Cigarettes, ENDS Use, and Chronic Obstructive Pulmonary Disease Incidence: A Prospective Longitudinal Study

Comparing smoking-related disease rates from e-cigarette use with those from tobacco cigarette use: a reanalysis of a recently-published study

BACKGROUND

A recent meta-analysis by Glantz et al. combined odds ratios (ORs) relating e-cigarette use (vaping) to cardiovascular disease, stroke, chronic obstructive pulmonary disease (COPD) and other endpoints. They assessed all included studies as having a low risk of bias, and concluded that vaping and smoking have a "comparable" disease odds, with dual use associated with more risk than smoking.

AIM

To examine the accuracy of these conclusions, giving particular attention to myocardial infarction (MI), stroke and COPD.

METHODS

We determined (1) whether the pooled random-effect estimates were correctly calculated from the ORs included, (2) whether the detailed outcomes were correctly described and appropriate and whether additional OR estimates could have been included from the studies considered, (3) whether the data were correctly extracted from the source papers, (4) whether some studies should definitely or possibly have been excluded, (5) what the pooled OR estimates were for MI, stroke and COPD after excluding definitely invalid results and restricting attention to data based on appropriate disease definitions, (6) how estimates of the excess risk (ER = OR - 1) for vaping compare to those we estimate for quitting, (7) whether various sources of bias were adequately accounted for, and (8) whether conclusions were confirmed in studies where reverse causation was not an issue, i.e. where disease onset could not have preceded uptake of vaping.

RESULTS

We found no major issues regarding pooled estimation, description of diagnoses and extraction of data from the source papers, but some studies should have been excluded, and one further result was available for MI. Using data appropriately extracted for valid diagnoses, we derived pooled OR estimates for vaping vs. smoking of 0.48 (95%CI: 0.35-0.67) for MI, 0.65 (0.49-0.86) for stroke and 0.46 (0.35-0.60) for COPD. These showed a significantly reduced risk for vaping, similar to or lower than expected for quitting smoking for 5 to 10 years, highly relevant given the short period of vaping following earlier smoking for most study participants. For dual use vs. smoking, pooled OR estimates were 1.41 (1.18-1.68) for MI, 1.39 (1.06-1.82) for stroke and 1.32 (1.17-1.50) for COPD. The studies considered were predominantly cross-sectional so could not account for reverse causation, or for those who smoked and became dual users possibly having smoked more cigarettes or smoked for a longer period than those not doing so. Only three publications accounted for reverse causation, each using the same data source, and each found a significant effect of smoking, but not vaping, on the diseases considered.

CONCLUSION

The claim in the original meta-analysis that the studies had a low risk of bias is demonstrably incorrect, and even the biased data suggests that switching to e-cigarettes may reduce disease risk similarly to quitting. Biases may also explain the somewhat higher risk observed in those who smoked and vaped than in those smoking exclusively. Very limited unbiased data found no significant effect of vaping on the diseases considered. Though more good studies are urgently needed, the conclusions of Glantz et al. are not supported by the currently available evidence.

Inaccurate and misleading meta-analysis of E-cigarettes and population-based diseases

A random-effects meta-analysis by Glantz et al. recently concluded that the odds of several diseases among current e-cigarette users and smokers were similar. This report details serious deficiencies. We used descriptive analysis methods to assess the studies the authors selected for cardiovascular disease (CVD), stroke and chronic obstructive pulmonary disease (COPD) among e-cigarette users vs. nonusers. We examined all of the source studies for these categories. We demonstrate that the meta-analysis by Glantz et al. had three principal deficits that were avoidable: (1) mixing unjustified and incomprehensible disease outcomes, such as erectile dysfunction with fatal CVDs and influenza with COPD; (2) using survey datasets containing no temporal information about smoking/vaping initiation and disease diagnosis; (3) using longitudinal studies that didn't account for changes in vaping and smoking during follow-up waves. The meta-analysis by Glantz et al. is misleading and inaccurate. The deficits are only apparent to investigators thoroughly experienced with the data from the source studies. We conclude that Glantz et al. failed to meet basic criteria for the quality of source studies; the results of their meta-analysis are invalid.

Association between electronic cigarette use and respiratory outcomes among people with no established smoking history: a comprehensive review and critical appraisal

Nicotine consumption in many countries is shifting away from combustible cigarettes and toward electronic cigarettes (ECs). Understanding the overall population-level impact requires weighing their possible benefits (e.g., for smoking cessation/switching) vs harms (e.g., long-term health risks). However, current evidence on health risks is limited by the absence of long-term data and confounding by prior cigarette smoking history. Focusing on short- to medium-term respiratory outcomes associated with EC use among people who never smoked (PWNS) is informative. We perform a narrative review and critical appraisal of studies examining the prospective association between exclusive EC use and respiratory outcomes among PWNS (either true never-smoking or never-established smoking). We included 12 studies with prospective designs that examine a range of respiratory outcomes subsequent to EC use among PWNS. Eight studies did not find statistically significant differences in respiratory risk associated with baseline EC use. The remaining five studies reported a significant association in at least one analysis, but in four of these studies, associations were not robust across models. Limitations included overreliance on data from the U.S. Population Assessment of Tobacco and Health, uncertain directionality (i.e., pre-existing respiratory conditions were not always ruled out), confounding by other combustible tobacco use, and small sample sizes. All but one study lacked clear and statistically significant evidence of self-reported respiratory diagnoses associated with EC use among PWNS, or showed a tenuous association with mild respiratory symptoms. This has favorable implications for ECs' population health impact; however, small sample sizes and statistical biases limit this evidence. A formal systematic review on this topic is forthcoming.

The impact of electronic cigarette use on chronic obstructive pulmonary disease: A systematic review and meta-analysis

OBJECTIVES

Electronic cigarette (or e-cigarette) use is increasing globally. To date, there are limited pooled estimates regarding the impact of e-cigarette use on chronic obstructive pulmonary disease (COPD). The present meta-analysis of large-scale population-based observational studies evaluates the impact of e-cigarette use on COPD.

METHODS

A systematic search of observational studies published between 1/2020-1/2024 was conducted in MEDLINE and Scopus based on PRISMA Guidelines.

RESULTS

Of 3670 originally retrieved papers, 7 observational studies (including 4 cross-sectional studies and 3 prospective cohort studies) fulfilled all search criteria and were used for the present meta-analysis which encompassed in total, 3,552,424 participants, including 138,698 cases with COPD. The findings from the random-effects meta-analysis (I2 = 22 %, Cochran Q (6) = 7.19, p = 0.307) suggested that use of e-cigarette among non-cigarette users was associated with (pooled Relative Risk, pRR) 1.50-times higher likelihood of COPD (95 % Confidence Interval (CI): 1.27, 1.73). Sensitivity analysis by leave-one-out analysis confirmed the aforementioned results (range of pRR values: 1.46 to 1.61, all p < 0.001). Stratified pooled effect estimates of cross-sectional studies only (pOR = 1.55, 95 % CI: 1.26, 1.84) and of prospective cohort studies only (pRR = 1.52, 95 % CI: 0.98-2.06), revealed that the e-cigarette users exhibit between 52 % and 55 % significantly higher likelihood of COPD.

CONCLUSIONS

The current meta-analysis highlights that e-cigarette users face an increased risk of developing COPD. Therefore, public health interventions aimed at diminishing e-cigarette are necessary for preventing COPD.

Observational studies of exposure to tobacco and nicotine products: Best practices for maximizing statistical precision and accuracy

Non-randomized observational studies can track risk-induction and -reduction associated with real-world use of non-combusted nicotine and tobacco products. The objective of this analysis was to evaluate the precision and accuracy of recent studies and to identify opportunities for further optimizing future study designs. The ROBINS framework for minimizing statistical bias was translated to specific considerations that spanned the selection and quantification of cohorts, exposure, and outcomes. These principles were then considered within the context of a recent comprehensive meta-analysis, representing 107 observational studies, which evaluated the effects of using electronic cigarettes (ECs), combusted cigarettes (CCs) and dual use of both. The meta-analysis had previously reported the relative risk from all-sources, including tobacco use and non-tobacco use. We now report the product use-specific risk associated with displacing CCs with ECs indicated from the primary references, along with observations regarding the precision of characterization of CC and EC exposure in the cited studies.

Association of e-cigarette and cigarette use with self-reported chronic obstructive pulmonary disease (COPD): a multivariable analysis of a large United States data set

BACKGROUND

Prior research has linked e-cigarette use with chronic obstructive pulmonary disease (COPD). We examined the relationship between e-cigarette use and COPD prevalence in older adults with varying cigarette use status.

METHODS

Data from the 2020 National Health Interview Survey were used to estimate the association between each of 9 exposure categories based on cigarette use (never, former, current) and e-cigarette use (never, former, current), with respondent-reported physician-diagnosed COPD prevalence in individuals 40 years and older (N = 22,997). Weighted multivariable analysis accounted for cigarette pack years, age of cigarette smoking onset, race, income-to-poverty ratio, rurality, gender, age, and medical comorbidities. Sensitivity of results was tested in 3 separate models with addition of years since quit cigarettes, smoking intensity and duration.

RESULTS

39.7% of individuals reported ever smoking cigarettes and 10.2% reported ever using e-cigarettes. Among individuals with ever e-cigarette use, 88.5% also reported current or former cigarette smoking. The weighted prevalence of COPD was 7.2%; Among those who reported former cigarette smoking, the highest risk of COPD prevalence compared to never cigarette/never e-cigarette use was in those currently using e-cigarettes (adjusted risk ratio (ARR) 2.82, 95% confidence interval (CI) [1.5, 5.3]). The ARR for former cigarette/current e-cigarette use was significantly larger than the ARR for former cigarette/never e-cigarette use (p < 0.002) in 3 out of 4 models; however, one model had the ARR attenuated to 1.35 (0.67, 2.76) when years since quitting smoking was added to the model. Other cigarette/e-cigarette combinations were also sensitive to how cigarette smoking history was modeled. For example, ARR for former cigarette/former e-cigarette (1.68 [1.00, 2.80] and current cigarette/former e-cigarette (2.50 [1.56,4.02]) were reduced to 1.05 (0.62, 1.77) and 1.04 (0.62, 1.75) respectively, when cigarette smoking duration was substituted for pack-years.

CONCLUSIONS

Current e-cigarette use among former cigarette smokers was associated with significantly higher COPD prevalence compared to never e-cigarette use. However, COPD risk for most cigarette/e-cigarette combinations could be greatly attenuated by how cigarette smoking history was modeled, raising questions about the robustness of these associations in prior research and the possibility of reverse causality in prior cross-sectional research.

Use of e-cigarettes, traditional combustible cigarettes, and high sensitivity C-reactive protein: The Cross Cohort Collaboration

This cross-sectional study included 18,797 participants from 6 longitudinal cohorts (CARDIA, FHS Gen III, HCHS/SOL, MESA, MiHeart, and REGARDS), and 5,806 of them had high-sensitivity C-reactive protein (hs-CRP) measurements. We found that exclusive electronic cigarette (EC) use was associated with significantly lower hs-CRP levels compared to exclusive combustible cigarette use, suggesting a potentially lower inflammatory burden. hs-CRP levels in dual users and former smokers currently using EC were comparable to those observed in exclusive cigarette smokers. Exclusive EC users showed no significant difference in hs-CRP levels compared to never cigarette smokers. These findings have important implications for tobacco regulation, public health, and clinical practice, highlighting the need for continued monitoring of potential EC-related health impacts.

Lifestyle Factors and Associations with Individual and Comorbid Cardiometabolic and Pulmonary Disease Among U.S. Adults

BACKGROUND

Although lifestyle factors have been linked to chronic diseases among adults, their association with diagnosed individual and comorbid cardiometabolic (CMD) and pulmonary disease (PD) is not fully known. This study aimed to examine the associations between lifestyle factors and individual and comorbid CMD and PD among U.S. adults.

METHODS

We used cross-sectional data from the 2017-2020 National Health and Nutrition Examination Survey (n = 7394). Health care provider's diagnosis of CMD and PD and lifestyle factors (i.e., past 5-day tobacco use, past 12-month alcohol use, diet, sleep troubles, and physical activity) were assessed. Adjusted odds ratios were estimated using logistic and multinomial logistic regression.

RESULTS

Trouble sleeping was associated with increased odds of CMD (OR: 2.47) and PD (OR: 2.29) individually, while physical activity was associated with lower odds (OR: 0.75, OR: 0.77). Past 5-day tobacco (OR: 2.36) and past year alcohol (OR: 1.61) use were associated with increased PD odds. Lifestyle factors were associated with increased odds of comorbid CMD and PD.

CONCLUSIONS

Lifestyle factors were associated with increased odds of individual and comorbid CMD and PD among adults. CMD and PD prevention should involve promoting lifestyle modification and implementation of policies that eliminate structural barriers to healthy lifestyle adoption.

Respiratory chronic health conditions and racial disparities associated with e-cigarette use: a cross-sectional analysis using behavioral risk factor surveillance data

Background

Chronic Obstructive Pulmonary Disease (COPD), mainly caused by cigarette smoking, is one of the leading causes of death in the United States (US) and frequent asthma attacks are often exacerbated by cigarette use. Electronic cigarettes (e-cigarettes) are often used to quit cigarette smoking. Prevalence of COPD, asthma, cigarette use, and e-cigarette use differs between racial/ethnic groups. The overall objective was to assess the associations between e-cigarette use and COPD and asthma and how race/ethnicity and cigarette smoking modifies these associations.

Methods

Data were retrieved from the 2016-2018 and 2020-2021 Behavioral Risk Factor Surveillance System datasets, a national annual health survey representing the US general adult population. Frequency and weighted percentages or means and standard deviations were obtained. Rao-Scott Chi-square test, two-sample t tests, and logistic regression were used to evaluate binary associations between current e-cigarette use and lifetime diagnosis of COPD and asthma. Multivariable analyses using logistic regression were conducted to assess associations between variables. Interaction effects between e-cigarette use and race/ethnicity were assessed and stratified analyses were performed as indicated. All multivariate analyses were stratified by cigarette smoking status.

Results

Prevalence of e-cigarette use was 5.1%, COPD was 6.7%, and asthma was 9.2%. Individuals who currently smoked cigarettes among all racial/ethnic groups, excluding non-Hispanic (NH) American Indian/Alaska Native individuals, were more likely to report current asthma if using e-cigarettes compared to non-use (p < 0.05). Among individuals who never smoked, Non-Hispanic White (NHW), NH-Black and Hispanic individuals using e-cigarettes had greater odds of COPD compared to NHW, NH-Black and Hispanic individuals who did not use these products, respectively (p < 0.05). Among NHW, Hispanic, and NH-Other persons who currently used cigarettes, individuals currently using e-cigarettes had greater odds of COPD compared to NHW, Hispanic, and NH-Hispanic individuals who did not use e-cigarettes, respectively (p < 0.05). Among individuals who formerly used cigarettes, current e-cigarette use was associated with COPD and asthma. Among individuals who never used cigarettes, current e-cigarette use was associated with reporting current asthma.

Conclusion

The association between e-cigarette use and COPD and asthma was dependent on smoking status and racial/ethnic groups. Further studies should be conducted to explore this association.

Reprint of: Smoking and pulmonary health in women: A narrative review and behavioral health perspective

OBJECTIVE

Cigarette smoking prevalence has declined slower among women than men, and smoking-related pulmonary disease (PD) has risen among women. Given these trends, there is a critical need to understand and mitigate PD risk among women who smoke. The purpose of this narrative review and commentary is to highlight important evidence from the literature on smoking and PD among women.

METHODS

This review focuses broadly on examining cigarette smoking and PD among women within six topic areas: (1) demographic characteristics and prevalence of smoking, (2) smoking behavior, (3) lung cancer, (4) obstructive PD, (5) diagnostic and treatment disparities, and (6) gaps in the literature and potential directions for future research and treatment.

RESULTS

Growing evidence indicates that compared to men, women are at increased risk for developing smoking-related PD and poorer PD outcomes. Gender disparities in smoking-related PD may be largely accounted for by genetic differences and sex hormones contributing to PD pathogenesis and presentation, smoking behavior, nicotine dependence, and pathogen/carcinogen clearance. Moreover, gender disparities in smoking-related PD may be exacerbated by important social determinants (e.g., women with less formal education and those from minoritized groups may be at especially high risk for poor PD outcomes due to higher rates of smoking).

CONCLUSION

Rising rates of smoking-related PD among women risk widening diagnostic and treatment disparities. Ongoing research is needed to explore potentially complex relationships between sex, gender, and smoking-related PD processes and outcomes, and to improve smoking-cessation and PD treatment for women.

Smoking and pulmonary health in women: A narrative review and behavioral health perspective

OBJECTIVE

Cigarette smoking prevalence has declined slower among women than men, and smoking-related pulmonary disease (PD) has risen among women. Given these trends, there is a critical need to understand and mitigate PD risk among women who smoke. The purpose of this narrative review and commentary is to highlight important evidence from the literature on smoking and PD among women.

METHODS

This review focuses broadly on examining cigarette smoking and PD among women within six topic areas: (1) demographic characteristics and prevalence of smoking, (2) smoking behavior, (3) lung cancer, (4) obstructive PD, (5) diagnostic and treatment disparities, and (6) gaps in the literature and potential directions for future research and treatment.

RESULTS

Growing evidence indicates that compared to men, women are at increased risk for developing smoking-related PD and poorer PD outcomes. Gender disparities in smoking-related PD may be largely accounted for by genetic differences and sex hormones contributing to PD pathogenesis and presentation, smoking behavior, nicotine dependence, and pathogen/carcinogen clearance. Moreover, gender disparities in smoking-related PD may be exacerbated by important social determinants (e.g., women with less formal education and those from minoritized groups may be at especially high risk for poor PD outcomes due to higher rates of smoking).

CONCLUSION

Rising rates of smoking-related PD among women risk widening diagnostic and treatment disparities. Ongoing research is needed to explore potentially complex relationships between sex, gender, and smoking-related PD processes and outcomes, and to improve smoking-cessation and PD treatment for women.

The prevalence and mortality risks of PRISm and COPD in the United States from NHANES 2007-2012

BACKGROUND

We estimated the prevalence and mortality risks of preserved ratio impaired spirometry (PRISm) and chronic obstructive pulmonary disease (COPD) in the US adult population.

METHODS

We linked three waves of pre-bronchodilator spirometry data from the US National Health and Nutritional Examination Survey (2007-2012) with the National Death Index. The analytic sample included adults ages 20 to 79 without missing data on age, sex, height, BMI, race/ethnicity, and smoking status. We defined COPD (GOLD 1, 2, and 3-4) and PRISm using FEV1/FVC cut points by the Global Initiative for Chronic Obstructive Lung Disease (GOLD). We compared the prevalence of GOLD stages and PRISm by covariates across the three waves. We estimated adjusted all-cause and cause-specific mortality risks by COPD stage and PRISm using all three waves combined.

RESULTS

Prevalence of COPD and PRISm from 2007-2012 ranged from 13.1%-14.3% and 9.6%-10.2%, respectively. We found significant differences in prevalence by sex, age, smoking status, and race/ethnicity. Males had higher rates of COPD regardless of stage, while females had higher rates of PRISm. COPD prevalence increased with age, but not PRISm, which was highest among middle-aged individuals. Compared to current and never smokers, former smokers showed lower rates of PRISm but higher rates of GOLD 1. COPD prevalence was highest among non-Hispanic White individuals, and PRISm was notably higher among non-Hispanic Black individuals (range 31.4%-37.4%). We found associations between PRISm and all-cause mortality (hazard ratio [HR]: 2.3 95% CI: 1.9-2.9) and various cause-specific deaths (HR ranges: 2.0-5.3). We also found associations between GOLD 2 (HR: 2.1, 95% CI: 1.7-2.6) or higher (HR: 4.2, 95% CI: 2.7-6.5) and all-cause mortality. Cause-specific mortality risk varied within COPD stages but typically increased with higher GOLD stage.

CONCLUSIONS

The prevalence of COPD and PRISm remained stable from 2007-2012. Greater attention should be paid to the potential impacts of PRISm due to its higher prevalence in minority groups and its associations with mortality across various causes including cancer.

Association of cigarette and electronic cigarette use patterns with all-cause mortality: A national cohort study of 145,390 US adults

OBJECTIVE

While e-cigarette use is associated with adverse cardiopulmonary health effects, the mortality risks associated with e-cigarette use alone and combined with smoking remain unexamined.

METHODS

Data between 2014 and 2018 were obtained from the National Health Interview Survey (NHIS), an annual cross-sectional survey of US adults. All-cause mortality and date of death were obtained via linkage of the NHIS to the National Death Index through December 31, 2019. A 6-category composite cigarette (never, former, current) and e-cigarette (current, non-current) exposure variable was created. We examined the association of cigarette and e-cigarette use patterns with all-cause mortality using adjusted Cox models.

RESULTS

Among 145,390 participants (79,294 women [51.5%]; 60,560 aged 18-44 [47.4%]), 5220 deaths were observed over a median follow-up of 3.5 years (508,545 total person-years). Dual use of cigarettes and e-cigarettes was associated with higher mortality risk compared with non-current e-cigarette use in combination with never smoking (hazard ratio [HR] 2.44; 95% CI, 1.90-3.13) and had a risk that did not differ from current exclusive smoking (HR, 1.06; 95% CI, 0.83-1.37). Current e-cigarette use in combination with former smoking was associated with a lower mortality risk than current exclusive cigarette smoking (HR 0.64; 95% CI, 0.41-0.99).

CONCLUSIONS

The addition of e-cigarette use to smoking does not reduce mortality risk compared with exclusive smoking. However, transitioning completely from cigarettes to e-cigarettes may be associated with mortality risk reduction. Further research is needed to verify these findings in larger cohorts and over longer periods of follow-up.

The potential impact of removing a ban on electronic nicotine delivery systems using the Mexico smoking and vaping model (SAVM)

Objective

To develop the Mexico Smoking and Vaping Model (Mexico SAVM) to estimate cigarette and electronic nicotine delivery systems (ENDS) prevalence and the public health impact of legalizing ENDS use.

Methods

SAVM, a cohort-based discrete-time simulation model, compares two scenarios. The ENDS-Restricted Scenario estimates smoking prevalence and associated mortality outcomes under the current policy of an ENDS ban, using Mexico-specific population projections, death rates, life expectancy, and smoking and e-cigarette prevalence. The ENDS-Unrestricted Scenario projects smoking and vaping prevalence under a hypothetical scenario where ENDS use is allowed. The impact of legalizing ENDS use is estimated as the difference in smoking- and vaping-attributable deaths (SVADs) and life-years lost (LYLs) between the ENDS-Restricted and Unrestricted scenarios.

Results

Compared to a national ENDS ban, The Mexico SAVM projects that legalizing ENDS use could decrease smoking prevalence by 40.1% in males and 30.9% in females by 2049 compared to continuing the national ENDS ban. This reduction in prevalence would save 2.9 (2.5 males and 0.4 females) million life-years and avert almost 106 (91.0 males and 15.5 females) thousand deaths between 2025 and 2049. Public health gains decline by 43% to 59,748 SVADs averted when the switching rate is reduced by half and by 24.3% (92,806 SVADs averted) with a 25% ENDS risk level from that of cigarettes but increased by 24.3% (121,375 SVADs averted) with the 5% ENDS risk.

Conclusions

Mexico SAVM suggests that greater access to ENDS and a more permissive ENDS regulation, simultaneous with strong cigarette policies, would reduce smoking prevalence and decrease smoking-related mortality. The unanticipated effects of an ENDS ban merit closer scrutiny, with further consideration of how specific ENDS restrictions may maximize public health benefits.

Population-Based Disease Odds for E-Cigarettes and Dual Use versus Cigarettes

BACKGROUND: E-cigarettes are promoted as less harmful than cigarettes. There has not been a direct comparison of health effects of e-cigarettes or dual use (concurrently using e-cigarettes and cigarettes) with those of cigarettes in the general population. METHODS: Studies in PubMed, EMBASE, Web of Science, and PsychINFO published through October 1, 2023, were pooled in a random-effects meta-analysis if five or more studies were identified with a disease outcome. We assessed risk of bias with Risk Of Bias In Non-randomized Studies of Exposure and certainty with Grading of Recommendations, Assessment, Development, and Evaluations. Outcomes with fewer studies were summarized but not pooled. RESULTS: We identified 124 odds ratios (94 cross-sectional and 30 longitudinal) from 107 studies. Pooled odds ratios for current e-cigarette versus cigarette use were not different for cardiovascular disease (odds ratio, 0.81; 95% confidence interval, 0.58 to 1.14), stroke (0.73; 0.47 to 1.13), or metabolic dysfunction (0.99; 0.91 to 1.09) but were lower for asthma (0.84; 0.74 to 0.95), chronic obstructive pulmonary disease (0.53; 0.38 to 0.74), and oral disease (0.87; 0.76 to 1.00). Pooled odds ratios for dual use versus cigarettes were increased for all outcomes (range, 1.20 to 1.41). Pooled odds ratios for e-cigarettes and dual use compared with nonuse of either product were increased (e-cigarette range, 1.24 to 1.47; dual use, 1.49 to 3.29). All included studies were assessed as having a low risk of bias. Results were generally not sensitive to study characteristics. Limited studies of other outcomes suggest that e-cigarette use is associated with additional diseases. CONCLUSIONS: There is a need to reassess the assumption that e-cigarette use provides substantial harm reduction across all cigarette-caused diseases, particularly accounting for dual use.

Association between cigar use, with and without cigarettes, and incident diagnosed COPD: a longitudinal cohort study

BACKGROUND

While regular cigar smoking is believed to carry similar health risks as regular cigarette smoking, the impact of cigar use, alone or in combination with cigarettes, on obstructive pulmonary disease (COPD) has not been well characterized. The purpose of this study was to examine the prospective association between exclusive and dual cigar and cigarette use and incident self-reported diagnosed COPD.

METHODS

This study used data from Waves 1-5 (2013-2019) of the Population Assessment of Tobacco and Health (PATH) Study, a nationally representative survey of U.S. adults. Longitudinal data from adults aged 40 to 79 at Wave 1, without a pre-existing COPD diagnosis who participated at follow-up interview were analyzed. A time-varying current tobacco exposure, lagged by one wave and categorized as: (a) never/non-current use; (b) exclusive cigar use; (c) exclusive cigarette use; and (d) dual cigar/cigarette use. Multivariable models adjusted for demographics (age, sex, race or ethnicity, education), clinical risk factors (asthma, obesity), and smoking-related confounders (second-hand smoke exposure, other combustible tobacco product use, e-cigarette use, time since quitting, cigarette pack-years). The incidence of self-reported diagnosed COPD was estimated using discrete-time survival models, using a general linear modeling (GLM) approach with a binomial distribution and a complementary log-log link function.

RESULTS

The analytic sample consisted of 9,556 adults with a mean (SD) age of 56 (10.4), who were predominately female (52.8%) and Non-Hispanic White (70.8%). A total of 906 respondents reported a diagnosis of COPD at follow-up. In the fully adjusted model, exclusive cigar use (adjusted hazard ratio (aHR) = 1.57, 95% CI: 0.77, 3.21) was not associated with increased COPD risk compared to non-use, while exclusive cigarette use (aHR = 1.48, 95% CI: 1.13, 1.93) and dual cigar/cigarette use (aHR = 1.88, 95% CI: 1.24, 2.85) were.

CONCLUSIONS

Exclusive cigarette use and dual cigar/cigarette use were associated with diagnosed incident COPD. These results suggest that cigars, when used in combination with cigarettes, may be associated with poorer COPD health outcomes. Dual use may promote a higher likelihood of inhaling cigar smoke, and future research would benefit from examining whether inhalation of cigar smoke increases COPD risk.

Sex Differences in E-Cigarette Use and Related Health Effects

BACKGROUND

Electronic cigarettes (e-cigarettes) comprise a variety of products designed to deliver nicotine, flavorings, and other substances. To date, multiple epidemiological and experimental studies have reported a variety of health issues associated with their use, including respiratory toxicity, exacerbation of respiratory conditions, and behavioral and physiological effects. While some of these effects appear to be sex- and/or gender-related, only a portion of the research has been conducted considering these variables. In this review, we sought to summarize the available literature on sex-specific effects and sex and gender differences, including predictors and risk factors, effects on organ systems, and behavioral effects.

METHODS

We searched and selected articles from 2018-2023 that included sex as a variable or reported sex differences on e-cigarette-associated effects.

RESULTS

We found 115 relevant studies published since 2018 that reported sex differences in a variety of outcomes. The main differences reported were related to reasons for initiation, including smoking history, types of devices and flavoring, polysubstance use, physiological responses to nicotine and toxicants in e-liquids, exacerbation of lung disease, and behavioral factors such as anxiety, depression, sexuality, and bullying.

CONCLUSIONS

The available literature supports the notion that both sex and gender influence the susceptibility to the negative effects of e-cigarette use. Future research needs to consider sex and gender variables when addressing e-cigarette toxicity and other health-related consequences.