Assessing the impact of increasing lung screening eligibility by relaxing the maximum years-since-quit threshold: A simulation modeling study.

BACKGROUND: In 2021, the US Preventive Services Task Force expanded its lung screening recommendation to include persons aged 50-80 years who had ever smoked and had at least 20 pack-years of exposure and less than 15 years since quitting (YSQ). However, studies have suggested that screening persons who formerly smoked with longer YSQ could be beneficial. METHODS: The authors used two validated lung cancer models to assess the benefits and harms of screening using various YSQ thresholds (10, 15, 20, 25, 30, and no YSQ) and the age at which screening was stopped. The impact of enforcing the YSQ criterion only at entry, but not at exit, also was evaluated. Outcomes included the number of screens, the percentage ever screened, screening benefits (lung cancer deaths averted, life-years gained), and harms (false-positive tests, overdiagnosed cases, radiation-induced lung cancer deaths). Sensitivity analyses were conducted to evaluate the effect of restricting screening to those who had at least 5 years of life expectancy. RESULTS: As the YSQ criterion was relaxed, the number of screens and the benefits and harms of screening increased. Raising the age at which to stop screening age resulted in additional benefits but with more overdiagnosis, as expected, because screening among those older than 80 years increased. Limiting screening to those who had at least 5 years of life expectancy would maintain most of the benefits while considerably reducing the harms. CONCLUSIONS: Expanding screening to persons who formerly smoked and have greater than 15 YSQ would result in considerable increases in deaths averted and life-years gained. Although additional harms would occur, these could be moderated by ensuring that screening is restricted to only those with reasonable life expectancy.

Cross-sectional patterns and longitudinal transitions of unflavored and flavored cigar use without and with cigarettes among United States adults.

INTRODUCTION: Over half of US adults who smoke cigars use flavored cigars, illustrating their broad appeal; however, their long-term impact on cigar and cigarette use is unknown. METHODS: Using restricted data from Waves 1-5 (2013-2019) of the Population Assessment of Tobacco and Health Study, we investigated cross-sectional patterns and longitudinal transition rates of unflavored and flavored cigar use with and without cigarettes among a nationally representative sample of US adults. RESULTS: Proportionally, more adults who used flavored cigars without or with cigarettes were younger and female. More adults with exclusive cigar use were non-Hispanic Black. More adults with dual use had lower educational attainment. The median number of cigars smoked daily and tobacco dependence was highest among adults who used flavored cigars with cigarettes. Only 14.6% of adults with exclusive flavored cigar use at Wave 1 continued their use to Wave 5, with most transitioning to non-current (46.4%) or exclusive cigarette use (22.9%). Likewise, 13.8% of adults with dual flavored cigar and cigarette use at Wave 1 continued their use to Wave 5, with 57.6% transitioning to exclusive cigarette use and 19.7% transitioning to non-current use. Comparatively, 72.9% of adults with exclusive cigarette use continued their use to Wave 5, while 23.6% transitioned to non-current use. CONCLUSION: Adult cigar use was less stable than cigarette use, particularly among those who use flavored cigars. Future research should investigate whether these transition patterns between flavored and unflavored cigar and cigarette use vary across sociodemographic groups and their potential long-term health implications.

Birth-cohort patterns of e-cigarette and other tobacco use among adolescents in the US.

BACKGROUND: E-cigarette use has increased considerably among US adolescents. While many studies have described cross-sectional prevalence trends of youth e-cigarette use, less is known about cohort or generational initiation and use patterns. METHODS: We used data from the US National Youth Tobacco Survey (NYTS) from 2014 to 2022 and age-period-cohort models to analyze age-specific patterns of e-cigarette use initiation and prevalence by cohort and calendar. For comparison, we also examined initiation and prevalence for cigarettes, cigars, and smokeless tobacco, using NYTS data from 1999 to 2022. RESULTS: Age-specific e-cigarette initiation and prevalence varied considerably by calendar year and birth cohort. There was a rapid increase in e-cigarette initiation and prevalence starting with the 1995 birth cohort, peaking with the 2005 birth cohort, and showing signs of decline with more recent cohorts. In contrast, there were substantial continuous reductions in cigarette, cigar, and smokeless use initiation and prevalence by birth cohort. While the reductions in cigarette smoking started with the 1980s birth cohorts, cigar and smokeless initiation and prevalence did not decrease until the 1990-1995 cohorts. CONCLUSIONS: Despite their recent emergence, e-cigarette use has varied considerably across US adolescent cohorts. After early increases, e-cigarette use and initiation peaked with the 2005 birth cohort. These patterns are in contrast with the continuous decreases by cohort in cigarette, cigar, and smokeless use and initiation. As the tobacco product landscape continues to evolve, it will be essential to monitor patterns of use of adolescent and young adult cohorts as they age into adulthood.

The Public Health Impact of a Ban on Flavored Cigars: A Decision-Theoretic Policy Framework.

INTRODUCTION: Half of adult cigar users report flavored cigars as their usual brand. The FDA proposed prohibiting "all characterizing flavors in cigars" and "menthol… in cigarettes." We provide evidence on cigar and cigarette transitions and a framework to assess the impact of a U.S. flavored cigar ban. METHODS: Using PATH Waves 1-4, we estimated use patterns and annual transitions among flavored cigars, non-flavored cigars, cigarettes, and among adults aged 18-34 and aged 35+. We also consider ENDS-related transitions. We developed a decision-theoretic framework for examining the impact of a flavored cigar ban alone, and the impact of a flavored cigar with a menthol cigarette ban with and without a non-tobacco flavored ENDS ban. RESULTS: Cigar users exhibited less stable use than cigarette users, with a large portion of cigar users switching to cigarette use each year. Past studies provide limited information on transitions between cigar and ENDS use. Our policy framework suggests that imposing a flavored cigar ban alone may be partially undermined by the substitution of menthol cigarettes for flavored cigars. While adding a menthol cigarette to a flavored cigar ban is expected to improve public health, a simultaneously implemented ENDS may offset some of the gains. DISCUSSION: Our analysis suggests the information necessary to gauge the public health impact of a cigar flavor ban alone and with flavor bans on cigarettes and ENDS. Further research is needed on ENDS vis-a'-vis cigar use, and the impact of enforcement and non-flavor-related policies on flavor ban effectiveness. IMPLICATIONS: Unlike menthol cigarette use and menthol bans, flavored cigar use and flavored cigar bans have received minimal attention. Transitions from cigars, especially dual and flavored use, are generally common compared to cigarettes. Our policy framework suggests important public health impacts. A flavored cigar ban absent a menthol cigarette ban may be partially undermined by the substitution of menthol cigarettes for flavored cigars. Adding a menthol cigarette ban is expected to offset such substitution and improve public health. However, simultaneously adding an ENDS with a flavored cigar and menthol cigarette ban may reduce the public health impact of a menthol cigarette and cigar flavor ban since flavored cigar users would be less able to substitute a lower-risk alternative.

Risk Model-Based Lung Cancer Screening : A Cost-Effectiveness Analysis.

BACKGROUND: In their 2021 lung cancer screening recommendation update, the U.S. Preventive Services Task Force (USPSTF) evaluated strategies that select people based on their personal lung cancer risk (risk model-based strategies), highlighting the need for further research on the benefits and harms of risk model-based screening. OBJECTIVE: To evaluate and compare the cost-effectiveness of risk model-based lung cancer screening strategies versus the USPSTF recommendation and to explore optimal risk thresholds. DESIGN: Comparative modeling analysis. DATA SOURCES: National Lung Screening Trial; Surveillance, Epidemiology, and End Results program; U.S. Smoking History Generator. TARGET POPULATION: 1960 U.S. birth cohort. TIME HORIZON: 45 years. PERSPECTIVE: U.S. health care sector. INTERVENTION: Annual low-dose computed tomography in risk model-based strategies that start screening at age 50 or 55 years, stop screening at age 80 years, with 6-year risk thresholds between 0.5% and 2.2% using the PLCOm2012 model. OUTCOME MEASURES: Incremental cost-effectiveness ratio (ICER) and cost-effectiveness efficiency frontier connecting strategies with the highest health benefit at a given cost. RESULTS OF BASE-CASE ANALYSIS: Risk model-based screening strategies were more cost-effective than the USPSTF recommendation and exclusively comprised the cost-effectiveness efficiency frontier. Among the strategies on the efficiency frontier, those with a 6-year risk threshold of 1.2% or greater were cost-effective with an ICER less than $100 000 per quality-adjusted life-year (QALY). Specifically, the strategy with a 1.2% risk threshold had an ICER of $94 659 (model range, $72 639 to $156 774), yielding more QALYs for less cost than the USPSTF recommendation, while having a similar level of screening coverage (person ever-screened 21.7% vs. USPSTF's 22.6%). RESULTS OF SENSITIVITY ANALYSES: Risk model-based strategies were robustly more cost-effective than the 2021 USPSTF recommendation under varying modeling assumptions. LIMITATION: Risk models were restricted to age, sex, and smoking-related risk predictors. CONCLUSION: Risk model-based screening is more cost-effective than the USPSTF recommendation, thus warranting further consideration. PRIMARY FUNDING SOURCE: National Cancer Institute (NCI).

Cross-sectional Patterns and Longitudinal Transitions of Premium and Non-Premium Cigar Use in the United States.

INTRODUCTION: Cigar use is common in the United States; however, knowledge about trends and longitudinal patterns of premium and non-premium cigar use is limited. We analyzed cross-sectional and transition patterns of cigar use in the United States by cigar type, age, race/ethnicity, and socioeconomic status. AIMS AND METHODS: Using data from the Population Assessment of Tobacco and Health (PATH) Study, we compared characteristics of cigar users by Wave (1-5) and type; premium versus non-premium traditional cigars, cigarillos, and filtered cigars. We then calculated longitudinal transition rates of cigar and cigarette use between PATH Study Waves and longitudinal trajectories across all five Waves. RESULTS: Premium cigars were predominantly used by males, non-Hispanic White individuals, and those with high educational attainment. Premium cigar use was mostly non-daily and less likely to be dual with cigarettes or other cigar types. About three-quarters of exclusive premium cigar users remained so after one year. However, dual-use of premium cigars with either other cigar types or cigarettes was transient. Those who smoked premium cigars fairly regularly for at least one year were more likely to be exclusive premium cigar users or have dropped combustible tobacco product use by Wave 5. CONCLUSIONS: Cigar use patterns vary significantly by cigar type. Premium cigar users have distinctive characteristics compared to other cigar-type users. When studying cigar use and related health outcomes, it is critical to distinguish cigar type. IMPLICATIONS: Continuous monitoring of longitudinal use patterns of premium and non-premium cigar use and their co-use and transitions to other tobacco products, including inhalation and a more precise measure of the intensity of use, is essential for a better assessment of their health implications.

Associations Between E-cigarette Use and E-cigarette Flavors With Cigarette Smoking Quit Attempts and Quit Success: Evidence From a U.S. Large, Nationally Representative 2018-2019 Survey.

INTRODUCTION: Although many studies have examined the association between e-cigarette use and smoking cessation, fewer have considered the impact of e-cigarette flavors on cessation outcomes. This study extends previous studies by examining the effects of e-cigarette use and e-cigarette flavors on quit attempts and quit success of smoking. AIMS AND METHODS: We used data from the 2018-2019 Tobacco Use Supplement-Current Population Survey (TUS-CPS) survey. Multivariate logistic regression analyses were used to investigate the associations between flavored e-cigarette use with quit attempts and quit success of smoking among individuals who smoked 12 months ago. Two current e-cigarette use definitions were used in these logistic regression analyses; currently use every day or some days versus 20+ days in the past 30 days. RESULTS: Compared to those not using e-cigarettes, current every day or someday e-cigarette use with all nontobacco flavors had an adjusted odds ratio (AOR) of 2.9 (95% CI: 2.4 to 3.5) for quit attempts and 1.7 (95% CI: 1.3 to 2.2) for quit success. 20+ days e-cigarette use with flavors had stronger associations with quit attempts (AOR = 4.2, 95% CI: 3.1 to 5.5) and quit success (AOR = 4.0, 95% CI: 2.9 to 5.4). E-cigarette users with nontobacco flavors were more likely to succeed in quitting compared to those exclusively using non-flavored or tobacco-flavored e-cigarettes. Menthol or mint flavor users had slightly higher odds of quit attempts and success than users of other nontobacco flavors. CONCLUSIONS: E-cigarette use is positively associated with both making smoking quit attempts and quit success. Those using flavored e-cigarettes, particularly menthol or mint, are more likely to quit successfully. IMPLICATIONS: E-cigarette use is positively associated with both making a quit attempt and quit success, and those using flavored e-cigarettes are more likely to successfully quit smoking, with no statistically significant differences between the use of menthol or mint-flavored e-cigarettes versus the use of other nontobacco flavored products. This suggests that the potential for e-cigarettes to help people who currently smoke quit could be maintained with the availability of menthol or mint-flavored e-cigarettes, even if other nontobacco flavored products, which are associated with e-cigarette use among youth, were removed from the market.

Longitudinal Associations Between Exclusive and Dual Use of Electronic Nicotine Delivery Systems and Cigarettes and Self-Reported Incident Diagnosed Cardiovascular Disease Among Adults.

INTRODUCTION: The cardiovascular health effects of electronic nicotine delivery systems (ENDS) use are not well characterized, making it difficult to assess ENDS as a potential harm reduction tool for adults who use cigarettes. AIMS AND METHODS: Using waves 1-5 of the Population Assessment of Tobacco and Health Study (2013-2019), we analyzed the risk of self-reported incident diagnosed myocardial infarction (MI; 280 incident cases) and stroke (186 incident cases) associated with ENDS and/or cigarette use among adults aged 40 + using discrete time survival models. We employed a time-varying exposure lagged by one wave, defined as exclusive or dual established use of ENDS and/or cigarettes every day or some days, and controlled for demographics, clinical factors, and past smoking history. RESULTS: The analytic samples (MI = 11 031; stroke = 11 076) were predominantly female and non-Hispanic White with a mean age of 58 years. At baseline, 14.2% of respondents exclusively smoked cigarettes, 0.6% exclusively used ENDS, and 1.0% used both products. Incident MI and stroke were rare during follow-up (< 1% at each wave). Compared to no cigarette or ENDS use, exclusive cigarette use increased the risk of MI (aHR 1.99, 95% CI = 1.40-2.84) and stroke (aHR 2.26, 95% CI = 1.51-3.39), while exclusive ENDS use (MI: aHR 0.61, 95% CI = 0.12-3.04; stroke: aHR 1.74, 95% CI = 0.55-5.49) and dual use (MI: aHR 1.84, 95% CI = 0.64-5.30; stroke: aHR 1.12, 95% CI = 0.33-3.79) were not significantly associated with the risk of either outcome. CONCLUSIONS: Compared to non-use, exclusive cigarette use was associated with an increased risk of self-reported incident diagnosed cardiovascular disease over a 5-year period, while ENDS use was not associated with a statistically significant increase in the outcomes. IMPLICATIONS: Existing literature on the health effects of ENDS use has important limitations, including potential reverse causation and improper control for cigarette smoking. We accounted for these issues by using a prospective design and adjusting for current and former smoking status and cigarette pack-years. In this context, we did not find that ENDS use was associated with a statistically significant increase in self-reported incident diagnosed myocardial infarction or stroke over a 5-year period. While more studies are needed, this analysis provides an important foundation and key methodological considerations for future research on the health effects of ENDS use.

Patterns of poly tobacco use among adults in the Population Assessment of Tobacco and Health (PATH) study, 2013-2017: a multistate Markov transition analysis.

BACKGROUND: A better understanding of sociodemographic transition patterns between single, dual and poly tobacco product use may help improve tobacco control policy interventions. METHODS: HRs of transition between never, non-current (no past 30-day use), cigarette, e-cigarette, other combustible, smokeless tobacco (SLT), dual and poly tobacco use states in adults were estimated for age, sex, race/ethnicity, education and income using a multistate model for waves 1-4 of the Population Assessment of Tobacco and Health study (2013-2017), a US-based cohort study, accounting for complex survey design. RESULTS: Sole cigarette and SLT use were persistent, with 77% and 78% of adults continuing use after one wave. Other use states were more transient, with 29%-48% of adults reporting the same pattern after one wave. If single-product users transitioned, it was most likely to non-current use while dual or poly cigarette users were most likely to transition to exclusive cigarette use. Males were more likely than females to initiate combustible product use after a history of no use, and after a period of tobacco use cessation. Hispanic and non-Hispanic black participants initiated cigarette use at higher rates than non-Hispanic white participants, and had higher rates of experimentation with tobacco products between study waves. Lower socioeconomic status was associated with higher rates of transition into combustible tobacco use. CONCLUSIONS: Dual and poly tobacco use is largely transient, while single-use patterns are more stable over time. Transitions differ by age, sex, race/ethnicity, education and income, which may influence the impact of current and future tobacco control efforts.

Changing patterns of cigarette and ENDS transitions in the USA: a multistate transition analysis of youth and adults in the PATH Study in 2015-2017 vs 2017-2019.

INTRODUCTION: It is unknown how recent changes in the tobacco product marketplace have impacted transitions in cigarette and electronic nicotine delivery system (ENDS) use. METHODS: A multistate transition model was applied to 24 242 adults and 12 067 youth in waves 2-4 (2015-2017) and 28 061 adults and 12 538 youth in waves 4 and 5 (2017-2019) of the Population Assessment of Tobacco and Health Study. Transition rates for initiation, cessation and product transitions were estimated in multivariable models, accounting for gender, age group, race/ethnicity and daily versus non-daily product use. RESULTS: Changes in ENDS initiation/relapse rates depended on age, including among adults. Among youth who had never established tobacco use, the 1-year probability of ENDS initiation increased after 2017 from 1.6% (95% CI 1.4% to 1.8%) to 3.8% (95% CI 3.4% to 4.2%). Persistence of ENDS-only use (ie, 1-year probability of continuing to use ENDS only) increased for youth from 40.7% (95% CI 34.4% to 46.9%) to 65.7% (95% CI 60.5% to 71.1%) and for adults from 57.8% (95% CI 54.4% to 61.3%) to 78.2% (95% CI 76.0% to 80.4%). Persistence of dual use similarly increased for youth from 48.3% (95% CI 37.4% to 59.2%) to 60.9% (95% CI 43.0% to 78.8%) and for adults from 40.1% (95% CI 37.0% to 43.2%) to 63.8% (95% CI 59.6% to 67.6%). Youth and young adults who used both products became more likely to transition to ENDS-only use, but middle-aged and older adults did not. CONCLUSIONS: ENDS-only and dual use became more persistent. Middle-aged and older adults who used both products became less likely to transition to cigarette-only use but not more likely to discontinue cigarettes. Youth and young adults became more likely to transition to ENDS-only use.

Public health impact of a US ban on menthol in cigarettes and cigars: a simulation study.

INTRODUCTION: The US Food and Drug Administration most recently announced its intention to ban menthol cigarettes and cigars nationwide in April 2021. Implementation of the ban will require evidence that it would improve public health. This paper simulates the potential public health impact of a ban on menthol in cigarettes and cigars through its impacts on smoking initiation, smoking cessation and switching to nicotine vaping products (NVPs). METHODS: After calibrating an established US simulation model to reflect recent use trends in cigarette and NVP use, we extended the model to incorporate menthol and non-menthol cigarette use under a status quo scenario. Applying estimates from a recent expert elicitation on the behavioural impacts of a menthol ban, we developed a menthol ban scenario with the ban starting in 2021. We estimated the public health impact as the difference between smoking and vaping-attributable deaths and life-years lost in the status quo scenario and the menthol ban scenario from 2021 to 2060. RESULTS: As a result of the ban, overall smoking was estimated to decline by 15% as early as 2026 due to menthol smokers quitting both NVP and combustible use or switching to NVPs. These transitions are projected to reduce cumulative smoking and vaping-attributable deaths from 2021 to 2060 by 5% (650 000 in total) and reduce life-years lost by 8.8% (11.3 million). Sensitivity analyses showed appreciable public health benefits across different parameter specifications. CONCLUSIONS AND RELEVANCE: Our findings strongly support the implementation of a ban on menthol in cigarettes and cigars.

The smoking and vaping model, A user-friendly model for examining the country-specific impact of nicotine VAPING product use: application to Germany.

BACKGROUND: Simulation models play an increasingly important role in tobacco control. Models examining the impact of nicotine vaping products (NVPs) and smoking tend to be highly specialized and inaccessible. We present the Smoking and Vaping Model (SAVM),a user-friendly cohort-based simulation model, adaptable to any country, that projects the public health impact of smokers switching to NVPs. METHODS: SAVM compares two scenarios. The No-NVP scenario projects smoking rates in the absence of NVPs using population projections, deaths rates, life expectancy, and smoking prevalence. The NVP scenario models vaping prevalence and its impact on smoking once NVPs became popular. NVP use impact is estimated as the difference in smoking- and vaping-attributable deaths (SVADs) and life-years lost (LYLs) between the No-NVP and NVP scenarios. We illustrate SAVM's adaptation to the German adult ages 18+ population, the Germany-SAVM by adjusting the model using population, mortality, smoking and NVP use data. RESULTS: Assuming that the excess NVP mortality risk is 5% that of smoking, Germany-SAVM projected 4.7 million LYLs and almost 300,000 SVADs averted associated with NVP use from 2012 to 2060. Increasing the excess NVP mortality risk to 40% with other rates constant resulted in averted 2.8 million LYLs and 200,000 SVADs during the same period. CONCLUSIONS: SAVM enables non-modelers, policymakers, and other stakeholders to analyze the potential population health effects of NVP use and public health interventions.

Invited Commentary: Mechanistic and Biologically Based Models in Epidemiology-A Powerful Underutilized Tool.

Mechanistic and biologically based mathematical models of chronic and behavioral disease processes aim to capture the main mechanistic or biological features of the disease development and to connect these with epidemiologic outcomes. These approaches have a long history in epidemiologic research and are complementary to traditional epidemiologic or statistical approaches to investigate the role of risk factor exposures on disease risk. Simonetto et al. (Am J Epidemiol. 2022;191(10):1766-1775) present a mechanistic, process-oriented model to investigate the role of smoking, hypertension, and dyslipidemia in the development of atherosclerotic lesions and their progression to myocardial infarction. Their approach builds on and brings to cardiovascular disease the ideas and perspectives of earlier mechanistic and biologically based models for the epidemiology of cancer and other chronic diseases, providing important insights into the mechanisms and epidemiology of smoking related myocardial infarction. We argue that although mechanistic modeling approaches have demonstrated their value and place in epidemiology, they are highly underutilized. We call for efforts to grow mechanistic and biologically based modeling research, expertise, and awareness in epidemiology, including the development of training and collaboration opportunities to attract more students and researchers from science, technology, engineering, and medical field into the epidemiology field.

A longitudinal study of menthol cigarette use and smoking cessation among adult smokers in the US: Assessing the roles of racial disparities and E-cigarette use.

Using nationally representative longitudinal data from Wave 1 to Wave 4 of the Population Assessment of Tobacco and Health Study in the United States, we examined whether the association between menthol cigarette use and smoking cessation was modified by race/ethnicity and e-cigarette use. Multivariable discrete-time survival models were fit to an unbalanced person-period data set (person n = 7423, risk period n = 18,897) for adult respondents (ages 25+) who were current established cigarette smokers at baseline. We found that adults who smoke menthol cigarettes had lower odds of smoking cessation, but the effect was modified by race/ethnicity as non-Hispanic (NH) Black menthol smokers had lower odds of quitting smoking than NH White or Hispanic menthol smokers. We also found that e-cigarette use was associated with higher odds of smoking cessation among both menthol and non-menthol smokers, but the association was stronger among menthol smokers. Our results suggest that a menthol smoking ban may have a favorable impact on smoking cessation for NH Black adults. In addition, our results also suggest that a menthol smoking ban may be more effective if menthol smokers have access to e-cigarettes as a way to quit cigarette use.

The Impact of Current Tobacco Product Use Definitions on Estimates of Transitions Between Cigarette and ENDS Use.

INTRODUCTION: Definitions of current tobacco and nicotine delivery product use vary and depend on frequency of use, established-use criteria, and the product type. Previous research has not considered how transition rates between current use of different products depend on the current use definition. AIMS AND METHODS: We applied a multistate transition model to data on U.S. adults from waves 1-4 (2013-2017) of the Population Assessment of Tobacco and Health (PATH) study. We estimated transition rates between never, non-current, cigarette, electronic nicotine delivery systems (ENDS), and dual use states with and without established-use criteria (has smoked 100+ cigarettes in their lifetime; ever fairly regularly used ENDS) and different frequency thresholds (1+, 10+, 20+, and 30 days of the past 30 days). We considered use below a frequency threshold as either non-current use or a distinct, infrequent use category. RESULTS: When treating use below a frequency threshold as non-current use, transition probability estimates were largely robust to the choice of use frequency threshold, although sole ENDS users were more likely to transition to non-current use or dual use as the current use threshold increased. Removing the established-use criterion for ENDS reduced the estimates of sole ENDS and dual users staying in their use state. When treating infrequent use as a separate category, transition probability estimates were dependent on the use frequency threshold, particularly transitions among the dual use states. CONCLUSIONS: Product use definitions have important implications for assessing product use transitions and thus the public health implications of cigarette and ENDS control strategies. IMPLICATIONS: How we define "current use" of tobacco and nicotine delivery products changes our estimates of how individuals transition to, between, and from different patterns of use. We show that the robustness of transition estimates to whether or not non-established users are included as current users and to different frequency-of-use threshold depends in part on whether low-frequency users are categorized as non-current users or as a distinct category. Our results emphasize the importance of intentional definitions of product use that reflect the larger goals of public health and tobacco control.

Cumulative Burden of Colorectal Cancer-Associated Genetic Variants Is More Strongly Associated With Early-Onset vs Late-Onset Cancer.

BACKGROUND & AIMS: Early-onset colorectal cancer (CRC, in persons younger than 50 years old) is increasing in incidence; yet, in the absence of a family history of CRC, this population lacks harmonized recommendations for prevention. We aimed to determine whether a polygenic risk score (PRS) developed from 95 CRC-associated common genetic risk variants was associated with risk for early-onset CRC. METHODS: We studied risk for CRC associated with a weighted PRS in 12,197 participants younger than 50 years old vs 95,865 participants 50 years or older. PRS was calculated based on single nucleotide polymorphisms associated with CRC in a large-scale genome-wide association study as of January 2019. Participants were pooled from 3 large consortia that provided clinical and genotyping data: the Colon Cancer Family Registry, the Colorectal Transdisciplinary Study, and the Genetics and Epidemiology of Colorectal Cancer Consortium and were all of genetically defined European descent. Findings were replicated in an independent cohort of 72,573 participants. RESULTS: Overall associations with CRC per standard deviation of PRS were significant for early-onset cancer, and were stronger compared with late-onset cancer (P for interaction = .01); when we compared the highest PRS quartile with the lowest, risk increased 3.7-fold for early-onset CRC (95% CI 3.28-4.24) vs 2.9-fold for late-onset CRC (95% CI 2.80-3.04). This association was strongest for participants without a first-degree family history of CRC (P for interaction = 5.61 × 10-5). When we compared the highest with the lowest quartiles in this group, risk increased 4.3-fold for early-onset CRC (95% CI 3.61-5.01) vs 2.9-fold for late-onset CRC (95% CI 2.70-3.00). Sensitivity analyses were consistent with these findings. CONCLUSIONS: In an analysis of associations with CRC per standard deviation of PRS, we found the cumulative burden of CRC-associated common genetic variants to associate with early-onset cancer, and to be more strongly associated with early-onset than late-onset cancer, particularly in the absence of CRC family history. Analyses of PRS, along with environmental and lifestyle risk factors, might identify younger individuals who would benefit from preventive measures.

Latent class analysis of use frequencies for multiple tobacco products in US adults.

A persistent challenge is characterizing patterns of tobacco use in terms of product combinations and frequency. Using Wave 4 (2016-17) Population Assessment of Tobacco and Health Study adult data, we conducted latent class analyses (LCA) of past 30-day frequency of use for 9 tobacco products. One-step LCA with joint multinomial logistic regression models compared sociodemographic factors between users (n = 13,716) and non-users (n = 17,457), and between latent classes of users. We accounted for survey design and weights. Our analyses identified 6 classes: in addition to non-users (C0: 75.7%), we found 5 distinct latent classes of users: daily exclusive cigarette users (C1: 15.5%); occasional cigarette and polytobacco users (C2: 3.8%); frequent e-product and occasional cigarette users (C3: 2.2%); daily smokeless tobacco (SLT) and infrequent cigarette users (C4: 2.0%); and occasional cigar users (C5: 0.8%). Compared to C1: C2 and C3 had higher odds of being male (versus female), younger (especially 18-24 versus 55 years), and having higher education; C2 had higher, while C3 and C4 had lower, odds of being a racial/ethnic minority (versus Non-Hispanic White); C4 and C5 had much higher odds of being male (versus female) and heterosexual (versus sexual minority) and having higher income; and C5 had higher odds of college or more education. We identified three classes of daily or frequent users of a primary product (cigarettes, SLT or e-products) and two classes of occasional users (cigarettes, cigars and polytobacco). Sociodemographic differences in class membership may influence tobacco-related health disparities associated with specific patterns of use.

Public health implications of vaping in the USA: the smoking and vaping simulation model.

BACKGROUND: Nicotine vaping products (NVPs) are increasingly popular worldwide. They may provide public health benefits if used as a substitute for smoking, but may create public health harms if used as a gateway to smoking or to discourage smoking cessation. This paper presents the Smoking and Vaping Model (SAVM), a user-friendly model which estimates the public health implications of NVPs in the USA. METHODS: SAVM adopts a cohort approach. We derive public health implications by comparing smoking- and NVP-attributable deaths and life-years lost under a No-NVP and an NVP Scenario. The No-NVP Scenario projects current, former, and never smoking rates via smoking initiation and cessation rates, with their respective mortality rates. The NVP Scenario allows for smoking- and NVP-specific mortality rates, switching from cigarette to NVP use, separate NVP and smoking initiation rates, and separate NVP and smoking cessation rates. After validating the model against recent US survey data, we present the base model with extensive sensitivity analyses. RESULTS: The SAVM projects that under current patterns of US NVP use and substitution, NVP use will translate into 1.8 million premature smoking- and vaping-attributable deaths avoided and 38.9 million life-years gained between 2013 and 2060. When the NVP relative risk is set to 5%, the results are sensitive to the level of switching and smoking cessation rates and to a lesser extent smoking initiation rates. When the NVP relative risk is raised to 40%, the public health gains in terms of averted deaths and LYL are reduced by 42% in the base case, and the results become much more sensitive to variations in the base case parameters. DISCUSSION: Policymakers, researchers, and other public health stakeholders can apply the SAVM to estimate the potential public health impact of NVPs in their country or region using their own data sources. In developing new simulation models involving NVPs, it will be important to conduct extensive sensitivity analysis and continually update and validate with new data. CONCLUSION: The SAVM indicates the potential benefits of NVP use. However, given the uncertainty surrounding model parameters, extensive sensitivity analysis becomes particularly important.

A comparison of tobacco product prevalence by different frequency of use thresholds across three US surveys.

BACKGROUND: With the increasing changes in tobacco use patterns, "current use" definition and the survey used may have important implications for monitoring population use trends. METHODS: Using three US surveys (2014/15 TUS-CPS, NHIS and PATH), we compared the adult (age 18+) prevalence of four product groups (cigarettes, other combustibles, smokeless tobacco, and e-cigarettes) based on three past 30-day frequency of use thresholds: 1+, 10+, and 25+ days. We also examined mutually exclusive single, dual, and polytobacco users as a percentage of total users for each product group. RESULTS: Regardless of threshold or product, the prevalence was higher in PATH followed by NHIS and TUS-CPS, in some cases by large percentages. The differences in cigarette and smokeless tobacco use prevalence in going from the 1+ to 10+ days and to the 25+ days threshold were minimal. Applying different frequency thresholds had the largest impact on other combustibles prevalence, with a 60% reduction with the 10+ days threshold and a 80% reduction with the 25+ days threshold, compared to the 1+ days threshold, followed by e-cigarettes with 40 and 60% reductions, respectively. The proportion of dual and polytobacco users decreased considerably when using the 10+ vs. the 1+ days threshold and polytobacco use was almost non-existent with the 25+ days threshold. CONCLUSION: The estimated prevalence of each tobacco product use depends largely on the survey and frequency of use threshold adopted. The choice of survey and frequency threshold merits serious consideration when monitoring patterns of tobacco use.

Evaluation of the Benefits and Harms of Lung Cancer Screening With Low-Dose Computed Tomography: Modeling Study for the US Preventive Services Task Force.

Importance: The US Preventive Services Task Force (USPSTF) is updating its 2013 lung cancer screening guidelines, which recommend annual screening for adults aged 55 through 80 years who have a smoking history of at least 30 pack-years and currently smoke or have quit within the past 15 years. Objective: To inform the USPSTF guidelines by estimating the benefits and harms associated with various low-dose computed tomography (LDCT) screening strategies. Design, Setting, and Participants: Comparative simulation modeling with 4 lung cancer natural history models for individuals from the 1950 and 1960 US birth cohorts who were followed up from aged 45 through 90 years. Exposures: Screening with varying starting ages, stopping ages, and screening frequency. Eligibility criteria based on age, cumulative pack-years, and years since quitting smoking (risk factor-based) or on age and individual lung cancer risk estimation using risk prediction models with varying eligibility thresholds (risk model-based). A total of 1092 LDCT screening strategies were modeled. Full uptake and adherence were assumed for all scenarios. Main Outcomes and Measures: Estimated lung cancer deaths averted and life-years gained (benefits) compared with no screening. Estimated lifetime number of LDCT screenings, false-positive results, biopsies, overdiagnosed cases, and radiation-related lung cancer deaths (harms). Results: Efficient screening programs estimated to yield the most benefits for a given number of screenings were identified. Most of the efficient risk factor-based strategies started screening at aged 50 or 55 years and stopped at aged 80 years. The 2013 USPSTF-recommended criteria were not among the efficient strategies for the 1960 US birth cohort. Annual strategies with a minimum criterion of 20 pack-years of smoking were efficient and, compared with the 2013 USPSTF-recommended criteria, were estimated to increase screening eligibility (20.6%-23.6% vs 14.1% of the population ever eligible), lung cancer deaths averted (469-558 per 100 000 vs 381 per 100 000), and life-years gained (6018-7596 per 100 000 vs 4882 per 100 000). However, these strategies were estimated to result in more false-positive test results (1.9-2.5 per person screened vs 1.9 per person screened with the USPSTF strategy), overdiagnosed lung cancer cases (83-94 per 100 000 vs 69 per 100 000), and radiation-related lung cancer deaths (29.0-42.5 per 100 000 vs 20.6 per 100 000). Risk model-based vs risk factor-based strategies were estimated to be associated with more benefits and fewer radiation-related deaths but more overdiagnosed cases. Conclusions and Relevance: Microsimulation modeling studies suggested that LDCT screening for lung cancer compared with no screening may increase lung cancer deaths averted and life-years gained when optimally targeted and implemented. Screening individuals at aged 50 or 55 years through aged 80 years with 20 pack-years or more of smoking exposure was estimated to result in more benefits than the 2013 USPSTF-recommended criteria and less disparity in screening eligibility by sex and race/ethnicity.