Assessing the relationship between biomarkers of exposure and biomarkers of potential harm: PATH Study Wave 1 (2013-2014).

BACKGROUND: The adequacy of biomarkers of potential harm (BOPH) for assessing tobacco products was explored based on their ability to distinguish tobacco use from non-use, change with cessation, and to show biological gradient. METHODS: The sample included individuals with biomarker data in Wave 1 of the Population Assessment of Tobacco Health (PATH) Study who never used tobacco, currently smoke cigarettes exclusively, used to smoke cigarettes exclusively (quit in past 12 months), currently use smokeless tobacco exclusively, and currently use e-cigarettes exclusively. We compared BOPH levels between groups and assessed the relationships between log-transformed biomarkers of exposure (BOE) [Total Nicotine Equivalents including seven nicotine metabolites (TNE-7), 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanonol (NNAL), N-acetyl-S-(2-cyanoethyl)-L-cysteine (CYMA), 1-Hydroxypyrene (1-OHP), cadmium, and serum cotinine (SCOT)], and BOPH [high-sensitivity C-reactive protein (hs-CRP), interleukin-6 (IL-6), fibrinogen, soluble intercellular adhesion molecule-1 (sICAM-1) and 8-isoprostane]. RESULTS: Among people who smoke, both sICAM-1 and 8-isoprostane distinguished smoking from non-use and were associated with all six BOE. Among people who use smokeless tobacco, 8-isoprostane was associated with TNE-7 and NNAL whereas hs-CRP was associated with SCOT. Among people who use e-cigarettes, no associations between BOPH and BOE were observed. CONCLUSIONS: Both sICAM-1 and 8-isoprostane may be useful for assessing the use or changes in use of some tobacco products. Studies examining their predictive validity could further strengthen our understanding of these two biomarkers. IMPACT: We found that two BOPH, sICAM-1 and 8-isoprostane, may have utility in studies assessing the potential harm of tobacco use in absence of long-term epidemiological studies.

Use patterns of flavored non-cigarette tobacco products among US adults, 2010-2019.

OBJECTIVE: Flavored non-cigarette tobacco product (NCTP) use is common among US adult tobacco users. To update the estimates of use patterns of flavored NCTPs, this study assessed current NCTP use among adults by flavor use and flavor categories from 2010 to 2019. METHODS: We analyzed data from the 2010-2019 Tobacco Use Supplement to the Current Population Survey to estimate the weighted proportion of adult NCTP users by flavor use across survey waves. Flavor use was defined as past 30-day use of any menthol/mint or fruit/other flavors. We used the 2018-2019 data to examine the differences in demographic characteristics and tobacco use patterns among users of menthol/mint or fruit/other flavors compared to exclusive users of tobacco flavor, by product type. RESULTS: Compared to 2014-2015, electronic nicotine delivery system (ENDS) users were more likely (79.0% vs. 66.6%, p < 0.001) to report flavor use in 2018-2019, whereas cigar (26.9% vs. 31.2%, p = 0.030) and pipe (56.3% vs. 65.5%, p = 0.015) smokers were less likely to report flavor use in 2018-2019. In 2018-2019, the most prevalent flavor categories were exclusive use of tobacco flavor among cigar (73.1%) and smokeless tobacco (48.3%) users, and use of fruit/other flavors among ENDS (64.9%) and pipe (48.4%) users. Flavored users were more likely to be young adults aged 18-24 years (cigars, ENDS, smokeless tobacco) and Non-Hispanic Black or Hispanic persons (cigars, ENDS, pipes) compared to tobacco-flavored users. CONCLUSIONS: Flavored product use increased among adult ENDS users but decreased among cigar and pipe smokers. These findings could inform tobacco regulatory efforts concerning flavored NCTPs.

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.

Characteristics and Patterns of Cigarette Smoking and Vaping By Past-Year Smokers Who Reported Using Electronic Nicotine Delivery System to Help Quit Smoking in the Past Year: Findings From the 2018-2019 Tobacco Use Supplement to the Current Population Survey.

INTRODUCTION: Cigarette smoking has declined, while electronic nicotine delivery system (ENDS) use has increased in the United States. Understanding the role of ENDS in adult smoking quit attempts and cessation is important for estimating their population health impact. AIMS AND METHODS: We used data from 2018 to 2019 tobacco use supplement to the current population survey to examine demographic characteristics and ENDS use patterns among adult ENDS users who reported quitting smoking in the past year by trying to switch to ENDS ("switchers") and smokers who did or did not make a quit attempt in the past year. χ2 tests of proportions and t-tests were used to compare characteristics between groups. RESULTS: In 2018-2019, about three-quarters of switchers reported daily use of ENDS compared to only one-third of dual users with a recent quit attempt by trying to switch to ENDS. Compared to dual users who made a quit attempt by trying to switch to ENDS, switchers were more likely to use menthol/mint-flavored ENDS exclusively (5.6% vs. 13.1%; p = .004) but less likely to use tobacco-flavored ENDS exclusively (21.2% vs. 13.7%; p = .01). CONCLUSIONS: ENDS users who quit smoking in the past year and reported trying to quit by switching to ENDS were more likely to use menthol/mint flavors exclusively and use ENDS daily compared to dual users who made a quit attempt by trying to switch to ENDS. Longer-term prospective data may better clarify the role of ENDS in smoking quit attempts and cessation. IMPLICATIONS: This study provides information on patterns of ENDS use in former smokers and current smokers who tried to quit smoking by switching to ENDS in a national sample of U.S. adults. These results can inform policy actions concerning ENDS products.

The contribution of smoking-attributable mortality to differences in mortality and life expectancy among US African-American and white adults, 2000-2019.

BACKGROUND: The role of smoking in racial disparities in mortality and life expectancy in the United States has been examined previously, but up-to-date estimates are generally unavailable, even though smoking prevalence has declined in recent decades. OBJECTIVE: We estimate the contribution of smoking-attributable mortality to observed differences in mortality and life expectancy for US African-American and white adults from 2000-2019. METHODS: The indirect Preston-Glei-Wilmoth method was used with national vital statistics and population data and nationally representative never-smoker lung cancer death rates to estimate the smoking-attributable fraction (SAF) of deaths in the United States by sex-race group from 2000-2019. Mortality rates without smoking-attributable mortality were used to estimate life expectancy at age 50 (e 50) by group during the period. RESULTS: African-American men had the highest estimated SAF during the period, beginning at 26.4% (95% CI:25.0%-27.8%) in 2000 and ending at 12.1% (95% CI:11.4%-12.8%) in 2019. The proportion of the difference in e 50 for white and African-American men that was due to smoking decreased from 27.7% to 14.8%. For African-American and white women, the estimated differences in e 50 without smoking-attributable mortality were similar to observed differences. CONCLUSIONS: Smoking continues to contribute to racial disparities in mortality and life expectancy among men in the United States. CONTRIBUTION: We present updated estimates of the contribution of smoking to mortality differences in the United States using nationally representative data sources.

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.

Characteristics of Past 30-Day Cigar Smoking, U.S. Adolescents, 2020.

INTRODUCTION: Data from the 2019 National Youth Tobacco Survey indicated that cigars were the most commonly used combustible tobacco product in the past 30 days among youth. This study uses 2020 National Youth Tobacco Survey data to report the prevalence estimates and characteristics of current cigar use, overall and by cigar type, among middle- and high-school students in the U.S. METHODS: Weighted prevalence estimates and 95% CIs were calculated in 2020 for overall cigar use and by cigar type. RESULTS: In 2020, current cigar smoking was reported by 3.5% of students (1.5% middle school and 5.0% high school). Cigarillos (44.1%) were the most reported cigar type smoked, followed by regular (33.1%) and little (22.6%) cigars; 21.8% did not know the cigar type. Most cigar smokers were in high school (81.2%) and were male (52.4%), and 42.3% were non-Hispanic White. More than half of cigar smokers reported smoking flavored cigars (58.3%), with fruit (61.5%), candy/desserts/other sweets (34.0%), and mint (30.4%) as the most frequently reported flavor categories. Approximately 1 in 5 current cigar smokers (18.4%) smoked on ≥20 days in the past 30 days, and 78.8% reported multiple tobacco product use. CONCLUSIONS: Cigar smoking was highest among non-Hispanic Black and Hispanic youth. More than half of youth cigar smokers reported using flavored cigars, and most were also currently using other tobacco products. Cigarillos were the most reported cigar type used by youth, followed by regular cigars. These findings highlight the continued importance of youth tobacco use reduction strategies and can inform policy development.

Modeling mortality risk effects of cigarettes and smokeless tobacco: results from the National Health Interview Survey Linked Mortality File Data.

BACKGROUND: Cigarettes and smokeless tobacco (SLT) products are among a wide range of tobacco products that are addictive and pose a significant health risk. In this study, we estimated smoking- and SLT use-related mortality hazard ratios (HRs) among U.S. adults by sex, age group, and cause of death, for nine mutually exclusive categories of smoking and/or SLT use. METHODS: We used data from the public-use National Health Interview Survey Linked Mortality with mortality follow-up through 2015. We used Cox proportional hazard models to estimate mortality HRs, adjusted by race/ethnicity, education, poverty level, body mass index, and tobacco-use status. RESULTS: With never users as reference group, HRs for smoking-related diseases for male exclusive current smokers aged 35-64 and 65+ were 2.18 (95% confidence interval [CI]: 1.79-2.65), and 2.45 (95% CI: 2.14-2.79), respectively. Similar significant HR estimates were found for females and for all-cause mortality (ACM) and other-cause mortality (OCM) outcomes. HRs for exclusive current SLT users were only significant for males aged 35-64 for ACM (HR: 2.04, 95% CI: 1.27-3.27) and OCM (HR: 2.80, 95% CI: 1.50-5.25). HRs for users who switched from cigarettes to SLT products were significant for males aged 65+ for smoking-related diseases (HR: 2.06, 95% CI: 1.47-2.88), SLT-related diseases (HR: 1.99, 95% CI: 1.36-2.89), and ACM (HR: 1.63, 95% CI: 1.21-2.19). CONCLUSIONS: Male exclusive current SLT users aged 35-64 had a significant HR for ACM and OCM outcomes, suggesting that deaths not attributed to SLT use could be contributing to the ACM elevated HR for exclusive current SLT users.

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.

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

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

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.

Cigarette Smoking Reduction and Health Risks: A Systematic Review and Meta-analysis.

INTRODUCTION: Studies have shown the health benefits of cigarette smoking cessation. However, the literature remains unclear about the relationship between smoking reduction and health risks. This comprehensive review and meta-analysis updates previous reviews with the newest estimates. AIMS AND METHODS: We conducted a systematic review and meta-analysis evaluating the association between smoking reduction and some health risks in observational studies. We defined the following smoking categories: heavy smokers smoked ≥15-20 cigarettes per day (CPD), moderate smokers smoked 10-19 CPD, and light smokers smoked <10 CPD. The relative risks (RRs) and 95% confidence intervals (CIs) were estimated using random-effect models. RESULTS: We identified 19 studies including four case-control and 15 cohort studies. Compared with continuing heavy smokers, we found decreased lung cancer risk for those who reduced CPD by more than 50% (RR = 0.72, 95% CI: 0.52, 0.91), from heavy to moderate (RR = 0.66, 95% CI: 0.46, 0.85), and from heavy to light (RR = 0.60, 95% CI: 0.49, 0.72). We also found lower risk of cardiovascular disease (CVD) for those who reduced from heavy to light smoking (RR = 0.78, 95% CI: 0.67, 0.89) but not those who reduced by more than 50% and reduced smoking from heavy to moderate. We did not find any significant difference in all-cause mortality, all-cancer risks, and smoking-/tobacco-related cancer risk among those who reduced. CONCLUSIONS: Substantial smoking reduction may decrease lung cancer risk but results on CVD (coronary heart disease and stroke combined) risk were mixed. The relationships between smoking reduction and other endpoints examined were not significant. IMPLICATIONS: This meta-analysis helps clarify our understanding of various smoking reduction levels on some health risks. While smoking reduction may decrease risks of lung cancer, the relationships between smoking reduction and other endpoints, including all-cause mortality and cardiovascular disease, remain unclear. Although smoking reduction may decrease lung cancer risks, the magnitude of lung cancer risk remain high. Among smokers, complete cessation remains the most effective approach for cancer and CVD prevention.

National Estimates of ENDS Liquid Nicotine Exposures, U.S., 2013-2017.

INTRODUCTION: Increased use of ENDS in the U.S. is related to acute adverse events from liquid nicotine exposure. This paper provides national estimates of U.S. hospital emergency department visits for exposures from liquid nicotine exposure in individuals aged ≥5 years. METHODS: In 2018-2019, data from the 2013-2017 National Electronic Injury Surveillance System All Injury Program were used to identify cases of liquid nicotine-related exposures in individuals aged ≥5 years. National estimates of exposures related to liquid nicotine exposure in ENDS for those aged ≥5 years by demographic characteristics, symptoms, diagnoses, and treatment dispositions were calculated. RESULTS: From 2013 to 2017, an estimated 2,718 cases related to liquid nicotine among those aged ≥5 years were treated in U.S. hospital emergency departments. Most exposures occurred among those who were aged ≥25 years (51.7%), white (74.1%), and male (51.9%). Most case patients were treated and released from the hospitals, and 7.5% were admitted. Poisoning was the most common diagnosis of these exposures (82.7%). The most common symptoms were cardiovascular (29.7%). CONCLUSIONS: This study provides national estimates of emergency department visits for injury and poisoning cases related to nicotine exposure from ENDS among individuals aged ≥5 years. Although long-term health outcome studies of liquid nicotine exposure are not available, these estimates provide some insight into the acute health effects. Findings from this study may inform education programs aimed at preventing exposures related to ENDS products.

Nicotine Exposure by Device Type among Adult Electronic Nicotine Delivery System Users in the Population Assessment of Tobacco and Health Study, 2015-2016.

BACKGROUND: Previous studies have examined the characteristics of open and closed system electronic nicotine delivery system (ENDS) users, but population-level information on nicotine exposure among these users has not been available. METHODS: We analyzed nicotine biomarker and survey data from Wave 3 of the Population Assessment of Tobacco and Health (PATH) study collected from October 2015 to October 2016. We identified 277 exclusive ENDS users and 468 dual cigarette and ENDS users and analyzed concentrations of nicotine and its metabolites obtained from urine samples by device type and other characteristics, such as frequency of use and e-liquid flavor. RESULTS: Among exclusive ENDS users, open system users had higher levels of total nicotine exposure (TNE-2) than closed system users [8.8 µmol/g creatinine (95% confidence interval [CI] = 5.3-14.8 µmol/g vs. 2.0 µmol/g (95% CI = 0.7-5.4 µmol/g)]. However, TNE-2 concentrations were similar when open and closed system users were stratified as daily [26.4 µmol/g (95% CI = 20.1-34.7 µmol/g) vs. 27.1 µmol/g (95% CI = 16.4-44.9 µmol/g)] and nondaily [0.5 µmol/g (95% CI = 0.1-1.9 µmol/g) vs. 0.2 µmol/g (95% CI = 0.0-0.7 µmol/g)] ENDS users. Dual users generally had higher nicotine exposure than exclusive users. CONCLUSIONS: Nicotine exposure was observed to be higher among exclusive open system ENDS users compared with closed system users, but levels were similar when users were stratified by frequency of use. IMPACT: These results suggest that exclusive ENDS users with similar use patterns receive comparable levels of nicotine, regardless of whether they use open or closed system devices.

Dose-Response Association of Low-Intensity and Nondaily Smoking With Mortality in the United States.

Importance: An increasing proportion of US smokers smoke at low intensity and not every day. Some nondaily smokers have always had this pattern, whereas others previously smoked daily. The effect of reducing the level of smoking from daily to nondaily smoking and the dose response at low smoking levels are poorly understood. Objective: To evaluate risk of all-cause and cause-specific mortality among nondaily and daily cigarette smokers, by cigarettes per month, years after reducing from daily to nondaily smoking, and years since quitting. Design, Setting, and Participants: A prospective cohort study using harmonized data from multiple cycles of the Tobacco Use Supplements to the Current Population Survey (TUS-CPS), linked to the National Death Index, were analyzed during the period from 2018 to 2020. Adults completed the 1992-1993, 1995-1996, 1998-1999, 2000, 2001-2002, 2003, 2006-2007, or 2010-2011 TUS-CPS. Cigarette smokers were classified as daily or nondaily users; current nondaily smokers were further categorized by whether they previously smoked every day. Main Outcomes and Measures: Hazard ratios (HRs) and 95% CIs for risks of mortality vs never smoking. Age was the underlying time metric, adjusted for sex, race/ethnicity, education, survey year, and household income. Results: Among 505 500 participants (aged 18-103 years), approximately 47 000 deaths occurred. The median number of cigarettes smoked per month was 600 (interquartile range, 300-600) (20 cigarettes per day [interquartile range, 10-20 cigarettes per day]) for daily cigarette smokers and 40 (interquartile range, 15-90) for lifelong nondaily smokers. Nevertheless, both current daily (HR, 2.32; 95% CI, 2.25-2.38) and lifelong nondaily (HR, 1.82; 95% CI, 1.65-2.01) smokers had higher all-cause mortality risks than never smokers. Associations were observed for 6 to 10 cigarettes per month and increased with greater-intensity use. Nondaily smokers who previously smoked every day had lower mortality risks than daily smokers, with similar HRs after 10 or more years of nondaily smoking as lifelong nondaily smokers (HR vs never smokers, 1.73; 95% CI, 1.56-1.92). Yet, their risks were higher than former smokers who quit 10 or more years before (HR vs never smokers, 1.18; 95% CI, 1.15-1.22). Conclusions and Relevance: Although reducing smoking from daily to nondaily was associated with decreased mortality risk, cessation was associated with far greater benefit. Lifelong nondaily smokers have higher mortality risks than never smokers, even among those smoking 6 to 10 cigarettes per month. Thus, all smokers should quit, regardless of how infrequently they smoke.

Changes in Cigarettes per Day and Biomarkers of Exposure Among US Adult Smokers in the Population Assessment of Tobacco and Health Study Waves 1 and 2 (2013-2015).

INTRODUCTION: Some studies have found some reduction in tobacco exposure and tobacco-related disease risk with decreased numbers of cigarettes smoked per day (CPD), but biomarker of exposure estimates by change in CPD are generally unavailable for the US population. METHODS: We analyzed biomarker of exposure data by smoking status from over 1100 adult exclusive daily cigarette smokers in Wave 1 of the Population Assessment of Tobacco and Health (PATH) Study who were either exclusive daily smokers or had quit tobacco use entirely at Wave 2. Wave 1 smoking categories consisted of "very light" (1-4 CPD), "light" (5-9 CPD), "moderate" (10-19 CPD), and "heavy" (20+ CPD), and Wave 2 categories were "quitters" (stopped smoking entirely), exclusive cigarette "reducers" (CPD decreased ≥ 50%), "maintainers" (CPD within 50%-150% of Wave 1 value), and "increasers" (CPD increased ≥ 50%). RESULTS: Complete quitters had significantly lower levels of TNE-2, NNAL, NNN, 2-Fluorene, HPMA, CYMA, and MHB3 at Wave 2 for all Wave 1 CPD categories, and decreases were often large. Moderate "reducers" had lower levels of NNAL and 1-Hydroxypyrene at Wave 2, and heavy "reducers" had lower levels of NNAL, 2-Fluorene, and MHB3. Light "increasers" had higher levels of TNE-2, NNAL, 2-Fluorene, CYMA, and cadmium at Wave 2, and heavy "increasers" had higher levels of NNAL and HPMA. CONCLUSIONS: Smoking "reducers" and "increasers" had changes in some biomarker of tobacco exposure levels, but reductions were much greater and more consistent for complete quitters. IMPLICATIONS: PATH longitudinal cohort study data show that some exclusive daily cigarette smokers increase or decrease CPD over time. These differences may result in moderate changes in the levels of some biomarkers such as NNAL. Even so, however, reductions in biomarker levels are much greater with complete smoking cessation.

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.

ENDS Flavor Preference by Menthol Cigarette Smoking Status among US Adults, 2018-2019.

E-cigarette flavor preference may differ among smokers using e-cigarettes, but little information is available on preferences by menthol cigarette status. Using nationally representative data for US adults from the 2018-2019 Tobacco Use Supplement to the Current Population Survey, we analyzed e-cigarette flavor preference by menthol cigarette status and e-cigarette device type for dual-cigarette and e-cigarette users and e-cigarette users who had recently quit smoking by trying to switch to e-cigarettes ("switchers"). Approximately half (52.2%) of dual users of menthol cigarettes and e-cigarettes reported using menthol/mint-flavored e-cigarettes as did 41.4% of "switchers" who had smoked menthol cigarettes; exclusive menthol/mint flavor use was 13.1% for dual users and 21.3% for "switchers." A similar proportion (45.1%) of dual users who smoked nonmenthol cigarettes used tobacco-flavored e-cigarettes, but only 26.7% of "switchers" who had smoked nonmenthol cigarettes used tobacco-flavored e-cigarettes. Approximately 60% of dual users and "switchers" used fruit/other flavors, regardless of menthol cigarette use. By device type, 63.9% of dual users of cartridge-based e-cigarettes and menthol cigarettes used menthol/mint-flavored e-cigarettes. Approximately 75% of dual users and 85% of "switchers" who used tank or mod systems used fruit/other flavors. Menthol cigarette smokers may be particularly likely to use menthol/mint e-cigarettes, and a majority of dual users and "switchers" used fruit/other flavors. These results can inform policy measures concerning flavored electronic nicotine delivery system products.