Cigarette and ENDS dual use longitudinal transitions among adults in the Population Assessment of Tobacco and Health (PATH) Study, Waves 4-5 (2016-2019)

Introduction

The study assessed longitudinal transitions among adult (18 and older) past 30-day daily and non-daily dual users of cigarettes and electronic nicotine delivery systems (ENDS).

Methods

Using data from Wave 4 (W4; 2016/17) and Wave 5 (W5; 2018/19) of the Population Assessment of Tobacco and Health (PATH) Study, a nationally representative, longitudinal cohort study of US adults, multivariable regressions were conducted among W4 dual users of cigarettes and ENDS to examine past 30-day cigarette smoking at W5. The study also analyzed changes in frequency of past 30-day smoking and cigarettes smoked per day between W4 and W5, stratified by W4/W5 daily/non-daily ENDS use among W4 daily and non-daily cigarette smokers.

Results

Among W4 dual users, those smoking daily and using ENDS non-daily had higher odds of daily cigarette smoking at W5 than daily users of both products (AOR: 2.32, 95 % CI: 1.38-3.90). W4 daily smokers who used ENDS daily at Wave 5 smoked cigarettes on fewer days at Wave 5 than W4 daily smokers who were either daily ENDS users at Wave 4 (B = -4.59; SE = 1.43, p < 0.01) or non-daily ENDS users at Wave 4 (B = -4.55; SE = 1.24, p < 0.001). Among W4 non-daily cigarette smokers, W4 non-daily ENDS users who used daily at W5 smoked cigarettes on fewer days (B = -4.04, SE = 1.82) at W5 than those who were non-daily ENDS users at W4 and W5.

Conclusions

Findings highlight the importance of frequency of ENDS use in reducing cigarette smoking and could inform smoking cessation interventions among daily cigarette smokers.

Respiratory symptoms and outcomes among cigar smokers: findings from the Population Assessment of Tobacco and Health (PATH) study waves 2-5 (2014-2019)

BACKGROUND

The mechanisms by which cigarette smoking increases the risk of respiratory disease have been studied. However, less is known about risks of respiratory symptoms and outcomes associated with smoking cigars, and risks by cigar types have not been previously explored. The aim of this study was to examine associations between cigar use, including traditional cigars, cigarillos, filtered cigars, and dual cigar and cigarette use, and functionally important respiratory symptoms (FIRS), lifetime asthma diagnosis, uncontrolled asthma, and new cases of FIRS.

METHODS

Data from Waves 2-5 (2014-19) of the Population Assessment of Tobacco and Health (PATH) Study, a nationally representative longitudinal study, were analyzed in two ways. For cross-sectional analysis, the analytic sample included adults 18 and older at each wave, resulting in 44,040 observations. Separately, longitudinal analyses were assessed among adults 18 and older at Wave 2, resulting in 7,930 individuals. Both analyses excluded adults with chronic obstructive pulmonary disease (COPD) or non-asthma respiratory disease.

RESULTS

Current established cigarillo smokers had higher odds of having FIRS (Adjusted odds ratio (AOR): 1.72; 95% CI: 1.08, 2.74) compared to never smokers of cigarillos and cigarettes, after adjusting for covariates. Current established filtered cigar smokers had higher odds of asthma diagnosis (AOR: 1.35; 95% CI: 1.10, 1.66) while current established dual smokers of filtered cigars and cigarettes had higher odds of uncontrolled asthma (AOR: 5.13; 95% CI: 1.75, 15.02) compared to never smokers of filtered cigars or cigarettes. Both current established cigar smokers and current established dual smokers of cigarettes and cigars had higher odds of new FIRS compared to never cigar or cigarette smokers (AORs: 1.62; 95% CI: 1.02, 2.60 for exclusive cigars and 2.55; 95% CI 1.57, 4.14 for dual smokers).

CONCLUSIONS

This study provides evidence that cigar smokers or dual smokers of cigars and cigarettes have greater odds of FIRS, asthma, and uncontrolled asthma and that new incidence of FIRS is higher among any cigar smokers compared to never cigar or cigarette smokers. Understanding health impacts associated with cigar use provides information for supporting policy development, as well as for designing clinical interventions focused on smoking cessation for cigars.

Divergence in Cigarette Discontinuation Rates by Use of Electronic Nicotine Delivery Systems (ENDS): Longitudinal Findings From the United States PATH Study Waves 1-6

INTRODUCTION

We compare real-world trends in population-level cigarette discontinuation rates among adults (ages ≥21) who smoked cigarettes, by electronic nicotine delivery systems (ENDS) use.

AIMS AND METHODS

U.S nationally representative data from adults in the Population Assessment of Tobacco and Health (PATH) Study (2013/14-2021, Waves 1-6) who smoked cigarettes in the past 30 days (P30D) were analyzed (n = 13 640). The exposure was P30D ENDS use. The outcome was P30D cigarette discontinuation at biennial follow-up. Weighted trend analyses were conducted to test for differences in cigarette discontinuation trends by ENDS use.

RESULTS

Between 2013/14 and 2015/16, cigarette discontinuation rates were both 16% for those who used ENDS and for those who did not; between 2018/19 and 2021, rates were ~30% for those who used ENDS and ~20% for those who did not; the time by ENDS use interaction was significant.

CONCLUSIONS

The relationship between adults' ENDS use and cigarette discontinuation in the context of an expanded ENDS marketplace, new tobacco regulatory actions, and COVID-19 differs from the relationship in earlier years.

IMPLICATIONS

It is important for public health decisions to be informed by research based on the contemporary ENDS marketplace and circumstances.

Relationship Between Tobacco Product Use and Health-Related Quality of Life Among Individuals With COPD in Waves 1-5 (2013-2019) of the Population Assessment of Tobacco and Health Study

Introduction

We examined the association between tobacco product use and health-related quality of life (HRQoL) among individuals with chronic obstructive pulmonary disease (COPD) in Waves 1-5 of the Population Assessment of Tobacco and Health (PATH) Study.

Methods

Adults ≥40 years with an ever COPD diagnosis were included in cross-sectional (Wave 5) and longitudinal (Waves 1 to 5) analyses. Tobacco use included 13 mutually exclusive categories of past 30-day (P30D) single use and polyuse with P30D exclusive cigarette use and ≥5-year cigarette cessation as reference groups. Multivariable linear regression and generalized estimating equations (GEE) were used to examine the association between tobacco use and HRQoL as measured by the Patient-Reported Outcomes Measurement Information System (PROMIS) Global-10 questionnaire.

Results

Of 1670 adults, 79.4% ever used cigarettes; mean (standard error [SE]) pack years was 30.9 (1.1). In cross-sectional analysis, P30D exclusive cigarette use, and e-cigarette/cigarette dual use were associated with worse HRQoL compared to ≥5-year cigarette cessation. Compared to P30D exclusive cigarette use, never tobacco use and ≥5-year cigarette cessation were associated with better HRQoL, while e-cigarette/cigarette dual use had worse HRQoL. Longitudinally (n=686), e-cigarette/cigarette dual use was associated with worsening HRQoL compared to both reference groups. Only never tobacco use was associated with higher HRQoL over time compared to P30D exclusive cigarette use.

Conclusions

E-cigarette/cigarette dual use was associated with worse HRQoL compared to ≥5-year cigarette cessation and exclusive cigarette use. Never use and ≥5-year cigarette cessation were the only categories associated with higher HRQoL compared to exclusive cigarette use. Findings highlight the importance of complete smoking cessation for individuals with COPD.

Cardiovascular disease outcomes among established cigar users 40 years and older: Findings from the population assessment of tobacco and health (PATH) study, waves 1-5 (2013-2019)

This study examined associations between established cigar use and prevalence and incidence of cardiovascular diseases (CVD; congestive heart failure, stroke, or heart attack/needed bypass surgery) among U.S. adults, 40 years or older. Using Waves 1-5 (2013-2019) of the Population Assessment of Tobacco and Health (PATH) Study, incidence (Nindividuals (Nind) = 6,692; Nobservations (Nobs) = 23,738) and prevalence (Nind = 7,819; Nobs = 33,952) of CVD outcomes were examined using weighted generalized estimating equations (WGEEs) among adults who were exclusive current/former established cigar smokers (ever cigar smokers who have smoked fairly regularly), exclusive current/former established cigarette smokers (lifetime smokers of 100 or more cigarettes), dual current/former established cigarette and cigar smokers compared with never smokers of cigars or cigarettes, adjusting for covariates. The population-averaged incidence of CVD from one wave to next among exclusive current/former established cigar smokers during a six-year period based on WGEEs was low (overall average rate of 3.0 %; 95 % CI: 1.2, 7.0). Compared with never users, exclusive current/former established cigar smokers (OR = 1.67, 95 % CI: 1.11, 2.51) and exclusive current/former established cigarette smokers (OR = 2.12, 95 % CI: 1.45, 3.09) were more likely to have any CVD outcome in unadjusted analyses. When adjusted for covariates, only exclusive current/former established cigarette use was associated with CVD outcomes (AOR = 1.60, CI: 1.07, 2.40). Results suggest that exclusive established use of cigars or duration of exclusive cigar use was not associated with lifetime CVD prevalence compared with never cigar or cigarette smokers, which is important in understanding health outcomes in cigar users.

Chemical and Cellular Formation of Reactive Oxygen Species from Secondary Organic Aerosols in Epithelial Lining Fluid

INTRODUCTION

Oxidative stress mediated by reactive oxygen species (ROS) is a key process for adverse aerosol health effects. Secondary organic aerosols (SOA) account for a major fraction of particulate matter with aerodynamic diameter ≤2.5 µm (PM2.5). PM2.5 inhalation and deposition into the respiratory tract causes the formation of ROS by chemical reactions and phagocytosis of macrophages in the epithelial lining fluid (ELF), but their relative contributions are not well quantified and their link to oxidative stress remains uncertain. The specific aims of this project were (1) elucidating the chemical mechanism and quantifying the formation kinetics of ROS in the ELF by SOA; (2) quantifying the relative importance of ROS formation by chemical reactions and macrophages in the ELF.

METHODS

SOA particles were generated using reaction chambers from oxidation of various precursors including isoprene, terpenes, and aromatic compounds with or without nitrogen oxides (NOx). We collected size-segregated PM at two highway sites in Anaheim, CA, and Long Beach, CA, and at an urban site in Irvine, CA, during two wildfire events. The collected particles were extracted into water or surrogate ELF that contained lung antioxidants. ROS generation was quantified using electron paramagnetic resonance (EPR) spectroscopy with a spin-trapping technique. PM oxidative potential (OP) was also quantified using the dithiothreitol assay. In addition, kinetic modeling was applied for analysis and interpretation of experimental data. Finally, we quantified cellular superoxide release by RAW264.7 macrophage cells upon exposure to quinones and isoprene SOA using a chemiluminescence assay as calibrated with an EPR spin-probing technique. We also applied cellular imaging techniques to study the cellular mechanism of superoxide release and oxidative damage on cell membranes.

RESULTS

Superoxide radicals (·O2-) were formed from aqueous reactions of biogenic SOA generated by hydroxy radical (·OH) photooxidation of isoprene, β-pinene, α-terpineol, and d-limonene. The temporal evolution of ·OH and ·O2- formation was elucidated by kinetic modeling with a cascade of aqueous reactions, including the decomposition of organic hydroperoxides (ROOH), ·OH oxidation of primary or secondary alcohols, and unimolecular decomposition of α-hydroxyperoxyl radicals. Relative yields of various types of ROS reflected the relative abundance of ROOH and alcohols contained in SOA, which generated under high NOx conditions, exhibited lower ROS yields. ROS formation by SOA was also affected by pH. Isoprene SOA had higher ·OH and organic radical yields at neutral than at acidic pH. At low pH ·O2- was the dominant species generated by all types of SOA. At neutral pH, α-terpineol SOA exhibited a substantial yield of carbon-centered organic radicals (R·), while no radical formation was observed by aromatic SOA.

Organic radicals in the ELF were formed by mixtures of Fe2+ and SOA generated from photooxidation of isoprene, α-terpineol, and toluene. The molar yields of organic radicals by SOA were 5-10 times higher in ELF than in water. Fe2+ enhanced organic radical yields by a factor of 20-80. Ascorbate mediated redox cycling of iron ions and sustained organic peroxide decomposition, as supported by kinetic modeling reproducing time- and concentration-dependence of organic radical formation, as well as by additional experiments observing the formation of Fe2+ and ascorbate radicals in mixtures of ascorbate and Fe3+. ·OH and superoxide were found to be efficiently scavenged by antioxidants.

Wildfire PM mainly generated ·OH and R· with minor contributions from superoxide and oxygen-centered organic radicals (RO·). PM OP was high in wildfire PM, exhibiting very weak correlation with radical forms of ROS. These results were in stark contrast with PM collected at highway and urban sites, which generated much higher amounts of radicals dominated by ·OH radicals that correlated well with OP. By combining field measurements of size-segregated chemical composition, a human respiratory tract model, and kinetic modeling, we quantified production rates and concentrations of different types of ROS in different regions of the ELF by considering particle-size-dependent respiratory deposition. While hydrogen peroxide (H2O2) and ·O2- production were governed by Fe and Cu ions, ·OH radicals were mainly generated by organic compounds and Fenton-like reactions of metal ions. We obtained mixed results for correlations between PM OP and ROS formation, providing rationale and limitations of the use of oxidative potential as an indicator for PM toxicity in epidemiological and toxicological studies.

Quinones and isoprene SOA activated nicotinamide adenine dinucleotide phosphate (NADPH) oxidase in macrophages, releasing massive amounts of superoxide via respiratory burst and overwhelming the superoxide formation by aqueous chemical reactions in the ELF. The threshold dose for macrophage activation was much smaller for quinones compared with isoprene SOA. The released ROS caused lipid peroxidation to increase cell membrane fluidity, inducing oxidative damage and stress. Further increases of doses led to the activation of antioxidant response elements, reducing the net cellular superoxide production. At very high doses and long exposure times, chemical production became comparably important or dominant if the escalation of oxidative stress led to cell death.

CONCLUSIONS

The mechanistic understandings and quantitative information on ROS generation by SOA particles provided a basis for further elucidation of adverse aerosol health effects and oxidative stress by PM2.5. For a comprehensive assessment of PM toxicity and health effects via oxidative stress, it is important to consider both chemical reactions and cellular processes for the formation of ROS in the ELF. Chemical composition of PM strongly influences ROS formation; further investigations are required to study ROS formation from various PM sources. Such research will provide critical information to environmental agencies and policymakers for the development of air quality policy and regulation.

Changes in Tobacco Dependence and Association With Onset and Progression of Use by Product Type From Waves 1 to 3 of the Population Assessment of Tobacco and Health (PATH) Study

INTRODUCTION

This study examined trajectories of tobacco dependence (TD) in relationship to changes in tobacco product use, and explored the effects of product-specific adding, switching, or discontinued use on dependence over time.

AIMS AND METHODS

Data were analyzed from the first three waves from the Population Assessment of Tobacco and Health (PATH) Study, a nationally representative, longitudinal study of adults and youth in the United States. Data included 9556 wave 1 (2013-2014) adult current established tobacco users aged 18 or older who completed all three interviews and had established use at ≥2 assessments. Mutually exclusive groups included: users of cigarettes only, e-cigarettes only, cigars only, hookah only, any smokeless only, cigarette + e-cigarette dual users, and other multiple product users. A validated 16-item scale assessed TD across product users.

RESULTS

People who used e-cigarettes exclusively at wave 1 had small increases in TD through wave 3. Wave 1 multiple product users' TD decreased across waves. TD for all other wave 1 user groups remained about the same. For wave 1 cigarette only smokers, switching to another product was associated with lower levels of TD than smokers whose use stayed the same. Movement to no established use of any tobacco product was consistently associated with lower TD for all product users.

CONCLUSIONS

Except for wave 1 e-cigarette only users (who experienced small increases in TD), TD among U.S. tobacco product users was stable over time, with daily users less likely to vary from baseline.

IMPLICATIONS

The level of TD among most U.S. tobacco users was stable over the first three waves of the PATH Study and trends in levels of TD were predominantly unrelated to changes in patterns of continued product use. Stable levels of TD suggest a population at persistent risk of health impacts from tobacco. Wave 1 e-cigarette users experienced small increases in levels of TD over time, perhaps due to increases in quantity or frequency of their e-cigarette use or increasing efficiency of nicotine delivery over time.

Validating Wave 1 (2014) Urinary Cotinine and TNE-2 Cut-points for Differentiating Wave 4 (2017) Cigarette Use from Non-use in the United States Using Data from the PATH Study

BACKGROUND

Sex and racial/ethnic identity-specific cut-points for validating tobacco use using Wave 1 (W1) of the Population Assessment of Tobacco and Health (PATH) Study were published in 2020. The current study establishes predictive validity of the W1 (2014) urinary cotinine and total nicotine equivalents-2 (TNE-2) cut-points on estimating Wave 4 (W4; 2017) tobacco use.

METHODS

For exclusive and polytobacco cigarette use, weighted prevalence estimates based on W4 self-report alone and with exceeding the W1 cut-point were calculated to identify the percentage missed without biochemical verification. Sensitivity and specificity of W1 cut-points on W4 self-reported tobacco use status were examined. ROC curves were used to determine the optimal W4 cut-points to distinguish past 30-day users from non-users, and evaluate whether the cut-points significantly differed from W1.

RESULTS

Agreement between W4 self-reported use and exceeding the W1 cut-points was high overall and when stratified by demographic subgroups (0.7%-4.4% of use was missed if relying on self-report alone). The predictive validity of using the W1 cut-points to classify exclusive cigarette and polytobacco cigarette use at W4 was high (>90% sensitivity and specificity, except among polytobacco Hispanic smokers). Cut-points derived using W4 data did not significantly differ from the W1-derived cut-points [e.g., W1 exclusive = 40.5 ng/mL cotinine (95% confidence interval, CI: 26.1-62.8), W4 exclusive = 29.9 ng/mL cotinine (95% CI: 13.5-66.4)], among most demographic subgroups.

CONCLUSIONS

The W1 cut-points remain valid for biochemical verification of self-reported tobacco use in W4.

IMPACT

Findings from can be used in clinical and epidemiologic studies to reduce misclassification of cigarette smoking status.

Indicators of Tobacco Dependence Among Youth: Findings From Wave 1 (2013-2014) of the Population Assessment of Tobacco and Health Study

BACKGROUND

Prior work established a measure of tobacco dependence (TD) among adults that can be used to compare TD across different tobacco products. We extend this approach to develop a common, cross-product metric for TD among youth.

METHODS

One thousand one hundred and forty-eight youth aged 12-17 who used a tobacco product in the past 30 days were identified from 13 651 youth respondents in Wave 1 of the Population Assessment of Tobacco and Health (PATH) Study.

FINDINGS

Analyses confirmed a single primary latent construct underlying responses to TD indicators for all mutually exclusive tobacco product user groups. Differential Item Functioning analyses supported the use of 8 of 10 TD indicators for comparisons across groups. With TD levels anchored at 0.0 (standard deviation [SD] = 1.0) among cigarette only (n = 265) use group, mean TD scores were more than a full SD lower for e-cigarette only (n = 150) use group (mean = -1.09; SD = 0.64). Other single product use group (cigar, hookah, pipe, or smokeless; n = 262) on average had lower TD (mean = -0.60; SD = 0.84), and the group with the use of multiple tobacco products (n = 471) experienced similar levels of TD (mean = 0.14; SD = 0.78) as the cigarette only use group. Concurrent validity was established with product use frequency among all user groups. A subset of five TD items comprised a common metric permitting comparisons between youth and adults.

CONCLUSION

The PATH Study Youth Wave 1 Interview provided psychometrically valid measures of TD that enable future regulatory investigations of TD across tobacco products and comparisons between youth and adult tobacco product use group.

IMPLICATIONS

A measure of tobacco dependence (TD) has been established previously among adults to compare TD across tobacco products. This study established the validity of a similar, cross-product measure of TD among youth. Findings suggest a single latent TD construct underlying this measure, concurrent validity of the scale with product use frequency across different types of tobacco users, and a subset of common items that can be used to compare TD between youth and adults who use tobacco.

Patterns of Premium and Nonpremium Cigar Use in the United States: Findings from Wave 6 (2021) of the Population Assessment of Tobacco and Health Study

INTRODUCTION

Understanding the characteristics of premium cigar use patterns is essential for minimizing public health harms. Typically, premium cigars are handmade, larger, more expensive, and without the characterizing flavors that are present in other cigar types: Nonpremium traditional cigars, cigarillos, and filtered cigars.

AIMS AND METHODS

Self-reported brand and price data were used from Wave 6 of the Population Assessment of Tobacco and Health (PATH) Study to define and estimate premium versus nonpremium cigar use among U.S. adults, as well as to explore cigar smoking patterns, purchasing behavior, and reasons for use by cigar type.

RESULTS

In 2021, 0.9% (95% CI = 0.7-1.0) of adults were premium cigar users, compared to 0.4% of nonpremium traditional cigar users (95% CI = 0.3-0.5), 1.1% of cigarillo users (95% CI = 1.0-1.2), and 0.6% filtered cigar users (95% CI = 0.5-0.7). Premium cigar users were overwhelmingly male (97.7%), and 35.8% were aged ≥55 years. The average premium cigar price/stick was $8.67, $5.50-7.00 more than other cigar types. Compared to other cigar types, significantly fewer premium cigar users had a regular brand with a flavor other than tobacco (~15% vs. 38%-53%). Though flavors remained the top reason for premium cigar use, they were less likely to endorse flavors as a reason for use than other cigar users (~40% vs. 68-74%). Premium cigar users had a lower prevalence (aRR: 0.37, 95% CI = 0.25-0.55) of dual use of cigars and cigarettes.

CONCLUSIONS

Although <1% of U.S. adults use premium cigars, their use and purchasing characteristics continue to differ from other cigar types, highlighting the importance of capturing data specific to premium cigar use.

IMPLICATIONS

This manuscript extends previous research from the National Academies of Science, Engineering, and Medicine report, "Premium cigars: Patterns of use, marketing, and health effects" by utilizing the most recent PATH Study data (Wave 6) to examine patterns of cigar use, including purchasing behavior and reasons for use, by cigar type (eg, premium traditional cigars, nonpremium traditional cigars, cigarillos, and filtered cigars). The findings support continued research on patterns of premium cigar use, which differ from use patterns of other cigar types.

Associations between biomarkers of nicotine/tobacco exposure and respiratory symptoms among adults who exclusively smoke cigarettes in the U.S.: Findings from the PATH Study Waves 1-4 (2013-2017)

Significance

Determining if tobacco-related biomarkers of exposure (BOE) are associated with respiratory symptoms is an important public health tool that can be used to evaluate the potential harm of different tobacco products.

Methods

Adult data from people who exclusively smoked cigarettes (N = 2,438) in Waves 1-4 (2013-2017) of the Population Assessment of Tobacco and Health Study were stacked to examine associations between baseline and follow-up within wave pairs (W1-W2, W2-W3, W3-W4). Weighted generalized estimating equation models were used to evaluate associations between biomarkers of nicotine, tobacco-specific nitrosamines, acrolein, acrylonitrile, cadmium, and lead at baseline/follow-up and respiratory symptom(s) (wheezing/whistling in the chest, wheezing during exercise, and/or dry cough in the past 12 months) at follow-up.

Results

Higher acrolein metabolite (CEMA) levels at follow-up were associated with increased odds of respiratory symptoms at follow-up for people who exclusively smoked cigarettes (aOR = 1.34; 95% CI = 1.06, 1.70), including when limited to those without a diagnosed respiratory disease (aOR = 1.46; 95% CI = 1.12, 1.90) and those who smoked daily (aOR = 1.40; 95% CI = 1.06, 1.84). Higher cadmium levels at baseline (while controlling for follow-up levels) were associated with reduced odds of respiratory symptoms at follow-up (aOR = 0.80; 95% CI = 0.65, 0.98) among people who exclusively smoked cigarettes without a respiratory disease. There were no significant associations between baseline/follow-up BOE and follow-up respiratory symptoms for people who smoked cigarettes non-daily.

Conclusions

This research supports measuring biomarkers of acrolein, such as CEMA, as a potential intermediate measurement for increased respiratory symptom development. Measuring these biomarkers could help alleviate the clinical burden of respiratory disease.

RETRACTED: Changes in Tobacco Dependence and Association With Onset and Progression of Use by Product Type From Wave 1 to Wave 3 of the Population Assessment of Tobacco and Health (PATH) Study

INTRODUCTION

This study examined trajectories of tobacco dependence (TD) in relation to changes in tobacco product use and explored the effects of product-specific adding, switching, or discontinued use on dependence over time.

AIMS AND METHODS

Data were analyzed from the first three waves of the Population Assessment of Tobacco and Health (PATH) Study, a nationally representative, longitudinal study of adults and youth in the United States. Data included 9556 Wave 1 (2013/2014) adult current established tobacco users who completed all three interviews and had established use at ≥2 assessments. Groups included cigarettes-only users, e-cigarettes-only users, cigars-only users, hookah-only users, any smokeless-only users, cigarette + e-cigarette dual users, and multiple product users. A validated 16-item scale assessed TD across product users.

RESULTS

Wave 1 e-cigarette-only users' who maintained exclusive e-cigarette use increased levels of TD through Wave 3 as did those who added or switched to another product. Wave 1 multiple product users' TD decreased across waves. TD for all other Wave 1 user groups remained about the same. For Wave 1 cigarette-only smokers, switching to another product or moving to a pattern of no established use was associated with lower levels of TD than smokers whose use stayed the same. Movement to no established use of any tobacco product was consistently associated with lower TD for all other product users.

CONCLUSIONS

Except for Wave 1 e-cigarette-only users, TD among US tobacco product users was stable over time, with daily users less likely to vary from baseline.

IMPLICATIONS

The level of TD among most US tobacco users was stable over the first three waves of the PATH Study and trends in levels of TD were predominantly unrelated to changes in patterns of continued product use. Stable levels of TD suggest a population at persistent risk of health impacts from tobacco. Wave 1 e-cigarette users, including those maintaining exclusive e-cigarette use, experienced increasing levels of TD over time, perhaps because of increases in quantity or frequency of their e-cigarette product use or increasing efficiency of nicotine delivery over time.

Association between tobacco product use and asthma among US adults from the Population Assessment of Tobacco and Health (PATH) Study waves 2-4

BACKGROUND

Research on cigarettes and adult asthma offers mixed findings, perhaps due to overlap with chronic obstructive pulmonary disease (COPD) and inadequate adjustment for other smoke exposures. Associations between other tobacco products, including e-cigarettes, and asthma are also understudied.

RESEARCH QUESTION

Using Population Assessment of Tobacco and Health Study waves 2-4 (2014/2015-2016/2017) data, we assessed the relation between tobacco product use and asthma in persons unlikely to have COPD.

STUDY DESIGN AND METHODS

Prospective study of 10 267 adults aged 18-39 years without COPD diagnoses. Past-month tobacco use at wave 2 was modelled first as combustible versus non-combustible use and second as specific product categories (former, cigarettes, e-cigarettes, cigars, hookah, smokeless tobacco). Outcomes included lifetime asthma prevalence at wave 2, incidence (waves 3 and 4) and Asthma Control Test score (lower=worse). Multivariable regressions adjusted for predictors of asthma, including other smoke exposures: cigarette pack-years, secondhand smoke and marijuana use. Sensitivity analyses examined findings when persons >39 years and those with both COPD and asthma were added, and when smoke exposure adjustments were removed.

RESULTS

No product, including cigarettes and e-cigarettes, was associated with prevalence or incidence of asthma. Among people with asthma at wave 2, combustible tobacco (beta=-0.86, 95% CI (-1.32 to -0.39)) and cigarettes (beta=-1.14, 95% CI (-1.66 to -0.62)) were associated with worse asthma control. No tobacco product was associated with asthma control over time. In sensitivity analyses, tobacco use became associated with incident asthma as adults >39 years and those with asthma+COPD were added, and as adjustments for other smoke exposures were omitted.

INTERPRETATION

Although cigarette use was associated with worse asthma control, there were no longitudinal associations between combustible tobacco or e-cigarette use and new onset or worsening asthma in these preliminary analyses. Research on tobacco and asthma should exclude COPD and adjust for smoking history and other smoke exposures.

Tobacco Use and Respiratory Symptoms Among Adults: Findings From the Longitudinal Population Assessment of Tobacco and Health (PATH) Study 2014-2016

INTRODUCTION

We examined the relationship between current tobacco use and functionally important respiratory symptoms.

METHODS

Longitudinal cohort study of 16 295 US adults without COPD in Waves 2-3 (W2-3, 2014-2016) of the Population Assessment of Tobacco and Health Study. Exposure-Ten mutually exclusive categories of tobacco use including single product, multiple product, former, and never use (reference). Outcome-Seven questions assessing wheezing/cough were summed to create a respiratory symptom index; cutoffs of ≥2 and ≥3 were associated with functional limitations and poorer health. Multivariable regressions examined both cutoffs cross-sectionally and change over approximately 12 months, adjusting for confounders.

RESULTS

All tobacco use categories featuring cigarettes (>2/3's of users) were associated with higher risk (vs. never users) for functionally important respiratory symptoms at W2, for example, at symptom severity ≥ 3, risk ratio for exclusive cigarette use was 2.34 [95% CI, 1.92, 2.85] and for worsening symptoms at W3 was 2.80 [2.08, 3.76]. There was largely no increased symptom risk for exclusive use of cigars, smokeless tobacco, hookah, or e-cigarettes (adjustment for pack-years and marijuana attenuated the cross-sectional e-cigarette association from 1.53(95% CI 0.98, 2.40) to 1.05 (0.67, 1.63); RRs for these products were also significantly lower compared to exclusive use of cigarettes. The longitudinal e-cigarette-respiratory symptom association was sensitive to the respiratory index cutoff level; exclusive e-cigarette use was associated with worsening symptoms at an index cutoff ≥ 2 (RR = 1.63 [1.02, 2.59]) and with symptom improvement at an index cutoff of ≥ 3 (RR = 1.64 [1.04, 2.58]).

CONCLUSIONS

Past and current cigarette smoking drove functionally important respiratory symptoms, while exclusive use of other tobacco products was largely not associated. However, the relationship between e-cigarette use and symptoms was sensitive to adjustment for pack-years and symptom severity.

IMPLICATIONS

How noncigarette tobacco products affect respiratory symptoms is not clear; some studies implicate e-cigarettes. We examined functionally important respiratory symptoms (wheezing/nighttime cough) among US adults without COPD. The majority of adult tobacco users smoke cigarettes and have higher risk of respiratory symptoms and worsening of symptoms, regardless of other products used with them. Exclusive use of other tobacco products (e-cigarettes, cigars, smokeless, hookah) was largely not associated with functionally important respiratory symptoms and risks associated with their use was significantly lower than for cigarettes. The association for e-cigarettes was greatly attenuated by adjustment for cigarette pack-years and sensitive to how symptoms were defined.

Association of tobacco product use with chronic obstructive pulmonary disease (COPD) prevalence and incidence in Waves 1 through 5 (2013-2019) of the Population Assessment of Tobacco and Health (PATH) Study

BACKGROUND

We examined the association of non-cigarette tobacco use on chronic obstructive pulmonary disease (COPD) risk in the Population Assessment of Tobacco and Health (PATH) Study.

METHODS

There were 13,752 participants ≥ 40 years with Wave 1 (W1) data for prevalence analyses, including 6945 adults without COPD for incidence analyses; W1-5 (2013-2019) data were analyzed. W1 tobacco use was modeled as 12 mutually-exclusive categories of past 30-day (P30D) single and polyuse, with two reference categories (current exclusive cigarette and never tobacco). Prevalence and incidence ratios of self-reported physician-diagnosed COPD were estimated using weighted multivariable Poisson regression.

RESULTS

W1 mean (SE) age was 58.1(0.1) years; mean cigarette pack-years was similar for all categories involving cigarettes and exclusive use of e-cigarettes (all > 20), greater than exclusive cigar users (< 10); and COPD prevalence was 7.7%. Compared to P30D cigarette use, never tobacco, former tobacco, and cigar use were associated with lower COPD prevalence (RR = 0.33, (95% confidence interval-CI) [0.26, 0.42]; RR = 0.57, CI [0.47, 0.70]; RR = 0.46, CI [0.28, 0.76], respectively); compared to never tobacco use, all categories except cigar and smokeless tobacco use were associated with higher COPD prevalence (RR former = 1.72, CI [1.33, 2.23]; RR cigarette = 3.00, CI [2.37, 3.80]; RR e-cigarette = 2.22, CI [1.44, 3.42]; RR cigarette + e-cigarette = 3.10, CI [2.39, 4.02]; RR polycombusted = 3.37, CI [2.44, 4.65]; RR polycombusted plus noncombusted = 2.75, CI]1.99, 3.81]). COPD incidence from W2-5 was 5.8%. Never and former tobacco users had lower COPD risk compared to current cigarette smokers (RR = 0.52, CI [0.35, 0.77]; RR = 0.47, CI [0.32, 0.70], respectively). Compared to never use, cigarette, smokeless, cigarette plus e-cigarette, and polycombusted tobacco use were associated with higher COPD incidence (RR = 1.92, CI [1.29, 2.86]; RR = 2.08, CI [1.07, 4.03]; RR = 1.99, CI [1.29, 3.07]; RR = 2.59, CI [1.60, 4.21], respectively); exclusive use of e-cigarettes was not (RR = 1.36, CI [0.55, 3.39]).

CONCLUSIONS

E-cigarettes and all use categories involving cigarettes were associated with higher COPD prevalence compared to never use, reflecting, in part, the high burden of cigarette exposure in these groups. Cigarette-but not exclusive e-cigarette-use was also strongly associated with higher COPD incidence. Compared to cigarette use, only quitting tobacco was protective against COPD development.

Tobacco Product Use and Functionally Important Respiratory Symptoms Among US Adolescents/Young Adults

OBJECTIVE

The relation between respiratory symptoms and the range of tobacco product use among US adolescents/young adults is not yet clear. This cross-sectional analysis examines tobacco product use and respiratory symptoms in a nationally representative sample of 21,057 adolescents/young adults aged 12-24 years from Wave 4 (2016-17) of the Population Assessment of Tobacco and Health Study.

METHODS

Presence of functionally important respiratory symptoms was defined by questions regarding wheezing and nighttime cough at a cutoff score associated with poorer functional health status. Past-30-day tobacco use was analyzed 2 ways: never-tobacco users (reference) versus combustible users, noncombustible-only users, and former users; or frequency of use of cigarettes and/or e-cigarettes. Weighted Poisson regression adjusted for past-30-day marijuana use, secondhand smoke exposure, and asthma.

RESULTS

Functionally important respiratory symptoms were present in 10.0% overall: 13.8% of combustible users, 9.0% of noncombustible users, 8.2% of noncurrent users and 9.7% of never users. Functionally important respiratory symptoms were associated with combustible tobacco use (relative risk [RR] = 1.52[95% CI 1.29, 1.80]), marijuana use (RR = 1.54[1.34, 1.77]) and secondhand smoke exposure (RR = 1.04[1.03, 1.05]). Higher cigarette smoking frequency was also associated with functionally important respiratory symptoms for frequency categories >14 days/month (eg, RR = 1.93[1.50, 2.49] for 15-29 days/month). Frequency of e-cigarette use was not associated with functionally important respiratory symptoms.

CONCLUSIONS

During 2016-17, smoking cigarettes, marijuana use, and secondhand smoke exposure were cross-sectionally associated with functionally important respiratory symptoms in adolescents/young adults. Risk increased with increased frequency of cigarette use but not e-cigarette use. Given changes to contemporary e-cigarettes and use, findings may not generalize to newer products.

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.

Changes in Biomarkers of Tobacco Exposure among Cigarette Smokers Transitioning to ENDS Use: The Population Assessment of Tobacco and Health Study, 2013-2015

Limited data are available for how biomarkers of tobacco exposure (BOE) change when cigarette smokers transition to using electronic nicotine delivery systems (ENDS). Using biomarker data from Waves 1 (2013-2014) and 2 (2014-2015) of the PATH Study, we examined how mean BOE concentrations, including metabolites of nicotine, tobacco-specific nitrosamines (TSNA), polycyclic aromatic hydrocarbons (PAH), and volatile organic compounds (VOC) and metals, changed when 2475 adult smokers transitioned to using ENDS or quit tobacco products. Exclusive smokers who transitioned to dual use had a significant decrease in NNAL (4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol), but not nicotine metabolites, most PAHs, metals, or VOCs. Exclusive smokers who became dual users had significant reductions in total nicotine equivalents, NNAL, and 2CyEMA (acrylonitrile metabolite), but only in those who reduced cigarettes per day (CPD) by >=50%. Smokers who transitioned to exclusive ENDS use had significant reductions in most TSNAs, PAHs, and VOCs; however, nicotine metabolites did not decrease in dual users who became exclusive ENDS users. Smokers who quit tobacco use had significant decreases in nicotine metabolites, all TSNAs, most PAHs, and most VOCs. Cigarette smokers who became dual users did not experience significant reductions in most BOEs. Reductions were impacted by changes in CPD. However, transitioning from smoking to no tobacco or exclusive ENDS use was associated with reduced exposure to most BOEs measured. Future analyses could incorporate additional waves of PATH data and examine changes in biomarker exposure by ENDS device type and CPD.

E-cigarette use and change in plans to quit cigarette smoking among adult smokers in the United States: Longitudinal findings from the PATH Study 2014-2019

INTRODUCTION

Much of the population-based e-cigarette use and cigarette cessation literature is restricted to smokers who have expressed intention to quit smoking, though experimental studies suggest e-cigarette use might motivate some smokers to change their quit intentions. We used U.S. nationally representative data to evaluate whether e-cigarette use by smokers initially not planning to ever quit is associated with change in plans to quit.

METHODS

Longitudinal Population Assessment of Tobacco and Health (PATH) Study data collected between 2014 and 2019 were analyzed. Main analyses were conducted among adult daily cigarette smokers not currently using e-cigarettes with no plans to ever quit smoking (n = 2366 observations from n = 1532 individuals). Generalized estimating equations were used to evaluate the association between change in e-cigarette use and change in plans to quit smoking within the next six months, over three assessment pairs.

RESULTS

Daily cigarette smokers with no plans to quit had a higher rate of change to plan to quit if at follow-up they used e-cigarettes daily (41.4%, 95% CI: 27.1-57.3%) versus not at all (12.4%, 95% CI: 10.6-14.5%; aOR = 5.7, 95% CI: 2.9-11.2). Rate of change to plan to quit did not statistically differ between those who at follow-up used e-cigarettes some days versus not at all.

CONCLUSIONS

Among adult daily cigarette smokers initially not planning to ever quit, subsequent daily e-cigarette use is associated with subsequent plans to quit smoking. Population-level research on e-cigarette use that is focused on smokers already motivated to quit may limit a complete evaluation of the smoker population.

Validation of the Wave 1 and Wave 2 Population Assessment of Tobacco and Health (PATH) Study Indicators of Tobacco Dependence Using Biomarkers of Nicotine Exposure Across Tobacco Products

INTRODUCTION

This study examined the predictive relationships between biomarkers of nicotine exposure and 16-item self-reported level of tobacco dependence (TD) and subsequent tobacco use outcomes.

AIMS AND METHODS

The Population Assessment of Tobacco and Health (PATH) Study surveyed adult current established tobacco users who provided urine biospecimens at Wave 1 (September 2013-December 2014) and completed the Wave 2 (October 2014-October 2015) interview (n = 6872). Mutually exclusive user groups at Wave 1 included: Cigarette Only, E-cigarette Only, Cigar Only, Hookah Only, Smokeless Tobacco Only, Cigarette Plus E-cigarette, multiple tobacco product users who smoked cigarettes, and multiple tobacco product users who did not smoke cigarettes. Total Nicotine Equivalents (TNE-2) and TD were measured at Wave 1. Approximate one-year outcomes included frequency/quantity used, quitting, and adding/switching to different tobacco products.

RESULTS

For Cigarette Only smokers and multiple tobacco product users who smoked cigarettes, higher TD and TNE-2 were associated with: a tendency to smoke more, smoking more frequently over time, decreased likelihood of switching away from cigarettes, and decreased probability of quitting after one year. For other product user groups, Wave 1 TD and/or TNE-2 were less consistently related to changes in quantity and frequency of product use, or for adding or switching products, but higher TNE-2 was more consistently predictive of decreased probability of quitting.

CONCLUSIONS

Self-reported TD and nicotine exposure assess common and independent aspects of dependence in relation to tobacco use behaviors for cigarette smokers. For other product user groups, nicotine exposure is a more consistent predictor of quitting than self-reported TD.

IMPLICATIONS

This study suggests that smoking cigarettes leads to the most coherent pattern of associations consistent with a syndrome of TD. Because cigarettes continue to be prevalent and harmful, efforts to decrease their use may be accelerated via conventional means (eg, smoking cessation interventions and treatments), but also perhaps by decreasing their dependence potential. The implications for noncombustible tobacco products are less clear as the stability of tobacco use patterns that include products such as e-cigarettes continue to evolve. TD, nicotine exposure measures, and consumption could be used in studies that attempt to understand and predict product-specific tobacco use behavioral outcomes.

Association of e-Cigarette Use With Discontinuation of Cigarette Smoking Among Adult Smokers Who Were Initially Never Planning to Quit

IMPORTANCE

Cigarette smokers not planning to quit are often overlooked in population studies evaluating the risk-benefit potential of electronic nicotine delivery products (e-cigarettes).

OBJECTIVE

To evaluate whether e-cigarette use is associated with discontinuing cigarette smoking among smokers who were initially never planning to quit.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study used US nationally representative data from the longitudinal Population Assessment of Tobacco and Health Study (waves 2-5 conducted between October 2014 and November 2019), with participants evaluated in 3 pairs of interviews. Adult daily cigarette smokers initially not using e-cigarettes and with no plans to ever quit smoking for good (2489 observations from 1600 individuals) were included.

EXPOSURES

e-Cigarette use (ie, daily use, nondaily use, or no use) at follow-up interview among smokers not using e-cigarettes at baseline interview.

MAIN OUTCOMES AND MEASURES

The main outcomes were discontinuation of cigarette smoking (ie, no cigarette smoking) and discontinuation of daily cigarette smoking (ie, no daily cigarette smoking) at follow-up interview. Generalized estimating equations were used to evaluate the association between the exposure and each outcome, controlling for demographic characteristics and cigarettes smoked per day at baseline interview; all estimates were weighted.

RESULTS

The weighted population of adult daily cigarette smokers who were not using e-cigarettes and had no plans to ever quit smoking, based on data from 1600 participants, was 56.1% male (95% CI, 53.4%-58.7%), 10.1% Hispanic (95% CI, 8.2%-12.3%), 10.1% non-Hispanic Black (95% CI, 8.7%-11.7%), 75.6% non-Hispanic White (95% CI, 72.9%-78.2%), and 4.2% of other non-Hispanic race (95% CI, 3.3%-5.4%); 29.3% were aged 55 to 69 years (95% CI, 26.2%-32.6%), 8.9% were aged 70 years or older (95% CI, 6.8%-11.5%), 36.8% did not graduate from high school (95% CI, 34.1%-39.6%), 55.2% had an annual household income of less than $25 000 (95% CI, 52.3%-58.1%), 37.6% smoked 20 to 29 cigarettes per day (95% CI, 34.7%-40.6%), and 12.7% smoked 30 or more cigarettes per day (95% CI, 10.9%-14.7%). Overall, 6.2% of the population (95% CI, 5.0%-7.5%) discontinued cigarette smoking. Discontinuation rates were higher among those who used e-cigarettes daily (28.0%; 95% CI, 15.2%-45.9%) compared with not at all (5.8%; 95% CI, 4.7%-7.2%; adjusted odds ratio [aOR], 8.11; 95% CI, 3.14-20.97). Furthermore, 10.7% (95% CI, 9.1%-12.5%) discontinued daily cigarette smoking, with higher rates of discontinuation observed among those who used e-cigarettes daily (45.5%; 95% CI, 27.4%-64.9%) compared with not at all (9.9%; 95% CI, 8.2%-11.8%; aOR, 9.67; 95% CI, 4.02-23.25). Nondaily e-cigarette use was not associated with cigarette discontinuation (aOR, 0.53; 95% CI, 0.08-3.35) or daily cigarette discontinuation (aOR, 0.96; 95% CI, 0.44-2.09).

CONCLUSIONS AND RELEVANCE

In this cohort study, daily e-cigarette use was associated with greater odds of cigarette discontinuation among smokers who initially had no plans to ever quit smoking. These findings support the consideration of smokers who are not planning to quit when evaluating the risk-benefit potential of e-cigarettes for smoking cessation in the population.

Validation of an Index for Functionally Important Respiratory Symptoms among Adults in the Nationally Representative Population Assessment of Tobacco and Health Study, 2014-2016

The purpose of this study is to validate the seven-item wheezing module from the International Study of Asthma and Allergies in Children (ISAAC) in the nationally representative Population Assessment of Tobacco and Health Study. Adult participants with complete Wave 2-3 data were selected, including those with asthma but excluding those with COPD and other respiratory diseases (n = 16,295). We created a nine-point respiratory symptom index from the ISAAC questions, assessed the reliability of the index, and examined associations with self-reported asthma diagnosis. Threshold values were assessed for association with functional outcomes. The weighted prevalence for one or more respiratory symptom was 18.0% (SE = 0.5) for adults without asthma, 70.1% (SE = 1.3) for those with lifetime asthma, 75.7% (SE = 3.7) for adults with past-year asthma not on medications, and 92.6% (SE = 1.6) for those on medications. Cronbach's alpha for the respiratory symptom index was 0.86. Index scores of ≥2 or ≥3 yielded functionally important respiratory symptom prevalence of 7-10%, adequate sensitivity and specificity for identifying asthma, and consistent independent associations with all functional outcomes and tobacco use variables. Respiratory symptom index scores of ≥2 or ≥3 are indicative of functionally important respiratory symptoms and could be used to assess the relationship between tobacco use and respiratory health.

Biomarkers of Inflammation and Oxidative Stress among Adult Former Smoker, Current E-Cigarette Users-Results from Wave 1 PATH Study

BACKGROUND

Former smokers who currently use e-cigarettes have lower concentrations of biomarkers of tobacco toxicant exposure than current smokers. It is unclear whether tobacco toxicant exposure reductions may lead to health risk reductions.

METHODS

We compared inflammatory biomarkers (high-sensitivity C-reactive protein, IL6, fibrinogen, soluble intercellular adhesion molecule-1) and an oxidative stress marker (F2-isoprostane) among 3,712 adult participants in Wave 1 (2013-2014) of the Population Assessment of Tobacco and Health Study by tobacco user groups: dual users of cigarettes and e-cigarettes; former smokers who currently use e-cigarettes-only; current cigarette-only smokers; former smokers who do not currently use any tobacco; and never tobacco users. We calculated geometric means (GM) and estimated adjusted GM ratios (GMR).

RESULTS

Dual users experienced greater concentration of F2-isoprostane than current cigarette-only smokers [GMR 1.09 (95% confidence interval, CI, 1.03-1.15)]. Biomarkers were similar between former smokers who currently use e-cigarettes and both former smokers who do not use any tobacco and never tobacco users, but among these groups most biomarkers were lower than those of current cigarette-only smokers. The concentration of F2-isoprostane decreased by time since smoking cessation among both exclusive e-cigarette users (P _trend = 0.03) and former smokers who do not currently use any tobacco (P _trend = 0.0001).

CONCLUSIONS

Dual users have greater concentration of F2-isoprostane than smokers. Exclusive e-cigarette users have biomarker concentrations that are similar to those of former smokers who do not currently use tobacco, and lower than those of exclusive cigarette smokers.

IMPACT

This study contributes to an understanding of the health effects of e-cigarettes.

Overview of tobacco use transitions for population health

The Family Smoking Prevention and Tobacco Control Act provided the US Food and Drug Administration authority to regulate tobacco products using a population health standard. Models have been developed to estimate the population health impacts of tobacco initiation, cessation and relapse transitions. Models should be informed by high-quality, longitudinal data to estimate these constructs. Simulation studies have generated data to predict the impact of various tobacco control interventions, including the influence of regulations on tobacco use behaviours and health. The purpose of this paper is to provide a high-level conceptual overview for understanding tobacco transition behaviours and correlates of these behaviours using data from the Population Assessment of Tobacco and Health (PATH) Study, a US nationally representative longitudinal tobacco study of about 46 000 persons aged 12+ years. The papers that follow in this journal issue build and expand on this conceptual overview using data from the first three waves of the PATH Study. These papers describe use patterns of different tobacco products and their correlates, and can serve as foundations for more in-depth papers that will help the research community better understand the population health impacts and drivers of different tobacco use patterns.

Longitudinal pathways of exclusive and polytobacco cigarette use among youth, young adults and adults in the USA: findings from the PATH Study Waves 1-3 (2013-2016)

OBJECTIVE

Cigarettes are the most harmful and most prevalent tobacco product in the USA. This study examines cross-sectional prevalence and longitudinal pathways of cigarette use among US youth (12-17 years), young adults (18-24 years) and adults 25+ (25 years and older).

DESIGN

Data were drawn from the first three waves (2013-2016) of the Population Assessment of Tobacco and Health Study, a nationally representative, longitudinal cohort study of US adults and youth. Respondents with data at all three waves (youth, N=11 046; young adults, N=6478; adults 25+, N=17 188) were included in longitudinal analyses.

RESULTS

Among Wave 1 (W1) any past 30-day (P30D) cigarette users, more than 60%, persistently used cigarettes across three waves in all age groups. Exclusive cigarette use was more common among adult 25+ W1 P30D cigarette users (62.6%), while cigarette polytobacco use was more common among youth (57.1%) and young adults (65.2%). Persistent exclusive cigarette use was the most common pathway among adults 25+ and young adults; transitioning from exclusive cigarette use to cigarette polytobacco use was most common among youth W1 exclusive cigarette users. For W1 youth and young adult cigarette polytobacco users, the most common pattern of use was persistent cigarette polytobacco use.

CONCLUSIONS

Cigarette use remains persistent across time, regardless of age, with most W1 P30D smokers continuing to smoke at all three waves. Policy efforts need to continue focusing on cigarettes, in addition to products such as electronic nicotine delivery systems that are becoming more prevalent.

Longitudinal pathways of exclusive and polytobacco cigar use among youth, young adults and adults in the USA: findings from the PATH Study Waves 1-3 (2013-2016)

OBJECTIVE

The goal of this study is to examine the cross-sectional prevalence of use and 3-year longitudinal pathways of cigar use in US youth (12-17 years), young adults (18-24 years), and adults 25+ (25 years or older).

DESIGN

Data were drawn from the first three waves (2013-2016) of the Population Assessment of Tobacco and Health Study, a nationally representative, longitudinal cohort study of US youth and adults. Respondents with data at all three waves (youth, n=11 046; young adults, n=6478; adults 25+, n=17 188) were included in longitudinal analyses.

RESULTS

Weighted cross-sectional prevalence of past 30-day (P30D) use was stable for adults 25+ (~6%), but decreased in youth (Wave 1 (W1) to Wave 3 (W3)=2.5% to 1.2%) and young adults (W1 to W3=15.7% to 14.0%). Among W1 P30D cigar users, over 50% discontinued cigar use (irrespective of other tobacco use) by Wave 2 (W2) or W3. Across age groups, over 70% of W1 P30D cigar users also indicated P30D use of another tobacco product, predominantly cigar polytobacco use with cigarettes. Discontinuing all tobacco use by W2 or W3 was greater in adult exclusive P30D cigar users compared with polytobacco cigar users.

CONCLUSIONS

Although the majority of P30D cigar users discontinued use by W3, adult polytobacco users of cigars were less likely to discontinue all tobacco use than were exclusive cigar users. Tracking patterns of cigar use will allow further assessment of the population health impact of cigars.

Correlates of tobacco product reuptake and relapse among youth and adults in the USA: findings from the PATH Study Waves 1-3 (2013-2016)

OBJECTIVE

This study examines sociodemographic and tobacco use correlates of reuptake and relapse to tobacco use across a variety of tobacco products (cigarettes, electronic nicotine delivery systems, cigars, hookah and smokeless tobacco) among the US population.

DESIGN

Data were drawn from the first three waves (2013-2016) of the Population Assessment of Tobacco and Health Study, a nationally representative, longitudinal cohort study of US youth (ages 12-17) and adults (ages 18+). Reuptake (past 30-day use among previous tobacco users) and relapse (current use among former established users; adults only) were examined among previous users of at least one type of tobacco product at Wave 1 (W1) or Wave 2 (W2) (n=19 120 adults, n=3039 youth). Generalised estimating equations were used to evaluate the association between demographic and tobacco use characteristics at baseline, with reuptake/relapse at follow-up, over two 1-year periods (W1-W2 and W2-Wave 3).

RESULTS

Any tobacco product reuptake occurred in 7.8% of adult previous users and 30.3% of youth previous users. Correlates of any tobacco reuptake included being male, non-Hispanic black and bisexual in adults, but race and sexual orientation were not consistent findings in youth. Among recent former users, relapse rates were greater (32.9%). Shorter time since last use and greater levels of tobacco dependence showed the strongest association with any tobacco relapse.

DISCUSSION

Continued clinical and public health efforts to provide adults with tools to cope with tobacco dependence symptoms, especially within the first year or two after quitting, could help prevent relapse.

Exposure to Nicotine and Toxicants Among Dual Users of Tobacco Cigarettes and E-Cigarettes: Population Assessment of Tobacco and Health (PATH) Study, 2013-2014

INTRODUCTION

Concurrent use of tobacco cigarettes and e-cigarettes ("dual use") is common among tobacco users. Little is known about differences in demographics and toxicant exposure among subsets of dual users.

AIMS AND METHODS

We analyzed data from adult dual users (current every/some day users of tobacco cigarettes and e-cigarettes, n = 792) included in the PATH Study Wave 1 (2013-2014) and provided urine samples. Samples were analyzed for biomarkers of exposure to nicotine and selected toxicants (tobacco-specific nitrosamine NNK [NNAL], lead, cadmium, naphthalene [2-naphthol], pyrene [1-hydroxypyrene], acrylonitrile [CYMA], acrolein [CEMA], and acrylamide [AAMA]). Subsets of dual users were compared on demographic, behavioral, and biomarker measures to exclusive cigarette smokers (n = 2411) and exclusive e-cigarette users (n = 247).

RESULTS

Most dual users were predominant cigarette smokers (70%), followed by daily dual users (13%), non-daily concurrent dual users (10%), and predominant vapers (7%). Dual users who smoked daily showed significantly higher biomarker concentrations compared with those who did not smoke daily. Patterns of e-cigarette use had little effect on toxicant exposure. Dual users with high toxicant exposure were generally older, female, and smoked more cigarettes per day. Dual users who had low levels of biomarkers of exposure were generally younger, male, and smoked non-daily.

CONCLUSIONS

In 2013-2014, most dual users smoked cigarettes daily and used e-cigarettes occasionally. Cigarette smoking appears to be the primary driver of toxicant exposure among dual users, with little-to-no effect of e-cigarette use on biomarker levels. Results reinforce the need for dual users to stop smoking tobacco cigarettes to reduce toxicant exposure.

IMPLICATIONS

With considerable dual use of tobacco cigarettes and e-cigarettes in the United States, it is important to understand differences in toxicant exposure among subsets of dual users, and how these differences align with user demographics. Findings suggest most dual users smoke daily and use e-cigarettes intermittently. Low exposure to toxicants was most common among younger users, males, and intermittent smokers; high exposure to toxicants was most common among older users, females, and heavier cigarette smokers. Results underscore the heterogeneity occurring within dual users, and the need to quit smoking cigarettes completely in order to reduce toxicant exposure.

E-Cigarette Flavors and Frequency of E-Cigarette Use among Adult Dual Users Who Attempt to Quit Cigarette Smoking in the United States: Longitudinal Findings from the PATH Study 2015/16-2016/17

Potential mechanisms by which e-cigarette use may relate to combustible cigarette smoking cessation are not well-understood. We used U.S. nationally representative data to prospectively evaluate the relationship between e-cigarette flavor use and frequency of e-cigarette use among adult cigarette/e-cigarette dual users who attempted to quit smoking cigarettes. Analyses used Population Assessment of Tobacco and Health (PATH) Study data from adult dual users (2015/16) who attempted to quit smoking between 2015/16 and 2016/17 (Wave 3-Wave 4, n = 685, including those who did/did not quit by 2016/17). E-cigarette flavor use (usual/last flavor, past 30-day flavor; assessed in 2015/16) was categorized into Only tobacco; Only menthol/mint; Only non-tobacco, non-menthol/mint; and Any combination of tobacco, menthol/mint, other flavor(s). The key outcome, evaluated at follow-up in 2016/17, was frequent e-cigarette use, which was defined as use on 20+ of past 30 days. Logistic regression was used to evaluate associations between e-cigarette flavor use in 2015/16 and frequent e-cigarette use at follow-up in 2016/17. Dual users who attempted to quit smoking had greater odds of frequent e-cigarette use at follow-up when they used only non-tobacco, non-menthol/mint flavor than when they used only tobacco flavor as their regular/last e-cigarette flavor (OR = 1.9, 95% CI: 1.1-3.4); findings were no longer significant when adjusted for factors including e-cigarette device type (AOR = 1.4, 95% CI: 0.7-2.8). Past 30-day e-cigarette flavor use results were generally similar, although frequent e-cigarette use at follow-up was highest among those who used any combination of tobacco, menthol/mint, or other flavors. Findings indicate that e-cigarette flavor use among dual users who attempt to quit smoking may be related to e-cigarette use frequency overall, which may indicate a mechanism underlying findings for e-cigarette use and smoking cessation. Further longitudinal research may help to disentangle how e-cigarette characteristics uniquely impact e-cigarette use frequency and smoking cessation/sustained use.

Urinary Cotinine and Cotinine + Trans-3'-Hydroxycotinine (TNE-2) Cut-points for Distinguishing Tobacco Use from Nonuse in the United States: PATH Study (2013-2014)

BACKGROUND

Determine the overall, sex-, and racially/ethnically-appropriate population-level cotinine and total nicotine equivalents (TNE-2, the molar sum of the two major nicotine metabolites) cut-points to distinguish tobacco users from nonusers across multiple definitions of use (e.g., exclusive vs. polytobacco, and daily vs. non-daily).

METHODS

Using Wave 1 (2013-2014) of the U.S. Population Assessment of Tobacco and Health (PATH) Study, we conducted weighted Receiver Operating Characteristic (ROC) analysis to determine the optimal urinary cotinine and TNE-2 cut-points, stratified by sex and race/ethnicity.

RESULTS

For past 30-day exclusive cigarette users, the cotinine cut-point that distinguished them from nonusers was 40.5 ng/mL, with considerable variation by sex (male: 22.2 ng/mL; female: 43.1 ng/mL) and between racial/ethnic groups (non-Hispanic other: 5.2 ng/mL; non-Hispanic black: 297.0 ng/mL). A similar, but attenuated, pattern emerged when assessing polytobacco cigarette users (overall cut-point = 39.1 ng/mL, range = 5.5 ng/mL-80.4 ng/mL) and any tobacco users (overall cut-point = 39.1 ng/mL, range = 4.8 ng/mL-40.0 ng/mL). Using TNE-2, which is less impacted by racial differences in nicotine metabolism, produced a comparable pattern of results although reduced the range magnitude.

CONCLUSIONS

Because of similar frequency of cigarette use among polytobacco users, overall cut-points for exclusive cigarette use were not substantially different from cut-points that included polytobacco cigarette use or any tobacco use. Results revealed important differences in sex and race/ethnicity appropriate cut-points when evaluating tobacco use status and established novel urinary TNE-2 cut-points.

IMPACT

These cut-points may be used for biochemical verification of self-reported tobacco use in epidemiologic studies and clinical trials.

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.

Initiation of any tobacco and five tobacco products across 3 years among youth, young adults and adults in the USA: findings from the PATH Study Waves 1-3 (2013-2016)

OBJECTIVE

This study reports weighted cross-sectional prevalence of never use of tobacco, and longitudinal past 12-month (P12M), past 30-day (P30D) and frequent P30D any tobacco or specific tobacco product initiation across three 1-year waves. Longitudinal three-wave pathways are examined to outline pathways of exclusive and polytobacco initiation, as well as pathways of new initiators of electronic nicotine delivery systems (ENDS) or cigarettes.

DESIGN

Data were drawn from the first three waves (2013-2016) of the Population Assessment of Tobacco and Health Study, a nationally representative, longitudinal cohort study of US youth and adults. Respondents with data at all three waves (youth, N = 11 046; young adults, N = 6478; adults 25+, N = 17 188) were included in longitudinal analyses.

RESULTS

Across the three age groups, weighted cross-sectional analyses revealed never any tobacco use decreased each year from 2013 to 2016, reflecting overall increases in tobacco initiation in the population during this time. Compared with cigarettes, cigars, hookah and smokeless tobacco, ENDS had the highest proportion of P12M initiation from Wave 1 to Wave 3 (W3) for each age group. Among youth Wave 2 P30D initiators of exclusive ENDS or cigarettes, the most common W3 outcome was not using any tobacco (ENDS: 59.0% (95% CI 48.4 to 68.8); cigarettes: 40.3% (95% CI 28.7 to 53.1)).

CONCLUSIONS

Initiation rates of ENDS among youth and young adults have increased the number of ever tobacco users in the US prevention strategies across the spectrum of tobacco products which can address youth initiation of tobacco products.

Longitudinal transitions of exclusive and polytobacco electronic nicotine delivery systems (ENDS) use among youth, young adults and adults in the USA: findings from the PATH Study Waves 1-3 (2013-2016)

OBJECTIVE

Electronic nicotine delivery systems (ENDS; including e-cigarettes) are rapidly evolving in the US marketplace. This study reports cross-sectional prevalence and longitudinal pathways of ENDS use across 3 years, among US youth (12-17 years), young adults (18-24 years) and adults 25+ (25 years and older).

DESIGN

Data were from the first three waves (2013-2016) of the Population Assessment of Tobacco and Health Study, a nationally representative, longitudinal cohort study of US youth and adults. Respondents with data at all three waves (youth, n=11 046; young adults, n=6478; adults 25+, n=17 188) were included in longitudinal analyses.

RESULTS

Weighted cross-sectional ever use of ENDS increased at each wave. Across all three waves, young adults had the highest percentages of past 12-month, past 30-day (P30D) and daily P30D ENDS use compared with youth and adults 25+. Only about a quarter of users had persistent P30D ENDS use at each wave. Most ENDS users were polytobacco users. Exclusive Wave 1 ENDS users had a higher proportion of subsequent discontinued any tobacco use compared with polytobacco ENDS users who also used cigarettes.

CONCLUSIONS

ENDS use is most common among young adults compared with youth and adults 25+. However, continued use of ENDS over 2 years is not common for any age group. Health education efforts to reduce the appeal and availability of ENDS products might focus on reducing ENDS experimentation, and on reaching the smaller subgroups of daily ENDS users to better understand their reasons for use.

Correlates of tobacco product cessation among youth and adults in the USA: findings from the PATH Study Waves 1-3 (2013-2016)

OBJECTIVE

To report on demographic and tobacco use correlates of cessation behaviours across tobacco products (cigarettes, electronic nicotine delivery systems (ENDS), cigars, hookah and smokeless tobacco) among the US population.

DESIGN

Data were drawn from the first three waves (2013-2016) of the Population Assessment of Tobacco and Health Study, a nationally representative, longitudinal cohort study of US youth (ages 12-17) and adults (ages 18+) . Past 30-day (P30D) tobacco users at Wave 1 (W1) or Wave 2 (W2) were included (n=1374 youth; n=14 389 adults). Generalised estimating equations were used to evaluate the association between demographic and tobacco use characteristics at baseline, with cessation behaviours at follow-up (discontinuing use, attempting to quit, quitting), over two 1-year periods (W1-W2, W2-Wave 3).

RESULTS

Among adult users of each type of tobacco product, frequency of use was negatively associated with discontinuing use. Among adult cigarette smokers, non-Hispanic white smokers, those with lower educational attainment and those with lower household income were less likely to discontinue cigarette use; ENDS use was positively associated with making quit attempts but was not associated with cigarette quitting among attempters; smokeless tobacco use was positively associated with quitting among attempters; tobacco dependence was negatively associated with quitting among attempters. Among youth cigarette smokers, tobacco dependence was negatively associated with making quit attempts.

DISCUSSION

Demographic correlates of tobacco cessation behaviours underscore tobacco use disparities in the USA. Use of ENDS and use of smokeless tobacco products are positively associated with some adult cigarette cessation behaviours.

The Role of Compensation in Nicotine Reduction

The available research on switching from normal nicotine to very low nicotine content cigarettes shows minimal evidence of compensatory smoking. Mathematical estimations suggest that substantial compensation after switching to very low nicotine cigarettes would be impossible. It is likely that smokers who are unable to tolerate the extent of proposed nicotine reduction would switch to other sources of nicotine, rather than try to compensate by smoking more very low nicotine content cigarettes more intensely.

Longitudinal pathways of exclusive and polytobacco hookah use among youth, young adults and adults in the USA: findings from the PATH Study Waves 1-3 (2013-2016)

OBJECTIVE

The goal of this study is to examine cross-sectional rates of use and longitudinal pathways of hookah use among US youth (ages 12-17), young adults (ages 18-24), and adults 25+ (ages 25 and older).

DESIGN

Data were drawn from the first three waves (2013-2016) of the Population Assessment of Tobacco and Health Study, a nationally representative, longitudinal cohort study of US adults and youth. Respondents with data at all three waves (youth, n=11 046; young adults, n=6478; adults 25+, n=17 188) were included in longitudinal analyses.

RESULTS

Young adults had higher ever, past 12-month (P12M) and past 30-day cross-sectional prevalence of hookah use at each wave than youth or adults 25+. The majority of Wave 1 (W1) hookah users were P12M users of other tobacco products (youth: 73.9%, young adults: 80.5%, adults 25+: 83.2%). Most youth and adult W1 P12M hookah users discontinued use in Wave 2 or Wave 3 (youth: 58.0%, young adults: 47.5%, adults 25+: 63.4%). Most W1 P12M hookah polytobacco users used cigarettes (youth: 49.4%, young adults: 59.4%, adults 25+: 63.2%) and had lower rates of quitting all tobacco than exclusive hookah users or hookah polytobacco users who did not use cigarettes.

CONCLUSIONS

Hookah use is more common among young adults than among youth or adults 25+. Discontinuing hookah use is the most common pathway among exclusive or polytobacco hookah users. Understanding longitudinal transitions in hookah use is important in understanding behavioural outcomes at the population level.

Correlates of tobacco product initiation among youth and adults in the USA: findings from the PATH Study Waves 1-3 (2013-2016)

OBJECTIVE

To report on demographic and tobacco product use correlates of tobacco product initiation (cigarettes, electronic nicotine delivery systems (ENDS), cigars, hookah and smokeless tobacco) among the US population.

DESIGN

Data were from the first three waves (2013-2016) of the Population Assessment of Tobacco and Health Study, a nationally representative, longitudinal cohort study of US youth (aged 12-17 years) and adults (aged 18+ years). Never users of at least one type of tobacco product at Wave 1 (W1, 2013/14) or Wave 2 (W2, 2014/15) were included (n=12 987 youth; n=25 116 adults). Generalised estimating equations were used to evaluate the association between demographic and tobacco product use characteristics at baseline, and tobacco product initiation at follow-up (ever, past 30 day (P30D), frequent (use on 20 or more of thepast 30 days)) over two 1-year periods (W1-W2 and W2-Wave 3).

RESULTS

Youth aged 15-17 years were more likely than youth aged 12-14 years and adults aged 18-24 years were more likely than older adults to initiate P30D tobacco use across products; non-heterosexuals were more likely than heterosexuals to initiate P30D cigarette and ENDS use. Older adults were more likely than young adults, and males were more likely than females, to be frequent users of ENDS on initiation. Ever use of another tobacco product predicted P30D initiation of each tobacco product.

DISCUSSION

Other tobacco product use and age predict P30D tobacco initiation across products whereas associations with other demographic characteristics vary by product. Continued contemporary evaluation of initiation rates within the changing tobacco product marketplace is important.

Longitudinal pathways of exclusive and polytobacco smokeless use among youth, young adults and adults in the USA: findings from the PATH Study Waves 1-3 (2013-2016)

OBJECTIVE

Use of smokeless tobacco (SLT) with other tobacco products is growing, yet gaps in understanding transitions among SLT and other product use remain. The aim of this study is to examine cross-sectional prevalence and longitudinal pathways of SLT use among US youth (12-17 years), young adults (18-24 years) and adults 25+ (25 years and older).

DESIGN

Data were drawn from the first three waves (2013-2016) of the Population Assessment of Tobacco and Health Study, a nationally representative, longitudinal cohort study of US youth and adults. Respondents with data at all three waves (youth, n=11 046; young adults, n=6478; adults 25+, n=17 188) were included in longitudinal analyses.

RESULTS

Young adults had the highest current SLT use compared with other age groups. Among Wave 1 (W1) past 30-day youth and young adult SLT users, most were SLT and cigarette polytobacco users compared with adults 25+, who more often used SLT exclusively. Among W1 exclusive SLT users, persistent exclusive use across all three waves was more common among adults 25+, while transitioning from exclusive SLT use to SLT polytobacco use at Wave 2 or Wave 3 was more common among youth and young adults. Among W1 SLT and cigarette polytobacco users, a common pathway was discontinuing SLT use but continuing other tobacco use.

CONCLUSIONS

Our results showed distinct longitudinal transitions among exclusive and SLT polytobacco users. Deeper understanding of these critical product transitions will allow for further assessment of population health impact of these products.

Longitudinal Analysis of Associations Between Reasons for Electronic Cigarette Use and Change in Smoking Status Among Adults in the Population Assessment of Tobacco and Health Study

INTRODUCTION

Electronic cigarette (ECIG) use and changes in cigarette smoking status may be influenced by self-reported reasons for using ECIGs.

METHODS

We analyzed adult current and former cigarette smokers who were also current or former ECIG users at wave 1 (n = 3044) using wave 1 and wave 2 Population Assessment of Tobacco and Health Study data (2013-2015). Prevalence of reporting 13 reasons for ECIG use at wave 1 was examined and weighted logistic regressions were conducted predicting smoking status changes from wave 1 to wave 2.

RESULTS

Reasons for ECIG use ranged from 18.1% (people in the media or public figures use them) to 82.5% (they might be less harmful to people around me than cigarettes). From wave 1 to wave 2, 27.2% of former smokers (n = 249) became current smokers and 11.6% of current smokers (n = 246) became former smokers. Among wave 1 former smokers, using ECIGs because of the availability of flavors (AOR = 0.57, 95% CI = 0.39-0.85) or because they don't smell (AOR = 0.64, 95% CI = 0.42-0.97) was associated with lower odds of relapse to smoking, but using ECIGs because using them helps people quit smoking (AOR = 1.55, 95% CI = 1.01-2.38) was associated with greater odds of relapse. Among wave 1 current smokers, using ECIGs because they can be used where smoking is not allowed (AOR = 0.56, 95% CI = 0.38-0.85) was associated with reduced odds of quitting cigarettes.

CONCLUSIONS

Some reasons for ECIG use are associated with changes in self-reported smoking status. Researchers should examine ECIG user characteristics when assessing associations between ECIG use and smoking status transitions.

IMPLICATIONS

Given that certain reasons for ECIG use, such as using ECIGs in locations are where smoking is not allowed, may inhibit smoking reduction, policies may be developed to prevent ECIG use in locations where smoking is banned. In addition, because certain reasons for ECIG use may aid in relapse prevention, such as availability of desired flavors, efforts should be made to identify ECIG device characteristics that are appealing to smokers but not youth or nontobacco users. These results provide support for future research on reasons for ECIG use to inform regulatory policies.

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.

Association of Flavored Tobacco Use With Tobacco Initiation and Subsequent Use Among US Youth and Adults, 2013-2015

IMPORTANCE

Flavors in tobacco products may appeal to young and inexperienced users.

OBJECTIVE

To examine among youth (aged 12-17 years), young adults (aged 18-24 years), and adults (aged ≥25 years) the prevalence of first use of flavored tobacco products among new tobacco users and the association between first flavored use of a given tobacco product and tobacco use 1 year later, including progression of tobacco use.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study represents a longitudinal analysis of data from the Population Assessment of Tobacco and Health (PATH) Study, a nationally representative study with data collected in 2013 to 2014 (wave 1) and 2014 to 2015 (wave 2). Participants were noninstitutionalized individuals, including 11 996 youth and 26 447 adults, in selected households who participated in both waves of the PATH Study. Data analysis was conducted from July 2016 to June 2019.

MAIN OUTCOMES AND MEASURES

Prevalence of tobacco product use at wave 2.

RESULTS

The mean (SE) age of the participants was 14.5 (0.0) years for youth, 21.1 (0.0) years for young adults, and 50.3 (0.0) for adults. Most youth (71.9%; 95% CI, 69.7%-74.0%) and young adults (57.6%; 95% CI, 54.9%-60.3%) who were new users of tobacco products over the 10- to 13-month follow-up period used flavored products. First use of a menthol or mint or other flavored cigarette documented at wave 1 was positively associated with past 12-month and past 30-day cigarette use in all age groups at wave 2 compared with first use of a nonflavored cigarette (youth, flavored cigarette, past 12-month use adjusted prevalence ratio [aPR], 1.14 [95% CI, 1.05-1.25] and past 30-day use aPR, 1.15 [95% CI, 1.00-1.31]; youth, menthol or mint cigarette, past 12-month use aPR, 1.18 [95% CI, 1.08-1.29] and past 30-day use aPR, 1.19 [95% CI, 1.04-1.37]; young adult, flavored cigarette, past 12-month use aPR, 1.09 [95% CI, 1.04-1.15] and past 30-day use aPR, 1.13 [95% CI, 1.06-1.21]; young adult menthol or mint cigarette, past 12-month use aPR, 1.10 [95% CI, 1.05-1.16] and past 30-day use aPR, 1.15 [95% CI, 1.07-1.23]; adult flavored cigarette, past 12-month use aPR, 1.10 [95% CI, 1.05-1.15] and past 30-day use aPR, 1.09 [95% CI, 1.04-1.14]; adult menthol or mint cigarette, past 12-month use aPR, 1.13 [95% CI, 1.08-1.18] and past 30-day use aPR, 1.12 [95% CI, 1.07-1.17]). Among young adults, first use of flavored e-cigarettes (aPR, 2.05; 95% CI, 1.61-2.61), any cigars (aPR, 1.60; 95% CI, 1.26-2.02), cigarillos (aPR, 1.49; 95% CI, 1.08-2.05), filtered cigars (aPR, 3.69; 95% CI, 2.08-6.57), hookah (aPR, 1.91; 95% CI, 1.23-2.98), and any smokeless tobacco (aPR, 1.54; 95% CI, 1.08-2.20) was prospectively associated with current regular use of those products at wave 2 compared with first nonflavored use. Among adults aged 25 years and older, first use of flavored e-cigarettes (aPR, 1.60; 95% CI, 1.41-1.82), any cigars (aPR, 1.56; 95% CI, 1.29-1.87), cigarillos (aPR, 1.29; 95% CI, 1.01-1.64), filtered cigars (aPR, 1.79; 95% CI, 1.25-2.54), hookah (aPR, 5.66; 95% CI, 2.04-15.71), and any smokeless tobacco (aPR, 1.55; 95% CI, 1.32-1.82) was prospectively associated with current regular use of those products at wave 2 compared with first nonflavored use.

CONCLUSIONS AND RELEVANCE

In this longitudinal cohort study, flavors in tobacco products were associated with youth and young adult tobacco experimentation. First use of a flavored tobacco product may place youth, young adults, and adults at risk of subsequent tobacco use.

Flavour types used by youth and adult tobacco users in wave 2 of the Population Assessment of Tobacco and Health (PATH) Study 2014-2015

BACKGROUND

Most youth and young adult (YA) tobacco users use flavoured products; however, little is known about specific flavours used.

METHODS

We report flavour types among US tobacco users from the Population Assessment of Tobacco and Health Study, wave 2, 2014-2015. At wave 2, we examined (1) flavour use and type at past 30-day use; (2) new flavoured tobacco product use and type; (3) product-specific flavour patterns across youth (ages 12-17) (n=920), YA (18-24) (n=3726) and adult (25+) (n=10 346) past 30-day and new tobacco users and (4) concordance between self-coded and expert-coded brand flavour type among all adults (18+).

RESULTS

Prevalence of flavoured tobacco product use was highest among youth, followed by YA and adult 25+ any tobacco users. Within each age group, flavoured use was greatest among hookah, e-cigarette and snus users. Overall, menthol/mint, fruit and candy/sweet were the most prevalent flavour types at first and past 30-day use across age groups. For past 30-day use, all flavour types except menthol/mint exhibited an inverse age gradient, with more prevalent use among youth and YAs, followed by adults 25+. Prevalence of menthol/mint use was high (over 50% youth, YAs; 76% adults 25+) and exhibited a positive age gradient overall, though the reverse for cigarettes. Brand-categorised and self-reported flavour use measures among adults 18+ were moderately to substantially concordant across most products.

CONCLUSIONS

Common flavours like menthol/mint, fruit and candy/sweet enhance appeal to young tobacco users. Information on flavour types used by product and age can inform tobacco flavour regulations to addess flavour appeal especially among youth.

Investigating the role of expectancy in caffeine withdrawal using the balanced placebo design

OBJECTIVE

This study investigated psychological influences on drug withdrawal symptomatology using a caffeine-based model.

METHODS

Using the 2 × 2 balanced placebo design caffeine dose (given caffeinated vs decaffeinated coffee) was crossed with dose expectancy (told caffeine vs. decaf) among 87 (16-hr abstinent) regular coffee consumers in a 2-day study.

RESULTS

There were effects of expectancy and pharmacology that differed depending on the measure. Those told decaf reported greater caffeine cravings than those told caffeine 45 min and 8 hr postmanipulation. There were no expectancy effects on withdrawal symptoms or cognitive performance. There were pharmacological effects on all measures. Those given decaf reported greater withdrawal symptoms and showed poorer cognitive performance 45 min and 8 hr postmanipulation, with effects for headache and flu-like symptoms first emerging 8 hr postmanipulation (i.e., 24 hr abstinence in given decaf conditions). Caffeine readministration alleviated all withdrawal symptoms and cognitive decrements within 45 min. No drug by expectancy interactions were observed.

CONCLUSIONS

These findings confirm a strong pharmacological basis for caffeine withdrawal and an important role of cognition in drug craving. Future research should investigate the role of expectancy in drug withdrawal and craving and the potential use of expectancy manipulations in symptom prevention and management.

Biomarkers of Exposure among U.S. Adult Cigar Smokers: Population Assessment of Tobacco and Health (PATH) Study Wave 1 (2013-2014)

BACKGROUND

Given the diverse cigar market and limited data on biomarker patterns by cigar type, we compared biomarkers of nicotine and tobacco toxicants among cigar smokers and other groups.

METHODS

Using Wave 1 urinary biomarker data from 5,604 adults in the Population Assessment of Tobacco and Health (PATH) Study, we compared geometric mean concentrations among cigar-only smokers (all cigars and separately for traditional, cigarillo, and filtered cigars), cigarette-only smokers, dual cigar/cigarette smokers, and never users of tobacco. We calculated geometric mean ratios comparing groups with never users adjusting for sex, age, race/ethnicity, education and creatinine.

RESULTS

Some day cigar-only smokers had lower biomarker concentrations than every day cigar-only smokers, but higher than never users. Every day cigar-only smokers (n = 61) had lower TNE-2 (cotinine+trans-3'-hydroxycotinine) compared to every day cigarette-only (n = 2217; P < 0.0001) and dual cigar/cigarette smokers (n = 601; P < 0.0001). Several biomarkers, including NNAL (NNK metabolite) and CYMA (metabolite of acrylonitrile), were comparable in these groups. In exploratory analyses, every day filtered cigar-only (n = 7) smokers had higher biomarker concentrations compared with every day traditional cigar-only smokers (n = 12) and cigarillo-only smokers (n = 24). Every day smokers of each cigar type were similar to exclusive cigarette smokers. For some biomarkers, particularly for every day filtered cigar-only smokers, concentrations were higher.

CONCLUSIONS

For some biomarkers, every day cigar-only smokers were comparable with every day cigarette-only smokers. Exploratory analyses suggest that biomarkers vary by cigar type with every day filtered cigar-only smokers having the highest concentrations.

IMPACT

High exposure to harmful constituents among cigar smokers is a continuing health issue.

Urinary concentrations of monohydroxylated polycyclic aromatic hydrocarbons in adults from the U.S. Population Assessment of Tobacco and Health (PATH) Study Wave 1 (2013-2014)

BACKGROUND

Polycyclic aromatic hydrocarbons (PAHs) are environmental pollutants formed from incomplete combustion of organic matter; some PAHs are carcinogens. Smoking, diet, and other activities contribute to exposure to PAHs. Exposure data to PAHs among combustible tobacco product users (e.g. cigarette smokers) exist; however, among non-combustible tobacco products users (e.g., e-cigarette users), such data are rather limited.

OBJECTIVES

We sought to evaluate exposure to PAHs among participants in Wave 1 (2013-2014) of the Population Assessment of Tobacco and Health (PATH) Study based on the type of tobacco product (combustible vs non-combustible), and frequency and intensity of product use.

METHODS

We quantified seven PAH urinary biomarkers in 11,519 PATH Study participants. From self-reported information, we categorized 8327 participants based on their use of tobacco products as never-tobacco user (never user, n = 1700), exclusive current established combustible products user (combustible products user, n = 5767), and exclusive current established non-combustible products user (non-combustible products user, n = 860). We further classified tobacco users as exclusive cigarette user (cigarette user, n = 3964), exclusive smokeless product user (SLT user, n = 509), and exclusive e-cigarette user (e-cigarette user, n = 280). Last, we categorized frequency of product use (everyday vs some days) and time since use (last hour, within 3 days, over 3 days). We calculated geometric mean (GM) concentrations, and evaluated associations between tobacco product user categories and PAH biomarkers concentrations.

RESULTS

Combustible products users had significantly higher GMs of all biomarkers than non-combustible products users and never users; non-combustible products users had significantly higher GMs than never users for four of seven biomarkers. For all biomarkers examined, cigarette users had the highest GMs compared to other tobacco-product users. Interestingly, GMs of 2-hydroxyfluorene, 3-hydroxyfluorene and ∑2,3-hydroxyphenanthrene were significantly higher in SLT users than in e-cigarette users; 3-hydroxyfluorene and 1-hydroxypyrene were also significantly higher in e-cigarette and SLT users than in never users. Everyday cigarette and SLT users had significantly higher GMs for most biomarkers than some days' users; cigarette and SLT users who used the product in the last hour had significantly higher GMs of most biomarkers than other occasional cigarette or SLT users respectively. By contrast, everyday e-cigarette users' GMs of most biomarkers did not differ significantly from those in some days' e-cigarette users; we did not observe clear trends by time of last use among e-cigarette users.

CONCLUSIONS

Users of tobacco products had higher PAH urinary biomarker concentrations compared to never users, and concentrations differed by type and frequency of tobacco product use.

Comparison of Nicotine and Toxicant Exposure in Users of Electronic Cigarettes and Combustible Cigarettes

IMPORTANCE

Use of electronic cigarettes (e-cigarettes) is increasing. Measures of exposure to known tobacco-related toxicants among e-cigarette users will inform potential health risks to individual product users.

OBJECTIVES

To estimate concentrations of tobacco-related toxicants among e-cigarette users and compare these biomarker concentrations with those observed in combustible cigarette users, dual users, and never tobacco users.

DESIGN, SETTING, AND PARTICIPANTS

A population-based, longitudinal cohort study was conducted in the United States in 2013-2014. Cross-sectional analysis was performed between November 4, 2016, and October 5, 2017, of biomarkers of exposure to tobacco-related toxicants collected by the Population Assessment of Tobacco and Health Study. Participants included adults who provided a urine sample and data on tobacco use (N = 5105).

EXPOSURES

The primary exposure was tobacco use, including current exclusive e-cigarette users (n = 247), current exclusive cigarette smokers (n = 2411), and users of both products (dual users) (n = 792) compared with never tobacco users (n = 1655).

MAIN OUTCOMES AND MEASURES

Geometric mean concentrations of 50 individual biomarkers from 5 major classes of tobacco product constituents were measured: nicotine, tobacco-specific nitrosamines (TSNAs), metals, polycyclic aromatic hydrocarbons (PAHs), and volatile organic compounds (VOCs).

RESULTS

Of the 5105 participants, most were aged 35 to 54 years (weighted percentage, 38%; 95% CI, 35%-40%), women (60%; 95% CI, 59%-62%), and non-Hispanic white (61%; 95% CI, 58%-64%). Compared with exclusive e-cigarette users, never users had 19% to 81% significantly lower concentrations of biomarkers of exposure to nicotine, TSNAs, some metals (eg, cadmium and lead), and some VOCs (including acrylonitrile). Exclusive e-cigarette users showed 10% to 98% significantly lower concentrations of biomarkers of exposure, including TSNAs, PAHs, most VOCs, and nicotine, compared with exclusive cigarette smokers; concentrations were comparable for metals and 3 VOCs. Exclusive cigarette users showed 10% to 36% lower concentrations of several biomarkers than dual users. Frequency of cigarette use among dual users was positively correlated with nicotine and toxicant exposure.

CONCLUSIONS AND RELEVANCE

Exclusive use of e-cigarettes appears to result in measurable exposure to known tobacco-related toxicants, generally at lower levels than cigarette smoking. Toxicant exposure is greatest among dual users, and frequency of combustible cigarette use is positively correlated with tobacco toxicant concentration. These findings provide evidence that using combusted tobacco cigarettes alone or in combination with e-cigarettes is associated with higher concentrations of potentially harmful tobacco constituents in comparison with using e-cigarettes alone.

Effects of Nicotine Metabolic Rate on Withdrawal Symptoms and Response to Cigarette Smoking After Abstinence

This study investigated the influence of the rate of nicotine metabolism, as indicated by the nicotine metabolite ratio (NMR), on tobacco dependence. We stratified 136 smokers on the basis of saliva NMR as fast (n = 65) and slow (n = 71) metabolizers. Two "loading cigarettes" were smoked after overnight, and a "reward cigarette" was smoked after 6 hours of daytime, abstinence. Blood nicotine concentrations, expired carbon monoxide, withdrawal/craving, and reward questionnaires were collected before/after smoking and during daytime abstinence. Compared with slow metabolizers, fast metabolizers had a shorter nicotine elimination half-life (P < 0.001), lower plasma nicotine concentrations (P < 0.001), and higher withdrawal/craving scores (P < 0.05) for most times during daytime abstinence, indicating that fast metabolizers are likely smoking more to relieve withdrawal symptoms (negative reinforcement). Reward/satisfaction scores were similar in fast and slow metabolizers, suggesting that faster nicotine metabolism, assessed by NMR, is not associated with greater positive reinforcement. CYP2A6 normal (n = 82) and reduced (n = 42) genotype predicted plasma nicotine concentrations but not withdrawal symptoms.