Similar exposure to a tobacco-specific carcinogen in smokeless tobacco users and cigarette smokers

High throughput and sensitive quantitation of tobacco-specific alkaloids and nitrosamines in wastewater

Tobacco-specific alkaloids and nitrosamines are important biomarkers for the estimation of tobacco use and human exposure to tobacco-specific nitrosamines that can be monitored by wastewater analysis. Thus far their analysis has used solid phase extraction, which is costly and time-consuming. In this study, we developed a direct injection liquid chromatography-tandem mass spectrometry method for the quantification of two tobacco-specific alkaloids and five nitrosamines in wastewater. The method achieved excellent linearity (R2 > 0.99) for all analytes, with calibration ranging from 0.10 to 800 ng/L. Method limits of detection and quantification were 0.17 ng/L (N-nitrosonornicotine, NNN) and 1.0 ng/L (N-nitrosoanatabine (NAT) and NNN), with acceptable accuracy (100 % ± 20 %) and precision (± 15 %). Analyte loss during filtration was < 15 %, and the relative matrix effect was < 10 %. The method was applied to 43 pooled wastewater samples collected from three wastewater treatment plants in Australia between 2017 and 2021. Anabasine and anatabine were detected in all samples at concentrations of 5.0 - 33 ng/L and 12 - 41 ng/L, respectively. Three of the five tobacco-specific nitrosamines (NAT, NNN, and (4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol) (NNAL)) were detected, in < 50 % of the wastewater samples, with concentrations nearly ten times lower than the tobacco alkaloids (< 1.0 - 6.2 ng/L). In-sewer stability of the nitrosamines was also assessed in this study, with four (NAT, NNAL, NNN, and N-nitrosoanabasine (NAB)) being stable (i.e. < 20 % transformation over 12 h in both control reactor (CR) and rising main reactor (RM) and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) being moderately stable (< 40 % loss over 12 h in RM). This direct injection method provides a high-throughput approach in simultaneous investigation of tobacco use and assessment of public exposure to tobacco-specific nitrosamines.

Oral Cancer Risk Assessment for Different Types of Smokeless Tobacco Products Sold Worldwide: A Review of Reviews and Meta-analyses

Smokeless tobacco (SLT) use is a significant cause of lip and oral cavity cancers. Globally, oral cancer prevalence is strongly linked to the types of tobacco products used, their chemical composition, and their pattern of use. Except snus, all SLT products sold in different World Health Organization regions are strongly associated with oral cancer incidence. Shammah showed the highest association OR with 95% confidence intervals (CI; OR, 38.74; 95% CI, 19.50-76.96), followed by oral snuff (OR, 11.80; 95% CI, 8.45-16.49), gutkha (OR, 8.67; 95% CI, 3.59-20.93), tobacco with betel quid (OR, 7.74; 95% CI, 5.38-11.13), toombak (OR, 4.72; 95% CI, 2.88-7.73), and unspecified chewing tobacco (OR, 4.72; 95% CI, 3.13-7.11). Most SLT products containing high levels of carcinogenic tobacco-specific nitrosamines (TSNA) exhibit a high risk of oral cancer. There is an urgent need to frame and implement international policies for oral cancer prevention through legal control of the TSNA levels in all SLT product types.

PREVENTION RELEVANCE

Most smokeless tobacco products sold worldwide, mainly shammah, toombak, gutkha, betel quid with tobacco, and dry snuff, are associated with a high risk of oral cancer. A high concentration of tobacco-specific nitrosamines in smokeless tobacco products is the major causative factor for oral cancer development.

Associations of Smokeless Tobacco Use With Cardiovascular Disease Risk: Insights From the Population Assessment of Tobacco and Health Study

INTRODUCTION

Cigarette smoking is strongly associated with the development of cardiovascular disease (CVD). However, evidence is limited as to whether smokeless tobacco (ST) use is associated with CVD.

AIMS AND METHODS

Using data from 4347 adults in the Population Assessment of Tobacco and Health Study (2013-2014), we compared geometric mean concentrations of CVD-related harm biomarkers and biomarkers of exposure among exclusive ST users and exclusive cigarette smokers-in relation to recent nicotine exposure-and never tobacco users, adjusting for age, sex, race/ethnicity, income, body mass index, and CVD. Biomarker levels among exclusive ST users who were former established cigarette smokers were compared with exclusive cigarette smokers.

RESULTS

Compared with cigarette smokers, ST users had significantly higher concentrations of total nicotine equivalents (TNE) but lower concentrations of inflammatory (high-sensitivity C-reactive protein, interleukin-6, intercellular adhesion molecule, fibrinogen) and oxidative stress (8-isoprostane) biomarkers (all p < .05). Biomarker levels among ST users were similar to never smokers. ST users who were former cigarette smokers had lower levels of inflammatory and oxidative stress biomarkers and biomarkers of exposure (cadmium, lead, 1-hydroxypyrene, acrylonitrile, and acrolein), compared with cigarettes smokers (p < .05), despite having higher TNE levels (p < .05). Among cigarette smokers, but not among ST users, inflammatory biomarkers and TNE were highly correlated.

CONCLUSIONS

ST use is not associated with increases in biomarkers of CVD-related harm and exposure, compared with never smokers, despite exposure to nicotine at levels higher than those observed among cigarette smokers. These findings support the concept that increases in CVD risk among cigarette smokers is caused primarily by constituents of tobacco smoke other than nicotine.

IMPLICATIONS

Despite having higher levels of nicotine and compared with exclusive cigarette smokers, exclusive ST users (including those who were former cigarette smokers) had significantly lower concentrations of inflammatory and oxidative stress biomarkers, comparable to levels observed among never tobacco users. These findings suggest that increases in CVD risk among cigarette smokers is caused primarily by tobacco constituents other than nicotine and that switching to ST is likely associated with lower CVD risk.

Serum Concentrations of Cotinine and Trans-3'-Hydroxycotinine in US Adults: Results From Wave 1 (2013-2014) of the Population Assessment of Tobacco and Health Study

INTRODUCTION

The Population Assessment of Tobacco and Health (PATH) Study is a nationally representative cohort of tobacco product users and nonusers. The study's main purpose is to obtain longitudinal epidemiologic data on tobacco use and exposure among the US population.

AIMS AND METHODS

Nicotine biomarkers-cotinine (COT) and trans-3'-hydroxycotinine (HCT)-were measured in blood samples collected from adult daily tobacco users and nonusers during Wave 1 of the PATH Study (2013-2014; n = 5012; one sample per participant). Participants' tobacco product use and exposure to secondhand smoke were categorized based on questionnaire responses. Nonusers were subdivided into never users and recent former users. Daily tobacco users were classified into seven tobacco product use categories: exclusive users of cigarette, smokeless tobacco, electronic cigarette, cigar, pipe, and hookah, as well as polyusers. We calculated sample-weighted geometric mean (GM) concentrations of cotinine, HCT, and the nicotine metabolite ratio (NMR) and evaluated their associations with tobacco use with adjustment for potential confounders.

RESULTS

The GMs (95% confidence intervals) of COT and HCT concentrations for daily tobacco users were 196 (184 to 208) and 72.5 (67.8 to 77.4) ng/mL, and for nonusers they were 0.033 (0.028 to 0.037) and 0.021 (0.018 to 0.023) ng/mL. Exclusive smokeless tobacco users had the highest COT concentrations of all user groups examined. The GM NMR in daily users was 0.339 (95% confidence interval: 0.330 to 0.350).

CONCLUSIONS

These nationally representative estimates of serum nicotine biomarkers could be the basis for reference ranges characterizing nicotine exposure for daily tobacco users and nonusers in the US adult population.

IMPLICATIONS

This report summarizes the serum nicotine biomarker measurements in Wave 1 of the PATH Study. We are reporting the first estimates of HCT in serum for daily tobacco users and nonusers in the noninstitutionalized, civilian US adult population; the first nationally representative serum COT estimates for daily exclusive users of different tobacco products and daily polyusers; and the first nationally representative estimate of the serum NMR in daily tobacco users by age, race/ethnicity, and sex.

Urinary Nicotine Metabolites and Self-Reported Tobacco Use Among Adults in the Population Assessment of Tobacco and Health (PATH) Study, 2013-2014

INTRODUCTION

The Population Assessment of Tobacco and Health (PATH) Study is a longitudinal cohort study on tobacco use behavior, attitudes and beliefs, and tobacco-related health outcomes, including biomarkers of tobacco exposure in the U.S. population. In this report we provide a summary of urinary nicotine metabolite measurements among adult users and non-users of tobacco from Wave 1 (2013-2014) of the PATH Study.

METHODS

Total nicotine and its metabolites including cotinine, trans-3'-hydroxycotinine (HCTT), and other minor metabolites were measured in more than 11 500 adult participants by liquid chromatography tandem mass spectrometry methods. Weighted geometric means (GM) and least square means from statistical modeling were calculated for non-users and users of various tobacco products.

RESULTS

Among daily users, the highest GM concentrations of nicotine, cotinine and HCTT were found in exclusive smokeless tobacco users, and the lowest in exclusive e-cigarette users. Exclusive combustible product users had intermediate concentrations, similar to those found in users of multiple products (polyusers). Concentrations increased with age within the categories of tobacco users, and differences associated with gender, race/ethnicity and educational attainment were also noted among user categories. Recent (past 12 months) former users had GM cotinine concentrations that were more than threefold greater than never users.

CONCLUSIONS

These urinary nicotine metabolite data provide quantification of nicotine exposure representative of the entire US adult population during 2013-2014 and may serve as a reference for similar analyses in future measurements within this study.

IMPLICATIONS

Nicotine and its metabolites in urine provide perhaps the most fundamental biomarkers of recent nicotine exposure. This report, based on Wave 1 of the Population Assessment of Tobacco and Health (PATH) Study, provides the first nationally representative data describing urinary nicotine biomarker concentrations in both non-users, and users of a variety of tobacco products including combustible, e-cigarette and smokeless products. These data provide a urinary biomarker concentration snapshot in time for the entire US population during 2013-2014, and will provide a basis for comparison with future results from continuing, periodic evaluations in the PATH Study.

Nicotine Exposure in the U.S. Population: Total Urinary Nicotine Biomarkers in NHANES 2015-2016

We characterize nicotine exposure in the U.S. population by measuring urinary nicotine and its major (cotinine, trans-3′-hydroxycotinine) and minor (nicotine 1′-oxide, cotinine N-oxide, and 1-(3-pyridyl)-1-butanol-4-carboxylic acid, nornicotine) metabolites in participants from the 2015−2016 National Health and Nutrition Examination Survey. This is one of the first U.S. population-based urinary nicotine biomarker reports using the derived total nicotine equivalents (i.e., TNEs) to characterize exposure. Serum cotinine data is used to stratify tobacco non-users with no detectable serum cotinine (−sCOT), non-users with detectable serum cotinine (+sCOT), and individuals who use tobacco (users). The molar concentration sum of cotinine and trans-3′-hydroxycotinine was calculated to derive the TNE2 for non-users. Additionally, for users, the molar concentration sum of nicotine and TNE2 was calculated to derive the TNE3, and the molar concentration sum of the minor metabolites and TNE3 was calculated to derive the TNE7. Sample-weighted summary statistics are reported. We also generated multiple linear regression models to analyze the association between biomarker concentrations and tobacco use status, after adjusting for select demographic factors. We found TNE7 is positively correlated with TNE3 and TNE2 (r = 0.99 and 0.98, respectively), and TNE3 is positively correlated with TNE2 (r = 0.98). The mean TNE2 concentration was elevated for the +sCOT compared with the −sCOT group (0.0143 [0.0120, 0.0172] µmol/g creatinine and 0.00188 [0.00172, 0.00205] µmol/g creatinine, respectively), and highest among users (33.5 [29.6, 37.9] µmol/g creatinine). Non-daily tobacco use was associated with 50% lower TNE7 concentrations (p < 0.0001) compared with daily use. In this report, we show tobacco use frequency and passive exposure to nicotine are important sources of nicotine exposure. Furthermore, this report provides more information on non-users than a serum biomarker report, which underscores the value of urinary nicotine biomarkers in extending the range of trace-level exposures that can be characterized.

Simultaneous analysis of urinary total 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol, N'-nitrosonornicotine, and cotinine by liquid chromatography-tandem mass-spectrometry

Biomarkers of exposure to harmful tobacco constituents are key tools for identifying individuals at risk and developing interventions and tobacco control measures. However, tobacco biomarker studies are scarce in many parts of the world with high prevalence of tobacco use. Our goal was to establish a robust method for simultaneous analysis of urinary total 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), N'-nitrosonornicotine (NNN), and cotinine at the Advanced Centre for Treatment, Research and Education in Cancer (ACTREC) in Mumbai, India. These biomarkers are validated measures of exposure to the carcinogenic tobacco nitrosamines 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) and NNN and the addictive alkaloid nicotine, respectively. The established method is characterized by excellent accuracy, linearity, and precision, and was successfully applied to the analysis of 15 smokeless tobacco (SLT) users and 15 non-users of tobacco recruited in Mumbai. This is the first report of establishment of such procedure in a laboratory in India, which offers the first in-country capacity for research on tobacco carcinogenesis in Indian SLT users.

A qualitative study to assess perceptions, barriers, and motivators supporting smokeless tobacco cessation in the US fire service

While firefighters currently have low smoking rates, rates of smokeless tobacco (SLT) use among this population are remarkably high and substantially greater than similar occupational groups, and the general population. This study explored determinants associated with SLT use, barriers to cessation, and motivators for SLT cessation in the fire service. Key informant interviews were conducted in 23 career firefighters who were current (n = 14) and former (n = 9) SLT users from across the U.S. Discussions were recorded and independently coded according to questions and themes. Major themes that developed among firefighters regarding SLT use determinants included positive perceptions of SLT products, social influences from their peers and family members, acceptability of SLT use in the fire service, and a coping resource for job stress. Firefighters discussed several barriers to SLT cessation, including intrapersonal barriers such as SLT use habits and its dependency, concerns about withdrawal symptoms; and social-environmental barriers including lack of support from health and other services providers, and lack of enforcement of existing tobacco policies regarding SLT use. Firefighters also mentioned both internal and external motivators for cessation. Internal motivators included self-motivation and their health concerns while external motivators included friends and family support, incentives or rewards, and price of SLT products. Findings provide unique perspectives from firefighters on factors that influence SLT use and barriers and motivators to SLT cessation. These are insufficiently assessed and considered by the fire service organizations and their health care providers. Thus, the organizations must understand these issues in order to mitigate barriers and motivate the personnel to quit using SLT. Information gained from firefighters who were current and former SLT users can be used to develop an effective, culturally-tailored intervention that is acceptable to fire service personnel.

Tobacco-Specific Nitrosamines (NNAL, NNN, NAT, and NAB) Exposures in the US Population Assessment of Tobacco and Health (PATH) Study Wave 1 (2013-2014)

INTRODUCTION

The tobacco-specific nitrosamines (TSNAs) are an important group of carcinogens found in tobacco and tobacco smoke. To describe and characterize the levels of TSNAs in the Population Assessment of Tobacco and Health (PATH) Study Wave 1 (2013-2014), we present four biomarkers of TSNA exposure: N'-nitrosonornicotine, N'-nitrosoanabasine, N'-nitrosoanatabine, and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) which is the primary urinary metabolite of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone.

METHODS

We measured total TSNAs in 11 522 adults who provided urine using automated solid-phase extraction coupled to isotope dilution liquid chromatography-tandem mass spectrometry. After exclusions in this current analysis, we selected 11 004 NNAL results, 10 753 N'-nitrosonornicotine results, 10 919 N'-nitrosoanatabine results, and 10 996 N'-nitrosoanabasine results for data analysis. Geometric means and correlations were calculated using SAS and SUDAAN.

RESULTS

TSNA concentrations were associated with choice of tobacco product and frequency of use. Among established, every day, exclusive tobacco product users, the geometric mean urinary NNAL concentration was highest for smokeless tobacco users (993.3; 95% confidence interval [CI: 839.2, 1147.3] ng/g creatinine), followed by all types of combustible tobacco product users (285.4; 95% CI: [267.9, 303.0] ng/g creatinine), poly tobacco users (278.6; 95% CI: [254.9, 302.2] ng/g creatinine), and e-cigarette product users (6.3; 95% CI: [4.7, 7.9] ng/g creatinine). TSNA concentrations were higher in every day users than in intermittent users for all the tobacco product groups. Among single product users, exposure to TSNAs differed by sex, age, race/ethnicity, and education. Urinary TSNAs and nicotine metabolite biomarkers were also highly correlated.

CONCLUSIONS

We have provided PATH Study estimates of TSNA exposure among US adult users of a variety of tobacco products. These data can inform future tobacco product and human exposure evaluations and related regulatory activities.

Exposure to a Tobacco-Specific Carcinogen Among Adolescent Smokeless Tobacco Users in Rural California, United States

INTRODUCTION

Approximately the same percentage of male high school students in the United States currently uses conventional smokeless tobacco as smokes cigarettes, resulting in toxin exposure.

METHODS

This study assessed tobacco product use (smokeless, combustible, and electronic cigarettes) and nicotine and carcinogen exposures in a sample of 594 male rural high school baseball players-a population traditionally at risk for smokeless tobacco use. Salivary specimens were assayed for cotinine (a biomarker of nicotine exposure) and urine specimens for 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL, a biomarker of the carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) using liquid chromatography-tandem mass spectrometry.

RESULTS

The prevalence of past 30-day use of any tobacco product was 29%. Past 7-day smokeless tobacco use (prevalence: 13%) was associated with the highest levels of cotinine and NNAL observed in the sample, whether smokeless tobacco was used exclusively (geometric means: cotinine 11.1 ng/mL; NNAL 31.9 pg/mg-creatinine) or in combination with combustible products (geometric means: cotinine 31.6 ng/mL; NNAL 50.0 pg/mg creatinine). Cotinine and NNAL levels were incrementally higher in each increasing category of smokeless tobacco use frequency. However, observed levels were lower than previously reported for adults, likely reflecting less smokeless use per day among adolescents.

CONCLUSIONS

Based on these biomarker observations, adolescents who use conventional smokeless tobacco products are exposed to substantial levels of nicotine and NNK. Although exposed to lower levels than adult smokeless users, the findings are concerning given the young age of the sample and tendency for smokeless tobacco users to increase use intensity over time.

IMPLICATIONS

This study demonstrates that adolescents using smokeless tobacco are exposed to levels of nicotine and NNK that increase with use frequency and that exceed exposures among peers using other tobacco products. Youth smokeless tobacco use in the United States has not declined along with youth smoking prevalence, giving greater importance to this health concern. To reduce youth (and adult) exposures, needed actions include effective smokeless tobacco use prevention, potentially in combination with reducing the levels of harmful and potentially harmful chemicals in smokeless tobacco products currently popular among adolescents.

Applying Tobacco, Environmental, and Dietary-Related Biomarkers to Understand Cancer Etiology and Evaluate Prevention Strategies

Many human cancers are caused by environmental and lifestyle factors. Biomarkers of exposure and risk developed by our team have provided critical data on internal exposure to toxic and genotoxic chemicals and their connection to cancer in humans. This review highlights our research using biomarkers to identify key factors influencing cancer risk as well as their application to assess the effectiveness of exposure intervention and chemoprevention protocols. The use of these biomarkers to understand individual susceptibility to the harmful effects of tobacco products is a powerful example of the value of this type of research and has provided key data confirming the link between tobacco smoke exposure and cancer risk. Furthermore, this information has led to policy changes that have reduced tobacco use and consequently, the tobacco-related cancer burden. Recent technological advances in mass spectrometry led to the ability to detect DNA damage in human tissues as well as the development of adductomic approaches. These new methods allowed for the detection of DNA adducts in tissues from patients with cancer, providing key evidence that exposure to carcinogens leads to DNA damage in the target tissue. These advances will provide valuable insights into the etiologic causes of cancer that are not tobacco-related.See all articles in this CEBP Focus section, "Environmental Carcinogenesis: Pathways to Prevention."

Biomarkers of Exposure among Adult Smokeless Tobacco Users in the Population Assessment of Tobacco and Health Study (Wave 1, 2013-2014)

BACKGROUND

Monitoring population-level toxicant exposures from smokeless tobacco (SLT) use is important for assessing population health risks due to product use. In this study, we assessed tobacco biomarkers of exposure (BOE) among SLT users from the Wave 1 (2013-2014) of the Population Assessment of Tobacco and Health (PATH) Study.

METHODS

Urinary biospecimens were collected from adults ages 18 and older. Biomarkers of nicotine, tobacco-specific nitrosamines (TSNA), polycyclic aromatic hydrocarbons (PAH), volatile organic compounds (VOC), metals, and inorganic arsenic were analyzed and reported among exclusive current established SLT users in comparison with exclusive current established cigarette smokers, dual SLT and cigarette users, and never tobacco users.

RESULTS

In general, SLT users (n = 448) have significantly higher concentrations of BOE to nicotine, TSNAs, and PAHs compared with never tobacco users; significant dose-response relationships between frequency of SLT use and biomarker concentrations were also reported among exclusive SLT daily users. Exclusive SLT daily users have higher geometric mean concentrations of total nicotine equivalent-2 (TNE2) and TSNAs than exclusive cigarette daily smokers. In contrast, geometric mean concentrations of PAHs and VOCs were substantially lower among exclusive SLT daily users than exclusive cigarette daily smokers.

CONCLUSIONS

Our study produced a comprehensive assessment of SLT product use and 52 biomarkers of tobacco exposure. Compared with cigarette smokers, SLT users experience greater concentrations of some tobacco toxicants, including nicotine and TSNAs.

IMPACT

Our data add information on the risk assessment of exposure to SLT-related toxicants. High levels of harmful constituents in SLT remain a health concern.

[In vitro exposure of human nasal mucous membrane cells and lymphocytes to snuff]

BACKGROUND

While an abundant number of studies concerning tobacco smoke and chewing tobacco show carcinogenic potential, there is little data on the consequences of snuff, especially on the cellular level. Therefore, the mutagenic effect of snuff is difficult to estimate and the WHO assessment of snuff being not carcinogenic is based on very limited data.

OBJECTIVES

This paper investigates the potential cytotoxic and genotoxic effects of snuff on human lymphocytes and nasal mucosa cells.

MATERIALS AND METHODS

Two types of snuff were used: one without menthol and one with a high degree of menthol. The necessary nasal mucosa cells and lymphocytes were collected from 10 subjects undergoing nasal obstruction surgery and incubated for one hour with a snuff-DMSO mixture (range 0.01-2000 µg/ml). Methods included the trypan blue test, the comet assay, and the micronucleus test.

RESULTS

The trypan blue test showed no decrease in cell viability for either cell type. The comet assay revealed a significant increase in the Olive Tail Moment for lymphocytes starting at 100 µg/ml and at 1000 µg/ml for nasal mucosa cells. There was no significant increase in micronuclei according to the micronucleus test. No differences between these two types of tobacco were observed.

CONCLUSION

The present study demonstrated genotoxic damage, such as DNA strand breaks, which may be repaired, but no non-repairable elevated micronuclei. The present findings cast doubts on the WHO assessment that snuff is not carcinogenic. However, for a sound assessment of the risk potential of snuff, further research on various genotoxic endpoints in human cells is warranted.

Naswar (Smokeless Tobacco) Use and the Risk of Oral Cancer in Pakistan: A Systematic Review With Meta-Analysis

Introduction

With an annual increase of 16000 new cases each year, oral cancer is the second most common cancer in Pakistan. There is conflicting evidence regarding the carcinogenicity of different forms of smokeless tobacco (SLT) from different countries. This difference in evidence may be attributed to the varied composition of SLT products used around the world, necessitating the establishment of individual risks related to each SLT product.

Methods

An electronic search in relevant databases yielded 119 publications, out of which six were included in this review. Effect estimates (odds ratios (ORs)) were abstracted or calculated from the given data. A fixed effects meta-analysis was performed to assess the risk of oral cancer with the use of Naswar. Population attributable fractions (PAF) were also calculated.

Results

The Meta Odds Ratio (mOR) for oral cancer associated with the "ever use" of Naswar compared to "never use" was 11.8 (95% CI = 8.4-16.4), I2 = 67%. The pooled estimate for oral cancer in "Ever-users" of Naswar compared to "Never-users," in the Khyber Pakhtunkhwa province was 18.3 (95% CI = 8.7-38.5), I2 = 0%. The PAF for oral cancer associated with the use of Naswar in Pakistan was 44% (95% CI = 35-53).

Discussion

This review highlights a strong relationship between oral cancer incidence and the use of Naswar in Pakistan and adds to the evidence base on the carcinogenicity of SLT products in humans. Although the synthesized evidence may not be of a high quality, it represents the "best available evidence" which can be used to inform policy.

Implications

The carcinogenicity of Naswar, a form of smokeless tobacco used extensively in Pakistan, Afghanistan, and Central Asia, has yet to be recognized by the International Agency for Research on Cancer (IARC), partly due to the lack of evidence on the association of Naswar use and cancer. Additionally, Naswar is yet un-regulated in Pakistan and evades the tax net, resulting in it being freely available to both adults and children at very cheap prices compared to cigarettes, which has been the main focus of tobacco control in Pakistan. This review provides ample evidence for the IARC to declare Naswar as carcinogenic, as well as the Government of Pakistan to regulate the production and sale of Naswar.

Health Care Utilization and Expenditures Attributable to Smokeless Tobacco Use Among US Adults

Introduction

This study estimated the health care utilization and expenditures attributable to the use of smokeless tobacco (ST) which includes chewing tobacco, snuff, dip, snus, and dissolvable tobacco among US adults aged 18 and older.

Methods

We used data from the 2012-2015 National Health Interview Surveys (n = 139451 adults) to estimate a zero-inflated Poisson (ZIP) regression model on four health care utilization measures among US adults (hospital nights, emergency room [ER] visits, doctor visits, and home care visits) specified as a function of tobacco use status, and other covariates. Tobacco use status was classified into four categories: current ST users, former ST users, non-ST tobacco users, and never tobacco users. ST-attributable utilization was calculated based on the estimated ZIP model using an "excess utilization" approach. It was then multiplied by the unit cost estimated from the 2014 Medical Expenditures Panel Survey data to derive ST-attributable health care expenditures.

Results

During 2012-2015, 2.1% of adults were current ST users and 7.7% were former ST users. ST-attributable health care utilization amounted to 681000 hospital nights, 624000 ER visits, and 4.6 million doctor visits per year (home care visits results were not significant). This resulted in annual excess expenditures of $1.8 billion for hospitalizations, $0.7 billion for ER visits, and $0.9 billion for doctor visits, totaling over $3.4 billion (in 2014 dollars).

Conclusion

Comprehensive tobacco control policies and interventions are needed to reduce ST use and the associated health care burden.

Implications

This is the first study to assess the impact of ST use on health care burden in the United States. Findings indicate that excess annual health care expenditures attributable to ST use for US adults were $3.4 billion in 2014 dollars.

Associations of Cigarettes Smoked Per Day with Biomarkers of Exposure Among U.S. Adult Cigarette Smokers in the Population Assessment of Tobacco and Health (PATH) Study Wave 1 (2013-2014)

BACKGROUND

The dose-response relationships between number of cigarettes smoked per day (CPD) and health outcomes, such as cancer and heart disease, are well established, but much less is known about the relationships between CPD and biomarkers of exposure.

METHODS

We analyzed biomarker data by CPD from more than 2,700 adult daily cigarette smokers in Wave 1 of the Population Assessment of Tobacco and Health Study. Tobacco use categories consisted of exclusive cigarette smokers, dual cigarette and e-cigarette users, and dual cigarette and smokeless tobacco users.

RESULTS

Biomarker concentrations consistently increased with CPD for each tobacco user group, although concentrations tended to level off at high smoking levels, such as those at and above 20 CPD. Dual cigarette and e-cigarette users had higher levels of some biomarkers such as Total Nicotine Equivalents-2 (P = 0.0036) than exclusive cigarette smokers, and dual cigarette and smokeless tobacco users had higher levels of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (P < 0.0001) and N'-nitrosonornicotine (P = 0.0236) than exclusive cigarette smokers.

CONCLUSIONS

Among daily smokers, exposure to tobacco toxicants and constituents exhibits a dose-response relationship by number of cigarettes smoked, but the relationship is not necessarily linear in form. Dual users of cigarettes with either e-cigarettes or smokeless tobacco are exposed to higher levels of certain toxicants and carcinogens than exclusive cigarette smokers.

IMPACT

Availability of biomarker data by CPD may aid in comparisons between cigarette smoking and use of new and potentially reduced exposure tobacco products, which may result in different levels of constituent and toxicant exposure.

Analysis of coumarin and angelica lactones in smokeless tobacco products

Differences in health risks between different styles of smokeless tobacco products (STPs) have prompted interest in their relative levels of toxic chemicals. We report here the development of methods for the analysis of STPs for coumarin and for α-angelica lactone (α-AL), both of which have been included in various published lists of tobacco toxicants. We have also determined the concentrations of these lactones in commercial STPs from the US and Sweden, representing 80-90% of the 2010 market share for all the major STP categories in these two countries: 65 products (plus two reference products) for coumarin and 66 commercial products for α-AL. For coumarin, methanol extracts of the STPs were analysed by HPLC/MS/MS. The lower limit of quantification (LOQ) and limit of detection (LOD) were, respectively, 100 and 30 ng coumarin/g of STP on a wet weight basis (WWB). Alpha-AL was determined via direct headspace GC/MS. The LOQ and LOD were 65 and 30 ng/g WWB respectively. Coumarin was detected In 3/33 Swedish snus, 5/13 US chewing tobaccos, 16/16 moist snuffs and 5/6 dry snuffs. Concentrations in those samples with quantifiable coumarin contents ranged from 186 to 1656 ng/g WWB. Concentrations of coumarin measured in this study were consistent with levels naturally found in tobacco. None of the STPs analysed would significantly contribute to coumarin exposure in consumers compared with dietary sources, and estimated exposure levels were 1000× lower than the European Food Safety Authority Tolerable Daily Intake. Hence the relevance of coumarin to the toxicity of STPs and its inclusion in the FDA's list of harmful and potentially harmful compounds list is questionable. Measurements of α-AL in these STPs found that the majority did not have quantifiable contents, however, for three STPs concentrations of α-AL were above the LOQ (116-140 ng/g WWB) and for four other STPs concentrations of α-AL could be estimated between the LOD and LOQ. Beta-angelica lactone was tentatively identified in three of the STPs but the levels could not be reliably quantified. The levels of α-AL in tobacco products are reported here for the first time, but the relevance of α-AL to the toxicity of STPs is also highly questionable given that it has GRAS status as a permitted food additive.

Carcinogenicity of smokeless tobacco: Evidence from studies in humans & experimental animals

A Working Group of the Monographs programme of the International Agency for Research on Cancer has classified smokeless tobacco as carcinogenic to humans (Group 1). This review article summarizes the data that support the evaluations of sufficient evidence in humans and in experimental animals for the carcinogenicity of smokeless tobacco whether used alone or with betel quid. It also identifies compounds of smokeless tobacco relevant to carcinogenicity (prominently tobacco-specific nitrosamines) and addiction (nicotine). The epidemiological evidence is summarized for oral cancer, other cancers associated with smokeless tobacco and oral potentially malignant lesions with a focus on analytical studies from the SEARO Region. Studies on cancer in experimental animals are summarized with a focus on studies applying smokeless tobacco products typical for the regions, such as mishri and naswar.

Ethyl carbamate in Swedish and American smokeless tobacco products and some factors affecting its concentration

BACKGROUND

We are interested in comparing the levels of harmful or potentially harmful constituents in Swedish and American smokeless tobacco products (STPs). We report here the concentrations of the IARC Group 2 A (probable human) carcinogen ethyl carbamate (EC) in seventy commercial STPs from the US and Sweden, representing 80-90% of the market share of the major STP categories in these countries. We also examine the effects of various additives, processing and storage conditions on EC concentrations in experimental snus samples.

RESULTS

EC was determined from aqueous extracts of the STPs using ultra performance liquid chromatography tandem mass spectrometry (UPLC/MS/MS). EC was undetectable (< 20 ng/g wet weight basis WWB) in 60% of the commercial STPs, including all the chewing tobacco (CT), dry snuff (DS), hard pellet (HP), soft pellet (SP), and plug products. Measurable levels of EC were found in 11/16 (69%) of the moist snuff (MS) samples (average 154 ng/g in those samples containing EC) and 19/32 (59%) of the Swedish snus samples (average 35 ng/g). For the experimental snus samples, EC was only observed in ethanol treated samples. EC concentrations increased significantly with ethanol concentrations (0-4%) and with storage time (up to 24 weeks) and temperature (8 °C vs 20 °C). EC concentrations were lower at lower pHs but were unaffected by adding nitrogenous precursors identified from food studies (citrulline and urea), increasing water content or by pasteurisation. Added EC was stable in the STP matrix, but evaporative losses were significant when samples were stored for several weeks in open containers at 8 °C.

CONCLUSIONS

EC was found in measurable amounts only in some moist STPs i.e. pasteurised Swedish snus and unpasteurised US MS; it is not a ubiquitous contaminant of STPs. The presence of ethanol contributed significantly to the presence of EC in experimental snus samples, more significantly at higher pH levels. Sample age also was a key determinant of EC content. In contrast, pasteurisation and fermentation do not appear to directly influence EC levels. Using published consumption rates and mouth level exposures, on average STP consumers are exposed to lower EC levels from STP use than from food consumption.

Identification of more than 100 structurally unique DNA-phosphate adducts formed during rat lung carcinogenesis by the tobacco-specific nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone

The tobacco-specific nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) is a powerful lung carcinogen in animal models and is considered a causative factor for lung cancer in people who use tobacco products. NNK undergoes metabolic activation-a critical step in its mechanism of carcinogenesis-to an intermediate which reacts with DNA to form pyridyloxobutyl DNA base and phosphate adducts. Another important metabolic pathway of NNK is its conversion to 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), which similarly forms pyridylhydroxybutyl DNA base adducts that have been characterized previously. In this study, we investigated the potential formation of pyridylhydroxybutyl DNA phosphate adducts. We report the characterization and quantitation of 107 structurally unique pyridylhydroxybutyl DNA phosphate adducts in the lungs of rats treated chronically with a carcinogenic dose of 5 ppm of NNK in their drinking water for up to 70 weeks, by using a novel liquid chromatography-nanoelectrospray ionization-high-resolution tandem mass spectrometry method. Our findings demonstrate that pyridylhydroxybutyl phosphate adducts account for 38-55 and 34-40% of all the measured pyridine-containing DNA adducts in rat lung and liver, respectively, upon treatment with NNK. Some of the pyridylhydroxybutyl DNA phosphate adducts persisted in both tissues for over 70 weeks, suggesting that they could be potential biomarkers of chronic exposure to NNK and NNAL. This study provides comprehensive characterization and relative quantitation of a panel of NNK/NNAL-derived DNA phosphate adducts, thus identifying NNK as the source of the most structurally diverse set of DNA adducts identified to date from any carcinogen.

Smokeless Tobacco Decision-Making Among Rural Adolescent Males in California

Smokeless tobacco (ST) use among US high school males living in rural areas exceeds national levels. Subgroups at heightened risk of ST use have been identified, but less is known regarding ST decision-making within high-risk groups. The study objective was to describe rural adolescent males' perceived ST acceptability, health risks, and social implications and how those perceptions differ between ST users and never-users. Semi-structured individual interviews were conducted with a purposeful sample of 55 male students (32 ST ever-users) at three rural California high schools. Interviews were audio recorded and professionally transcribed. Investigators collaboratively developed a codebook based on thematic content and then independently coded transcripts, reconvening frequently to achieve consensus. Coded text was systematically organized into themes following a general inductive approach. ST users and non-users shared multiple ST-related perceptions, including: that ST is a common, normative way of life in rural "country" culture among certain groups; that ST use conveys oral health risks; and that the decision to use (or not to use) is rooted in personal choice. ST users' and never-users' perceptions differed regarding the immediacy, severity, and inevitability of health risks, particularly relative to cigarette smoking. Other differences included perceived parental permissiveness and the expected social benefits of ST use, such as peer acceptance and conveying maturity. Within this population of rural male adolescents, ST users emphasized the social benefits of ST use, while acknowledging but discounting health risks. Differences and similarities in tobacco perceptions among adolescents living in similar environments may inform effective health communication.

Biomarkers of exposure to new and emerging tobacco delivery products

Accurate and reliable measurements of exposure to tobacco products are essential for identifying and confirming patterns of tobacco product use and for assessing their potential biological effects in both human populations and experimental systems. Due to the introduction of new tobacco-derived products and the development of novel ways to modify and use conventional tobacco products, precise and specific assessments of exposure to tobacco are now more important than ever. Biomarkers that were developed and validated to measure exposure to cigarettes are being evaluated to assess their use for measuring exposure to these new products. Here, we review current methods for measuring exposure to new and emerging tobacco products, such as electronic cigarettes, little cigars, water pipes, and cigarillos. Rigorously validated biomarkers specific to these new products have not yet been identified. Here, we discuss the strengths and limitations of current approaches, including whether they provide reliable exposure estimates for new and emerging products. We provide specific guidance for choosing practical and economical biomarkers for different study designs and experimental conditions. Our goal is to help both new and experienced investigators measure exposure to tobacco products accurately and avoid common experimental errors. With the identification of the capacity gaps in biomarker research on new and emerging tobacco products, we hope to provide researchers, policymakers, and funding agencies with a clear action plan for conducting and promoting research on the patterns of use and health effects of these products.

Tobacco Product Use Patterns, and Nicotine and Tobacco-Specific Nitrosamine Exposure: NHANES 1999-2012

Background: Few studies have examined differences in product consumption patterns and nicotine and tobacco-specific nitrosamines (TSNA) exposure between single versus dual- and poly-tobacco users. We applied the Tobacco Product Use Patterns (T-PUPs) model to fill this gap in the literature.Methods: Data from adults (age ≥18 years) who used any tobacco products during the 5 days prior to participating in the 1999-2012 National Health and Nutrition Examination Survey (NHANES) were analyzed. Participants were classified into seven T-PUPs: (1) cigarettes only, (2) noncigarette combustibles only, (3) noncombustibles only, (4) dual noncigarette combustibles and noncombustibles, (5) dual cigarettes and noncombustibles, (6) dual cigarettes and noncigarette combustibles, and (7) poly-tobacco use. Weighted regression models were used to compare product consumption, serum cotinine, and urinary total 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (i.e., NNAL) levels between single-, dual-, and poly-tobacco T-PUPs.Results: Dual- and poly-tobacco T-PUPs were associated with lower product consumption compared with single-product T-PUPs only in some cases (e.g., dual cigarette and noncombustible users smoked cigarettes on 0.6 fewer days in the past 5 days compared with cigarette-only users; P < 0.05). Dual- and poly-tobacco T-PUPs had either nondistinguishable or higher levels of serum cotinine and urinary total NNAL than corresponding single-product T-PUPs.Conclusions: Product consumption, and nicotine and TSNAs exposure of dual- and poly-tobacco product category users somewhat differ from those of single-product category users as defined by the T-TUPs model.Impact: Higher levels of cotinine and NNAL among dual- and poly-tobacco T-TUPs users compared with the single-product T-TUPs users may indicate health concerns. Cancer Epidemiol Biomarkers Prev; 26(10); 1525-30. ©2017 AACR.

Prevention and Treatment of Smoking and Tobacco Use During Pregnancy in Selected Indigenous Communities in High-Income Countries of the United States, Canada, Australia, and New Zealand: An Evidence-Based Review

Tobacco smoking during pregnancy is the most important modifiable risk factor for adverse pregnancy outcomes and long-term health complications for mother and baby. Tobacco use during pregnancy has decreased in high-income countries but not in Indigenous women in Australia, New Zealand, the United States, and Canada. This evidence-based review focuses on tobacco use among Indigenous pregnant women in high-income countries that share a history of European colonization. Indigenous women are more likely to use tobacco because of socioeconomic disadvantage, social norms, and poor access to culturally appropriate tobacco cessation support. Complications arising from tobacco smoking during pregnancy, such as low birth weight, prematurity, perinatal death, and sudden infant death syndrome, are much higher in Indigenous populations. Effective approaches to cessation in pregnant nonindigenous women involves behavioral counseling, with or without nicotine replacement therapy (NRT). Higher nicotine metabolism during pregnancy and poor adherence may affect therapeutic levels of NRT. Only two randomized trials were conducted among Indigenous women: neither found a statistically significant difference in cessation rates between the treatment and comparison arms. Considerations should be given to (1) whole life course approaches to reduce tobacco use in Indigenous women, (2) prohibiting tobacco promotion and reducing access to alcohol for minors to prevent smoking initiation in Indigenous youth, and (3) training health-care professionals in culturally appropriate smoking cessation care to improve access to services. It is critical to ensure acceptability and feasibility of study designs, consult with the relevant Indigenous communities, and preempt implementation challenges. Research is needed into the effect of reducing or stopping smoking during pregnancy when using NRT on subsequent maternal and infant outcomes.

Use of rodent data for cancer risk assessment of smokeless tobacco in the regulatory context

To support risk management decisions, information from different fields has been integrated in this presentation to provide a realistic quantitative cancer risk assessment of smokeless tobacco. Smoking among Swedish men is currently below 10%, while about 20% use a special smokeless tobacco (snus) as a substitute for cigarettes. Epidemiological data and molecular biomarkers demonstrate that rodent bioassays with tobacco specific nitrosamines (TSNA) overestimate cancer risk from snus by more than one order of magnitude. The underlying reasons are discussed. DNA damage constitutes a necessary, although not sufficient prerequisite for cancer initiation. Individuals who have not used tobacco exhibit DNA lesions identical with those induced by TSNA. No increase above this adduct background can be shown from snus, and extensive epidemiological studies in Sweden have failed to demonstrate elevated cancer risks even in long term users. A "bench mark" for acceptable risk of 1/10(6) derived from rodent data has been suggested when regulating snus. By relating similarly derived estimates for some food contaminants, the implementation even of a limit of 1/10(4) may be unrealistic. The management of smokeless tobacco products has rarely been based on a scientifically sound risk assessment, where attention is given to the outstandingly higher hazards associated with smoking.

Smoking in Pregnancy Among Indigenous Women in High-Income Countries: A Narrative Review

INTRODUCTION

Pregnant women in socioeconomically disadvantaged circumstances, such as Indigenous women, have a high prevalence of smoking. Tobacco smoking is the most significant reversible risk factor for the health of Indigenous pregnant women and their babies.

METHODS

As researchers working in this specialized area, we conducted a narrative review of the literature on smoking among Indigenous pregnant women in the United States, Canada, New Zealand, and Australia. We summarize prevalence and factors influencing tobacco use, interventions, and evidence gaps for tobacco control and smoking cessation. Recommendations are made for future interventions, policy changes, and much-needed research.

RESULTS

Common themes emerging across the four countries reveal opportunities for cross-cultural collaborative studies and trials. These include the social-normative use of tobacco as barriers to quitting in pregnancy and the need for evaluations of interventions at the family and community level. Socioeconomic disparities underscore the importance of enhancing the implementation and reach of strategies to prevent and reduce prenatal tobacco smoking among Indigenous women. Elders and community health care providers as role models for nontobacco use could be explored. Qualitative work is needed to understand the barriers and opportunities, such as cultural strengths supporting quitting tobacco to develop more effective approaches.

CONCLUSIONS

Although a high-priority group, there remains a dearth of research on Indigenous women's smoking in pregnancy. Studies have assessed knowledge and attitudes to smoking in pregnancy, and small feasibility studies and a few empirical trials have been conducted. Recommendations for promising culturally appropriate cessation interventions have been made. Larger trials are warranted.

IMPLICATIONS

Strategies to support quitting among pregnant Indigenous women need to be multifactorial and take account of the social determinants of smoking including historical antecedents, community norms, cultural strengths, and recognition of individual and community needs. Cross-country research collaborations have the potential to leverage funding, share expertise, and strengthen approaches to tackle an important and poorly attended health disparity that has a profound impact on the entire life course for Indigenous peoples.

Tobacco Use and Cancer Risk in the Agricultural Health Study

Background: Cigarettes are well known to cause cancer, but less is known about the risks of other tobacco products and use of more than one product.Methods: We examined cancer incidence in relation to exclusive use of six tobacco products [cigarettes, other combustibles (pipe, cigar, cigarillo), and smokeless tobacco (chewing tobacco, snuff)] in the Agricultural Health Study. We also examined the added cancer risks associated with use of cigarettes and other tobacco products.Results: In our study population of 84,015, ever use of smokeless tobacco was higher than the general United States population, whereas cigarette use was lower and other combustible product use was about the same. The strongest associations for exclusive ever use were for lung cancer [cigarettes HR = 15.48; 95% confidence interval (CI), 11.95-20.06; other combustible tobacco HR = 3.44; 95% CI, 1.53-7.71; smokeless tobacco HR = 2.21; 95% CI, 1.11-4.42]. Compared with exclusive cigarette smokers, cigarette smokers who additionally ever-used another combustible product had higher risks of smoking-related cancers (HR = 1.16; 95% CI, 1.04-1.30), especially among those who smoked cigarettes for more than 15 years.Conclusions and Impact: Cigarette smokers who additionally ever used smokeless tobacco had cancer risks similar to exclusive cigarette smokers. Users of cigarettes and other combustible tobacco may have higher risks of certain cancers than exclusive cigarette users. Cancer Epidemiol Biomarkers Prev; 26(5); 769-78. ©2016 AACR.

Biomarkers of Tobacco Exposure: Summary of an FDA-Sponsored Public Workshop

Since 2009, the FDA Center for Tobacco Products (CTP) has had the authority to regulate the manufacturing, distribution, and marketing of tobacco products in order to reduce the death and disease caused by tobacco use. Biomarkers of exposure pertain to actual human exposure to chemicals arising from tobacco use and could play an important role across a number of FDA regulatory activities, including assessing new and modified-risk tobacco products and identifying and evaluating potential product standards. On August 3-4, 2015, FDA/CTP hosted a public workshop focused on biomarkers of exposure with participants from government, industry, academia, and other organizations. The workshop was divided into four sessions focused on: (i) approaches to evaluating and selecting biomarkers; (ii) biomarkers of exposure and relationship to disease risk; (iii) currently used biomarkers of exposure and biomarkers in development; and (iv) biomarkers of exposure and the assessment of smokeless tobacco and electronic nicotine delivery systems. This article synthesizes the main findings from the workshop and highlights research areas that could further strengthen the science around biomarkers of exposure and help determine their application in tobacco product regulation. Cancer Epidemiol Biomarkers Prev; 26(3); 291-302. ©2016 AACR.

Nicotine and Toxicant Exposure among U.S. Smokeless Tobacco Users: Results from 1999 to 2012 National Health and Nutrition Examination Survey Data

BACKGROUND

It has been suggested that smokeless tobacco users have high nicotine and toxicant exposure, but studies with nationally representative data have been limited.

METHODS

We analyzed biomarkers of tobacco exposure for 23,684 adult participants from the National Health and Nutrition Examination Survey from 1999 to 2012. The biomarkers analyzed were serum cotinine, urinary 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), blood lead, blood cadmium, blood mercury, urinary arsenic, and urinary N-acetyl-S-(2-cyanoethyl)-L-cysteine. We calculated geometric mean concentrations for each biomarker by tobacco use category and geometric mean ratios adjusting for demographic factors.

RESULTS

Exclusive smokeless tobacco users had higher geometric mean concentrations of serum cotinine [178.9 ng/mL, 95% confidence interval (CI), 145.5-220.0] and NNAL (583.0 pg/mg creatinine, 95% CI, 445.2-763.5) than exclusive cigarette smokers (130.6 ng/mL, 95% CI, 122.3-139.6 and 217.6 pg/mg creatinine, 95% CI, 193.0-245.2, respectively). Smokeless tobacco users also had higher concentrations of blood lead compared with nontobacco users (adjusted geometric mean ratio = 1.30, 95% CI, 1.21-1.38). Based on limited sample sizes, NNAL concentrations for smokeless tobacco users appear to have declined from 2007 to 2008 (geometric mean = 1013.7 pg/mg creatinine, 95% CI, 738.9-1390.8) to 2011 to 2012 (geometric mean = 325.7 pg/mg creatinine, 95% CI, 159.6-664.9).

CONCLUSIONS

Exclusive smokeless tobacco users have higher observed levels of exposure to nicotine and carcinogenic tobacco-specific nitrosamines, as measured by cotinine and NNAL biomarker concentrations, than exclusive cigarette smokers. These patterns in NNAL levels for smokeless tobacco users may be changing over time.

IMPACT

High exposure to harmful constituents among smokeless tobacco users is a continuing health issue.

Exposure and response to current text-only smokeless tobacco health warnings among smokeless tobacco users aged ≥18years, United States, 2012-2013

INTRODUCTION

We assessed US adult smokeless tobacco (SLT) users' exposure and response to SLT health warnings, which are currently in text-only format, covering 30% of the two primary surfaces of SLT containers and 20% of advertisements.

METHODS

Data were from the 2012-2013 National Adult Tobacco Survey. Past 30-day exposure to SLT health warnings among past 30-day SLT users (n=1626) was a self-report of seeing warnings on SLT packages: "Very often," "Often," or "Sometimes" (versus "Rarely" or "Never"). We measured the association between SLT health warning exposure and perceptions of SLT harmfulness and addictiveness using logistic regression.

RESULTS

Of past 30-day SLT users, 77.5% reported exposure to SLT health warnings, with lower prevalence reported among females and users of novel SLT products (snus/dissolvable tobacco). Furthermore, exposure reduced linearly with reducing education and annual household income (p<0.01). Among exposed past 30-day SLT users, 73.9% reported thinking about the health risks of SLT, while 17.1% reported stopping SLT use on ≥1 occasion within the past 30days. Exposure to SLT warnings was associated with perceived SLT harmfulness (AOR=2.16; 95% CI=1.15-4.04), but not with perceived SLT addictiveness.

CONCLUSION

Socioeconomic disparities found in exposure and response to SLT health warnings can be addressed through implementation of large pictorial warnings.

Chemical and toxicological characteristics of conventional and low-TSNA moist snuff tobacco products

Use of smokeless tobacco products (STPs) is associated with oral cavity cancer and other health risks. Comprehensive analysis for chemical composition and toxicity is needed to compare conventional and newer STPs with lower tobacco-specific nitrosamines (TSNAs) yields. Seven conventional and 12 low-TSNA moist snuff products purchased in the U.S., Sweden, and South Africa were analyzed for 18 chemical constituents (International Agency for Research on Cancer classified carcinogens), pH, nicotine, and free nicotine. Chemicals were compared in each product using Wilcoxon rank-sum test and principle component analysis (PCA). Conventional compared to low-TSNA moist snuff products had higher ammonia, benzo[a]pyrene, cadmium, nickel, nicotine, nitrate, and TSNAs and had lower arsenic in dry weight content and per mg nicotine. Lead and chromium were significantly higher in low-TSNA moist snuff products. PCA showed a clear difference for constituents between conventional and low-TSNA moist snuff products. Differences among products were reduced when considered on a per mg nicotine basis. As one way to contextualize differences in constituent levels, probabilistic lifetime cancer risk was estimated for chemicals included in The University of California's carcinogenic potency database (CPDB). Estimated probabilistic cancer risks were 3.77-fold or 3-fold higher in conventional compared to low-TSNA moist snuff products under dry weight or under per mg nicotine content, respectively. In vitro testing for the STPs indicated low level toxicity and no substantial differences. The comprehensive chemical characterization of both conventional and low-TSNA moist snuff products from this study provides a broader assessment of understanding differences in carcinogenic potential of the products. In addition, the high levels and probabilistic cancer risk estimates for certain chemical constituents of smokeless tobacco products will further inform regulatory decision makers and aid them in their efforts to reduce carcinogen exposure in smokeless tobacco products.

Chronic exposure to chewing tobacco selects for overexpression of stearoyl-CoA desaturase in normal oral keratinocytes

Chewing tobacco is a common practice in certain socio-economic sections of southern Asia, particularly in the Indian subcontinent and has been well associated with head and neck squamous cell carcinoma. The molecular mechanisms of chewing tobacco which leads to malignancy remains unclear. In large majority of studies, short-term exposure to tobacco has been evaluated. From a biological perspective, however, long-term (chronic) exposure to tobacco mimics the pathogenesis of oral cancer more closely. We developed a cell line model to investigate the chronic effects of chewing tobacco. Chronic exposure to tobacco resulted in higher cellular proliferation and invasive ability of the normal oral keratinocytes (OKF6/TERT1). We carried out quantitative proteomic analysis of OKF6/TERT1 cells chronically treated with chewing tobacco compared to the untreated cells. We identified a total of 3,636 proteins among which expression of 408 proteins were found to be significantly altered. Among the overexpressed proteins, stearoyl-CoA desaturase (SCD) was found to be 2.6-fold overexpressed in the tobacco treated cells. Silencing/inhibition of SCD using its specific siRNA or inhibitor led to a decrease in cellular proliferation, invasion and colony forming ability of not only the tobacco treated cells but also in a panel of head and neck cancer cell lines. These findings suggest that chronic exposure to chewing tobacco induced carcinogenesis in non-malignant oral epithelial cells and SCD plays an essential role in this process. The current study provides evidence that SCD can act as a potential therapeutic target in head and neck squamous cell carcinoma, especially in patients who are users of tobacco.

Nicotine: Carcinogenicity and Effects on Response to Cancer Treatment - A Review

Tobacco use is considered the single most important man-made cause of cancer that can be avoided. The evidence that nicotine is involved in cancer development is reviewed and discussed in this paper. Both tobacco smoke and tobacco products for oral use contain a number of carcinogenic substances, such as polycyclic hydrocarbons and tobacco-specific N-nitrosamines (TSNA), which undoubtedly contribute to tobacco related cancer. Recent studies have shown that nicotine can affect several important steps in the development of cancer, and suggest that it may cause aggravation and recurrence of the disease. TSNA may be formed from nicotine in the body. The role of nicotine as the major addictive component of tobacco products may have distracted our attention from toxicological effects on cell growth, angiogenesis, and tumor malignancy. Effects on cancer disease are important aspects in the evaluation of possible long-term effects from sources of nicotine, such as e-cigarettes and products for nicotine replacement therapy, which both have a potential for life-long use.

Risk perceptions of smokeless tobacco among adolescent and adult users and nonusers

The recent growth in smokeless tobacco (ST) consumption has raised questions about consumer risk perceptions of ST products, especially in high-risk vulnerable populations. This qualitative study examined risk perceptions of ST among adolescent and adult users and nonusers in Ohio Appalachia. Focus groups and interviews were held with adolescents (n = 53; M age = 17 years) and adults (n = 63; M age = 34 years) from four Ohio Appalachian counties. Participants were asked about their perceptions of ST-related health risks, ST safety, and the relative safety of ST compared with cigarettes. Transcriptions were coded independently by two individuals. Overall, participants were knowledgeable about health problems from ST use (e.g., oral cancers, periodontal disease). Nearly all participants stated that ST use is not safe; however, there was disagreement about its relative safety. Some perceived all tobacco products as equally harmful; others believed that ST is safer than cigarettes for either the user or those around the user. Disagreements about ST relative safety may reflect mixed public health messages concerning the safety of ST. Comprehensive consumer messages about the relative safety of ST compared with cigarettes are needed. Messages should address the effect of ST on the health of the user as well as those exposed to the user.

Study of cardiovascular disease biomarkers among tobacco consumers, part 1: biomarkers of exposure

A study was conducted to evaluate biomarkers of biological effect and physiological assessments related to cardiovascular disease (CVD) among adult male cigarette smokers (SMK), moist snuff consumers (MSC) and non-consumers of tobacco (NTC). Additionally, biomarkers of tobacco and tobacco smoke exposure (BoE) were measured in spot urines and are reported here. Except for the BoE to nicotine and NNK, BoE were generally greater in SMK compared with MSC, and BoE were generally not different in comparisons of MSC and NTC. Results demonstrated that MSC had lower systemic exposures to many harmful and potentially harmful constituents than SMK, which is consistent with epidemiological data that indicate a differential in CVD risk between these groups.

Mechanisms of Cancer Induction by Tobacco-Specific NNK and NNN

Tobacco use is a major public health problem worldwide. Tobacco-related cancers cause millions of deaths annually. Although several tobacco agents play a role in the development of tumors, the potent effects of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) and N'-nitrosonornicotine (NNN) are unique. Metabolically activated NNK and NNN induce deleterious mutations in oncogenes and tumor suppression genes by forming DNA adducts, which could be considered as tumor initiation. Meanwhile, the binding of NNK and NNN to the nicotinic acetylcholine receptor promotes tumor growth by enhancing and deregulating cell proliferation, survival, migration, and invasion, thereby creating a microenvironment for tumor growth. These two unique aspects of NNK and NNN synergistically induce cancers in tobacco-exposed individuals. This review will discuss various types of tobacco products and tobacco-related cancers, as well as the molecular mechanisms by which nitrosamines, such as NNK and NNN, induce cancer.

Quantitative analysis of five tobacco-specific N-nitrosamines in urine by liquid chromatography-atmospheric pressure ionization tandem mass spectrometry

A liquid chromatography tandem mass spectrometry (LC/MS/MS) method was developed and validated for the determination of five total tobacco-specific N-nitrosamines (TSNA), including free and conjugated forms in urine. The limits of detection for 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol, N'-nitrosonornicotine, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone, N'-nitrosoanatabine and N'-nitrosoanabasine were 0.6, 0.6, 10.0, 0.4 and 0.4 pg/mL, respectively, with a linear calibration range of up to 20,000 pg/mL. Intra- and inter-day precision for TSNA measurements ranged from 0.82 to 3.67% and from 2.04 to 7.73% respectively. For total TSNAs, the β-glucuronidase amount was optimized for hydrolysis time and yield. Different liquid chromatography columns and mobile phases with different pH conditions were evaluated. The validated method was then applied to 50 smoker and 30 nonsmoker urine samples. Our results suggest that this sensitive and relatively simple analytical method is suitable for application to epidemiological investigations of health risks associated with the exposure to tobacco smoke or secondhand smoke in both smokers and nonsmokers.

Identification of tobacco-specific nitrosamines as disinfection byproducts in chloraminated water

Tobacco-specific nitrosamines (TSNAs) exist in environmental waters; however, it is unknown whether TSNAs can be produced during water disinfection. Here we report on the investigation and evidence of TSNAs as a new class of disinfection byproducts (DBPs). Using five common TSNAs, including (methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) as the targets, we first developed a solid phase extraction (SPE) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) method capable of rapidly determining these TSNAs at levels as low as 0.02 ng/L in treated water. Using this highly sensitive method, we investigated the occurrence and formation potential (FP) (precursor test conducted in the presence of chloramines) of TSNAs in treated water from two wastewater treatment plants (WWTPs) and seven drinking water treatment plants (DWTPs). NNAL was detected in the FP samples, but not in the samples before the FP test, confirming NNAL as a DBP. NNK was detected in the treated wastewater before the FP test, but its concentration increased significantly after chloramination in two of three tests. Thus, NNK could be a DBP and/or a contaminant in wastewater. Moreover, these TSNAs were detected in FP tests of wastewater-impacted DWTP plant influents in 9 of 11 samples. However, TSNAs were not detected at full-scale DWTPs, except for at one DWTP with high ammonia where breakpoint chlorination was not achieved. The concentration of the sum of five TSNAs (0.3 ng/L) was 100-fold lower than NDMA, suggesting that TSNAs have a minor contribution to total nitrosamines in water. We examined several factors in the treatment process and found that chlorine or ozone may destroy TSNA precursors and granular activated carbon (GAC) treatment may remove the precursors. Further research is warranted into the efficiency of these processes at different DWTPs using sources of varying water quality.

Clinical and biochemical studies support smokeless tobacco's carcinogenic potential in the human oral cavity

In 2007, the International Agency for Research on Cancer presented compelling evidence that linked smokeless tobacco use to the development of human oral cancer. Although these findings imply vigorous local carcinogen metabolism, little is known about levels and distribution of phase I, II, and III (drug egress) enzymes in human oral mucosa. In this study here, we integrated clinical data, and imaging and histopathologic analyses of an oral squamous cell carcinoma that arose at the site of smokeless tobacco quid placement in a patient. Immunoblot and immunohistochemical (IHC) analyses were used to identify tumor and normal human oral mucosal smokeless tobacco-associated metabolic activation and detoxification enzymes. Human oral epithelium contains every known phase I enzyme associated with nitrosamine oxidative bioactivation with approximately 2-fold interdonor differences in protein levels. Previous studies have confirmed approximately 3.5-fold interdonor variations in intraepithelial phase II enzymes. Unlike the superficially located enzymes in nonreplicating esophageal surface epithelium, IHC studies confirmed that oral mucosal nitrosamine metabolizing enzymes reside in the basilar and suprabasilar region, which notably is the site of ongoing keratinocyte DNA replication. Clearly, variations in product composition, nitrosamine metabolism, and exposure duration will modulate clinical outcomes. The data presented here form a coherent picture consistent with the abundant experimental data that link tobacco-specific nitrosamines to human oral cancer.

Cigarette rod length and its impact on serum cotinine and urinary total NNAL levels, NHANES 2007-2010

INTRODUCTION

Research suggests that smokers of slim, long, or ultralong cigarettes may have a perception of reduced harm from their own brand. This study compared serum cotinine and urinary total 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanonol (NNAL) levels among smokers of regular-sized (68-72mm), king-sized (79-88mm), and long (94-101mm) or ultralong (110-121mm) cigarettes.

METHODS

Nationally representative data from the 2007-2008 and 2009-2010 National Health and Nutrition Examination Survey were analyzed for 3,699 current smokers aged ≥20 years. Biomarker levels were summarized using geometric means (GMs). Multivariate linear regression analyses were performed to assess the effect of cigarette rod length on log-transformed serum cotinine and creatinine-adjusted urinary total NNAL levels.

RESULTS

The GM of serum cotinine level was higher among smokers of long/ultralong cigarettes (263.15ng/ml) compared with smokers of regular-sized (173.13ng/ml) or king-sized (213.79ng/ml) cigarettes. Similarly, the GM of creatinine-adjusted NNAL levels was higher among smokers of long/ultralong cigarettes (0.48ng NNAL/mg of creatinine) compared with smokers of regular-sized (0.34ng NNAL/mg of creatinine) or king-sized (0.33ng NNAL/mg of creatinine) cigarettes. After adjusting for potential confounders, mean cotinine and NNAL levels were both significantly higher among smokers of long/ultralong cigarettes compared with levels observed in smokers of either regular-sized or king-sized cigarettes. However, no significant differences were observed between smokers of regular-sized and king-sized cigarettes in mean levels of cotinine or NNAL.

CONCLUSIONS

Significantly elevated tobacco biomarker levels were observed among smokers of long/ultralong cigarettes compared with smokers of regular-sized or king-sized cigarettes. This underscores the need to educate the public about the dangers of all tobacco products.

Proposed cutoff for identifying adult smokeless tobacco users with urinary total 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanonol: an aggregated analysis of NHANES 2007-2010 data

INTRODUCTION

NNAL [4-(methylnitrosamino)-1-(3-pyridyl)-1-butanonol] is a valid biomarker of tobacco use. However; no study has assessed its use in distinguishing current smokeless tobacco (SLT) users from nonusers. Therefore, this study used aggregated data from the 2007-2008 and 2009-2010 waves of the National Health and Nutrition Examination Survey to determine an optimal threshold for identifying SLT users with NNAL.

METHODS

Optimal urinary total NNAL concentrations for discriminating SLT-only users from nonusers of any tobacco were determined using receiver operating characteristic analysis. Percentage agreement between self-reported SLT use status and NNAL levels was calculated overall and by sociodemographic characteristics. All analyses were weighted and performed with Stata, Version 11, and MedCalc for Windows, Version 9.5.0.0.

RESULTS

In total, 264 individuals reported exclusively using SLT (and no other combustible tobacco product) within the past 5 days, whereas 14,824 were self-reported nonusers of any combustible or smokeless tobacco product. The optimal NNAL cutoff point was 34.0 pg/ml, which was associated with a high sensitivity (95.2%), specificity (93.4%), and overall correct classification rate (93.5%). The area under the curve was 98.3% and the corresponding Youden's Index was 88.7%. There was high agreement between the proposed NNAL cutoff point and self-reported SLT-only use (95.6%) and self-reported SLT nonuse (93.9%).

CONCLUSION

The proposed cutoff point of 34.0 pg/ml had high sensitivity and specificity and may be used by clinicians and researchers to verify or detect recent SLT use. This study also indicated that self-reported SLT use among adults is a reliable measure and has high agreement with biochemical assessment.

Comparison of the Carcinogenic Potential of Smokeless Tobacco and Smoked Tobacco by Quantifying the Excretion of Nicotine Metabolite NNAL in Patients with Oral Leukoplakia

The case control study was conducted to quantify the amount of the carcinogenic tobacco specific nitrosamine in smokeless tobacco users and smokers in patients with oral leukoplakia and also to emphasize the role of tobacco-specific nitrosamine in the incidence of oral leukoplakia. The study was conducted on 30 patients. The urine samples were obtained from smokeless tobacco users with oral leukoplakia, smokers with oral leukoplakia and non-tobacco users (i.e. people who do not use tobacco in any form). The collected samples were processed by gas chromatography-mass spectrometry. A highly significant difference of NNAL[4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol] in smokeless tobacco users than tobacco smokers P = 0.0002 (Table 1) was obtained. This significant difference shows smokeless tobacco is more carcinogenic than smoked tobacco. This study confirmed that NNAL is a potent biomarker for calculating the risk of occurrence of carcinoma in smokeless tobacco users and smokers, and that smokeless tobacco is more harmful than smoked tobacco.

Multi-analyte approach for determining the extraction of tobacco constituents from pouched snus by consumers during use

BACKGROUND

Snus is a smokeless oral tobacco product with a significant history of use in Sweden, where it is regulated under food legislation. Users place a small porous sachet or a pinch of loose snus between the upper jaw and cheek for approximately one hour, leading to partial intake of tobacco constituents. To understand user exposure to tobacco, a multi-analyte approach based on the extraction of pouches by methanol, ethanol and water was validated and applied to the measurement of various constituents, including nicotine, four tobacco-specific nitrosamines (TSNAs), propylene glycol, water, ammonium, nitrate, sodium, chloride, linalool, citronellol, linalyl acetate and geraniol, extracted from snus pouches during use by human consumers.

RESULTS

After validation against established single-analyte methods, the multi-analyte approach was used to determine constituent levels in snus pouches before and after one hour of use. Although the concentrations in the snus pouches varied from nanogram (e.g. TSNAs) to milligram (e.g. nicotine, sodium and propylene glycol) quantities (25.1 ng to 35.3 mg per 1 g pouch), the mean percentage extracted varied only from 19.2% for linalyl acetate to 37.8% for the TSNA 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) among all constituents analyzed. The TSNAs, some of which are known carcinogens, showed the highest percentage extraction (range 34.6%-37.8%). Measurement variability was low for all analytes, ranging from 2.4% (total TSNAs, NAT) to 9.5% (geraniol). By contrast, inter-subject variability ranged from 6.7% (NAB) to 52.2% (linalyl acetate), and was greater than 20% for eight of the constituents analyzed. Intra-subject variability ranged from 3.4% (citronellol) to 29.7% (geraniol).

CONCLUSIONS

Generally, less than a third of each constituent tested was extracted during one hour of snus use, independent of constituent concentration. The variable nature of in-use extraction was shown to be driven by inter-subject variability. The results provide insight into possible mechanisms controlling constituent extraction in the mouth during snus use, and provide reference data for the development of in-vitro laboratory systems for estimating extraction of tobacco constituents from snus.

Charcoal burning as a source of polyaromatic hydrocarbons in waterpipe smoking

Polyaromatic hydrocarbons (PAH) content from seven commercial waterpipe charcoals were determined during the smoking process to estimate how much PAHs would not be trapped by the water trap and could reach the lungs of the smokers. Naphthalene, 2-methylnaphthalene, acenaphthylene, acenaphthene, phenanthrene and fluoranthene were the most abundant PAH compounds produced during smoking. Naphthalene was the highest in all of the smoke contents and levels of 5 to 405 μg/15 minutes could be inhaled by the smoker. The amounts of PAHs produced during the smoking events in absence of tobacco varied greatly among different brands of charcoal. The amount and composition of the emitted PAH were not related to the amount and composition of the original chemicals in the charcoal prior to burning. Our findings suggest that public health agencies should regulate smoked charcoal products alongside tobacco.

Exposure to nicotine and carcinogens among Southwestern Alaskan Native cigarette smokers and smokeless tobacco users

BACKGROUND

The prevalence of tobacco use, both cigarette smoking and smokeless, including iqmik (homemade smokeless tobacco prepared with dried tobacco leaves mixed with alkaline ash), and of tobacco-related cancer is high in Alaskan Native people (AN). To investigate possible mechanisms of increased cancer risk we studied levels of nicotine and tobacco-specific nitrosamines (TSNA) in tobacco products and biomarkers of tobacco toxicant exposure in Southwestern AN people.

METHODS

Participants included 163 cigarette smokers, 76 commercial smokeless tobacco, 20 iqmik, 31 dual cigarette smokers and smokeless tobacco, and 110 nontobacco users. Tobacco use history, samples of tobacco products used, and blood and urine samples were collected.

RESULTS

Nicotine concentrations were highest in cigarette tobacco and TSNAs highest in commercial smokeless tobacco products. The AN participants smoked on average 7.8 cigarettes per day. Nicotine exposure, assessed by several biomarker measures, was highest in iqmik users, and similar in smokeless tobacco and cigarette smokers. TSNA exposure was highest in smokeless tobacco users, and polycyclic aromatic hydrocarbon exposure was highest in cigarette smokers.

CONCLUSIONS

Despite smoking fewer cigarettes per day, AN cigarette smokers had similar daily intake of nicotine compared to the general U.S. population. Nicotine exposure was greatest from iqmik, likely related to its high pH due to preparation with ash, suggesting high addiction potential compared to other smokeless tobacco products. TSNA exposure was much higher with smokeless tobacco than other product use, possibly contributing to the high rates of oral cancer.

IMPACT

Our data contribute to an understanding of the high addiction risk of iqmik use and of the cancer-causing potential of various forms of tobacco use among AN people.

Nicotine, carbon monoxide, and carcinogen exposure after a single use of a water pipe

BACKGROUND

Smoking tobacco preparations in a water pipe (hookah) is widespread in many places of the world, including the United States, where it is especially popular among young people. Many perceive water pipe smoking to be less hazardous than cigarette smoking. We studied systemic absorption of nicotine, carbon monoxide, and carcinogens from one water pipe smoking session.

METHODS

Sixteen subjects smoked a water pipe on a clinical research ward. Expired carbon monoxide and carboxyhemoglobin were measured, plasma samples were analyzed for nicotine concentrations, and urine samples were analyzed for the tobacco-specific nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) and polycyclic aromatic hydrocarbon (PAH) metabolite biomarker concentrations.

RESULTS

We found substantial increases in plasma nicotine concentrations, comparable to cigarette smoking, and increases in carbon monoxide levels that are much higher than those typically observed from cigarette smoking, as previously published. Urinary excretion of NNAL and PAH biomarkers increased significantly following water pipe smoking.

CONCLUSIONS

Absorption of nicotine in amounts comparable to cigarette smoking indicates a potential for addiction, and absorption of significant amounts of carcinogens raise concerns of cancer risk in people who smoke tobacco products in water pipes.

IMPACT

Our data contribute to an understanding of the health impact of water pipe use.