Risk of incident cardiovascular disease among users of smokeless tobacco in the Atherosclerosis Risk in Communities (ARIC) study

Impact of Smokeless Tobacco on Cardiovascular Disease Risk in a Nigerian Metropolitan City

The use of smokeless tobacco products (STP) as a substitute for tobacco smoking is driving increasing consumption of these products especially in developing countries. The study sought to make comparison of cardiovascular risk profile between chronic STP users and suitably matched tobacco-naïve controls. This is a preliminary report from the cross sectional part of a two-arm prospective study of Smokeless Tobacco Products Composition and Exposure Outcome in Enugu metropolis, Nigeria. Consecutively recruited current Smokeless tobacco users, who had no history of cigarette smoking, aged 18 years and above, residing in selected communities in Enugu metropolis, Nigeria were recruited for the study from October 2022 to July 2023. Age and sex matched non-tobacco users from same localities as the study subjects served as controls. Written informed consent to participate in the study was obtained from all study participants. All participants were screened by the investigators, using the study case report forms, to obtain data on medical history, demographic, clinical, laboratory, and electrocardiographic evaluation. Data from 54 STP-users and 54 non-STP-users (mean age 56.58 ± 8.15 years) were analyzed. Anthropometric parameters were similar in both groups. Smokeless tobacco users had higher erect and supine blood pressure indices as well as greater postural drop in systolic blood pressure. The occurrence of diabetes mellitus (20.37% versus 5.56%) and hypertension (25.93%; 11.11%) was significantly higher in the STP-users than in the non-user population, (p = 0.02192 and 0.04751 respectively). Electrocardiographic evaluation showed significantly increased QTc and dispersions of P-wave, QRS and QT intervals as well as reduced PR interval in STP users. Electrocardiographic abnormalities observed in STP users include left ventricular hypertrophy, left atrial enlargement, ST-segment elevation, short PR interval and long QTc. Use of smokeless tobacco products is associated with increased risk burden of diabetes mellitus and hypertensive heart disease. Electrocardiographic findings linked to STP-use in this study are features consistent with arrhythmia, ventricular repolarization abnormality, myocardial hypertrophy and ischaemia, suggesting that smokeless tobacco products are not safe substitutes for tobacco smoking.

Diabetes risk among US adults with different socioeconomic status and behavioral lifestyles: evidence from the National Health and Nutrition Examination Survey

Background

Diabetes disproportionately affects minorities and those with low socioeconomic status (SES) in the United States, and differences in behavioral lifestyles are largely responsible for the unequal distribution of diabetes among different groups.

Methods

With data of 9,969 participants collected in the 2007-2008 and 2009-2010 cycles of the US National Health and Nutrition Examination Survey (NHANES), this study examined several mediators and their mediating effects in the connection between SES and the risk of diabetes. The SES is assessed by the income-to-poverty ratio (IPR), education level, and employment status. For the mediation analysis, we used health-related behaviors as mediators (smoking, alcohol use, consumption of green vegetables and fruits, physical activity and sedentary time, health insurance, and healthcare). In this study, the structural equation model was utilized to evaluate the mediating effects of behavioral lifestyle as a mediator in the relationship between SES and diabetes.

Results

A total of 9,969 participants were included in this study. We found a negative nonlinear association between IPR and diabetes risk (Poverall < 0.001; Pnon-linear = 0.46), which was independent of the majority of known or suspected risk factors and confounding variables (gender, age, race). Participants with lower SES had higher risk of diabetes compared with those with higher SES. In mediating analysis, we found alcohol intake (OR = 0.996), physical activity (OR = 0.993), health insurance (OR = 0.998), and healthcare (OR = 1.002) mediated the IPR-diabetes association. But in the relationship between education status and diabetes, the mediation effect of alcohol intake (OR = 0.995), physical activity (OR = 0.991), and health care (OR = 1.008) were obvious. Likewise, alcohol intake (OR = 0.996), fruit intake (OR = 0.998), and health care (OR = 0.975) were important mediators in the association between employment status and diabetes.

Conclusion

This study provides critical insights on the link between SES and diabetes. Our results highlight that poor health-related behaviors and limited access to healthcare are important pathways for increased diabetes risk related to those with low SES, particularly among Mexican Americans and males. They should be top priorities for agencies and healthcare providers to develop behavior-related interventions to reduce inequalities in diabetes risk.

Association of Smokeless Tobacco Use With Incident Peripheral Artery Disease: Results From the Atherosclerotic Risk in Communities Study

INTRODUCTION

Cigarette smoking is associated with an increased risk for peripheral artery disease. It is unknown whether smokeless tobacco, a noncombustible form of tobacco exposure, is also associated with increased peripheral artery disease risk. Using data from the Atherosclerosis Risk in Communities study, we tested the hypothesis that the use of smokeless tobacco is associated with a higher risk of developing peripheral artery disease.

METHODS

Participants with peripheral artery disease at baseline were excluded. Smokeless tobacco use was assessed 3 times from 1987 to 1995, and peripheral artery disease events accrued from 1987 to 2018. Smokeless tobacco was modeled as a time-dependent exposure in Cox regression models. Analyses were completed in 2021.

RESULTS

This study included 14,344 participants with a baseline mean (SD) age of 54.1 (5.7) years; 54.8% were female, and 26.4% were Black. There were 635 incident peripheral artery disease events over a median follow-up of 27.6 years (maximum of 32.1 years). The peripheral artery disease incidence rate was 4.44 per 1,000 person-years among those who used smokeless tobacco compared with 1.74 per 1,000 person-years for those who did not. The hazard ratio for current versus never smokeless tobacco use was 1.94 (95% CI=1.31, 2.88) after adjustment for sociodemographic characteristics and cigarette smoking. Peripheral artery disease incidence rate among those currently using smokeless tobacco was similar to that of those who currently smoke cigarette (3.39 per 1,000 person-years).

CONCLUSIONS

Current smokeless tobacco use was associated with high rates of peripheral artery disease, similar to cigarette smoking. Future research should evaluate the effect of cessation of noncombustible tobacco on incident peripheral artery disease.

Heart Disease and Stroke Statistics-2023 Update: A Report From the American Heart Association

BACKGROUND

The American Heart Association, in conjunction with the National Institutes of Health, annually reports the most up-to-date statistics related to heart disease, stroke, and cardiovascular risk factors, including core health behaviors (smoking, physical activity, diet, and weight) and health factors (cholesterol, blood pressure, and glucose control) that contribute to cardiovascular health. The Statistical Update presents the latest data on a range of major clinical heart and circulatory disease conditions (including stroke, congenital heart disease, rhythm disorders, subclinical atherosclerosis, coronary heart disease, heart failure, valvular disease, venous disease, and peripheral artery disease) and the associated outcomes (including quality of care, procedures, and economic costs).

METHODS

The American Heart Association, through its Epidemiology and Prevention Statistics Committee, continuously monitors and evaluates sources of data on heart disease and stroke in the United States to provide the most current information available in the annual Statistical Update with review of published literature through the year before writing. The 2023 Statistical Update is the product of a full year's worth of effort in 2022 by dedicated volunteer clinicians and scientists, committed government professionals, and American Heart Association staff members. The American Heart Association strives to further understand and help heal health problems inflicted by structural racism, a public health crisis that can significantly damage physical and mental health and perpetuate disparities in access to health care, education, income, housing, and several other factors vital to healthy lives. This year's edition includes additional COVID-19 (coronavirus disease 2019) publications, as well as data on the monitoring and benefits of cardiovascular health in the population, with an enhanced focus on health equity across several key domains.

RESULTS

Each of the chapters in the Statistical Update focuses on a different topic related to heart disease and stroke statistics.

CONCLUSIONS

The Statistical Update represents a critical resource for the lay public, policymakers, media professionals, clinicians, health care administrators, researchers, health advocates, and others seeking the best available data on these factors and conditions.

Smokeless Tobacco Use is Associated With Worse Outcomes Following Total Knee Arthroplasty

BACKGROUND

Studies have demonstrated increased complication risk after total knee arthroplasty (TKA) in patients who smoke cigarettes, but it is unclear if smokeless tobacco use confers a similar impact. The purpose of this study was to (1) evaluate rates of postoperative complications after TKA in smokeless tobacco users and smokers as compared to matched controls, and (2) compare rates of postoperative complications in smokeless tobacco users versus smokers to determine if one is associated with significantly higher rates of postoperative complications.

METHODS

A retrospective cohort study was conducted using a national database. For patients who underwent primary TKA, smokeless tobacco users (n = 1,535) and smokers (n = 28,953) were matched at a 1:4 with controls (n = 6,140 and 115,812, respectively), and smokeless tobacco users (n = 1,481) were matched at a 1:4 with smokers (n = 5,924). Rates of joint complications within 2 years and medical complications within 90 days postoperatively were compared using multivariable logistic regressions.

RESULTS

After primary TKA, compared to controls, smokeless tobacco users demonstrated significantly higher rates of aseptic loosening/mechanical failure within 2 years, longer lengths of stay, and higher rates of urinary tract infection, pneumonia, deep vein thrombosis, and acute kidney injury within 90 days. Compared to smokers, smokeless tobacco users demonstrated significantly lower rates of aseptic revision and lower rates of wound disruption.

CONCLUSION

Smokeless tobacco use is associated with higher rates of both medical and joint complications following primary TKA. However, smoking is associated with higher risk for complications than smokeless tobacco use.

LEVEL OF EVIDENCE

Level III.

Effect Comparison of E-Cigarette and Traditional Smoking and Association with Stroke-A Cross-Sectional Study of NHANES

Introduction: Tobacco use is one of the most significant risk factors for stroke. Besides traditional cigarettes and combustible products, the use of e-cigarettes and electronic nicotine delivery products has been widespread among young adults in the recent era. Furthermore, the trend of vaping has increased over the last decade. However, the relationship between e-cigarettes and stroke is largely unknown. The aim of this study was to evaluate the prevalence and identify the relationship between e-cigarette smoking and stroke. Methods: A cross-sectional study was performed using the NHANES database of the US population. Adults with a history of smoking were considered in our study and divided into three groups, e-cigarette users, traditional, and dual smokers. The Chi-squared test, Wilcoxon rank-sum test, and multivariable logistic regression analysis were used to identify the prevalence and association of e-cigarette consumption and stroke. Results: Out of a total of 266,058 respondents from 2015 to 2018, we found 79,825 respondents who smoked e-cigarettes (9.72%) or traditional (29.37%) or dual smoking (60.91%). Stroke prevalence among e-cigarette smokers was 1.57%. Stroke was more prevalent among traditional smokers than among e-cigarette smokers. (6.75% vs. 1.09%; p < 0.0001) E-cigarette smokers had early onset of stroke in comparison with traditional smokers. (median age: 48 vs. 59 years; p < 0.0001). Among females with stroke, the prevalence of e-cigarette use was higher in comparison with traditional smoking (36.36% vs. 33.91%; p < 0.0001). Among the stroke population, the prevalence of e-cigarette use was higher among Mexican-Americans (21.21% vs. 6.02%) and other Hispanics (24.24% vs. 7.70%) compared with traditional smoking (p < 0.0001). The regression analysis found higher odds of stroke history among e-cigarette users than traditional smokers [aOR: 1.15; 95% CI: 1.15−1.16)]. Conclusion: Though stroke was more prevalent in traditional smokers, the incidence of stroke was early-in-onset and was strongly associated with e-cigarette use compared to traditional smokers. We have also identified vascular effects of e-cigarettes components as possible triggers for the stroke.

Tobacco use disorder and cardiovascular health

This narrative review examines the impact of cigarette smoking and the use of other tobacco and nicotine products on cardiovascular disease. Smoking increases the incidence of both acute and chronic cardiovascular diseases, and the harmful effects are substantially and relatively quickly reversible after quitting. Recommended cessation treatment includes offering pharmacotherapy, counseling which should emphasize the rapid risk reduction that occurs after quitting and adequate follow-up contacts. Although most research on cardiovascular disease in relation to tobacco use has focused upon cigarette smoking, we also review available data related to other combustible tobacco products, smokeless tobacco, electronic nicotine delivery systems and second-hand smoke. We discuss the implications of smoking on clinical management of patients with heart disease and newer developments with potential relevance to treatment of such patients.

Smokeless Tobacco Use and Prevalence of Cardiovascular Disease Among Males in the Population Assessment of Tobacco and Health (PATH) Study, Waves 1–4

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Oral smokeless tobacco (SLT) products are non-combusted forms of tobacco that can be dependence producing.

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SLT use may pose health risks to users such as cardiovascular disease (CVD) through various pathways including influencing hemodynamics, endothelial dysfunction, inflammation, insulin resistance, hyperlipidemia, and arrhythmogenesis.

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Past studies have suggested a small, elevated risk of CVD among SLT users compared to never tobacco users.

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This study advances the literature by exploring how the duration of regular SLT use relates to CVD prevalence.

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In this study of ≥ 40-year-old men only, we did not find a consistent dose–response trend for years of SLT use and prevalence of CVD.

The purpose of this period prevalence study is to compare the prevalence of cardiovascular disease (CVD) in current/former established smokeless tobacco (SLT) users (ever SLT users who have used the product fairly regularly) to those who were: 1) never established cigarette smokers and SLT users, and 2) current/former established exclusive cigarette smokers (have smoked at least a 100 or more cigarettes in lifetime) only, adjusting for known risk factors for CVD. Analyses included 4,703 men ≥ 40 years of age who participated in the Population Assessment of Tobacco and Health (PATH) Study, Waves: 1–4, conducted between 2013 and 2017. Current users were those using SLT products daily or on some days, whereas former users had not used SLT and/or cigarettes in the past 12 months. CVD prevalence was defined as a self-reported diagnosis of congestive heart failure, stroke, or myocardial infarction. Among current/former established SLT users, years of use defined exposure history, while pack-years defined exposure history for smokers. Adjusted odds ratios (AOR) and 95% confidence intervals (CI) were reported with trend tests to examine dose–response associations. Current/former established exclusive SLT users were not significantly more likely to have had any CVD compared to never established cigarette and SLT users (OR = 1.7 [0.8–3.7]), or current/former established exclusive cigarette smokers (OR = 0.9 [0.5–1.8]). Current/former established exclusive cigarette smokers were more likely to have had any CVD compared to those who were never established cigarette and SLT users (OR = 1.6 [1.1–2.3]).

Heart Disease and Stroke Statistics-2022 Update: A Report From the American Heart Association

BACKGROUND

The American Heart Association, in conjunction with the National Institutes of Health, annually reports the most up-to-date statistics related to heart disease, stroke, and cardiovascular risk factors, including core health behaviors (smoking, physical activity, diet, and weight) and health factors (cholesterol, blood pressure, and glucose control) that contribute to cardiovascular health. The Statistical Update presents the latest data on a range of major clinical heart and circulatory disease conditions (including stroke, congenital heart disease, rhythm disorders, subclinical atherosclerosis, coronary heart disease, heart failure, valvular disease, venous disease, and peripheral artery disease) and the associated outcomes (including quality of care, procedures, and economic costs).

METHODS

The American Heart Association, through its Statistics Committee, continuously monitors and evaluates sources of data on heart disease and stroke in the United States to provide the most current information available in the annual Statistical Update. The 2022 Statistical Update is the product of a full year's worth of effort by dedicated volunteer clinicians and scientists, committed government professionals, and American Heart Association staff members. This year's edition includes data on the monitoring and benefits of cardiovascular health in the population and an enhanced focus on social determinants of health, adverse pregnancy outcomes, vascular contributions to brain health, and the global burden of cardiovascular disease and healthy life expectancy.

RESULTS

Each of the chapters in the Statistical Update focuses on a different topic related to heart disease and stroke statistics.

CONCLUSIONS

The Statistical Update represents a critical resource for the lay public, policymakers, media professionals, clinicians, health care administrators, researchers, health advocates, and others seeking the best available data on these factors and conditions.

Swedish snuff (snus) and risk of cardiovascular disease and mortality: prospective cohort study of middle-aged and older individuals

BACKGROUND

Cigarette smoking is a well-known risk factor for cardiovascular disease (CVD), but whether smokeless tobacco such as snuff is associated with the risk of CVD is still unclear. We investigated the association of the use of Swedish oral moist snuff (snus) with a broad range of CVDs and CVD mortality.

METHODS

We used data from a population-based cohort of 41,162 Swedish adults with a mean baseline age of 70 (56-94) years who completed questionnaires regarding snus use and other lifestyle habits and health characteristics. Participants were followed up for incident cardiovascular outcomes and death over 8 years through linkage to the Swedish National Patient and Death Registers. Hazard ratios (HR) were estimated by Cox proportional hazards regression. We conducted analyses among all subjects as well as among never smokers to reduce residual confounding from smoking.

RESULTS

After adjustment for smoking and other confounders, snus use was not associated with myocardial infarction, heart failure, atrial fibrillation, aortic valve stenosis, abdominal aortic aneurysm, stroke, or CVD mortality. However, in never smokers, snus use was associated with a statistically significant increased risk of total and ischemic stroke (HRs [95% confidence intervals] = 1.52 [1.01-2.30] and 1.63 [1.05-2.54], respectively) and non-significantly positively associated with some other CVDs.

CONCLUSIONS

In this middle-aged and elderly Swedish population, current Swedish snus use was not associated with the risk of major heart and valvular diseases, abdominal aortic aneurysm, or CVD mortality in the entire study population, but was linked to an increased risk of stroke in never smokers.

Effects of modified risk tobacco product claims on consumer comprehension and risk perceptions of IQOS

INTRODUCTION

Tobacco industry studies on consumers' perceptions of modified risk claims (MRCs) often had important omissions (eg, no control group, not investigating whether consumers understand what 'switching completely' means). This study examined the effects of IQOS MRCs on risk perceptions and behavioural intentions.

METHOD

Based on tobacco companies' MRCs, we manipulated three MRC language features: explanation about 'switching completely' (absent vs present), number of diseases (single vs multiple) and language certainty (hypothetical vs certain). In an online experiment, we randomised 1523 US adult current smokers and 1391 young adult non-smokers to 1 of 9 conditions following a 2×2×2+1 control design. People reported their comprehension of 'switching completely', IQOS risk perceptions and behavioural intentions after message exposure.

RESULTS

More smokers exposed to MRCs that included an explanation about 'switching completely' (22.2%) (vs explanation absent (11.2%) and control (10.7%)) mentioned that 'switching completely' meant smoking 0 cigarettes. Compared with the control, several MRCs (eg, certain language) produced lower perceived risk of IQOS, including for diseases not mentioned in the MRCs. MRCs using certain and hypothetical language did not differ on any outcomes. MRCs highlighting reduced risk for a single disease and multiple diseases did not differ on any outcomes. MRCs did not influence behavioural intentions.

CONCLUSION

The Food and Drug Administration should ensure that consumers understand what 'switching completely' means in an MRC and recognize that some language features may mislead consumers into believing that a product reduces the risk of diseases not mentioned in an MRC.

Heart Disease and Stroke Statistics-2021 Update: A Report From the American Heart Association

BACKGROUND

The American Heart Association, in conjunction with the National Institutes of Health, annually reports the most up-to-date statistics related to heart disease, stroke, and cardiovascular risk factors, including core health behaviors (smoking, physical activity, diet, and weight) and health factors (cholesterol, blood pressure, and glucose control) that contribute to cardiovascular health. The Statistical Update presents the latest data on a range of major clinical heart and circulatory disease conditions (including stroke, congenital heart disease, rhythm disorders, subclinical atherosclerosis, coronary heart disease, heart failure, valvular disease, venous disease, and peripheral artery disease) and the associated outcomes (including quality of care, procedures, and economic costs).

METHODS

The American Heart Association, through its Statistics Committee, continuously monitors and evaluates sources of data on heart disease and stroke in the United States to provide the most current information available in the annual Statistical Update. The 2021 Statistical Update is the product of a full year's worth of effort by dedicated volunteer clinicians and scientists, committed government professionals, and American Heart Association staff members. This year's edition includes data on the monitoring and benefits of cardiovascular health in the population, an enhanced focus on social determinants of health, adverse pregnancy outcomes, vascular contributions to brain health, the global burden of cardiovascular disease, and further evidence-based approaches to changing behaviors related to cardiovascular disease.

RESULTS

Each of the 27 chapters in the Statistical Update focuses on a different topic related to heart disease and stroke statistics.

CONCLUSIONS

The Statistical Update represents a critical resource for the lay public, policy makers, media professionals, clinicians, health care administrators, researchers, health advocates, and others seeking the best available data on these factors and conditions.

Effects of smokeless tobacco on cell viability, reactive oxygen species, apoptosis, and inflammatory cytokines in human umbilical vein endothelial cells

Smokeless tobacco products provide an alternative to cigarettes; however, smokeless tobacco is carcinogenic and harmful to human health. This study evaluated the toxicological effects of snus extracts and cigarette smoke total particulate matter (TPM) on human umbilical vein endothelial cells (HUVECs). Treated cells were examined for cell viability, reactive oxygen species (ROS), apoptosis, and inflammatory cytokines. Moreover, we explored the mechanism of programmed cell death induced by snus. The results showed that snus extracts significantly inhibited cell viability in a dose-dependent manner. ROS was significantly increased in treatment groups, and anti-oxidant treatment could not prevent snus extract-induced cell death. Snus extracts induced apoptosis, DNA damage, activation and cleavage of caspase-3 and caspase-8, pathway-related gene change, and interleukin (IL)-6 and IL-8 release in HUVECs. Snus extracts exposure may induce cytotoxicity, ROS generation, inflammatory cytokines release, and apoptosis or DNA damage through intrinsic and extrinsic pathways in HUVECs.

The role of traditional risk factors in explaining the social disparities in cardiovascular death: The national health and Nutrition Examination Survey III (NHANES III)

Objective

─ To assess the role of traditional risk factors in explaining the association between cumulative social risk exposure and disparities in CVD death among US adults.

Methods

─ The study included 15,906 participants from the Third National Health and Nutrition Examination Survey III who were CVD-free at enrollment. Baseline social risk factors (minority race, poverty-income ratio<1, education<12 grade, and living single) were used to create a cumulative social risk score (0 to ≥3). CVD death served as the primary outcome. We assessed the contribution of each major CVD risk factor to the link between cumulative social risk exposure and CVD death.

Results

─ During a median follow-up of 14 years, 1309 CVD deaths occurred. Participants with elevated cumulative social risk score were at increased risk of CVD death, with hazard ratio 1.19(95%CI 1.01–1.41), 1.52(95%CI 1.28–1.79), and 1.46 (95%CI 1.23–1.74) in individuals with score 1, 2 and ​≥ ​3 respectively, compared with individuals with score of 0. Traditional CVD risk factors explained about one third of the disparities in CVD death in individuals with the elevated social risk exposure. Among the one third effect by combined CVD risk factors, current smoking contributed the largest proportion, accounting for approximately one half of the combined risk factors effect, followed by obesity and diabetes.

Conclusions

─Among the traditional risk factors, control of smoking appears to be the greatest opportunity to attenuate the social disparities in CVD death. While these findings call for further studies to identify other pathways that explain the elevated CVD mortality in socially disadvantaged population.

Inferences beyond a claim: a typology of potential halo effects related to modified risk tobacco product claims

When tobacco products are marketed with modified risk tobacco product (MRTP) claims, consumers may infer additional health benefits not directly stated in the claims. We propose a typology of seven potential 'halo effects' (ie, an unintended generalisation) that may occur with MRTP marketing. Evidence currently exists that some of these types of halo effects occur after exposure to MRTP claims. These generalisations are likely unavoidable in certain situations and may sometimes produce accurate inferences. However, some halo effects may be problematic if they mislead consumers into false inferences and result in unintended consequences that have a negative public health impact (eg, reinitiation, dual tobacco product use). To help mitigate unintended consequences and guide regulatory decisions about MRTP claims, we encourage researchers studying MRTP claims to test for halo effects. Regulatory agencies should include potential unintended consequences associated with halo effects when assessing individual-level and population-level health impacts of MRTP claims. Moreover, tobacco manufacturers should be required to report both premarket and postmarket surveillance of halo effects to relevant regulatory agencies. If MRTP claims are to play a role in tobacco harm reduction, it is imperative that they be communicated and interpreted in ways that minimise harms and maximise public health benefits.

Smoke and Heart Should Stay Apart: A Look at E Cigarettes and Other Alternatives to Conventional Cigarettes, and Their Impact on Cardiovascular Health

The leading cause of preventable death in the world is smoking; leading to 7 million deaths attributable to tobacco use per year worldwide and 480,000 deaths per year in the United States. Though the actual rates of smoking in the United States have been on the decline, the advent of electronic cigarettes (E cigs) in 2007 was met with immense reception especially among the youth. Though initially thought to be a means to facilitate smoking cessation, recent evidence and the E cigs epidemic suggest its implications in significant morbidity and mortality. The other alternatives for conventional tobacco cigarettes have also been implicated in cardiovascular diseases. This manuscript aims to review E cigarettes and other alternatives to conventional cigarettes, and their impact on cardiovascular health. We conducted a Medline search using various combinations of "Cigarettes," "E cigarettes," "Smokeless tobacco," "hookah", and "cardiovascular risk" to identify pivotal trials published before May 10, 2020, for inclusion in this review. Concurrently, major practice guidelines, trial bibliographies, and pertinent reviews were examined to ensure inclusion of relevant trials. A consensus among the authors was used to choose items for narrative inclusion. The following section reviews data from pivotal trials to review the effects of E cigarettes, smokeless tobacco, hookah, nicotine replacement therapy on cardiovascular mortality and morbidity. There are many alternatives to conventional tobacco cigarette smoking, but none can be attributed as absolutely safe from a cardiovascular health perspective. The abundance of evidence regarding its impact on cardiovascular mortality and morbidity does not position it as a safe alternative, but an alternative means of smoking nicotine. The humongous rise in popularity and its gain in favor among the younger population poses a serious threat to the cardiovascular well-being of the exposed. Thus, E cigs and other alternatives of cigarette smoking do impart differing risks in cardiovascular mortality and morbidity, with the possible exception of nicotine replacement therapy.

Heart Disease and Stroke Statistics-2020 Update: A Report From the American Heart Association

BACKGROUND

The American Heart Association, in conjunction with the National Institutes of Health, annually reports on the most up-to-date statistics related to heart disease, stroke, and cardiovascular risk factors, including core health behaviors (smoking, physical activity, diet, and weight) and health factors (cholesterol, blood pressure, and glucose control) that contribute to cardiovascular health. The Statistical Update presents the latest data on a range of major clinical heart and circulatory disease conditions (including stroke, congenital heart disease, rhythm disorders, subclinical atherosclerosis, coronary heart disease, heart failure, valvular disease, venous disease, and peripheral artery disease) and the associated outcomes (including quality of care, procedures, and economic costs).

METHODS

The American Heart Association, through its Statistics Committee, continuously monitors and evaluates sources of data on heart disease and stroke in the United States to provide the most current information available in the annual Statistical Update. The 2020 Statistical Update is the product of a full year's worth of effort by dedicated volunteer clinicians and scientists, committed government professionals, and American Heart Association staff members. This year's edition includes data on the monitoring and benefits of cardiovascular health in the population, metrics to assess and monitor healthy diets, an enhanced focus on social determinants of health, a focus on the global burden of cardiovascular disease, and further evidence-based approaches to changing behaviors, implementation strategies, and implications of the American Heart Association's 2020 Impact Goals.

RESULTS

Each of the 26 chapters in the Statistical Update focuses on a different topic related to heart disease and stroke statistics.

CONCLUSIONS

The Statistical Update represents a critical resource for the lay public, policy makers, media professionals, clinicians, healthcare administrators, researchers, health advocates, and others seeking the best available data on these factors and conditions.

Electronic cigarettes and cardiovascular health: what do we know so far?

While tobacco cigarette (TC) smoking has continued to drop to all-time lows, the use of electronic cigarettes (ECs), introduced in the US in 2007, has been rising dramatically, especially among youth. In EC emissions, nicotine is the major biologically active element, while levels of carcinogens and harmful combustion products that typify TC smoke are very low or even undetectable. TCs cause cardiovascular harm by activation of inflammatory pathways and oxidative damage, leading to atherogenesis and thrombosis, as well as through sympathetic activation triggering ischemia and arrhythmia. While ECs are generally believed to be safer than TCs, there remain many uncertainties regarding the overall cardiovascular health effects of EC usage. In this review, we discuss the various components of EC smoke and review the potential mechanisms of cardiovascular injury caused by EC use. We also discuss the controversy regarding the increasing epidemic of youth EC use weighed against the use of ECs as a smoking-cessation aid.

Distinct gene expression changes in human peripheral blood mononuclear cells treated with different tobacco product preparations

Cigarette smoking exerts diverse physiological effects including immune suppression. To better characterize the biological effects of different categories of tobacco products, a genome-wide gene expression study was performed. Transcriptomic profiling was performed in PBMCs treated with different equi-nicotine units of aqueous extracts of cigarette smoke (termed Whole Smoke-Conditioned Medium, or WS-CM), or a single dose smokeless tobacco extract (STE) prepared from reference tobacco products. WS-CM induced dose-dependent changes in the expression of several genes. No significant expression differences between low WS-CM and media control were detected. However, transcripts were significantly affected by medium WS-CM (479), high WS-CM (2, 703), and STE (2, 156). The overlap between medium WS-CM and STE, and high WS-CM and STE, was minimal (34 and 65 transcripts, respectively). Hierarchical clustering revealed that gene expression profiles for STE and medium WS-CM co-clustered, while those affected by the high dose of WS-CM clustered distinctly. Functional analysis revealed that WS-CM, but not STE, uniquely affected genes involved in immune cell development and inflammatory response. Cascades of upstream regulators (e.g., TNF, IL1β, NFƙB) were identified for the observed gene expression changes and generally suppressed by WS-CM, but not by STE. Collectively, these findings demonstrate that combustible and non-combustible tobacco products elicit distinct biological effects, which could explain the observed chronic immune suppression in smokers.

Smokeless tobacco use and circulatory disease risk: a systematic review and meta-analysis

Objective

Smokeless tobacco use is a public health issue throughout the world, but reviews and analyses of circulatory disease risks associated with smokeless tobacco use may be outdated or incomplete. This study provides a thorough and comprehensive review and meta-analysis of circulatory disease risks in high-income countries, including recently published study estimates.

Methods

We conducted a systematic review of studies of circulatory disease risks associated with smokeless tobacco use in Europe and North America that were identified from electronic databases and reference lists. Study estimates were extracted by region, smokeless tobacco use status, cigarette smoking status, and circulatory condition and combined in meta-analysis using a random-effects model. We used the Newcastle-Ottawa scale to assess study quality and risk of bias.

Results

We identified 17 relevant cohort studies, two pooled analyses, five case-control studies and one cross-sectional analysis. We found increased risk of heart disease (relative risk (RR) 1.17, 95% CI 1.09 to 1.27) and stroke (RR 1.28, 95% CI 1.01 to 1.62) among US smokeless tobacco users compared with non-users. Increased circulatory disease risk was not observed among Swedish smokeless tobacco users.

Conclusion

US smokeless tobacco users were found to have increased risk of heart disease and stroke.

A National Comparison of Dual Users of Smokeless Tobacco and Cigarettes and Exclusive Cigarette Smokers, 2015-2016

Introduction

While smoking rates have declined, use of smokeless tobacco (ST) has remained constant. ST is heavily marketed to cigarette smokers, and many ST users smoke cigarettes. This study provides updated comparisons of the characteristics, smoking behaviors, and perceptions of US adult dual ST and cigarette users and exclusive cigarette smokers in 2015-2016.

Methods

Data were from nationally representative, cross-sectional surveys from 2015 and 2016. Adult smokers reported past 30-day use of ST, current cigarette smoking, risk perceptions, smoking, and quitting behaviors. We estimated Rao-Scott χ2 and adjusted odds ratios (AORs) to compare dual users and exclusive smokers.

Results

Dual users were more likely to be younger, reside in nonmetropolitan statistical areas (MSA) and outside the Northeast United States. Adjusting for covariates, dual users did not differ significantly from exclusive smokers on most smoker characteristics, including number of past year quit attempts. Dual users were more likely to report past 30-day use of novel tobacco products (AORs 2.90 [little cigars and cigarillos] to 11.02 [hookah]). Dual users who reported at least 1 past year cigarette quit attempt were more likely than exclusive smokers to report using ST, traditional cigars, hookah, or heat-not-burn as a past year quit method (AOR: 9.54 [95% CI: 3.22 to 28.23]).

Conclusions

Smokers who use ST are more likely than exclusive smokers to attempt to quit smoking cigarettes using other tobacco products. These findings may be attributed to increasing use prevalence of novel products. We recommend further monitoring to assess polytobacco use and differences among these populations.

Implications

Many current ST users smoke cigarettes and ST promotions often target cigarette smokers. As the FDA considers ST regulations and implements a nicotine centered regulatory framework, it is imperative to evaluate how these policies and promotion of ST as potentially reduced risk products impact dual and polytobacco use. Our study found that many dual users engage in novel tobacco use in general and as a cessation method. Consideration of ST and polytobacco use among smokers may be helpful in the development of forthcoming FDA regulations, messaging, and interventions.

A systematic review on association between smokeless tobacco & cardiovascular diseases

BACKGROUND & OBJECTIVES

The association of smokeless tobacco (SLT) with cardiovascular diseases has remained controversial due to conflicting reports from various countries. Earlier meta-analyses have shown significantly higher risk of fatal myocardial infarction and stroke in SLT users. However, the risk of hypertension (HTN) with SLT products has not been reviewed earlier. This systematic review was undertaken to summarize the evidence available from global literature on the association of SLT with cardiovascular outcomes - heart disease, stroke and HTN.

METHODS

A systematic literature search was performed in PubMed and Google Scholar since their inception till October 2017 using pre-decided search terms and inclusion/exclusion criteria. Data were extracted from studies included independently by two authors and reviewed.

RESULTS

The review included 50 studies - 23 on heart disease, 14 on stroke and 14 on HTN. Majority of the studies evaluating heart disease or stroke were conducted in the European Region and most of these did not find a significant association between SLT use and either of these outcomes. On the other hand, 70 per cent of the studies on HTN were reported from South-East Asian Region and about half of the studies found a higher risk of HTN in SLT users.

INTERPRETATION & CONCLUSIONS

Current available evidence is insufficient to conclusively support the association of cardiovascular diseases with SLT use due to variability in results and methodological constraints in most of the studies. Region and product-specific well-designed studies are required to provide this evidence to the policymakers. However, advice on cessation of SLT products should be offered to patients presenting with cardiovascular diseases.

The Risk of Hypertension and Other Chronic Diseases: Comparing Smokeless Tobacco with Smoking

BACKGROUND

In the past, studies have compared smokeless tobacco and non-tobacco users for the risk of various chronic diseases. The differences in the risk of chronic diseases between smokeless tobacco user and smokers have not been explored. The objective of this study is to estimate the risk of chronic diseases among smokeless tobacco users compared to smokers.

METHODS

The data were used from the Study on Global Ageing and Adult Health (SAGE) Wave-1, conducted in 2007-2008 in India. The study sample is the respondents who reported consuming any form of tobacco in last 1 month. The total sample size was 4,038 respondents. The odds ratio of chronic morbidities was estimated taking smokers as the reference category.

RESULTS

The odds ratios for (self-reported) diabetes, asthma, and hypertension were not significant for smokeless tobacco user compared to smoked tobacco users. The odds ratio of chronic lung diseases (CLDs) was significantly lower among smokeless tobacco users compared to smoked tobacco users. The odds ratio of hypertension (measured) combined with low education and belonging to lowest wealth quintiles were not significant for smokeless tobacco users compared to smoked tobacco users. Duration of the use of smokeless tobacco and quantity of use was found to have no significant relation with risk of chronic diseases as compared to smoking.

CONCLUSION

This study did not find the significantly higher risk of chronic morbidities except for CLD for smokeless tobacco users compared to smoked tobacco users. The study suggests that the use of any form of tobacco may have a similar risk of chronic diseases.

Cardiovascular effects of electronic cigarettes

Cardiovascular safety is an important consideration in the debate on the benefits versus the risks of electronic cigarette (EC) use. EC emissions that might have adverse effects on cardiovascular health include nicotine, oxidants, aldehydes, particulates, and flavourants. To date, most of the cardiovascular effects of ECs demonstrated in humans are consistent with the known effects of nicotine. Pharmacological and toxicological studies support the biological plausibility that nicotine contributes to acute cardiovascular events and accelerated atherogenesis. However, epidemiological studies assessing Swedish smokeless tobacco, which exposes users to nicotine without combustion products, generally have not found an increased risk of myocardial infarction or stroke among users, but suggest that nicotine might contribute to acute cardiovascular events, especially in those with underlying coronary heart disease. The effects of aldehydes, particulates, and flavourants derived from ECs on cardiovascular health have not been determined. Although ECs might pose some cardiovascular risk to users, particularly those with existing cardiovascular disease, the risk is thought to be less than that of cigarette smoking based on qualitative and quantitative comparisons of EC aerosol versus cigarette smoke constituents. The adoption of ECs rather than cigarette smoking might, therefore, result in an overall benefit for public health.

Gene expression profiles associated with cigarette smoking and moist snuff consumption

Background

Among the different tobacco products that are available on the US market, cigarette smoking is shown to be the most harmful and the effects of cigarette smoking have been well studied. US epidemiological studies indicate that non-combustible tobacco products are less harmful than smoking and yet very limited biological and mechanistic information is available on the effects of these alternative tobacco products. For the first time, we characterized gene expression profiling in PBMCs from moist snuff consumers (MSC), compared with that from consumers of cigarettes (SMK) and non-tobacco consumers (NTC).

Results

Microarray analysis identified 100 differentially expressed genes (DEGs) between the SMK and NTC groups and 46 DEGs between SMK and MSC groups. However, we found no significant differences in gene expression between MSC and NTC. Both hierarchical clustering and principle component analysis revealed that MSC and NTC expression profiles were more similar than to SMK. Random forest classification identified a subset of DEGs which predicted SMK from either NTC or MSC with high accuracy (AUC 0.98).

Conclusions

PMBC gene expression profiles of NTC and MSC are similar to each other, while SMK exhibit distinct profiles with alterations in immune related pathways. In addition to discovering several biomarkers, these studies support further understanding of the biological effects of different tobacco products.

Trial registration

ClinicalTrials.gov. Identifier: NCT01923402. Date of Registration: August 14, 2013. Study was retrospectively registered.

Electronic supplementary material

The online version of this article (doi:10.1186/s12864-017-3565-1) contains supplementary material, which is available to authorized users.

Non-Smoking Tobacco Affects Endothelial Function in Healthy Men in One of the Largest Health Studies Ever Performed; The Nord-Trøndelag Health Study in Norway; HUNT3

BACKGROUND

Oral tobacco (snuff) is taking a large market share in Scandinavia, especially with young users. However, long-term health effects are unknown. Small studies show association between snuff and reduced endothelial function, representing an early stage of vascular injury that often precedes manifest cardiovascular disease by several years. We therefore determined the associations between snuff and endothelial function in a large sample of healthy Norwegian men.

METHODS AND DESIGN

In the Fitness substudy of the Nord-Trøndelag Health Study (HUNT3), endothelial function was measured by flow-mediated dilation (FMD). Aerobic fitness was measured by peak oxygen uptake (VO2peak). A cross-sectional design including 1 592 self-reported healthy men compared these observations with records of present tobacco use, standard cardiovascular risk factors, and socioeconomic status, using general linear models.

RESULTS

FMD was lower in snuff users (FMD: 4.12%, 3.63, 4.61) compared to non-users (FMD: 4.52%, 4.27, 4.78) after adjustment for age (difference: -0.57%, -1.12, -0.01). After further adjustment for potential confounders, FMD still tended to be lower in snuff users than in non-users (difference: -0.53%, -1.09, 0.02). This difference was even more pronounced in the inactive snuff users (-0.83%, -1.59, -0.06) and in the low fit snuff users (-0.74%, CI -0.55, 0.079).

CONCLUSIONS

Oral tobacco is associated with a tendency towards reduced endothelial function, indicating vascular changes that precede cardiovascular disease. The strongest associations were found in men with low physical activity or reduced aerobic fitness.

Short-term acute effects of gutkha chewing on heart rate variability among young adults: A cross-sectional study

BACKGROUND AND OBJECTIVES

An increase in the consumption of smokeless tobacco has been noticed among high school, college students, and adults. Despite the antiquity and popularity of chewing tobacco in India, its effects have not been investigated systematically in humans. The aim of this study was to investigate acute effects of gutkha chewing on heart rate variability (HRV) among healthy young adults.

MATERIALS AND METHODS

A total of 60 young adult males were included in the study. Each individual was asked to chew tobacco and subjected to HRV analysis. HRV analysis using short-term electrocardiogram recording was used to measure HRV parameters before gutkha chewing and at 5, 15, and 30 min after chewing tobacco. One-way analysis of variance and paired t-test was used to assess changes over time.

RESULTS

There was a significant increase in heart rate (HR) during tobacco chewing. Mean HR at baseline measured 73.0 ± 6.2 bpm. There was a rise in mean HR to 83.7 ± 9.1 bpm at 5 min during tobacco chewing and gradual reduction to baseline observed after 15 min followed by no significant change till 30 min. The normalized low-frequency power and LF/high-frequency (HF) power ratio were elevated after 5 min; however, normalized HF power was reduced after 5 min tobacco chewing.

CONCLUSION

Gutkha is closely associated with traditional cardiovascular risk factors as detected by a transient enhancing sympathetic activity during tobacco chewing in the form of increased HRV parameters or an imbalance between sympathetic and parasympathetic neural activity among healthy young adults.

Cardiovascular toxicity of nicotine: Implications for electronic cigarette use

The cardiovascular safety of nicotine is an important question in the current debate on the benefits vs. risks of electronic cigarettes and related public health policy. Nicotine exerts pharmacologic effects that could contribute to acute cardiovascular events and accelerated atherogenesis experienced by cigarette smokers. Studies of nicotine medications and smokeless tobacco indicate that the risks of nicotine without tobacco combustion products (cigarette smoke) are low compared to cigarette smoking, but are still of concern in people with cardiovascular disease. Electronic cigarettes deliver nicotine without combustion of tobacco and appear to pose low-cardiovascular risk, at least with short-term use, in healthy users.

Testing messages to reduce smokers' openness to using novel smokeless tobacco products

INTRODUCTION

Tobacco manufacturers' aggressive promotion of new smokeless tobacco products such as snus warrants a timely and effective public health response. This study tested potential countermarketing messages to discourage current and former smokers from becoming dual users of smokeless tobacco and cigarettes.

METHODS

In a pretest-post-test experiment, 1836 adult current and recently former smokers from a national sample were randomised to view one of six antismokeless tobacco ads followed by a snus ad, to view a control ad followed by a snus ad; or to view two control ads. Perceived effectiveness of ads and actual changes in attitudes and openness to snus were compared across groups using analyses of variance.

RESULTS

Some ads that were perceived as most effective did not change attitudes or openness to trying snus, and conversely, some ads not perceived as effective changed attitudes and openness to snus. Ads portraying the negative health effects of smokeless tobacco were perceived as most effective, but ads with antitobacco industry themes significantly decreased favourable attitudes toward snus. Responses to ads were different for smokers who had ever used smokeless tobacco: for this group health effects and humorous/testimonial ads were effective.

CONCLUSIONS

Measures of perceived effectiveness of antitobacco ads need to be augmented with measures of actual effectiveness to assess countermarketing messages. Some of the developed ads, such as ads with anti-industry themes, were effective for the overall population of smokers whereas humorous/testimonial and health effects ads were particularly effective in changing attitudes of past users of smokeless tobacco.

A qualitative study of smokers' responses to messages discouraging dual tobacco product use

Cigarette companies increasingly promote novel smokeless tobacco products to smokers, encouraging them to use smokeless tobacco in smoke-free environments. New messages may counteract this promotion. We developed 12 initial anti-smokeless message ideas and tested them in eight online focus groups with 75 US smokers. Those smokers who never tried smokeless tobacco were unaware of health risks of novel smokeless tobacco products, perceived scary messages as effective and acknowledged the addictive nature of nicotine. Smokers who had tried smokeless tobacco shared their personal (mainly negative) experiences with smokeless tobacco, were aware of health risks of novel smokeless tobacco products, but denied personal addiction, and misinterpreted or disregarded more threatening messages. Portraying women as smokeless tobacco users was perceived as unbelievable, and emphasizing the lack of appeal of novel smokeless tobacco products was perceived as encouraging continued smoking. Future ads should educate smokers about risks of novel smokeless tobacco products, but past users and never users may require different message strategies.

A novel model mouth system for evaluation of In Vitro release of nicotine from moist snuff

Background

Pouch moist snuff, as a form of oral smokeless tobacco products, is becoming increasingly popular in North America, Scandinavia (where it is known as Snus), South Asia and parts of Africa. User usually places a pouch between the upper jaw and cheek to obtain euphoria from tobacco, leading to partial intake of tobacco constituents. To evaluate user exposure to tobacco, an approach with a novel model mouth system was developed and applied to evaluate release of nicotine from the pouch.

Results

A novel model mouth system has been developed to evaluate release behavior of tobacco constituents in pouch moist snuff. The system consists of the release medium reservoir module, the flow speed control module, the temperature control module, nicotine release module, and release solution collection module, and simulates buccal condition in terms of temperature, saliva compositions, and the rate of saliva production, etc. Artificial saliva was used as the release medium to evaluate release of nicotine in pouch moist snuff. The optimized test condition was that the release temperature of 37°C and the flow rate performed at 0.2 mL min-1 in the first 5 min and 0.1 mL min-1 in the next 55 min. The performance of the model mouth system was compared with in vivo data of nicotine release in human volunteers. Data from 23 brands of moist snuff indicated that nicotine release rates increased with extraction time and approximately 60-90% of nicotine was released after 30 min of extraction in most of the samples, and the release behavior of nicotine was affected by product weights, nicotine concentration, and product pH, etc.

Conclusion

The model mouth system can be used to evaluate the release behavior of constituents in pouch moist snuff, especially those directly related to human health such as nicotine and tobacco specific nitrosamine (TSNA), etc. This indicated that the system is an alternative tool to evaluate user exposure to tobacco. With further testing and validation, the model mouth system can be applied in risk evaluation of smokeless tobacco products.

Alternative tobacco product use and smoking cessation: a national study

OBJECTIVES

We investigated the frequency of alternative tobacco product use (loose leaf, moist snuff, snus, dissolvables, electronic cigarettes [e-cigarettes]) among smokers and the association with quit attempts and intentions.

METHODS

A nationally representative probability-based cross-sectional survey of 1836 current or recently former adult smokers was completed in November 2011. Multivariate logistic regressions evaluated associations between alternative tobacco product use and smoking cessation behaviors.

RESULTS

Of the smokers, 38% had tried an alternative tobacco product, most frequently e-cigarettes. Alternative tobacco product use was associated with having made a quit attempt, and those intending to quit were significantly more likely to have tried and to currently use the products than were smokers with no intentions to quit. Use was not associated with successful quit attempts. Interest in future use of alternative tobacco products was low, except for e-cigarettes.

CONCLUSIONS

Alternative tobacco products are attractive to smokers who want to quit smoking, but these data did not indicate that alternative tobacco products promote cessation. Unsubstantiated overt and implied claims that alternative tobacco products aid smoking cessation should be prohibited.

Is there any association between use of smokeless tobacco products and coronary heart disease in Bangladesh?

BACKGROUND

Most epidemiological studies exploring the association between smokeless tobacco (SLT) use and coronary heart disease (CHD) have been in Western populations, and have focused on SLT products used in those countries. Few studies come from South Asian countries. Our objective was to determine the association between SLT use and CHD among non-smoking adults in Bangladesh.

METHODS

A matched case-control study of non-smoking Bangladeshi adults aged 40-75 years was conducted in 2010. Incident cases of CHD were selected from two cardiac hospitals. Community controls, matched to CHD cases, were selected from neighbourhoods, and hospital controls were selected from outpatient departments of the same hospitals. The Rose Angina Questionnaire (RAQ) was also used to re-classify cases and controls.

RESULTS

The study enrolled 302 cases, 1,208 community controls and 302 hospital controls. Current use was higher among community controls (38%) compared to cases (33%) and hospital controls (32%). Current use of SLT was not significantly associated with an increased risk of CHD when community controls were used (adjusted OR 0.87, 95% CI 0.63-1.19), or when hospital controls were used (adjusted OR 1.00, 95% CI 0.63-1.60), or when both control groups were combined (adjusted OR 1.00, 95% CI 0.74-1.34). Risk of CHD did not increase with use of individual types except gul, frequency, duration, past use of SLT products, or using the RAQ to re-classify cases and controls. There was a significant association between gul use and CHD when both controls were combined (adjusted OR 2.93, 95% CI 1.28-6.70).

CONCLUSIONS

There was no statistically significant association between SLT use in general and CHD among non-smoking adults in Bangladesh. Further research on the association between gul use and CHD in Bangladesh along with SLT use and CHD in other parts of the subcontinent will guide public health policy and interventions that focus on SLT-related diseases.

Smokeless tobacco use in the United States military: a systematic review

INTRODUCTION

Smokeless tobacco (ST) use represents an important target for intervention in the U.S. military population because it impairs "military readiness" and harms the health of the military. This paper aims to provide a systematic review of ST studies conducted in the U.S. military population in order to assess the content of existing ST research in this population, provide estimates of prevalence and clinically relevant use patterns, and discuss how these findings might be used to guide future ST research among this population.

METHODS

We reviewed articles published through December 2010 using PubMed and PsycINFO databases, Google Scholar, and any relevant articles' reference lists. Inclusion criteria included focus on a U.S. military sample, English language, measured tobacco use, and ST prevalence was reported or could be calculated. To the extent possible, each article was coded for demographics, socioeconomic status, prevalence, amount, frequency, and length of use, and quit intentions/attempts.

RESULTS

Thirty-nine articles met criteria for inclusion. Less than half focused primarily on ST use among military personnel. The remaining studies measured ST use in the context of other behaviors. Findings related to clinically relevant behaviors included a need for more cohort and intervention studies, a better understanding of ST use in combination with cigarettes (i.e., concurrent use), and identifying risk factors for ST initiation and use.

DISCUSSION

ST use is prevalent among military personnel, as is concurrent use of cigarettes and ST. We provide a number of recommendations to guide future research in this important, yet understudied, area.

The scientific foundation for tobacco harm reduction, 2006-2011

Over the past five years there has been exponential expansion of interest in tobacco harm reduction (THR), with a concomitant increase in the number of published studies. The purpose of this manuscript is to review and analyze influential contributions to the scientific and medical literature relating to THR, and to discuss issues that continue to stimulate debate. Numerous epidemiologic studies and subsequent meta-analyses confirm that smokeless tobacco (ST) use is associated with minimal risks for cancer and for myocardial infarction; a small increased risk for stroke cannot be excluded. Studies from Sweden document that ST use is not associated with benign gastrointestinal disorders and chronic inflammatory diseases. Although any form of nicotine should be avoided during pregnancy, the highest risks for the developing baby are associated with smoking. It is documented that ST use has been a key factor in the declining rates of smoking and of smoking-related diseases in Sweden and Norway. For other countries, the potential population health benefits of ST are far greater than the potential risks. In follow-up studies, dual users of cigarettes and ST are less likely than exclusive smokers to achieve complete tobacco abstinence, but they are also less likely to be smoking. The health risks from dual use are probably lower than those from exclusive smoking. E-cigarette users are not exposed to the many toxicants, carcinogens and abundant free radicals formed when tobacco is burned. Although laboratory studies have detected trace concentrations of some contaminants, it is a small problem amenable to improvements in quality control and manufacturing that are likely with FDA regulation as tobacco products. There is limited evidence from clinical trials that e-cigarettes deliver only small doses of nicotine compared with conventional cigarettes. However, e-cigarette use emulates successfully the cigarette handling rituals and cues of cigarette smoking, which produces suppression of craving and withdrawal that is not entirely attributable to nicotine delivery. THR has been described as having "the potential to lead to one of the greatest public health breakthroughs in human history by fundamentally changing the forecast of a billion cigarette-caused deaths this century."

Association between smoking and outcomes in older adults with atrial fibrillation

Tobacco smoking is a risk factor for atrial fibrillation (AF), but little is known about the impact of smoking in patients with AF. Of the 4060 patients with recurrent AF in the Atrial Fibrillation Follow-up Investigation of Rhythm Management (AFFIRM) trial, 496 (12%) reported having smoked during the past two years. Propensity scores for smoking were estimated for each of the 4060 patients using a multivariable logistic regression model and were used to assemble a matched cohort of 487 pairs of smokers and nonsmokers, who were balanced on 46 baseline characteristics. Cox and logistic regression models were used to estimate the associations of smoking with all-cause mortality and all-cause hospitalization, respectively, during over 5 years of follow-up. Matched participants had a mean age of 70 ± 9 years (± S.D.), 39% were women, and 11% were non-white. All-cause mortality occurred in 21% and 16% of matched smokers and nonsmokers, respectively (when smokers were compared with nonsmokers, hazard ratio=HR=1.35; 95% confidence interval=95%CI=1.01-1.81; p=0.046). Unadjusted, multivariable-adjusted and propensity-adjusted HR (95% CI) for all-cause mortality associated with smoking in the pre-match cohort were: 1.40 (1.13-1.72; p=0.002), 1.45 (1.16-1.81; p=0.001), and 1.39 (1.12-1.74; p=0.003), respectively. Smoking had no association with all-cause hospitalization (when smokers were compared with nonsmokers, odds ratio=OR=1.21; 95%CI=0.94-1.57, p=0.146). Among patients with AF, a recent history of smoking was associated with an increased risk of all-cause mortality, but had no association with all-cause hospitalization.

Genetics of the association between intelligence and nicotine dependence: a study of male Swedish twins

AIMS

Previous studies have found inverse associations between intelligence quotient (IQ) and cigarette smoking, but the causal pathways linking IQ with smoking status and nicotine dependence (ND) are not well understood. The aim of this study was to explore the associations between IQ and ND using a genetically informative twin design to detect whether any association is because of shared genetic or environmental factors.

DESIGN

A population-based twin cohort with IQ measured in adolescence and ND later in life, analysed by classical twin modeling based on linear structural equations.

SETTING

Swedish national registry data.

PARTICIPANTS

A total of 5040 male twins born 1951-84.

MEASUREMENTS

IQ was measured at military conscription at a mean age of 18 years. ND was self-reported at the ages of 22-57 years using the Fagerström Test for ND scale (FTND). Both cigarette smoking and Swedish snus use were analysed.

FINDINGS

Both IQ and ND showed moderate heritability (0.58 and 0.39, respectively). The heritability of ND was similar for cigarette smoking and snus use. The phenotypic correlation between IQ and ND was weak: -0.11 (-0.16, -0.06) for total ND. Bivariate analysis revealed that this correlation was mainly because of genetic factors, but still the genetic correlation between IQ and ND from cigarette smoking was only -0.24.

CONCLUSIONS

Nicotine dependence, as measured by the Fagerström Test for Nicotine Dependence, shows moderate heritability in both smokers and snus users but is only weakly associated with intelligence quotient; common genetic factors underlying nicotine dependence and intelligence quotient probably account for little of the observed association between smoking and intelligence quotient.