Cigarette tar yields in relation to mortality from lung cancer in the cancer prevention study II prospective cohort, 1982-8

Illusion of filtration: Evidence from tobacco industry documents

INTRODUCTION

We compared the design features of popular filtered and non-filtered cigarettes sold in the United States between 1960 and 1990, to assess the relationship between cigarette filter and tobacco weight.

METHODS

We analyzed data on the design features of six popular filtered and three non-filtered cigarette brands sold in the US including the weight of tobacco used provided in the Cigarette Information Reports produced by Philip Morris Tobacco Company between 1960 and 1990. We also collected information on other design features such as stick length and circumference, the percentage of reconstituted tobacco in the blend, among other product parameters. We used joinpoint regression to test for trends in outcome variables for each brand assessed between 1960 and 1990.

RESULTS

In all years, filtered cigarettes had less tobacco by weight compared to non-filtered cigarettes. The lower average weight of tobacco found in filtered cigarettes appears to be due to a combination of factors including stick and filter length, and the amount of reconstituted tobacco in the blend. The average percentages of total alkaloids and expanded tobacco increased over time but were similar between filtered and non-filtered brands.

CONCLUSIONS

While various design features of popular filtered and non-filtered brands changed between 1960 and 1990, the observed reduction in tobacco weight among filtered brands was perhaps the most salient in terms of disease risk. Less tobacco in a filtered cigarette calls into question the presumed exclusive role of cigarette filter tips in the reduced health risks of filtered versus non-filtered cigarette smoking.

Risk Factors for Cancer Mortality in Spain: Population-Based Cohort Study

BACKGROUND

Cancer is considered a major public health problem due to its increasing incidence and high mortality. This study aims to identify risk factors for cancer mortality in Spain.

METHODS

Retrospective population-based cohort study in 20,397 participants of the 2011/2012 National Health Survey in Spain. Risk factors associated with mortality due to neoplasm from 2011 to 2017 were analyzed, and hazard ratios were calculated with a multivariate Cox model with competing risks for mortality from other causes.

RESULTS

Myocardial infarction, chronic obstructive pulmonary disease, cirrhosis, and mental disorders were associated with an increased risk of mortality due to neoplasm. Male sex, age over 50 years, history or current smoking habit, negligible intake of legumes, and poorer self-perceived health were also associated with increased cancer mortality.

CONCLUSIONS

Comorbidities, tobacco use, poor diet, and worse self-perceived health were the main risk factors for cancer mortality in Spain.

Characteristics of and reasons for patients with chronic obstructive pulmonary disease to continue smoking, quit smoking, and switch to heated tobacco products

INTRODUCTION

Smoking is the leading cause of chronic obstructive pulmonary disease (COPD), and smoking cessation is the most effective treatment for patients with COPD. However, few studies have investigated the continuation/cessation of smoking and heated tobacco products (HTP) in patients with COPD. The objective of this study was to examine the characteristics of patients with COPD, those who are current smokers and those who switched from cigarettes to HTP, and to examine the reason for the continuation or cessation of smoking.

METHODS

This multicenter, cross-sectional study included 411 outpatients with COPD. Data for this study were part of a study conducted for a comprehensive evaluation of the smoking status and clinical factors in patients with COPD and their families.

RESULTS

Logistic regression analysis revealed that a younger age, longer duration of smoking, fewer daily cigarettes, and lower modified Medical Research Council (mMRC) dyspnea score, and a lower Simplified Nutritional Appetite Questionnaire (SNAQ) score for appetite, were characteristics of current smokers (age OR=0.94; duration of smoking OR=1.07; number of cigarettes per day OR=0.94; mMRC OR=0.68; SNAQ OR=0.83; p<0.05). The logistic regression analysis model showed that a younger age and higher education level were associated with the use of HTP (age OR=0.83; higher education level OR=4.63; p<0.05). Many of the current smokers displayed smoking behaviors that are not guaranteed to be safe, such as reducing smoking or switching to lighter cigarettes or HTP.

CONCLUSIONS

Patients with COPD who continue smoking tended to have low appetite as well as smoking behaviors that are not guaranteed to be safe. Physicians should provide appropriate guidance to these patients on smoking cessation.

Health Claims, Marketing Appeals, and Warnings on Popular Brands of Waterpipe Tobacco Packaging Sold in the United States

INTRODUCTION

Waterpipe tobacco (WT) smoking is associated with misperceptions of harm, especially among users. WT packaging contains imagery, flavor descriptors, and text claims that may contribute to misperceptions. The study goal was to characterize visual and text elements of WT packaging.

AIMS AND METHODS

Using data from the U.S. Population Assessment on Tobacco and Health Study Wave 2 (October 2014-October 2015), we identified the 10 most popular WT brands. For each brand, we identified available flavors, including flavor collections with unique packaging elements. We randomly selected 10 flavors per brand for purchase (March-April 2018). We conducted descriptive content analysis to code all textual and visual design elements of each package.

RESULTS

Over half (54%) of WT packages had modified risk tobacco product (MRTP) claims prohibited by federal law, including substance-free MRTP claims (43%) and the descriptor "natural" (11%). No MRTP reduced exposure or reduced risk claims were found. Over a quarter (26%) of packaging including one or more of terms that may imply reduced harm including "fresh," "premium," "quality," and "pure." All packages included a text-only warning, yet none appeared on the primary display panel. Almost all packaging (99%) included imagery, with 72% including flavor imagery. The majority of packages (72%) included a smoking cue. The most popular marketing appeals were "well-made" (57%), "enjoyable" (55%), and "patriotic" (47%).

CONCLUSIONS

Prohibited MRTP claims, other descriptors, and flavor imagery are common on WT packaging, despite federal law. Future research is needed to evaluate if this marketing contributes to misperceptions of reduced harm.

IMPLICATIONS

Tobacco packaging is used to convey health-related messages, both explicitly and implicitly; however, information about WT packaging is virtually nonexistent. We conducted a content analysis of WT packaging from the 10 most popular US brands. Over half (54%) of packages had prohibited MRTP claims and over a quarter (26%) included one or more descriptors that may be perceived as implying reduced harm. Use of imagery, including smoking cues, was common. The widespread use of prohibited MRTP claims, other descriptors, and imagery on WT packaging may contribute to misperceptions of reduced harm.

Can the Public Be Educated About Constituents in Smokeless Tobacco? A Three-Wave Randomized Controlled Trial

INTRODUCTION

The U.S. Food and Drug Administration (FDA) is required by law to inform the public about levels of harmful and potentially harmful tobacco constituents in a format that is "understandable and not misleading to a lay person." Our study addresses a critical gap in research on communicating such information for smokeless tobacco (SLT) products.

METHODS

The design included random assignment to one of the experimental (online interactive) conditions differing in presentation format or a control condition (receiving no information). Experimental respondents viewed information on levels and health risks of 5 harmful constituents in up to 79 products. Outcome measures included knowledge of health risks of constituents, perception of constituent variability in SLT products, disease risk ratings, self-reported SLT use, and side-by-side product comparisons. The sample of 333 SLT users, 535 cigarette smokers, and 663 nontobacco users participated at baseline, time of intervention, and 6 weeks postintervention.

RESULTS

Presentation formats showed few systematic differences so were combined in analyses. Experimental condition respondents increased their knowledge about constituent health effects and their perceptions of constituent variability in SLT products, from baseline to postintervention, and relative to the control condition. Changes in respondents' ratings of disease risk and their estimates of constituent exposure from specific products were observed, but not in self-reported SLT use.

CONCLUSIONS

Interactive online graphic and numeric presentation formats can be efficient in increasing people's knowledge of health effects and perceived variation of constituents in SLT products. Further research on longer-term behavioral assessment, and usefulness of this approach for regulatory agencies, is needed.

IMPLICATIONS

Research on communicating the information about harmful constituents in SLT products to lay persons is critically lacking. This study proposes novel formats for effective communication about the levels and the health effects of SLT constituents to multiple user groups. The lack of misperceptions among study participants that some tobacco products are safe suggests that such formats can potentially be used for public display of SLT constituent data by the FDA and regulatory agencies in other countries.

The past is not the future in tobacco control

In this paper we have attempted to identify missed opportunities to change the trajectory of smoking and smoking caused diseases in America over the past 100 years. Many of the missed opportunities identified are due to the actions of cigarette manufacturers who misled the public about the dangers of cigarette smoking, the addictiveness of nicotine, and the feasibility of providing lower risk alternative nicotine delivery products to addicted smokers. An important lesson learned from the past is that treating all tobacco/nicotine products as equivalently harmful is counterproductive to public health as it only serves to protect the most lethal nicotine product - cigarettes. Since 2000, the evolving marketplace of lower risk nicotine products combined with regulatory authority over tobacco products represents a new opportunity to dramatically transform the cigarette business in ways that were never imagined when the war on tobacco was raging decades ago. However, this requires embracing risk-proportionate regulation, taxation policies, and providing consumers with accurate public messaging on product relative risks. A regulatory framework based on sound science that encourages and rewards new or existing manufacturers to invest in consumer acceptable lower risk products to replace cigarettes needs to be encouraged. The past is indeed not the future in smoking control, but it may be difficult to escape the past unless a realignment of market forces and policies can be achieved.

Association of Cigarette Type and Nicotine Dependence in Patients Presenting for Lung Cancer Screening

BACKGROUND

Over decades, there have been several alterations to cigarettes, including the addition of filters and flavoring. However, lung cancer remains the leading cause of cancer-related death in the United States.

RESEARCH QUESTION

The aim of this study was to examine the association of type of cigarette on nicotine dependence in the setting of lung cancer screening.

STUDY DESIGN AND METHODS

This study is a secondary analysis of the American College of Radiology Imaging Network arm of the National Lung Screening Trial. Tobacco dependence was evaluated by using the Fagerstrӧm Test for Nicotine Dependence, the Heaviness of Smoking Index, and time to first cigarette. Clinical outcomes, including nicotine dependence and tobacco abstinence, were assessed with descriptive statistics and χ2 tests, stratified according to cigarette tar level, flavor, and filter. Logistic regression was used to study the influence of variables on smoking abstinence.

RESULTS

More than one-third of individuals presenting for lung cancer screening are highly addicted to nicotine and smoke within 5 min of waking up. Smokers of unfiltered cigarettes were more nicotine dependent compared with filtered cigarette smokers (OR, 1.32; P < .01). Although smokers of light/ultralight cigarettes had lower dependence (OR, 0.76, P < .0001), there was no difference in smoking abstinence compared with regular cigarette smokers. There was no difference in outcomes when comparing smokers of menthol vs unflavored cigarettes.

INTERPRETATION

In a screening population, the type of cigarette smoked is associated with different levels of dependence. Eliciting type of cigarette and time to first cigarette has the potential to allow for tailored tobacco treatment interventions within this context.

Cumulative cigarette tar exposure and lung cancer risk among Japanese smokers

OBJECTIVE

Tar concentration in cigarette brands is chronologically decreasing in the USA and Japan. However, studies investigating lung cancer risk with cumulative tar exposure in Western and Asian countries are insufficient. To investigate the risk of lung cancer with cumulative cigarette tar exposure, we conducted a case-control study among Japanese current smokers.

METHODS

This study used data from the US-Japan lung cancer joint study in 1993-1998. A total of 282 subjects with histologically confirmed lung cancer and 162 hospital and 227 community controls were included in the study, and two control groups were combined. The information regarding tar concentration was obtained from the published documents and additional estimation using the equation of regression. Cumulative tar concentration was calculated by multiplying the annual value of brand-specific tar concentration by years of smoking. The odds ratios and 95% confidence intervals for lung cancer with cumulative tar exposure were estimated using a logistic model.

RESULTS

The odds ratios for lung cancer with both lower (1-59.8 × 105 mg) and higher (>59.8 × 105 mg) total cumulative tar exposure were statistically significant (3.81, 2.23-6.50 and 11.64, 6.56-20.67, respectively) with increasing trend (P < 0.001). The stratification analysis showed higher odds ratios in subjects with higher cumulative tar exposure regardless of inhalation, duration of smoking filtered cigarettes and histological type.

CONCLUSIONS

This study showed that cumulative tar exposure is a dose-dependent indicator for lung cancer risk, and low-tar exposure was still associated with increased cancer risk.

Smokers Awareness and Risk Perceptions of Filter Ventilation

Objectives

The addition of tiny rows of holes in the tipping paper (filter ventilation) of cigarettes allows air to mix with the smoke, which can change risk perceptions. In this study, we examine smokers' knowledge and beliefs about filter ventilation.

Methods

Web-based panel surveys conducted in 2016 and 2017 of current adult cigarette smokers (N = 2355) provided data on awareness and understanding of filter vents in their cigarettes, whether they believed blocking the holes would change the taste of their cigarettes, and their perceptions about their future risk of being diagnosed with lung cancer. The most commonly used cigarette brands reported by participants also were characterized on the presence and level of ventilation holes.

Results

Approximately 40% of participants (mostly younger and male) reported awareness of the filter ventilation in their cigarettes. Only 30% of the participants were both aware of and understood the function of filter ventilation; they also were significantly more likely to worry about developing lung cancer.

Conclusion

Although misleading descriptors associated with filter ventilation are prohibited, most smokers still smoked cigarettes with filter vents, and many are unaware and misunderstand the potential risks of filter ventilation.

β-Carotene Supplementation and Lung Cancer Incidence in the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study: The Role of Tar and Nicotine

INTRODUCTION

The Alpha-Tocopherol, Beta-Carotene Cancer Prevention (ATBC) Study demonstrated that β-carotene supplementation increases lung cancer incidence in smokers. Further, cigarettes with higher tar and nicotine content are associated with a higher risk of lung cancer. However, no studies have examined whether the increased risk associated with β-carotene supplementation in smokers varies by the tar or nicotine content of cigarettes.

METHODS

The ATBC Study was a randomized, double-blind intervention trial conducted in southwest Finland. A total of 29 133 male smokers, aged 50-69 years, were enrolled and randomly assigned to one of four groups (α-tocopherol, β-carotene, both, or placebo). Cox proportional hazards models were used to estimate the hazard ratio (HR) and 95% confidence intervals (CI) of lung cancer risk by β-carotene trial assignment stratified by a priori categories of cigarette tar and nicotine content.

RESULTS

The β-carotene supplementation group had significantly higher risk of developing lung cancer in all categories of tar content (yes vs. no β-carotene supplementation-ultralight cigarettes [≤7 mg tar]: HR = 1.31, 95% CI = 0.91 to 1.89; nonfiltered cigarettes [≥21 mg tar]: HR = 1.22, 95% CI = 0.91 to 1.64; p for interaction = .91). Similarly, there was no interaction with nicotine content (yes vs. no β-carotene supplementation-ventilated cigarettes [≤0.8 µg nicotine]: HR = 1.23, 95% CI = 0.98 to 1.54; nonfiltered cigarettes [≥1.3 µg nicotine]: HR = 1.22, 95% CI = 0.91 to 1.64; p for interaction = .83).

CONCLUSION

These findings support the conclusion that supplementation with β-carotene increases the risk of lung cancer in smokers regardless of the tar or nicotine content of cigarettes smoked. Our data suggest that all smokers should continue to avoid β-carotene supplementation.

IMPLICATIONS

Previous studies demonstrated that β-carotene supplementation increases risk of lung cancer in smokers. This study moves the field forward by examining the potential for modification of risk of lung cancer with different levels of tar and nicotine in cigarettes smoked, as interaction with carcinogens in these components of cigarette smoke is hypothesized to be the mechanism by which β-carotene increases risk. Our study provides evidence that the increased risk of lung cancer in smokers who take β-carotene supplements is not dependent upon the tar or nicotine level of cigarettes smoked and suggests that all smokers should continue to avoid β-carotene supplementation.

Low Tar Level Does Not Reduce Human Exposure to Polycyclic Aromatic Hydrocarbons in Environmental Tobacco Smoke

Environmental tobacco smoke (ETS) is known to pose potential risk to human health, but the effects of tar level remain to be clarified. In the present study, ETS samples from two cigarette types with different tar levels in a 72.5 m3 room were collected for measurement of 16 polycyclic aromatic hydrocarbons (PAHs). Urine samples of volunteers participating in smoking events were collected and analyzed for eight hydroxyl-PAHs. The concentrations, compositions, and particle size distribution patterns of PAHs from higher-tar and lower-tar cigarettes were similar, while the emission factors of PAHs from higher-tar cigarettes were lower than those from lower-tar cigarettes. Furthermore, the change in the concentrations of PAH metabolites in urine samples before and after smoking was not attributed to tar level. Assuming that a single cigarette was smoked in a 100 m3 room, the estimated average inhalation cancer risks for different age groups from exposure to PAHs in ETS were below 1.0 × 10-6, but potential risks should not be overlooked, especially considering that only inhaled particle-bound PAHs in ETS were included in this assessment. Apparently, reduced tar levels would not necessarily lead to lowered risk of exposure to PAHs. Kicking the habit is perhaps the best choice to minimize any potential health risk.

Association of Cigarette Type With Lung Cancer Incidence and Mortality: Secondary Analysis of the National Lung Screening Trial

This study uses data from the National Lung Screening Trial to investigate the association of cigarette tar level, flavor, and filter status with lung cancer diagnosis, mortality, and all-cause mortality.

Inflammatory status and lung function predict mortality in lung cancer screening participants

Supplemental Digital Content is available in the text.

Low-dose computed tomography (LDCT) screening trials have based their risk selection algorithm on age and tobacco exposure, but never on pulmonary risk-related biomarkers. In the present study, the baseline inflammatory status, measured by C-reactive protein (CRP) level, and lung function, measured by forced expiratory volume in 1 s (FEV₁), were tested as independent predictors of all-cause mortality in LDCT-screening participants. Between 2000 and 2010, 4413 volunteers were enrolled in two LDCT-screening trials, with evaluable baseline CRP and FEV₁ values: 2037 were included in the discovery set and 2376 were included in the validation set. The effect of low FEV₁ or high CRP alone or combined was evaluated by Kaplan–Meier mortality curves and hazard ratio (HR) with 95% confidence interval (CI) by fitting Cox proportional hazards models. The overall mortality risk was significantly higher in participants with FEV₁ of up to 90% (HR: 2.13, CI: 1.43–3.17) or CRP more than 2 mg/l (HR: 3.38, CI: 1.60–3.54) and was still significant in the fully adjusted model. The cumulative 10-year probability of death was 0.03 for participants with FEV₁ of more than 90% and CRP up to 2 mg/l, 0.05 with only FEV₁ of up to 90% or CRP above 2 mg/l, and 0.12 with FEV₁ of up to 90% and CRP above 2 mg/l. This predictive performance was confirmed in the two external validation cohorts with 10-year mortality rates of 0.06, 0.12, and 0.14, and 0.03, 0.07, and 0.14, respectively. Baseline inflammatory status and lung function reduction are independent predictors of all-cause long-term mortality in LDCT-screening participants. CRP and FEV₁ could be used to select higher-risk individuals for future LDCT screening and preventive programs.

A conflict of interest is strongly associated with tobacco industry-favourable results, indicating no harm of e-cigarettes

Researchers reach contradictory results when trying to assess the potential harm of e-cigarettes. This study investigated whether the findings and conclusions in papers published on e-cigarettes and health differ depending on whether the authors had a financial conflict of interest (COI) or not. A total of 94 studies (identified in a previous systematic review) that investigated the content of fluid/vapor of e-cigarettes or in vitro experiments were included. The type, level and direction of the financial COI were coded. Abstracts were blinded and evaluated by two assessors. Fischer's Test and Logistic regression analyses were used to investigate the associations between findings of harm/conclusions and COI. All three dimensions of COI showed the same tendency: studies with industry-related COI found potential harm significantly less often than studies without a COI. 95.1% of papers without and 39.4% of papers with a COI found potential harmful effects/substances. Only 7.7% of tobacco industry-related studies found potential harm. The odds of finding of no harm were significantly higher in studies with an industry-related COI (OR 66.92 (95% CI 8.1-552.9)) than in studies without a COI. A strong/moderate COI was associated with very high odds (OR 91.50 (95% CI 10.9-771.4)) of finding of no harm compared with studies with no/weak COI. This blinded assessment showed that almost all papers without a COI found potentially harmful effects of e-cigarettes. There was a strong association between industry-related COI and tobacco- and e-cigarette industry-favourable results, indicating that e-cigarettes are harmless.

Mixture risk assessment of selected mainstream cigarette smoke constituents generated from low-yield cigarettes in South Korean smokers

A total of 38 hazardous constituents in mainstream cigarette smoke of low-yield cigarettes sold in Korea were selected and analyzed using established methods. Risk calculations were performed using risk algorithms employed in previous studies and Korean population-based exposure parameters. The median cumulative incremental lifetime cancer risk of male smokers could vary from 828 × 10-6 to 2510 × 10-6, and that of female smokers could range from 440 × 10-6 to 1300 × 10-6, depending on the smoking regimens. The median hazard index as the sum of hazard quotients of male smokers varied from 367 to 1,225, and that of female smokers varied from 289 to 970, depending on the smoking regimens. The sensitivity analysis for this risk assessment indicated that the constituent yields in mainstream cigarette smoke, average number of cigarettes smoked per day or year, and mouth-spill rate are the main risk factors. Statistical positive correlations between the average daily dose calculated by the exposure algorithm used in this study for individual smokers and biomarkers verified the reliability of this assessment. It could be concluded that inhalation of the constituents present in the mainstream of low-yield cigarettes has significant cancer and non-cancer health risks, although its effect on risk reduction is still unknown under the fixed machine-smoking conditions.

Tar level of cigarettes smoked and risk of smoking-related diseases

BACKGROUND

Opinions differ on the relationship between tar level and risk of smoking-related disease. However, except for lung cancer, few reviews have evaluated the epidemiological evidence. Here the relationship of tar level to risk of the four main smoking-related diseases is considered.

METHODS

Papers comparing risk of lung cancer, COPD, heart disease or stroke in smokers of lower and higher tar yield cigarettes were identified from reviews and searches, relative risk estimates being extracted comparing the lowest and highest tar groups. Meta-analyses investigated heterogeneity by various study characteristics.

RESULTS

Twenty-six studies were identified, nine of prospective design and 17 case-control. Two studies grouped cigarettes by nicotine rather than tar. Seventeen studies gave results for lung cancer, 16 for heart disease, five for stroke and four for COPD. Preferring relative risks adjusted for daily amount smoked, where adjusted and unadjusted estimates were available, combined estimates for lowest versus highest tar (or nicotine) groups were 0.78 (95% confidence interval 0.70-0.88) for lung cancer, 0.86 (0.81-0.91) for heart disease, 0.77 (0.62-0.95) for stroke and 0.81 (0.65-1.02) for COPD. Lower risks were generally evident in subgroups by publication period, gender, study design, location and extent of confounder adjustment. Estimates were similar preferring data unadjusted for amount smoked or excluding nicotine-based estimates.

CONCLUSIONS

Despite evidence that smokers substantially compensate for reduced cigarette yields, the results clearly show lower risks in lower tar smokers. Limitations of the evidence are discussed, but seem unlikely to affect this conclusion.

Case-control study of cumulative cigarette tar exposure and lung and upper aerodigestive tract cancers

The development of comprehensive measures for tobacco exposure is crucial to specify effects on disease and inform public health policy. In this population-based case-control study, we evaluated the associations between cumulative lifetime cigarette tar exposure and cancers of the lung and upper aerodigestive tract (UADT). The study included 611 incident cases of lung cancer; 601 cases of UADT cancers (oropharyngeal, laryngeal and esophageal cancers); and 1,040 cancer-free controls. We estimated lifetime exposure to cigarette tar based on tar concentrations abstracted from government cigarette records and self-reported smoking histories derived from a standardized questionnaire. We analyzed the associations for cumulative tar exposure with lung and UADT cancer, overall and according to histological subtype. Cumulative tar exposure was highly correlated with pack-years among ever smoking controls (Pearson coefficient = 0.90). The adjusted odds ratio (95% confidence limits) for the estimated effect of about 1 kg increase in tar exposure (approximately the interquartile range in all controls) was 1.61 (1.50, 1.73) for lung cancer and 1.21 (1.13, 1.29) for UADT cancers. In general, tar exposure was more highly associated with small, squamous and large cell lung cancer than adenocarcinoma. With additional adjustment for pack-years, positive associations between tar and lung cancer were evident, particularly for small cell and large cell subtypes. Therefore, incorporating the composition of tobacco carcinogens in lifetime smoking exposure may improve lung cancer risk estimation. This study does not support the claim of a null or inverse association between "low exposure" to tobacco smoke and risk of these cancer types.

Obsolete tobacco control themes can be hazardous to public health: the need for updating views on absolute product risks and harm reduction

BACKGROUND

Leading themes have guided tobacco control efforts, and these themes have changed over the decades. When questions arose about health risks of tobacco, they focused on two key themes: 1) how bad is the problem (i.e., absolute risk) and 2) what can be done to reduce the risk without cessation (i.e., prospects for harm reduction). Using the United States since 1964 as an example, we outline the leading themes that have arisen in response to these two questions. Initially, there was the recognition that "cigarettes are hazardous to health" and an acceptance of safer alternative tobacco products (cigars, pipes, light/lower-tar cigarettes). In the 1980s there was the creation of the seminal theme that "Cigarettes are lethal when used as intended and kill more people than heroin, cocaine, alcohol, AIDS, fires, homicide, suicide, and automobile crashes combined." By around 2000, support for a less-dangerous light/lower tar cigarette was gone, and harm reduction claims were avoided for products like cigars and even for smokeless tobacco which were summarized as "unsafe" or "not a safe alternative to cigarettes."

DISCUSSION

The Surgeon General in 2014 concluded that by far the greatest danger to public health was from cigarettes and other combusted products. At the same time the evidence base for smokeless tobacco and alternative nicotine delivery systems (ANDS) had grown. Product innovation and tobacco/nicotine bio-behavioral, epidemiological and public health sciences demonstrate that low nitrosamine smokeless tobacco (e.g., Swedish snus), and ANDS have substantially lower harms than cigarettes. Going forward, it is important to sharpen themes and key messages of tobacco control, while continuing to emphasize the extreme lethality of the inhaled smoke from cigarettes or from use of any combusting tobacco product. Implications of updating the leading themes for regulation, policymaking and advocacy in tobacco control are proposed as an important next step. A new reframing can align action plans to more powerfully and rapidly achieve population-level benefit and minimize harm to eliminate in our lifetime the use of the most deadly combustible tobacco products and thus prevent the premature deaths of 1 billion people projected to occur worldwide by 2100.

Comparative evaluation of the mutagenicity and genotoxicity of smoke condensate derived from Korean cigarettes

OBJECTIVES

Cigarette smoking is associated with carcinogenesis owing to the mutagenic and genotoxic effects of cigarette smoke. The aim of this study was to evaluate the mutagenic and genotoxic effects of Korean cigarettes using in vitro assays.

METHODS

We selected 2 types of cigarettes (TL and TW) as benchmark Korean cigarettes for this study, because they represent the greatest level of nicotine and tar contents among Korean cigarettes. Mutagenic potency was expressed as the number of revertants per μg of cigarette smoke condensate (CSC) total particulate matter whereas genotoxic potency was expressed as a concentration-dependent induction factor. The CSC was prepared by the International Organization for Standardization 3308 smoking method. CHO-K1 cells were used in vitro micronucleus (MNvit) and comet assays. Two strains of Salmonella typhimurium (Salmonella enterica subsp.enterica; TA98 and TA1537) were employed in Ames tests.

RESULTS

All CSCs showed mutagenicity in the TA98 and TA1537 strains. In addition, DNA damage and micronuclei formation were observed in the comet and MNvit assays owing to CSC exposure. The CSC from the 3R4F Kentucky reference (3R4F) cigarette produced the most severe mutagenic and genotoxic potencies, followed by the CSC from the TL cigarette, whereas the CSC from the TW cigarette produced the least severe mutagenic and genotoxic potencies.

CONCLUSIONS

The results of this study suggest that the mutagenic and genotoxic potencies of the TL and TW cigarettes were weaker than those of the 3R4F cigarette. Further study on standardized concepts of toxic equivalents for cigarettes needs to be conducted for more extensive use of in vitro tests.

The importance of the belief that "light" cigarettes are smoother in misperceptions of the harmfulness of "light" cigarettes in the Republic of Korea: a nationally representative cohort study

BACKGROUND

A number of countries have banned misleading cigarette descriptors such as "light" and "low-tar" as called for by the WHO Framework Convention on Tobacco Control. These laws, however, do not address the underlying cigarette design elements that contribute to misperceptions about harm. This is the first study to examine beliefs about "light" cigarettes among Korean smokers, and the first to identify factors related to cigarette design that are associated with the belief that "light" cigarettes are less harmful.

METHODS

We analysed data from Wave 3 of the ITC Korea Survey, a telephone survey of a nationally representative sample of 1,753 adult smokers, conducted October - December 2010. A multinomial logistic regression was used to examine which factors were associated with the belief that "light" cigarettes are less harmful than regular cigarettes.

RESULTS

One quarter (25.0 %) of smokers believed that "light" cigarettes are less harmful than regular cigarettes, 25.8 % believed that smokers of "light" brands take in less tar, and 15.5 % held both of these beliefs. By far the strongest predictor of the erroneous belief that "light" cigarettes are less harmful was the belief that "light" cigarettes are smoother on the throat and chest (p < 0.001, OR = 44.8, 95 % CI 23.6-84.9).

CONCLUSIONS

The strong association between the belief that "light" cigarettes are smoother on the throat and chest and the belief that "light" cigarettes are less harmful, which is consistent with previous research, provides further evidence of the need to not only ban "light" descriptors, but also prohibit cigarette design and packaging features that contribute to the perception of smoothness.

Incarceration and Current Tobacco Smoking Among Black and Caribbean Black Americans in the National Survey of American Life

OBJECTIVES

We examined the relationship between having a history of incarceration and being a current smoker using a national sample of noninstitutionalized Black adults living in the United States.

METHODS

With data from the National Survey of American Life collected between February 2001 and March 2003, we calculated individual propensity scores for having a history of incarceration. To examine the relationship between prior incarceration and current smoking status, we ran gender-specific propensity-matched fitted logistic regression models.

RESULTS

A history of incarceration was consistently and independently associated with a higher risk of current tobacco smoking in men and women. Formerly incarcerated Black men had 1.77 times the risk of being a current tobacco smoker than did their counterparts without a history of incarceration (95% confidence interval [CI] = 1.20, 2.61) in the propensity score-matched sample. The results were similar among Black women (prevalence ratio = 1.61; 95% CI = 1.00, 2.57).

CONCLUSIONS

Mass incarceration likely contributes to the prevalence of smoking among US Blacks. Future research should explore whether the exclusion of institutionalized populations in national statistics obscures Black-White disparities in tobacco smoking.

Smokers' sensory beliefs mediate the relation between smoking a light/low tar cigarette and perceptions of harm

BACKGROUND

The sensory belief that 'light/low tar' cigarettes are smoother can also influence the belief that 'light/low tar' cigarettes are less harmful. However, the 'light' concept is one of several factors influencing beliefs. No studies have examined the impact of the sensory belief about one's own brand of cigarettes on perceptions of harm.

OBJECTIVE

The current study examines whether a smoker's sensory belief that their brand is smoother is associated with the belief that their brand is less harmful and whether sensory beliefs mediate the relation between smoking a 'light/low tar' cigarette and relative perceptions of harm among smokers in China.

METHODS

Data are from 5209 smokers who were recruited using a stratified multistage sampling design and participated in Wave 3 of the International Tobacco Control (ITC) China Survey, a face-to-face survey of adult smokers and non-smokers in seven cities.

RESULTS

Smokers who agreed that their brand of cigarettes was smoother were significantly more likely to say that their brand of cigarettes was less harmful (p<0.001, OR=6.86, 95% CI 5.64 to 8.33). Mediational analyses using the bootstrapping procedure indicated that both the direct effect of 'light/low tar' cigarette smokers on the belief that their cigarettes are less harmful (b=0.24, bootstrapped bias corrected 95% CI 0.13 to 0.34, p<0.001) and the indirect effect via their belief that their cigarettes are smoother were significant (b=0.32, bootstrapped bias-corrected 95% CI 0.28 to 0.37, p<0.001), suggesting that the mediation was partial.

CONCLUSIONS

These results demonstrate the importance of implementing tobacco control policies that address the impact that cigarette design and marketing can have in capitalising on the smoker's natural associations between smoother sensations and lowered perceptions of harm.

Histological subtypes of lung cancer in Chinese women from 2000 to 2012

BACKGROUND

The aim of the study was to characterize the histological and epidemiological features of lung cancer in Chinese women.

METHODS

Demographic and histological information on female lung cancer cases identified during 1 January 2000 through 31 December 2012 from the Cancer Hospital of the Chinese Academy of Medical Sciences were collected. The International Classification of Diseases for Oncology system was used to classify the histological subtypes. Relative frequencies (RF) were estimated for major histological subtypes and compared by the years of diagnosis and birth, and among residential areas. Statistical differences were tested for RFs in the time periods with a trend test and with Pearson Chi square tests for distribution.

RESULTS

Of 7070 female Chinese lung cancer cases, the major histological subtypes were adenocarcinoma (ADC) 65.79%; squamous cell carcinoma (SCC) 10.21%; small cell cancer 8.12%; large cell carcinoma, 2.79%; and adeno-squamous carcinoma (ASC), 2.19%. ADC increased, with RFs from 46.72% in the cases identified in 2000-2002 to 76.49% in 2011-2012 (Z = 16.998, P < 0.0001); SCC decreased from 15.69% to 5.97% (Z = -8.750, P < 0.0001). Compared to the cases identified in 2000-2006, the age-adjusted RFs of ADC in 2007-2012 consistently increased in all study areas.

CONCLUSION

The significant increase of ADC of the lung in Chinese women suggests that a persistently strong exposure to potential carcinogens in the Chinese population should be further and fully investigated.

Pollution in the working place and social status: co-factors in lung cancer carcinogenesis

INTRODUCTION

Apart from the association with tobacco consumption, other factors of importance for prevention and early diagnosis of lung cancer have received little attention. We present a case-control study focusing on professional exposure to carcinogens and social status.

METHODS

A written questionnaire was completed by 551 consecutive patients with lung cancer and 494 patients with large bowel cancer. The groups were balanced regarding gender and age distribution. The questionnaire included data on place of birth, education, smoking history, diet and alcohol intake, body weight and height, occupation, housing conditions and family income. According to standard epidemiological criteria, professional exposure to carcinogens was classified as professions with exposure to confirmed lung cancer carcinogens, professions with exposure to suspected lung cancer carcinogens and other professions.

RESULTS

As expected, there were significant differences between the two groups regarding smoking status. While there were no significant differences in educational levels, more immigrants were among patients with lung cancer (17.9% vs 11.6%, p=0.005). On average, lung cancer patients had a lower body mass index (BMI) at 24.77, as compared to 26.14 for large bowel cancer (p=0.000). Lung cancer patients had lower income and poorer housing conditions; the bivariate difference was significant both for income levels (p=0.046) and type of residence (p=0.009). The proportion of patients working in professions with exposures to known carcinogens was 33.5% for lung cancer, and 17.1% for large bowel cancer (p=0.000). In the multivariate analysis, smoking (p=0.000), BMI (p=0.000) and type of occupation (p=0.001) were significant factors.

CONCLUSIONS

While there is no doubt about smoking in lung cancer carcinogenesis, professional exposure to carcinogens and belonging to lower socio-economic strata also play an important role.

Empirical evaluation of meta-analytic approaches for nutrient and health outcome dose-response data

The objective of this study is to empirically compare alternative meta-analytic methods for combining dose-response data from epidemiological studies. We identified meta-analyses of epidemiological studies that analyzed the association between a single nutrient and a dichotomous outcome. For each topic, we performed meta-analyses of odds ratios with five approaches: using extreme exposure categories only, two-step approach (first calculated study-specific effects then combined across studies) using unadjusted data, two-step approach using adjusted data, one-step approach (analyzed all data in one regression model) using unadjusted data, and one-step approach using adjusted data. Meta-analyses including only extreme exposure categories gave consistently bigger effects and wider confidence intervals than meta-analyses using all data. Confidence intervals of effect sizes were generally wider in meta-analyses with the two-step approach, compared with the one-step approach. Meta-analyses using unadjusted data and adjusted data differed, with no consistent pattern of discordance in direction, statistical significance, or magnitude of effect. We discourage using meta-analysis approaches that only use data from extreme exposure categories. The one-step approach generally has higher precision than the two-step approach. Sensitivity analysis comparing results between meta-analyses of adjusted and unadjusted data may be useful in indicating the presence of confounding.

Relationship of cigarette-related perceptions to cigarette design features: findings from the 2009 ITC U.S. Survey

INTRODUCTION

Many governments around the world have banned the use of misleading cigarette descriptors such as "light" and "mild" because the cigarettes so labeled were found not to reduce smokers' health risks. However, underlying cigarette design features, which are retained in many brands, likely contribute to ongoing belief that these cigarettes are less harmful by producing perceptions of lightness/smoothness through lighter taste and reduced harshness and irritation.

METHODS

Participants (N = 320) were recruited from the International Tobacco Control U.S. Survey conducted in 2009 and 2010, when they answered questions about smoking behavior, attitudes and beliefs about tobacco products, and key mediators and moderators of tobacco use behaviors. Participants also submitted an unopened pack of their usual brand of cigarettes for analysis using established methods.

RESULTS

Own-brand filter ventilation level (M 29%, range 0%-71%) was consistently associated with perceived lightness (p < .001) and smoothness (p = .005) of own brand. Those whose brand bore a light/mild label (55% of participants) were more likely to report their cigarettes were lighter [71.9% vs. 41.9%; χ(2)(2) = 38.1, p < .001] and smoother than other brands [75.5% vs. 68.7%; χ(2)(2) = 7.8, p = .020].

CONCLUSION

Product design features, particularly filter ventilation, influence smokers' beliefs about product attributes such as lightness and smoothness, independent of package labels. Regulation of cigarette design features such as filter ventilation should be considered as a complement to removal of misleading terms in order to reduce smokers' misperceptions regarding product risks.

Epidemiology of lung cancer

Incidence and mortality attributed to lung cancer has risen steadily since the 1930s. Efforts to improve outcomes have not only led to a greater understanding of the etiology of lung cancer, but also the histologic and molecular characteristics of individual lung tumors. This article describes this evolution by discussing the extent of the current lung cancer epidemic including contemporary incidence and mortality trends, the risk factors for development of lung cancer, and details of promising molecular targets for treatment.

A randomized controlled trial of a smoking cessation intervention conducted among prisoners

AIM

To evaluate the efficacy of nortriptyline (NOR) added to a multi-component smoking cessation intervention, which included cognitive-behavioural therapy (CBT) and provision of nicotine replacement therapy (NRT).

DESIGN

Randomized controlled trial (RCT) comparing two study groups with blinded follow-up at 3, 6 and 12 months. Both groups received a multi-component smoking cessation intervention comprising two half-hour individual sessions of CBT and NRT with either active NOR or placebo.

SETTING

Prisons in New South Wales (17) and Queensland (one), Australia.

PARTICIPANTS

A total of 425 male prisoners met inclusion criteria and were allocated to either treatment (n = 206) or control group (n = 219).

MEASUREMENTS

Primary end-points at 3, 6 and 12 months were continuous abstinence, point prevalence abstinence and reporting a 50% reduction in smoking. Smoking status was confirmed by expired carbon monoxide, using a cut-point of ≤10 parts per million.

FINDINGS

Participants' demographics and baseline tobacco use were similar in treatment and control groups. Based on an intention-to-treat analysis, continuous abstinence between the treatment and control groups was not significantly different at 3 months (23.8 versus 16.4%), 6 months (17.5 versus 12.3%) and 12 months (11.7 versus 11.9%).

CONCLUSION

Adding nortriptyline to a smoking cessation treatment package consisting of behavioural support and nicotine replacement therapy does not appear to improve long-term abstinence rates in male prisoners.

Body mass index, lifetime smoking intensity and lung cancer risk

There is as yet no generally accepted explanation for the common finding that low body mass index (BMI) is associated with an increased risk of lung cancer. We investigated this association in a Canadian population-based case-control study (1996-2002) with a particular view to assessing the hypothesis that the observed association was due to residual confounding by smoking. Analyses were based on 1,076 cases and 1,439 controls who provided their height at enrollment and their weight at two points in time, at age 20 and 2 years before enrollment. BMI, in kg/m(2) , was classified into underweight (<18.5), normal (18.5-24.9), overweight (25.0-29.9), and obese (≥30). Smoking history was synthesized into a comprehensive smoking index (CSI) that integrated duration, intensity and time since quitting. Odds ratios (ORs) and 95% confidence intervals (CIs) for BMI-lung cancer associations were estimated, adjusting for CSI as well as several sociodemographic, lifestyle and occupational factors. The normal BMI category was used as the reference. Among those who were underweight at age 20, there was a lower risk of lung cancer (OR = 0.69, 95% CI: 0.50-0.95). Conversely, lung cancer risk was increased among those who were underweight 2 years before enrollment (OR = 2.30, 95% CI: 1.30-4.10). The results were almost identical when stratifying analyses based on smoking history into never/lighter and heavier smokers. The inverse association between recent BMI and lung cancer is unlikely to be largely attributable to residual confounding by smoking. Reverse causality or a true relationship between BMI and lung cancer remain plausible.

Cigarette smoking and lung cancer--relative risk estimates for the major histological types from a pooled analysis of case-control studies

Lung cancer is mainly caused by smoking, but the quantitative relations between smoking and histologic subtypes of lung cancer remain inconclusive. By using one of the largest lung cancer datasets ever assembled, we explored the impact of smoking on risks of the major cell types of lung cancer. This pooled analysis included 13,169 cases and 16,010 controls from Europe and Canada. Studies with population controls comprised 66.5% of the subjects. Adenocarcinoma (AdCa) was the most prevalent subtype in never smokers and in women. Squamous cell carcinoma (SqCC) predominated in male smokers. Age-adjusted odds ratios (ORs) were estimated with logistic regression. ORs were elevated for all metrics of exposure to cigarette smoke and were higher for SqCC and small cell lung cancer (SCLC) than for AdCa. Current male smokers with an average daily dose of >30 cigarettes had ORs of 103.5 (95% confidence interval (CI): 74.8-143.2) for SqCC, 111.3 (95% CI: 69.8-177.5) for SCLC and 21.9 (95% CI: 16.6-29.0) for AdCa. In women, the corresponding ORs were 62.7 (95% CI: 31.5-124.6), 108.6 (95% CI: 50.7-232.8) and 16.8 (95% CI: 9.2-30.6), respectively. Although ORs started to decline soon after quitting, they did not fully return to the baseline risk of never smokers even 35 years after cessation. The major result that smoking exerted a steeper risk gradient on SqCC and SCLC than on AdCa is in line with previous population data and biological understanding of lung cancer development.

Lung cancer: epidemiology, etiology, and prevention

Lung cancer is the leading cause of cancer death in the United States and around the world. A vast majority of lung cancer deaths are attributable to cigarette smoking, and curbing the rates of cigarette smoking is imperative. Understanding the epidemiology and causal factors of lung cancer can provide additional foundation for disease prevention. This article focuses on modifiable risk factors, including tobacco smoking, occupational carcinogens, diet, and ionizing radiation. It also discusses briefly the molecular and genetic aspects of lung carcinogenesis.

Lung cancer: epidemiology, etiology, and prevention

Lung cancer is the leading cause of cancer death in the United States and around the world. A vast majority of lung cancer deaths are attributable to cigarette smoking, and curbing the rates of cigarette smoking is imperative. Understanding the epidemiology and causal factors of lung cancer can provide additional foundation for disease prevention. This article focuses on modifiable risk factors, including tobacco smoking, occupational carcinogens, diet, and ionizing radiation. It also discusses briefly the molecular and genetic aspects of lung carcinogenesis.

Tobacco use by male prisoners under an indoor smoking ban

INTRODUCTION

Most correctional facilities have implemented tobacco restrictions in an effort to reduce costs and improve prisoner health, but little has been done to evaluate the impact of these policy changes. Patterns of tobacco use among prisoners were explored to determine the impact of incarceration in a facility with an indoor smoking ban on tobacco use behaviors.

METHODS

Recently incarcerated male inmates (n = 200) were surveyed about their tobacco use prior to and during incarceration.

RESULTS

Tobacco use was prevalent prior to arrest (77.5%) and increased during incarceration (81.0%). Though the number of cigarette smokers increased during imprisonment, per-capita cigarette consumption declined by 7.1 cigarettes/day (p < .001). Despite widespread tobacco use, most participants recognized that smoking is a cause of lung cancer (96.0%) and heart disease (75.4%) and that it can be addicting (97.5%). Most tobacco users (70.0%) reported a desire to quit, with 63.0% saying they intended to try quitting in the next year.

CONCLUSIONS

Indoor smoking bans do not promote cessation in prisons but may reduce the amount of tobacco consumed. Though smoking is commonplace in prisons, most prisoners recognize the risks involved and wish to quit. This creates an ideal setting for intervention. Evidence-based cessation assistance should be made freely available to all incarcerated smokers.

Schizophrenia, cancer and obstetric complications in an evolutionary perspective-an empirically based hypothesis

OBJECTIVE

Patients diagnosed with schizophrenia have reduced fecundity and premature mortality (both accidental and violent) with no obvious compensatory advantages among kin. The prevalence of the disorder is around 0.7/1%, higher than the expected prevalence of spontaneous mutations. Genes favoring schizophrenia may have been positively selected in the environment of evolutionary adaptation. Literature on potential adaptive genes is reviewed within an evolutionary framework.

METHODS

Literature search on major scientific search engine (PubMed/Medline, Ovid/PsychInfo) on papers aimed at investigating potential pathways justifying a mutation-selection balanced model. Findings are presented with a narrative touch to favor readability and understanding.

RESULTS

Reduced incidence of cancer in both patients diagnosed with schizophrenia and their siblings was reported worldwide. Such findings are notable given higher cancer risk factors in schizophrenia, i.e., smoking, alcohol abuse, obesity, poor diet, and poor adherence to therapy. Some genes involved in cancer proliferation might as well confer protective advantage in immune-surveillance, inflammation, vascular proliferation or apoptosis that otherwise will adversely affect early neurodevelopment.

CONCLUSION

Evidence that reduced risk of certain somatic diseases is associated with schizophrenia is quite significant to progress in the evolutionary epidemiological analysis of psychopathology.

Reconstruction of long-term tobacco consumption trends in Australia and their relationship to lung cancer mortality

OBJECTIVES

Analysis of long-term trends in smoking and causes of death in Australia are prevented by a lack of detailed tobacco consumption data prior to World War II. The objective of this study was to reconstruct data on tobacco consumption in Australia back to 1887 and examine its relationship with population-level lung cancer mortality, corrected for biases and miscoding.

METHODS

Back-extrapolation techniques and existing tobacco sales data were combined to estimate tobacco consumption prior to the 1940s. The relationship of tobacco and lung cancer mortality was examined with descriptive period and cohort analyses and log-linear Poisson regression models of cumulative cohort consumption.

RESULTS

The results show that tobacco consumption rose steadily in Australia for the majority of years from 1887 to World War II, before increasing drastically in the following years and then falling sharply to the present day. Lung cancer mortality was strongly influenced by tobacco consumption, peaking 20-25 years after the peak in tobacco consumption for men and 25-30 years for women. Regression models found cumulative consumption a very strong predictor of mortality.

CONCLUSIONS

Period and cohort trends in smoking and lung cancer were similar to many other Western countries. The effectiveness of smoking reduction campaigns in Australia clearly reduced male lung cancer mortality and provides guidance for other countries, such as China, where smoking prevalence remains high.

Mutagenicity of 11 cigarette smoke condensates in two versions of the mouse lymphoma assay

Cigarette smoke condensate (CSC) is genotoxic in nearly all assays in which it has been tested. In this study, we investigated the mutagenicity of 11 CSCs using the microwell and soft-agar versions of the mouse lymphoma assay (MLA). These CSCs were prepared from commercial or experimental cigarettes, 10 of them were produced using International Organisation for Standardisation (ISO) conditions and one CSC was generated using intense Massachusetts Department of Public Health (MDPH) conditions. In the presence of rat liver S9, the L5178Y/Tk(+/-) mouse lymphoma cells were treated with 11 CSCs at different concentrations (25-200 μg/ml) for 4 h. All CSCs resulted in dose-dependent increases of both cytotoxicity and mutagenicity in both versions of the MLA. The mutagenic potencies of the CSCs were calculated as mutant frequency per microgram CSC from the slope of the linear regression of the dose-response curves and showed no correlations with the tar yield of the cigarette or nicotine concentrations of the CSCs. Comparing two CSCs produced from the same commercial cigarettes using two different smoking conditions, the one generated under ISO conditions was more mutagenic than the other generated under intense conditions on a per microgram CSC basis. We also examined the loss of heterozygosity (LOH) at four microsatellite loci spanning the entire chromosome 11 for the mutants induced by 11 CSCs. The most common type of mutation observed was LOH with chromosome damage spanning less than ∼34 Mbp. These results indicate that the MLA identifies different genotoxic potencies among a variety of CSCs and that the results from both versions of the assay are comparable.

Carbon dioxide is largely responsible for the acute inflammatory effects of tobacco smoke

Tobacco smoking is responsible for a vast array of diseases, particularly chronic bronchitis and lung cancer. It is still unclear which constituent(s) of the smoke is responsible for its toxicity. The authors decided to focus on carbon dioxide, since its level of concentration in mainstream cigarette smoke is about 200 times higher than in the atmosphere. The authors previously demonstrated that inhalation of carbon dioxide concentrations above 5% has a deleterious effect on lungs. In this study, the authors assessed the inflammatory potential of carbon dioxide contained in cigarette smoke. Mice were exposed to cigarette smoke containing a high or reduced CO(2) level by filtration through a potassium hydroxyde solution. The inflammatory response was evaluated by histological analysis, protein phosphatase 2 A (PP2A) and nuclear factor (NF)-kappaB activation, and proinflammatory cytokine secretion measurements. The data show that the toxicity of cigarette smoke may be largely due to its high level of CO(2). Pulmonary injuries consequent to tobacco smoke inhalation observed by histology were greatly diminished when CO(2) was removed. Cigarette smoke exposure causes an inflammatory response characterized by PP2A and NF-kappaB activation followed by proinflammatory cytokine secretion. This inflammatory response was reduced when the cigarette smoke was filtered through a potassium hydroxide column, and reestablished when CO(2) was injected downstream from the filtration column.Given that there is an extensive literature linking a chronic inflammatory response to the major smoking-related diseases, these data suggest that carbon dioxide may play a key role in the causation of these diseases by tobacco smoking.

Applying tobacco carcinogen and toxicant biomarkers in product regulation and cancer prevention

Tobacco carcinogen and toxicant biomarkers are metabolites or protein or DNA adducts of specific compounds in tobacco products. Highly reliable analytical methods, based mainly on mass spectrometry, have been developed and applied in large studies of many of these biomarkers. A panel of tobacco carcinogen and toxicant biomarkers is suggested here, and typical values for smokers and nonsmokers are summarized. This panel of biomarkers has potential applications in the new and challenging area of tobacco product regulation and in the development of rational approaches to cancer prevention by establishing carcinogen and toxicant uptake and excretion in people exposed to tobacco products.

Activated charcoal filter effectively reduces p-benzosemiquinone from the mainstream cigarette smoke and prevents emphysema

In this paper, we have made a comparative evaluation of the cytotoxicity and pathophysiological effects of mainstream smoke from cellulose acetate (CA)-filtered cigarettes with that of charcoal-filtered cigarettes developed in our laboratory. Previously, we had demonstrated that the mainstream smoke from an Indian CA-filtered commercial cigarette contains p-benzosemiquinone (p-BSQ), a major, highly toxic, long-lived water-soluble radical. Here, we have examined 16 brands of different CA-filtered cigarettes including Kentucky research cigarettes, and observed that mainstream smoke from all the cigarettes contains substantial amounts of p-BSQ (100-200 μg/cigarette). We also show that when the CA filter is replaced by a charcoal filter, the amount of p-BSQ in the mainstream smoke is reduced by 73-80%, which is accompanied by a reduction of carbonyl formation in bovine serum albumin to the extent of 70- 90%. The charcoal filter also prevented cytotoxicity in A549 cells as evidenced by MTT assay, apoptosis as evidenced by FACS analysis, TUNEL assay, overexpression of Bax, activation of p53 and caspase 3, as well as emphysematous lung damage in a guinea pig model as seen by histology and morphometric analysis. The results indicate that the charcoal filter developed in our laboratory may protect smokers from cigarette smoke-induced cytotoxity, protein modification, apoptosis and emphysema.

Further considerations on the evaluation of potential reduced-risk tobacco products. Part II: Re-assessment of a heuristic using the CPS-II database

In a previous analysis (see Part I) we proposed a heuristic for assessing the efficacy of potential reduced-risk tobacco products (PRRPs) on lung cancer (LC) rates, using smoking cessation data published in a report from the Iowa Women's Health Study (IWHS) as a basis for sample size estimates. In this study, an additional analysis was performed using cessation data from the much larger Cancer Prevention Study II (CPS-II), which also provides data on different durations of cessation. Statistical methods were used to assess whether smokers switching to a PRRP would reduce their risk of LC. Furthermore, non-inferiority tests compared the LC risk in switchers to that in smokers who had quit smoking. The present work shows that similar sample size estimates were obtained whether the analysis was based on the IWHS or the CPS-II data sets, suggesting that the heuristic may be generally applicable to prospective real-life studies to evaluate PRRPs. Non-inferiority testing of switchers compared with quitters required approximately 10-fold more subjects than did superiority testing of switchers compared with smokers. Altogether, these estimates indicate that it is feasible, in terms of study duration and sample size, to clinically assess the LC risk-reducing potential of a PRRP.