Urinary Biomarkers of Carcinogenic Exposure among Cigarette, Waterpipe, and Smokeless Tobacco Users and Never Users of Tobacco in the Golestan Cohort Study

Volatile organic compounds and mortality from ischemic heart disease: A case-cohort study

Background

Volatile organic compounds (VOCs) are major components of air pollution and tobacco smoke, two known risk factors for cardiovascular diseases. VOCs are ubiquitous in the environment and originate from a wide range of sources, including the burning of biomass, fossil fuels, and consumer products. Direct evidence for associations between specific VOCs and ischemic heart disease (IHD) mortality in the general population is scarce.

Methods

In a case-cohort study (stratified by age groups, sex, residence, and tobacco smoking), nested within the population-based Golestan cohort study (n = 50,045, 40-75 years, 58% women, enrollment: 2004-2008) in northeastern Iran, we measured urinary concentrations of 20 smoking-related VOC biomarkers using ultra high-performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry. We calculated hazard ratio (HR) and 95% confidence interval (CI) for their associations with IHD mortality during follow-up to 2018, using Cox regression models adjusted for age, ethnicity, education, marital status, body mass index, physical activity, wealth, and urinary cotinine.

Results

There were 575 non-cases from random subcohort and 601 participants who died from IHD, mean (standard deviation) age, 58.2 (9.3) years, with a median of 8.4 years follow-up. Significant associations [3rd vs. 1st tertile, HR (95% CI), P for trend] were observed between biomarkers of acrylamide [1.68(1.05,2.69), 0.025], acrylonitrile [2.06(1.14,3.72), 0.058], acrolein [1.98(1.30,3.01), 0.003 and 2.44(1.43,4.18), 0.002], styrene/ethylbenzene [1.83(1.19,2.84), 0.007 and 1.44(1.01,2.07), 0.046], dimethylformamide/methylisocyanate [2.15(1.33,3.50), 0.001], and 1,3butadiene [2.35(1.52,3.63),<0.001] and IHD mortality. These associations were independent of tobacco smoking, and they were only present in the non-smoking subgroup.

Conclusion

Our findings provide direct evidence for associations between exposure to several VOCs with widespread household and commercial use and IHD mortality many years after these exposures. These results highlight the importance of VOC exposure in the general population as a risk factor for cardiovascular diseases and underline the importance of bio-monitoring non-tobacco VOC exposure.

Prevalence and Incidence of Metabolic Syndrome and Its Components Among Waterpipe Users

Objectives

To determine the associations between waterpipe use, duration, and intensity of use with prevalence and incidence of metabolic syndrome and its components (increased waist circumference, triglycerides, fasting glucose, blood pressure and decreased high-density lipoprotein cholesterol).

Methods

We conducted cross-sectional and prospective analyses using data from the Pars Cohort Study in southern Iran, encompassing 9,264 participants at the baseline, and 5,002 randomly selected in a repeated follow-up. We used multivariate logistic regression models adjusted for age, sex, education, wealth score, physical activity and cigarette pack-years to report odds ratios (OR) and 95% confidence intervals (CI).

Results

Among 9,264 participants, 3,119 (33.7%) had metabolic syndrome, and 3,482 (37.6%) had ever smoked waterpipe, with both more common in women than in men. In adjusted models, former waterpipe use was significantly associated with prevalence (OR = 1.43, 95% CI: 1.23-1.68) and incidence (OR = 1.57, 95% CI: 1.19-2.06) of the metabolic syndrome while current waterpipe use was not. Past use was associated with increased risk in all components of metabolic syndrome; current use was associated with increases in all except high blood glucose and hypertension. Past waterpipe users had higher waterpipe use intensity (before quitting) in comparison with current users (2.3 vs. 2.0 waterpipes per day, p < 0.01) and had started waterpipe smoking at a younger age (27.2 vs. 30.1 years, p < 0.01).

Conclusion

Waterpipe use was associated with metabolic syndrome and its components, especially among former users potentially due to higher intensity and earlier initiation of use.

Association between waterpipe smoking and lung cancer: a multicentre case-control study in Iran

OBJECTIVES

This study investigated the association between lung cancer and waterpipe smoking, which is an emerging global public health concern.

STUDY DESIGN

Multicentre case-control study.

METHODS

This study included 627 cases and 3477 controls from the Iranian Study of Opium and Cancer (IROPICAN) study, which was conducted between 2017 and 2020. One frequency-matched control for each lung cancer patient was selected by age, gender and residential place; however, this study used controls of four cancer types in the analyses. The multivariable logistic regression model estimated the odds ratio (OR) and 95% confidence intervals (CIs). Additional analyses were performed among 181 lung cancer cases and 2141 controls who were not cigarette smokers or opium or nass/pipe users.

RESULTS

The odds of lung cancer were higher among waterpipe smokers than never-smokers (OR = 1.3, 95% CI: 1.0-1.7). Results showed a higher OR of lung cancer for those who smoked the waterpipe daily (OR = 2.1, 95% CI: 1.4-3.0), smoked more than two heads per day (OR = 2.7, 95% CI: 1.8-4.0), had smoked for >20 years (OR = 1.9, 95% CI: 1.3-2.7), smoked more than 20 head-years (OR = 2.8, 95% CI: 1.9-4.1) and initiated smoking before the age of 30 years (OR = 1.7, 95% CI: 1.1-2.5). The association was only statistically significant for squamous cell carcinomas (OR = 1.8, 95% CI 1.2-2.7). Furthermore, this study observed a higher OR of lung cancer among exclusive waterpipe smokers (OR = 2.3, 95% CI: 1.6, 3.5).

CONCLUSIONS

Waterpipe smoking was associated with an increased risk of lung cancer. The association was stronger with higher frequency, duration and intensity of exposure to waterpipe smoking. The association increases in exclusive waterpipe smokers, which is likely due to controlling for residual confounding by cigarette smoking and opium consumption, and higher exposure levels in this subpopulation.

Biomarkers of Waterpipe Tobacco Smoke Exposure: A Systematic Review and Meta-Analysis

INTRODUCTION

The prevalence of waterpipe tobacco smoking is increasing globally. Biomarkers of waterpipe tobacco smoke (WTS) exposure are less studied.

AIMS AND METHODS

To identify the types of biomarkers of WTS exposure and estimate changes in biomarker concentrations pre- to post-WTS exposure. PubMed, Embase, Web of Science, CINAHL Plus, PsycINFO, and Cochrane Library were searched for studies up to April 24, 2023. The types of biomarkers were identified. Random-effects models were used to estimate changes in biomarker concentrations pre- to post-WTS exposure.

RESULTS

Seventy-three studies involving 3755 participants exposed to WTS (49% male, mean age: 24.8 years) and 11 types of biomarkers of WTS exposure were identified. The biomarkers included tobacco alkaloids, expired carbon monoxide (eCO), carboxyhemoglobin (COHb), tobacco-specific nitrosamines, volatile organic compounds (VOCs), polycyclic aromatic hydrocarbons (PAHs), heavy metals, unmetabolized VOCs, unmetabolized PAHs, furan metabolites, and heterocyclic aromatic amines. Compared with pre-WTS exposure, eCO (breath; mean difference [MD] 27.00 ppm; 95% confidence interval [CI]: 20.91 to 33.08), COHb (blood; MD 4.30%; 95%CI: 2.57 to 6.03), COHb (breath; MD 7.14%; 95%CI: 4.96 to 9.31), nicotine (blood; MD 8.23 ng/mL; 95%CI: 6.27 to 10.19), and cotinine (urine; MD 110.40 ng/mL; 95%CI: 46.26 to 174.54) significantly increased post-WTS exposure.

CONCLUSIONS

Biomarkers of WTS exposure were systematically identified. The similarity between the biomarkers of WTS exposure and those of cigarette smoke and higher concentrations of some biomarkers post-WTS exposure underscore the need for further research on applying biomarkers in surveillance, interventions, and regulations to mitigate the harms of waterpipe tobacco smoking.

IMPLICATIONS

This study provides the first comprehensive overview of biomarkers investigated and available for assessing WTS exposure and their concentration changes in the human body. Researchers can use biomarkers such as eCO, COHb, nicotine, and cotinine to measure the health risks associated with WTS exposure and objectively evaluate the effectiveness of public health interventions aimed at reducing waterpipe tobacco smoking. Public health policymaking can also be informed through increased biomarker concentrations following WTS exposure, to implement regulations and public health education campaigns on limiting or preventing waterpipe tobacco smoking.

Unveiling an Association between Waterpipe Smoking and Bladder Cancer Risk: A Multicenter Case-Control Study in Iran

BACKGROUND

Limited data exist for the association between bladder cancers and waterpipe smoking, an emerging global public health concern.

METHODS

We used the IROPICAN database in Iran and used multivariable logistic regression, adjusting for cigarette smoking, opium use, and other confounding factors. In addition, we studied the association between exclusive waterpipe smoking and bladder cancer.

RESULTS

We analyzed 717 cases and 3,477 controls and a subset of 215 patients and 2,145 controls who did not use opium or cigarettes. Although the OR adjusted for opium, cigarettes, and other tobacco products was 0.92 [95% confidence interval (CI), 0.69-1.20], we observed a statistically significant elevated risk in exclusive waterpipe smokers (OR = 1.78; 95% CI, 1.16-2.72) compared with non-users of opium or any tobacco. Associations were strongest for smoking more than two heads/day (OR = 2.25; 95% CI, 1.21-4.18) and for initiating waterpipe smoking at an age less than 20 (OR = 2.73; 95% CI, 1.11-6.72). The OR for urothelial bladder cancer was higher in ex-smokers (OR = 2.35; 95% CI, 1.24-4.42) than in current smokers (OR = 1.52; 95% CI, 0.72-3.15). All observed associations were consistently higher for urothelial histology.

CONCLUSIONS

Waterpipe smoking may be associated with an increased risk of bladder cancer, notably among individuals who are not exposed to cigarette smoking and opium.

IMPACT

The study provides compelling evidence that waterpipe smoking is a confirmed human carcinogen, demanding action from policymakers. See related In the Spotlight, p. 461.

Exposure to polycyclic aromatic hydrocarbons, volatile organic compounds, and tobacco-specific nitrosamines and incidence of esophageal cancer

BACKGROUND

Studying carcinogens in tobacco and nontobacco sources may be key to understanding the pathogenesis and geographic distribution of esophageal cancer.

METHODS

The Golestan Cohort Study has been conducted since 2004 in a region with high rates of esophageal squamous cell carcinoma. For this nested study, the cases comprised of all incident cases by January 1, 2018; controls were matched to the case by age, sex, residence, time in cohort, and tobacco use. We measured urinary concentrations of 33 exposure biomarkers of nicotine, polycyclic aromatic hydrocarbons, volatile organic compounds, and tobacco-specific nitrosamines. We used conditional logistic regression to calculate odds ratios (ORs) and 95% confidence intervals for associations between the 90th vs the 10th percentiles of the biomarker concentrations and incident esophageal squamous cell carcinoma.

RESULTS

Among individuals who did not currently use tobacco (148 cases and 163 controls), 2 acrolein metabolites, 2 acrylonitrile metabolites, 1 propylene oxide metabolite, and one 1,3-butadiene metabolite were significantly associated with incident esophageal squamous cell carcinoma (adjusted odds ratios between 1.8 and 4.3). Among tobacco users (57 cases and 63 controls), metabolites of 2 other volatile organic compounds (styrene and xylene) were associated with esophageal squamous cell carcinoma (OR = 6.2 and 9.0, respectively). In tobacco users, 2 tobacco-specific nitrosamines (NNN and N'-Nitrosoanatabine) were also associated with esophageal squamous cell carcinoma. Suggestive associations were seen with some polycyclic aromatic hydrocarbons (especially 2-hydroxynaphthalene) in nonusers of tobacco products and other tobacco-specific nitrosamines in tobacco users.

CONCLUSION

These novel associations based on individual-level data and samples collected many years before cancer diagnosis, from a population without occupational exposure, have important public health implications.

Supersulfide prevents cigarette smoke extract-induced mitochondria hyperfission and cardiomyocyte early senescence by inhibiting Drp1-filamin complex formation

Smoking is one of the most serious risk factors for cardiovascular diseases. Although cigarette mainstream and sidestream smoke are significant contributors to increased cardiovascular mortality and morbidity, the underlying mechanism is still unclear. Here, we report that exposure of rat neonatal cardiomyocytes to cigarette smoke extract (CSE) induces mitochondrial hyperfission-mediated myocardial senescence. CSE leads to mitochondrial fission and reactive oxygen species (ROS) production through the complex formation between mitochondrial fission factor Drp1 and actin-binding protein, filamin A. Pharmacological perturbation of interaction between Drp1 and filamin A by cilnidipine and gene knockdown of Drp1 or filamin A inhibited CSE-induced mitochondrial hyperfission and ROS production as well as myocardial senescence. We previously reported that Drp1 activity is controlled by supersulfide-induced Cys644 polysulfidation. The redox-sensitive Cys644 was critical for CSE-mediated interaction with filamin A. The administration of supersulfide donor, Na2S3 also improved mitochondrial hyperfission-mediated myocardial senescence induced by CSE. Our results suggest the important role of Drp1-filamin A complex formation on cigarette smoke-mediated cardiac risk and the contribution of supersulfide to mitochondrial fission-associated myocardial senescence.

Dental health and lung cancer risk in the Golestan Cohort Study

BACKGROUND

Poor oral health has been linked to various systemic diseases, including multiple cancer types, but studies of its association with lung cancer have been inconclusive.

METHODS

We examined the relationship between dental status and lung cancer incidence and mortality in the Golestan Cohort Study, a large, prospective cohort of 50,045 adults in northeastern Iran. Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for associations between three dental health measures (i.e., number of missing teeth; the sum of decayed, missing, or filled teeth (DMFT); and toothbrushing frequency) and lung cancer incidence or mortality with adjustment for multiple potential confounders, including cigarette smoking and opium use. We created tertiles of the number of lost teeth/DMFT score in excess of the loess adjusted, age- and sex-specific predicted numbers, with subjects with the expected number of lost teeth/DMFT or fewer as the reference group.

RESULTS

During a median follow-up of 14 years, there were 119 incident lung cancer cases and 98 lung cancer deaths. Higher DMFT scores were associated with a progressively increased risk of lung cancer (linear trend, p = 0.011). Compared with individuals with the expected DMFT score or less, the HRs were 1.27 (95% CI: 0.73, 2.22), 2.15 (95% CI: 1.34, 3.43), and 1.52 (95% CI: 0.81, 2.84) for the first to the third tertiles of DMFT, respectively. The highest tertile of tooth loss also had an increased risk of lung cancer, with a HR of 1.68 (95% CI: 1.04, 2.70) compared with subjects with the expected number of lost teeth or fewer (linear trend, p = 0.043). The results were similar for lung cancer mortality and did not change substantially when the analysis was restricted to never users of cigarettes or opium. We found no associations between toothbrushing frequency and lung cancer incidence or mortality.

CONCLUSION

Poor dental health indicated by tooth loss or DMFT, but not lack of toothbrushing, was associated with increased lung cancer incidence and mortality in this rural Middle Eastern population.

Influence of Half-life and Smoking/Nonsmoking Ratio on Biomarker Consistency between Waves 1 and 2 of the Population Assessment of Tobacco and Health Study

BACKGROUND

Biomarkers of exposure are tools for understanding the impact of tobacco use on health outcomes if confounders like demographics, use behavior, biological half-life, and other sources of exposure are accounted for in the analysis.

METHODS

We performed multiple regression analysis of longitudinal measures of urinary biomarkers of alkaloids, tobacco-specific nitrosamines, polycyclic aromatic hydrocarbons, volatile organic compounds (VOC), and metals to examine the sample-to-sample consistency in Waves 1 and 2 of the Population Assessment of Tobacco and Health (PATH) Study including demographic characteristics and use behavior variables of persons who smoked exclusively. Regression coefficients, within- and between-person variance, and intra-class correlation coefficients (ICC) were compared with biomarker smoking/nonsmoking population mean ratios and biological half-lives.

RESULTS

Most biomarkers were similarly associated with sex, age, race/ethnicity, and product use behavior. The biomarkers with larger smoking/nonsmoking population mean ratios had greater regression coefficients related to recency of exposure. For VOC and alkaloid metabolites, longer biological half-life was associated with lower within-person variance. For each chemical class studied, there were biomarkers that demonstrated good ICCs.

CONCLUSIONS

For most of the biomarkers of exposure reported in the PATH Study, for people who smoke cigarettes exclusively, associations are similar between urinary biomarkers of exposure and demographic and use behavior covariates. Biomarkers of exposure within-subject consistency is likely associated with nontobacco sources of exposure and biological half-life.

IMPACT

Biomarkers measured in the PATH Study provide consistent sample-to-sample measures from which to investigate the association of adverse health outcomes with the characteristics of cigarettes and their use.

Smoke exposure associated with higher urinary benzene biomarker muconic acid (MUCA) in Golestan Cohort Study participants

Background. Benzene is a known human carcinogen. Human exposure to benzene can be assessed by measuring trans, trans-muconic acid (MUCA) in urine. Golestan Province in northeastern Iran has been reported to have high incidence of esophageal cancer linked to the use of tobacco products. This manuscript evaluates the urinary MUCA concentrations among the participants of the Golestan Cohort Study (GCS).Methods. We analyzed MUCA concentration in 177 GCS participants' urine samples and performed nonparametric pairwise multiple comparisons to determine statistically significant difference among six different product use groups. Mixed effects model was fitted on 22 participants who exclusively smoked cigarette and 51 participants who were classified as nonusers. The urinary MUCA data were collected at the baseline and approximately five years later, and intraclass correlation coefficient (ICC) was calculated from the model.Results. Compared with nonusers, tobacco smoking was associated with higher urinary MUCA concentrations. Based on the nonparametric test of pairwise multiple comparisons, MUCA concentrations among participants who smoked combusted tobacco products were statistically significantly higher compared to nonusers. Urinary MUCA collected five years apart from the same individuals showed moderate reliability (ICC = 0.41), which was expected given the relatively short half-life (∼6 h) of MUCA.Conclusion. Our study revealed that tobacco smoke was positively associated with increased levels of urinary MUCA concentration, indicating that it is a significant source of benzene exposure among GCS participants.

Global Profiling of Urinary Mercapturic Acids Using Integrated Library-Guided Analysis

Urinary mercapturic acids (MAs) are often used as biomarkers for monitoring human exposures to occupational and environmental xenobiotics. In this study, we developed an integrated library-guided analysis workflow using ultraperformance liquid chromatography-quadrupole time-of-flight mass spectrometry. This method includes expanded assignment criteria and a curated library of 220 MAs and addresses the shortcomings of previous untargeted approaches. We employed this workflow to profile MAs in the urine of 70 participants─40 nonsmokers and 30 smokers. We found approximately 500 MA candidates in each urine sample, and 116 MAs from 63 precursors were putatively annotated. These include 25 previously unreported MAs derived mostly from alkenals and hydroxyalkenals. Levels of 68 MAs were comparable in nonsmokers and smokers, 2 MAs were higher in nonsmokers, and 46 MAs were elevated in smokers. These included MAs of polycyclic aromatic hydrocarbons and hydroxyalkenals and those derived from toxicants present in cigarette smoke (e.g., acrolein, 1,3-butadiene, isoprene, acrylamide, benzene, and toluene). Our workflow allowed profiling of known and unreported MAs from endogenous and environmental sources, and the levels of several MAs were increased in smokers. Our method can also be expanded and applied to other exposure-wide association studies.

Esophageal and gastric cancer incidence trends in Golestan, Iran: An age-period-cohort analysis 2004 to 2018

Golestan province in the northeast of Iran is part of the Asian esophageal cancer belt and is known as a high-risk area for esophageal (EC) and gastric cancers (GC). Data on incident cases of EC and GC during 2004 to 2018 were obtained from the Golestan Population-based Cancer Registry (GPCR). The age-standardized incidence rates (ASRs) were calculated and presented per 100 000 person-years. The estimated annual percentage change (EAPC) with 95% confidence interval (95% CI) were calculated. We also fitted age-period-cohort (APC) models to assess nonlinear period and cohort effects as incidence rate ratios (IRRs). Overall, 3004 new cases of EC (ASR = 15.7) and 3553 cases of GC (ASR = 18.3) were registered in the GPCR. We found significant decreasing trends in incidence rates of EC (EAPC = -5.0; 95% CI: -7.8 to -2.2) and less marked nonsignificant trends for GC (EAPC = -1.4; 95% CI: -4.0 to 1.4) during 2004 to 2018. There was a strong cohort effect for EC with a consistent decrease in the IRR across successive birth cohorts, starting with the oldest birth cohort (1924; IRR = 1.9 vs the reference birth cohort of 1947) through to the most recent cohort born in 1988 (IRR = 0.1). The marked declines in EC incidence rates in Golestan relate to generational changes in its underlying risk factors. Despite favorable trends, this population remains at high risk of both EC and GC. Further studies are warranted to measure the impact of the major risk factors on incidence with a view to designing effective preventative programs.

Manipulation of Menthol and Nicotine Content in Cigarettes: Effects on Smoking Behavior and Toxicant Exposure in Women Menthol Smokers

BACKGROUND

The purpose of this study was to determine the effects of smoking and other outcomes of assigning cigarettes with reduced nicotine and/or no menthol to female menthol smokers.

AIMS AND METHODS

Nontreatment-seeking female menthol smokers (N = 263) participated in a randomized controlled trial in which levels of menthol and nicotine in cigarettes were manipulated using experimental cigarettes. After a baseline period, participants were assigned to the following conditions for 6 weeks: (1) their own brand of cigarette (conventional nicotine with menthol), (2) a conventional nicotine cigarette with no menthol, (3) a cigarette with reduced nicotine (RNC) with menthol, or (4) a RNC cigarette and no menthol. Participants then returned to using their own brand and were followed for another 6 weeks. Outcomes included cigarettes smoked, biomarkers of exposure, and dependence measures.

RESULTS

Results indicated that, after an initial increase, rates of smoking of all three experimental cigarettes were at or below baseline rates of smoking of one's own brand. Levels of biomarkers also decreased during the experimental phase but rebounded somewhat after participants resumed smoking their own brand. There was evidence that the overall amount of smoking decreased similarly among women who switched to non-menthol and/or RNC cigarettes.

CONCLUSIONS

These results suggest that no detrimental effect will occur in nicotine or toxicant exposure levels with a ban on characterizing menthol and/or a product standard on nicotine content in cigarettes.

IMPLICATIONS

The implication of this work is that there would be no risk to women menthol smokers associated with regulations restricting nicotine and eliminating menthol in cigarettes.

Variability in Urinary Nicotine Exposure Biomarker Levels Between Waves 1 (2013-2014) and 2 (2014-2015) in the Population Assessment of Tobacco and Health Study

INTRODUCTION

To date, no studies have evaluated the consistency of biomarker levels in people who smoke over a long-time period in real-world conditions with a large number of subjects and included use behavior and measures of nicotine metabolism. We evaluated the variability of biomarkers of nicotine exposure over approximately a 1-year period in people who exclusively smoke cigarettes, including intensity and recency of use and brand switching to assess impact on understanding associations with product characteristics.

AIMS AND METHODS

Multivariate regression analysis of longitudinal repeated measures of urinary biomarkers of nicotine exposure from 916 adults in the Population Assessment of Tobacco and Health (PATH) Study with demographic characteristics and use behavior variables. Intraclass correlation coefficients (ICCs) were calculated to examine individual variation of nicotine biomarkers and the uncertainty of repeat measures at two time points (Waves 1 and 2).

RESULTS

Age, race, and urinary creatinine were significant covariates of urinary cotinine. When including use behavior, recency, and intensity of use were highly significant and variance decreased to a higher extent between than within subjects. The ICC for urinary cotinine decreased from 0.7530 with no use behavior variables in the model to 0.5763 when included. Similar results were found for total nicotine equivalents.

CONCLUSIONS

Urinary nicotine biomarkers in the PATH Study showed good consistency between Waves 1 and 2. Use behavior measures such as time since last smoked a cigarette and number of cigarettes smoked in the past 30 days are important to include when assessing factors that may influence biomarker concentrations.

IMPLICATIONS

The results of this study show that the consistency of the nicotine biomarkers cotinine and total nicotine equivalents in spot urine samples from Waves 1 to 2 of the PATH Study is high enough that these data are useful to evaluate the association of cigarette characteristics with biomarkers of exposure under real-world use conditions.

Urinary nitrate and sodium in a high-risk area for upper gastrointestinal cancers: Golestan Cohort Study☆

BACKGROUND

The epidemiological evidence regarding the carcinogenicity of nitrate and sodium in drinking water is limited, partly because measuring the exposure at the individual level is complex. Most studies have used nitrate in water supplies as a proxy for individual exposure, but dietary intakes and other factors may contribute to the exposure. The present study investigates the factors associated with urinary nitrate and sodium in a high-risk area for esophageal and gastric cancers.

METHODS

For this cross-sectional study, we used data and samples collected in 2004-2008 during the enrollment phase of the Golestan Cohort Study from a random sample of 349 participants (300 individuals from 24 rural villages and 49 from the city of Gonbad), stratified by average water nitrate in their district, the source of drinking water, and the usual dietary intake of nitrate and sodium. Nitrate, sodium, and creatinine were measured in a spot urine sample collected at the time of interview. We used the provincial cancer registry data to calculate the cumulative incidence rates of esophageal and gastric cancers for each location through June 1, 2020, and used weighted partial Pearson correlation to compare the incidence rates with median urinary nitrate and sodium in each village or the city.

RESULTS

Among 349 participants (mean age±SD: 50.7 ± 8.6 years), about half (n = 170) used groundwater for drinking, and the use of groundwater was significantly more common in high-elevation locations (75.8%). The geometric mean of the creatinine-corrected urinary nitrate concentration was 68.3 mg/g cr (95%CI: 64.6,72.3), and the corresponding geometric mean for urinary sodium was 150.0 mmoL/g cr (95%CI: 139.6,161.1). After adjusting for confounders, urinary nitrate was associated with being a woman, drinking groundwater, and living in high-elevation locations, but not with estimated dietary intake. Urinary sodium concentration was significantly associated with monthly precipitation at the time of sampling but not with elevation or drinking water source. There were significant positive correlations between both median urinary nitrate and sodium in each location and esophageal cancer incidence rates adjusted for sex and age (r = 0.65 and r = 0.58, respectively, p < 0.01), but not with gastric cancer incidence.

CONCLUSION

In a rural population at high risk for esophageal and gastric cancers, nitrate excretion was associated with living at a higher elevation and using groundwater for drinking. The associations between nitrate and sodium excretion with esophageal cancer incidence warrant future investigation.

Urinary concentrations of BTEX in waterpipe smokers and nonsmokers: Investigating the influence of conventional activities and multiple factors

The aim of this study was to compare the concentrations of the benzene, toluene, ethylbenzene, and xylene (BTEX) compounds in the urine of smokers and the control group considering the role of age, weight, job, history of waterpipe and cigarette smoking, and driving time. The chemicals in the urine of 99 smokers and 31 nonsmokers were extracted by liquid-liquid extraction method and their concentrations were measured by liquid injection GC/MS. The mean concentration of benzene, toluene, ethylbenzene, m-xylene, o-xylene, p-xylene, and total BTEX in waterpipe smokers were found to be 471.40, 670.90, 127.91, 167.64, 90.62, 46.04, and 1574.50 ng/g. creatinine, respectively. For the waterpipe&cigarette smokers, the concentration of the compounds were 708.00, 959.00, 146.40, 192.50, 93.30, 53.07, and 2152.00 ng/g.creatinine, respectively. For nonsmokers the concentrations of these compounds were 88.12, 140.40, 36.68, 57.29, 31.53, 26.21, and 380.30 ng/g.creatinine, respectively. Driving time, waterpipe smoking and cigarette smoking were positively associated with BTEX concentration (p < 0.05). Fruity tobacco showed higher concentrations of BTEX compared to the regular tobacco, and athlete persons had les urinary BTEX than the non-athletes. There was not significant correlation between the BTEX and age, height, weight, and BMI. High concentrations of BTEX compounds in the urine of waterpipe and cigarette smokers compared to nonsmokers indicate that waterpipe and cigarette can be an important source of exposure to these compounds and the known adverse effects of these compounds, especially carcinogenicity, threaten the health of smokers.

1,3-Butadiene: a ubiquitous environmental mutagen and its associations with diseases

1,3-Butadiene (BD) is a petrochemical manufactured in high volumes. It is a human carcinogen and can induce lymphohematopoietic cancers, particularly leukemia, in occupationally-exposed workers. BD is an air pollutant with the major environmental sources being automobile exhaust and tobacco smoke. It is one of the major constituents and is considered the most carcinogenic compound in cigarette smoke. The BD concentrations in urban areas usually vary between 0.01 and 3.3 μg/m³ but can be significantly higher in some microenvironments. For BD exposure of the general population, microenvironments, particularly indoor microenvironments, are the primary determinant and environmental tobacco smoke is the main contributor. BD has high cancer risk and has been ranked the second or the third in the environmental pollutants monitored in most urban areas, with the cancer risks exceeding 10^-5. Mutagenicity/carcinogenicity of BD is mediated by its genotoxic metabolites but the specific metabolite(s) responsible for the effects in humans have not been determined. BD can be bioactivated to yield three mutagenic epoxide metabolites by cytochrome P450 enzymes, or potentially be biotransformed into a mutagenic chlorohydrin by myeloperoxidase, a peroxidase almost specifically present in neutrophils and monocytes. Several urinary BD biomarkers have been developed, among which N-acetyl-S-(4-hydroxy-2-buten-1-yl)-L-cysteine is the most sensitive and is suitable for biomonitoring BD exposure in the general population. Exposure to BD has been associated with leukemia, cardiovascular disease, and possibly reproductive effects, and may be associated with several cancers, autism, and asthma in children. Collectively, BD is a ubiquitous pollutant that has been associated with a range of adverse health effects and diseases with children being a subpopulation with potentially greater susceptibility. Its adverse effects on human health may have been underestimated and more studies are needed.

Urinary volatomic profile of traditional tobacco smokers and electronic cigarettes users as a strategy to unveil potential health issues

Many harmful and potentially harmful constituents are present in tobacco products. Cigarette smoke is known to cause different forms of cancer and trigger the development of chronic diseases. In the last decade, electronic cigarettes have emerged as a healthier alternative associated to less harmful effects in comparison to traditional tobacco. However, the lack of standardization of electronic cigarettes products makes it difficult to establish and compare the real effects on health of products from different manufacturers. To better understand the impact of smoking and vaping, the volatomic composition of urine samples from traditional tobacco smokers and electronic cigarette users was established and compared with nonsmokers (control group), using headspace solid-phase microextraction combined with gas chromatography-mass spectrometry. A total of 45 urinary volatile organic metabolites belonging to different chemical families were identified in the urine of the studied groups. Benzene derivatives, terpenes, and aromatics were the chemical families that contributed the most to the urinary profile of smokers. The vapers urinary volatomic pattern was also dominated by terpenes and aromatics, in addition to alcohols. The orthogonal partial least squares-discriminant analysis of the data obtained indicated that the urinary profile of vapers is more closely related to the control group, reinforcing the hypothesis of the lowest harmfulness of electronic cigarettes. Further studies recruiting a higher number of subjects are therefore necessary to consolidate the data obtained.

Associations between Biomarkers of Exposure and Lung Cancer Risk among Exclusive Cigarette Smokers in the Golestan Cohort Study

Biomarkers of tobacco exposure are known to be associated with disease risk but previous studies are limited in number and restricted to certain regions. We conducted a nested case-control study examining baseline levels and subsequent lung cancer incidence among current male exclusive cigarette smokers in the Golestan Cohort Study in Iran. We calculated geometric mean biomarker concentrations for 28 matched cases and 52 controls for the correlation of biomarker levels among controls and for adjusted odds' ratios (ORs) for lung cancer incidence by biomarker concentration, accounting for demographic characteristics, smoking quantity and duration, and opium use. Lung cancer cases had higher average levels of most biomarkers including total nicotine equivalents (TNE-2), 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), and 3-hydroxyfluorene (3-FLU). Many biomarkers correlated highly with one another including TNE-2 with NNAL and N-Acetyl-S-(2-cyanoethyl)-L-cysteine (2CYEMA), and N-Acetyl-S-(4-hydroxy-2-buten-1-yl)-L-cysteine (t4HBEMA) with N-Acetyl-S-(3-hydroxypropyl-1-methyl)-L-cysteine (3HMPMA) and N-Acetyl-S-(4-hydroxy-2-methyl-2-buten-1-yl)-L-cysteine (4HMBEMA). Lung cancer risk increased with concentration for several biomarkers, including TNE-2 (OR = 2.22, 95% CI = 1.03, 4.78) and NNN (OR = 2.44, 95% CI = 1.13, 5.27), and estimates were significant after further adjustment for demographic and smoking characteristics for 2CYEMA (OR = 2.17, 95% CI = 1.03, 4.55), N-Acetyl-S-(2-carbamoylethyl)-L-cysteine (2CAEMA) (OR = 2.14, 95% CI = 1.01, 4.55), and N-Acetyl-S-(2-hydroxypropyl)-L-cysteine (2HPMA) (OR = 2.85, 95% CI = 1.04, 7.81). Estimates were not significant with adjustment for opium use. Concentrations of many biomarkers were higher at the baseline for participants who subsequently developed lung cancer than among the matched controls. Odds of lung cancer were higher for several biomarkers including with adjustment for smoking exposure for some but not with adjustment for opium use.

Indoor wood combustion, carcinogenic exposure and esophageal cancer in southwest Kenya

BACKGROUND

Exposure to polycyclic aromatic hydrocarbons (PAHs) is a risk factor for esophageal squamous cell carcinoma (ESCC) in high-incidence areas of China, Iran and Brazil, but PAH assessments have not been conducted in East Africa, another ESCC hot spot.

OBJECTIVE

To evaluate demographic or lifestyle factors associated with the PAH biomarker concentrations in the study population, and whether PAH metabolite concentrations showed any associations with esophageal precancerous lesions.

METHODS

We recruited a community-based sample of 289 asymptomatic adults from a rural area of Kenya and performed Lugol's chromoendoscopy to detect esophageal squamous dysplasia (ESD); participants completed a questionnaire and provided a spot urine specimen. We analyzed urine for seven hydroxylated metabolites of naphthalene, fluorene, phenanthrene, and pyrene at the U.S. National Center for Environmental Health, and compared creatinine-corrected PAH metabolite concentrations with questionnaire data and the presence of ESD.

RESULTS

PAH metabolite concentrations among never tobacco users in these rural Kenya residents were 2.4-28.1 times higher than those reported from never tobacco users in Iran, Brazil and the USA. Female sex, cooking indoors, having no post-primary education, and age <50, but not tobacco use, were positively and significantly associated with PAH metabolite concentrations. Almost all participants used wood as cooking fuel. Nine participants had advanced ESD. Adjusted logistic regression showed a significant association between 2-hydroxynaphthalene (OR = 4.19, 95%CI: 1.01-17.47) and advanced ESD. All other PAH metabolites had positive but non-significant associations with advanced ESD.

CONCLUSIONS

Urinary PAH metabolite concentrations among never tobacco users are markedly higher in this group from Kenya than in other populations and are associated with indoor cooking with wood on open, unvented stoves. These metabolite concentrations were also associated with the presence of advanced esophageal dysplasia. Our findings underline the importance of assessing alternative cooking conditions to reduce PAH exposure in this population.

Oral Health and Risk of Upper Gastrointestinal Cancers in a Large Prospective Study from a High-risk Region: Golestan Cohort Study

Tooth loss and periodontal disease have been associated with several cancers, and poor oral health may be an important risk factor for upper gastrointestinal (UGI, i.e., esophageal and gastric) cancers. We assessed the relationship between oral health and UGI cancers using a large prospective study of over 50,000 adults living in Golestan Province, Iran, a high-incidence area for these cancers. Hazard ratios (HRs) and 95% confidence intervals (CI) were estimated for the association between three different measures of oral health [frequency of tooth brushing; number of missing teeth; and the sum of decayed, missing, and filled teeth (DMFT)] and UGI cancers. During a median follow-up duration of 13 years, there were 794 incident UGI cancers (396 esophageal and 398 gastric cancers). Daily tooth brushing was associated with a decreased risk of developing both esophageal (HR = 0.670; 95% CI: 0.486-0.924) and gastric (HR = 0.741; 95% CI: 0.544-1.01) cancers (combined UGI cancer HR = 0.697; 95% CI: 0.558-0.871) compared with never brushing. Tooth loss in excess of the loess smoothed, age- and sex-specific median number of teeth lost was significantly associated with esophageal (HR = 1.64; 95% CI: 1.08-2.47) and gastric cancers (HR = 1.58; 95% CI: 1.05-2.38). There were some adverse associations between DMFT and UGI cancers but most were not statistically significant. These results suggest increased risk of developing UGI cancers among individuals with poor oral health, and those who do not perform regular oral hygiene. PREVENTION RELEVANCE: Poor oral health is associated with the risk of upper gastrointestinal cancers, and oral hygiene practices may help prevent these cancers.

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.

Harmonization of acronyms for volatile organic compound metabolites using a standardized naming system

Increased interest in volatile organic compound (VOC) exposure has led to an increased need for consistent, systematic, and informative naming of VOC metabolites. As analytical methods have expanded to include many metabolites in a single assay, the number of acronyms in use for a single metabolite has expanded in an unplanned and inconsistent manner due to a lack of guidance or group consensus. Even though the measurement of VOC metabolites is a well-established means to investigate exposure to VOCs, a formal attempt to harmonize acronyms amongst investigators has not been published. The aim of this work is to establish a system of acronym naming that provides consistency in current acronym usage and a foundation for creating acronyms for future VOC metabolites.

The mediation effect of serum metabolites on the relationship between long-term smoking exposure and esophageal squamous cell carcinoma

BACKGROUND

Long-term smoking exposure will increase the risk of esophageal squamous cell carcinoma (ESCC), whereas the mechanism is still unclear. We conducted a cross-sectional study to explore whether serum metabolites mediate the occurrence of ESCC caused by cigarette smoking.

METHODS

Serum metabolic profiles and lifestyle information of 464 participants were analyzed. Multiple logistic regression was used to estimate adjusted odds ratios (ORs) and 95% confidence intervals (CIs) of smoking exposure to ESCC risk. High-dimensional mediation analysis and univariate mediation analysis were performed to screen potential intermediate metabolites of smoking exposure for ESCC.

RESULTS

Ever smoking was associated with a 3.11-fold increase of ESCC risk (OR = 3.11, 95% CI 1.63-6.05), and for each cigarette-years increase in smoking index, ESCC risk increased by 56% (OR = 1.56, 95% CI 1.18-2.13). A total of 5 metabolites were screened as mediators by high-dimensional mediation analysis. In addition, glutamine, histidine, and cholic acid were further proved existing mediation effects according to univariate mediation analysis. And the proportions of mediation of histidine and glutamine were 40.47 and 30.00%, respectively. The mediation effect of cholic acid was 8.98% according to the analysis of smoking index.

CONCLUSIONS

Our findings suggest that cigarette smoking contributed to incident ESCC, which may be mediated by glutamine, histidine and cholic acid.

Characterization of acrylonitrile exposure in the United States based on urinary n-acetyl-S-(2-cyanoethyl)-L-cysteine (2CYEMA): NHANES 2011-2016

BACKGROUND

Acrylonitrile is a possible human carcinogen that is used in polymers and formed in tobacco smoke. We assessed acrylonitrile exposure in the US population by measuring its urinary metabolites N-acetyl-S-(4-hydroxy-2-methyl-2-buten-1-yl)-L-cysteine (2CYEMA) and N-acetyl-S-(1-cyano-2-hydroxyethyl)-L-cysteine (1CYHEMA) in participants from the 2011-2016 National Health and Nutrition Examination Survey.

OBJECTIVE

To assessed acrylonitrile exposure using population-based biomonitoring data of the US civilian, non-institutionalized population.

METHODS

Laboratory data for 8057 participants were reported for 2CYEMA and 1CYHEMA using ultrahigh-performance liquid chromatography/tandem mass spectrometry. Exclusive tobacco smokers were distinguished from non-users using a combination of self-reporting and serum cotinine data. We used multiple linear regression models to fit 2CYEMA concentrations with sex, age, race/Hispanic origin, and tobacco user group as predictor variables.

RESULTS

The median 2CYEMA level was higher for exclusive cigarette smokers (145 µg/g creatinine) than for non-users (1.38 µg/g creatinine). Compared to unexposed individuals (serum cotinine ≤0.015 ng/ml) and controlling for confounders, presumptive second-hand tobacco smoke exposure (serum cotinine >0.015 to ≤10 ng/ml and 0 cigarettes per day, CPD) was significantly associated with 36% higher 2CYEMA levels (p < 0.0001). Smoking 1-10 CPD was significantly associated with 6720% higher 2CYEMA levels (p < 0.0001).

SIGNIFICANCE

We show that tobacco smoke is an important source of acrylonitrile exposure in the US population and provide important biomonitoring data on acrylonitrile exposure.

Waterpipe smoke condensate influences epithelial to mesenchymal transition and interferes with the cytotoxic immune response in non-small cell lung cancer cell lines

Waterpipe tobacco smoking (WPS) continues to spread globally and presents serious health hazards. The aim of the present study was to investigate the effects of treatment with WPS condensate (WPSC) on lung cell proliferation and plasticity as well as tumor cell recognition and killing by natural killer (NK) cells using cytotoxicity assays. The results indicated that exposure of normal and cancer lung cell lines to WPSC resulted in a decrease in their in vitro growth in a dose-dependent manner and it induced tumor senescence. In addition, WPSC selectively caused DNA damage as revealed by an increase in γH2AX and 53BP1 in tumor lung cells. To gain further insight into the molecular mechanisms altered by WPSC, we conducted a global comprehensive transcriptome analysis of WPSC-treated tumor cells. Data analysis identified an expression profile of genes that best distinguished treated and non-treated cells involving several pathways. Of these pathways, we focused on those involved in epithelial to mesenchymal transition (EMT) and stemness. Results showed that WPSC induced an increase in SNAI2 expression associated with EMT, ACTA2 and SERPINE2 were involved in invasion and CD44 was associated with stemness. Furthermore, WPSC exposure increased the expression of inflammatory response genes including CASP1, IL1B, IL6 and CCL2. While immune synapse formation between NK and WPSC-treated lung cancer target cells was not affected, the capacity of NK cells to kill these target cells was reduced. The data reported in the present study are, to the best of our knowledge, the first in vitro demonstration of WPSC effects on lung cellular parameters providing evidence of its potential involvement in tumor physiology and development.

Acrolein and other toxicant exposures in relation to cardiovascular disease among marijuana and tobacco smokers in a longitudinal cohort of HIV-positive and negative adults

BACKGROUND

Marijuana smoke contains some of the same toxicants present in tobacco smoke. Marijuana smoking is prevalent among HIV+ individuals, but few studies have characterized smoke-related toxicants or associated health outcomes in exclusive marijuana users.

METHODS

This longitudinal study included 245 participants over age 40 (76% HIV+). 33 plasma and 28 urine metabolites of nicotine, ∆-9-trans-tetrahydrocannabinol, polycyclic aromatic hydrocarbons, and volatile organic compounds were assayed by liquid or gas chromatography/mass spectrometry. Exposures and health outcomes were assessed from surveys and medical records.

FINDINGS

At baseline, 18% of participants were marijuana-only smokers, 20% tobacco-only smokers, and 24% dual marijuana-tobacco smokers (median (IQR) age 53 (47-60) years, 78% male, 54% white race). Marijuana smoking was independently associated with elevated plasma naphthalenes, 2-hydroxyfluorene sulfate, 4-vinylphenol sulfate, and o-cresol sulfate (p<0·05) and urine acrylonitrile and acrylamide metabolites (p<0·05), but levels were lower than those associated with tobacco smoking. Acrolein metabolite N-Acetyl-S-(3-hydroxypropyl)-l-cysteine (3HPMA) was significantly elevated in plasma and urine in tobacco-only and dual but not marijuana-only smokers, and correlated with nicotine metabolites (p<0·05). The highest tertile of 3HPMA was associated with increased cardiovascular disease diagnoses independent of tobacco smoking, traditional risk factors, and HIV status (odds ratio [95% CI] 3·34 [1·31-8·57]; p = 0·012).

INTERPRETATION

Smoke-related toxicants, including acrylonitrile and acrylamide metabolites, are detectable in exclusive marijuana smokers, but exposures are lower compared with tobacco or dual smokers. Acrolein exposure is increased by tobacco smoking but not exclusive marijuana smoking in HIV+ and HIV- adults, and contributes to cardiovascular disease in tobacco smokers.

FUNDING

U.S. NIH.

Untargeted Metabolomics: Biochemical Perturbations in Golestan Cohort Study Opium Users Inform Intervention Strategies

Objective: Over 50 million people worldwide are estimated to use opioids, of which ~30 million use opiates (opium and its derivatives). Use of opiates has been associated with a variety of adverse complications such as neurological and behavioral outcomes, addiction, cancers, diabetes, and cardiovascular disease. While it is well known that opiates exert their neurobiological effects through binding with mu, kappa, and delta receptors to exert analgesic and sedative effects, mechanistic links to other health effects are not well understood. Our study focuses on the identification of biochemical perturbations in Golestan Cohort Study (GCS) opium users.

Methods: We used untargeted metabolomics to evaluate the metabolic profiles of 218 opium users and 80 non-users participating in the GCS. Urine samples were obtained from adult (age 40–75) opium users living in the Golestan Province of Iran. Untargeted analysis of urine was conducted using a UPLC-Q-Exactive HFx Mass Spectrometry and a 700 MHz NMR Spectrometry.

Results: These GCS opium users had a significantly higher intake of tobacco and alcohol and a significantly decreased BMI compared with non-users. Metabolites derived from opium (codeine, morphine, and related glucuronides), nicotine, and curing or combustion of plant material were increased in opium users compared with non-users. Endogenous compounds which differentiated the opium users and non-users largely included vitamins and co-factors, metabolites involved in neurotransmission, Kreb's cycle, purine metabolism, central carbon metabolism, histone modification, and acetylation.

Conclusions: Our study reveals biochemical perturbations in GCS opium users that are important to the development of intervention strategies to mitigate against the development of adverse effects of substance abuse.

Cluster analysis of urinary tobacco biomarkers among U.S. adults: Population Assessment of Tobacco and Health (PATH) biomarker study (2013-2014)

Tobacco use delivers nicotine, tobacco-specific nitrosamines (TSNAs), volatile organic compounds (VOCs), and polycyclic aromatic hydrocarbons (PAHs), which are metabolized and excreted in urine offering useful biomarkers of exposure. Previous studies compared individual toxicants across tobacco users. Based on a group of biomarkers, cluster analysis was used to define tobacco toxicant exposure profiles. Clusters with distinct exposure profiles, were determined and described, based on levels of urinary biomarkers of exposure to nicotine, TSNAs, VOCs, and PAHs among a national sample of current, established, adult tobacco users, and examine the association of use behavior and cluster membership. The PATH Biomarker Wave 1 data were analyzed. Current established tobacco users with complete urinary biomarker data were included (N = 6724). User groups included cigarette smokers, users of electronic cigarette (ECIG), smokeless tobacco (SLT), and dual and poly tobacco users. Cluster analysis, pairwise comparisons, and multinomial logistic regression were conducted. Cigarette smokers were primarily in clusters with high biomarker concentrations across all groups, but actual concentrations were associated with smoking quantity. A cluster with high TSNAs but low levels of PAHs and VOCs was heavily populated by SLT users. Exclusive ECIG users, depending on use frequency, were predominantly in clusters with low biomarker concentrations, except for one cluster that had relatively high TSNAs. Clusters heavily populated by dual and poly tobacco users were the same as those heavily populated by cigarette smokers. Ten exposure profiles (clusters) were determined and linked to tobacco use behavior. Findings could inform future research and policy initiatives.

Opiate and Tobacco Use and Exposure to Carcinogens and Toxicants in the Golestan Cohort Study

BACKGROUND

There is little information on human exposure to carcinogens and other toxicants related to opiate use, alone or in combination with tobacco.

METHODS

Among male participants of the Golestan Cohort Study in Northeast Iran, we studied 28 never users of either opiates or tobacco, 33 exclusive cigarette smokers, 23 exclusive users of smoked opiates, and 30 opiate users who also smoked cigarettes (dual users; 21 smoked opiates and 9 ingested them). We quantified urinary concentrations of 39 exposure biomarkers, including tobacco alkaloids, tobacco-specific nitrosamines, polycyclic aromatic hydrocarbons (PAH), and volatile organic compounds (VOC), and used decomposition to parse out the share of the biomarker concentrations explained by opiate use and nicotine dose.

RESULTS

Dual users had the highest concentrations of all biomarkers, but exclusive cigarette smokers and exclusive opiate users had substantially higher concentrations of PAH and VOC biomarkers than never users of either product. Decomposition analysis showed that opiate use contributed a larger part of the PAH concentrations than nicotine dose, and the sum of 2- and 3-hydroxyphenanthrene (∑2,3-phe) resulted almost completely from opiate use. Concentrations of most VOC biomarkers were explained by both nicotine dose and opiate use. Two acrylamide metabolites, a 1,3-butadiene metabolite and a dimethylformamide metabolite, were more strongly explained by opiate use. Acrylamide metabolites and ∑2,3-phe were significantly higher in opiate smokers than opiate eaters; other biomarkers did not vary by the route of opiate intake.

CONCLUSIONS

Both cigarette smokers and opiate users (by smoking or ingestion) were exposed to many toxicants and carcinogens.

IMPACT

This high exposure, particularly among dual opiate and cigarette users, can have a substantial global public health impact.

Quantitation of phenanthrene dihydrodiols in the urine of smokers and non-smokers by gas chromatography-negative ion chemical ionization-tandem mass spectrometry

Polycyclic aromatic hydrocarbons (PAH) are well-established environmental carcinogens likely to be causative agents for some human cancers. Bay-region diol epoxides are ultimate carcinogenic metabolites of multiple PAH. Dihydrodiols are the important intermediate products of this pathway and can be further oxidized to form diol epoxides. We quantified two dihydrodiol metabolites of phenanthrene (Phe), the simplest PAH with a bay-region, in the 6 h urine of smokers (N = 25) and non-smokers (N = 25) using a newly developed and validated analytical method. After hydrolysis by ß-glucuronidase and sulfatase, and solid phase extraction, the sample was silylated and analyzed by gas chromatography-negative ion chemical ionization-tandem mass spectrometry (GC-NICI-MS/MS). Levels (nmol/6h urine) of Phe-1,2-dihydrodiol (Phe-1,2-D) and Phe-3,4-dihydrodiol (Phe-3,4-D) were 2.04 ± 1.52 and 0.51 ± 0.35 , respectively, in smokers, significantly higher than those in non-smokers (1.35 ± 1.11 of Phe-1,2-D, p < 0.05; 0.27 ± 0.25 of Phe-3,4-D, p < 0.005). Cigarette smoking also influenced the regioselective metabolism of Phe, presenting as a significant difference in the urinary distribution pattern of Phe-1,2-D and Phe-3,4-D between smokers and non-smokers: the ratio Phe-3,4-D: Phe-1,2-D increased from 0.20 in non-smokers to 0.28 in smokers (p < 0.01), which can be explained by the induction of the phenanthrene metabolizing enzymes CYP1A2 and CYP1B1 by cigarette smoke. The method described here is the first example of facile quantitation of an intact human dihydrodiol metabolite of any PAH with three or more aromatic rings and will be applicable in clinical and molecular epidemiology studies of PAH metabolism and cancer susceptibility.