equivalents. Blood nicotine biomarker levels were lower in the cessation (75 %–96 %) and e-cigarette use groups (11 %–83 %); dual users had no significant reductions. All groups experienced significant decreases in exhaled CO (27 %–89 %). Exhaled NO increases (46 %–63 %) were observed in the cessation and e-cigarette use groups; dual users had minimal changes. By Day 5, all groups had greater reductions in smoking urge compared to cessation. However, reductions were larger in the dual use group. No serious adverse events were observed.

Conclusions

Exposures to harmful smoke toxicants were observed to be lower in smokers who completely or partially replaced their cigarettes with e-cigarettes over five days.

Reductions in biomarkers of exposure (BoE) to harmful or potentially harmful constituents (HPHCs) following partial or complete substitution of cigarettes with electronic cigarettes in adult smokers

Changes in fifteen urine, blood and exhaled breath BoEs of HPHCs representing classes of compounds reported by FDA to be significant contributors to smoking-associated disease risks were measured in 105 clinical-confined subjects following randomization and a five-day forced-switch from usual brand conventional combustible cigarettes to: (i) exclusive commercial e-cigarette use; (ii) dual-use of commercial e-cigarettes and the subject's usual cigarette brand; or (iii) discontinued use of all tobacco or nicotine products. Levels of urinary biomarkers in subjects that completely substituted their usual cigarette with e-cigarettes were significantly lower (29-95%) after 5 days. Percent reductions in eight of nine urinary BoEs were indistinguishable to smokers who had quit smoking, except for nicotine equivalents, which declined by 25-40%. Dual users who halved self-reported daily cigarette consumption with e-cigarettes exhibited reductions (7-38%) in eight of nine urinary biomarkers, but had increase (1-20%) in nicotine equivalents. Reductions were broadly proportional to the reduced numbers of cigarettes smoked. Dual user urinary nicotine equivalents were slightly higher, but not statistically significant. After 5 days, blood nicotine biomarker levels were lower in the cessation (75-96%) and exclusive use groups (11-83%); with dual users experiencing no significant reductions. All subjects experienced significant decreases in exhaled CO. Decreases in the cessation and exclusive groups ranged from 88-89% and 27-32% in dual users. Exhaled NO increased in the cessation and exclusive groups (46-63% respectively), whereas the dual users experienced minimal changes. Overall, smokers who completely or partially substituted conventional cigarettes with e-cigarettes over five days, experienced reductions in HPHCs.

Assessing human exposure to inorganic arsenic in high-arsenic areas of Latium: a biomonitoring study integrated with indicators of dietary intake

BACKGROUND

In Latium (central Italy), arsenic concentrations exceeding the regulatory limit of 10 μg/L for drinking water are present in groundwater from a large area of volcanic origin. At least in part of the area, high arsenic concentrations have been detected also in soil and phytoavailable geogenic arsenic enters the food chain. As a result, local population may be exposed to inorganic arsenic via water and also through consumption of food with higher than background arsenic concentrations.

METHODS

A cross sectional study was conducted to assess inorganic arsenic exposure and metabolism in 269 residents of 27 municipalities in the provinces of Viterbo, Rome and Latina. Total arsenic in toenails and the sum of inorganic arsenic and methylated metabolites in urine, the latter determined by HPLC-ICP-MS, were used as biomarkers of inorganic arsenic exposure. All the subjects involved in the study provided samples of the water(s) used for drinking and cooking as well as detailed information on water use. To get an insight into dietary intake from locally-processed food, inorganic arsenic in bread samples collected in affected municipalities of the three provinces was determined and compared to background levels of samples from reference areas.

RESULTS

30% of the sample used bottled water or resorted to water treatment in order to lower the arsenic content <10 μg/L (Group 1), 51% of the sample drank bottled water and used tap water with an arsenic content exceeding 10 μg/L for cooking only (Group 2), 19% of the sample used tap water with an arsenic content exceeding 10 μg/L for both drinking and cooking (Group 3). Nail arsenic was higher for Group 2 and 3 compared to Group 1, whereas all groups had higher nail arsenic than the reference group. The sum of inorganic arsenic and related metabolites in urine was higher in Group 3 than in the other two groups, and higher in Group 2 compared to Group 1. White bread from the study area showed significantly higher inorganic arsenic levels compared to samples from reference areas.

CONCLUSIONS

Use of toenail arsenic as biomarker of long-term exposure allowed to retrospectively reconstruct exposure irrespective of recent modifications due to changes in water use. In Group 3, urinary concentration of inorganic arsenic and metabolites exceeded the upper limit of the reference concentration range for the Italian population. Inter-individual variability of the efficiency of arsenic metabolism in the study population was substantial indicating that a subgroup of the population is more susceptible to the toxic effects of inorganic arsenic owing to a lower methylation capability.

A longitudinal study of smokers' exposure to cigarette smoke and the effects of spontaneous product switching

A challenge in investigating the effect of public health policies on cigarette consumption and exposure arises from variation in a smoker's exposure from cigarette to cigarette and the considerable differences between smokers. In addition, limited data are available on the effects of spontaneous product switching on a smoker's cigarette consumption and exposure to smoke constituents. Over 1000 adult smokers of the same commercial 10mg International Organization for Standardization (ISO) tar yield cigarette were recruited into the non-residential, longitudinal study across 10 cities in Germany. Cigarette consumption, mouth level exposure to tar and nicotine and biomarkers of exposure to nicotine and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone were measured every 6months over a 3 and a half year period. Cigarette consumption remained stable through the study period and did not vary significantly when smokers spontaneously switched products. Mouth level exposure decreased for smokers (n=111) who switched to cigarettes of 7mg ISO tar yield or lower. In addition, downward trends in mouth level exposure estimates were observed for smokers who did not switch cigarettes. Data from this study illustrate some of the challenges in measuring smokers' long-term exposure to smoke constituents in their everyday environment.

Effect of cigarette design on biomarkers of exposure, puffing topography and respiratory parameters

Despite the lack of evidence, many reports exist which have implied that smokers inhale low-yield cigarette smoke more deeply than that of high-yield cigarettes. The objective of this study was to investigate the effect of short-term switching between smoker’s own brand and test cigarettes with different smoke yields on puffing topography, respiratory parameters and biomarkers of exposure. Participants were randomly assigned to smoke either a Test Cigarette-High Tar (TCH), for two days, and then switched to a Test Cigarette-Low Tar (TCL), for two days or the reverse order (n = 10 each sequence). Puffing topography (CReSS microdevice), respiratory parameters (inductive plethysmography) and biomarkers of exposure (BOE, urinary nicotine equivalents – NE and blood carboxyhemoglobin – COHb) were measured at baseline and on days 2 and 4. The average puffs per cigarette, puff volume and puff durations were statistically significantly lower, and inter-puff interval was significantly longer for the TCH compared to the TCL groups. Respiratory parameters were not statistically significantly different between the TCH and TCL groups. Post-baseline NE and COHb were statistically significantly lower in the TCL compared to the TCH groups. Under the conditions of this study, we found no indication of changes in respiratory parameters, particularly inhalation time and volume, between study participants smoking lower versus higher yield cigarettes. Likewise, the BOE provides no indication of deeper inhalation when smoking low- versus high-yield cigarettes. These findings are consistent with the published literature indicating smoking low-yield cigarettes does not increase the depth of inhalation.

Toxicological importance of human biomonitoring of metallic and metalloid elements in different biological samples

Human biomonitoring has become an important tool for the assessment of internal doses of metallic and metalloid elements. These elements are of great significance because of their toxic properties and wide distribution in environmental compartments. Although blood and urine are the most used and accepted matrices for human biomonitoring, other non-conventional samples (saliva, placenta, meconium, hair, nails, teeth, breast milk) may have practical advantages and would provide additional information on health risk. Nevertheless, the analysis of these compounds in biological matrices other than blood and urine has not yet been accepted as a useful tool for biomonitoring. The validation of analytical procedures is absolutely necessary for a proper implementation of non-conventional samples in biomonitoring programs. However, the lack of reliable and useful analytical methodologies to assess exposure to metallic elements, and the potential interference of external contamination and variation in biological features of non-conventional samples are important limitations for setting health-based reference values. The influence of potential confounding factors on metallic concentration should always be considered. More research is needed to ascertain whether or not non-conventional matrices offer definitive advantages over the traditional samples and to broaden the available database for establishing worldwide accepted reference values in non-exposed populations.

Variance components of short-term biomarkers of manganese exposure in an inception cohort of welding trainees

Various biomarkers of exposure have been explored as a way to quantitatively estimate an internal dose of manganese (Mn) exposure, but given the tight regulation of Mn in the body, inter-individual variability in baseline Mn levels, and variability in timing between exposure and uptake into various biological tissues, identification of a valuable and useful biomarker for Mn exposure has been elusive. Thus, a mixed model estimating variance components using restricted maximum likelihood was used to assess the within- and between-subject variance components in whole blood, plasma, and urine (MnB, MnP, and MnU, respectively) in a group of nine newly-exposed apprentice welders, on whom baseline and subsequent longitudinal samples were taken over a three month period. In MnB, the majority of variance was found to be between subjects (94%), while in MnP and MnU the majority of variance was found to be within subjects (79% and 99%, respectively), even when controlling for timing of sample. While blood seemed to exhibit a homeostatic control of Mn, plasma and urine, with the majority of the variance within subjects, did not. Results presented here demonstrate the importance of repeat measure or longitudinal study designs when assessing biomarkers of Mn, and the spurious associations that could result from cross-sectional analyses.

Prenatal exposure to PCB-153, p,p'-DDE and birth outcomes in 9000 mother-child pairs: exposure-response relationship and effect modifiers

Low-level exposure to polychlorinated biphenyl-153 (PCB-153) and dichlorodiphenyldichloroethylene (p-p'-DDE) can impair fetal growth; however, the exposure-response relationship and effect modifiers of such association are not well established. This study is an extension of an earlier European meta-analysis. Our aim was to explore exposure-response relationship between PCB-153 and p-p'-DDE and birth outcomes; to evaluate whether any no exposure-effect level and susceptible subgroups exist; and to assess the role of maternal gestational weight gain (GWG). We used a pooled dataset of 9377 mother-child pairs enrolled in 14 study populations from 11 European birth cohorts. General additive models were used to evaluate the shape of the relationships between organochlorine compounds and birth outcomes. We observed an inverse linear exposure-response relationship between prenatal exposure to PCB-153 and birth weight [decline of 194g (95% CI -314, -74) per 1μg/L increase in PCB-153]. We showed effects on birth weight over the entire exposure range, including at low levels. This reduction seems to be stronger among children of mothers who were non-Caucasian or had smoked during pregnancy. The most susceptible subgroup was girls whose mothers smoked during pregnancy. After adjusting for absolute GWG or estimated fat mass, a reduction in birth weight was still observed. This study suggests that the association between low-level exposure to PCB-153 and birth weight exists and follows an inverse linear exposure-response relationship with effects even at low levels, and that maternal smoking and ethnicity modify this association.

Consumption patterns and biomarkers of exposure in cigarette smokers switched to Snus, various dissolvable tobacco products, Dual use, or tobacco abstinence

The objectives of this clinical study were to evaluate changes in tobacco product use behavior and levels of selected biomarkers of exposure (BOEs) for smokers who switched to one of six conditions during clinical confinement: exclusive use of; Camel Snus, Sticks, Strips or Orbs, controlled Dual use of cigarettes and Camel Snus, or tobacco abstinence. The controlled Dual use (DU) condition mandated a 60% reduction in cigarettes smoked per day (CPD). 167 healthy U.S. male and female smokers were randomized to the six groups (n=25-30/group). Subjects smoked their usual brand of cigarette for 1 day prior to switching to their designated intervention condition. Levels of thirty-two BOEs in plasma, whole blood, urine and feces were determined before and after switching. Questionnaires that scored nicotine dependence and withdrawal discomfort were also administered. After 5 days, exclusive Snus, Sticks, Strips, or Orbs use averaged 6.1, 5.9, 13.5, and 8.5 units/day, respectively. DU subjects smoked 7.6 CPD and used 3.2 Snus pouches/day, on average. After 5 days, substantial reductions of most biomarkers, including nicotine, were observed in all groups. Toxicant exposures were similar to being tobacco abstinent after switching exclusively to Camel Snus, Sticks, Strips or Orbs. DU reductions were more modest.

Biomarkers of tobacco smoke exposure

Diseases and death caused by exposure to tobacco smoke have become the single most serious preventable public health concern. Thus, biomarkers that can monitor tobacco exposure and health effects can play a critical role in tobacco product regulation and public health policy. Biomarkers of exposure to tobacco toxicants are well established and have been used in population studies to establish public policy regarding exposure to second-hand smoke, an example being the nicotine metabolite cotinine, which can be measured in urine. Biomarkers of biological response to tobacco smoking range from those indicative of inflammation to mRNA and microRNA patterns related to tobacco use and/or disease state. Biomarkers identifying individuals with an increased risk for a pathological response to tobacco have also been described. The challenge for any novel technology or biomarker is its translation to clinical and/or regulatory application, a process that requires first technical validation of the assay and then careful consideration of the context the biomarker assay may be used in the regulatory setting. Nonetheless, the current efforts to investigate new biomarker of tobacco smoke exposure promise to offer powerful new tools in addressing the health hazards of tobacco product use. This review will examine such biomarkers, albeit with a focus on those related to cigarette smoking.

Influence of household cleaning practices on the magnitude and variability of urinary monochlorinated bisphenol A

Low-dose health effects of BPA have not been adequately explored in the presence of BPA metabolites of chlorinated structure that may exert larger estrogenic effects than those of their parent compound. We hypothesized that chlorine-containing cleaning products used in household cleaning activities could modify the magnitude of total urinary BPA concentration measurements via the production of chlorinated BPA (ClBPA) derivatives. Our objective was to investigate the influence of typical household cleaning activities (dishwashing, toilet cleaning, mopping, laundry, etc.) on the magnitude and variability of urinary total BPA and mono-ClBPA levels in the general adult population. A cross-sectional study (n=224) included an adult (≥18 years) pool of participants from the general population of Nicosia, Cyprus. First morning urine voids were collected, and administered questionnaires included items about household cleaning habits, demographics, drinking water consumption rates and water source/usage patterns. Urinary concentrations of total BPA (range: 0.2-82 μg L(-1)), mono-ClBPA (16-340 ng L(-1)), and total trihalomethanes (0.1-5.0 μg L(-1)) were measured using gas chromatography coupled with triple quadrupole mass spectrometry and large volume injection. Linear multiple regression analysis revealed that dishwashing along with age and gender (females) were able to predict urinary mono-ClBPA levels (ng g(-1)), even after adjusting for covariates; this was not the case for urinary total BPA levels (ng g(-1)). Significant (p<0.001) association was observed between urinary mono-ClBPA and THM levels, underlying the important role of disinfectant (chlorine) in promoting formation of both ClBPA and THM. Urinary mono-ClBPA levels were measured for the first time using an appreciable sample size, highlighting the co-occurring patterns of both total BPA and mono-ClBPA. Epidemiological studies and probabilistic BPA risk assessment exercises should consider assessing daily intake estimates for chlorinated BPA compounds, as well.