Cigarette filter vent blocking: effects on smoking topography and carbon monoxide exposure

Resting-state functional connectivity and structural differences between smokers and healthy non-smokers

Previous studies have shown an association between cigarette use and altered resting-state functional connectivity (rsFC) in many large-scale networks, sometimes complemented by measures of cortical atrophy. In this study, we aimed to further explore the neural differences between smokers and healthy non-smokers through the integration of functional and structural analyses. Imaging data of fifty-two smokers and forty-five non-smokers were analyzed through an independent component analysis for group differences in rsFC. Smokers showed lower rsFC within the dorsal attention network (DAN) in the left superior and middle frontal gyrus and left superior division of the lateral occipital cortex compared to non-smokers; moreover, cigarette use was found to be associated with reduced grey matter volume in the left superior and middle frontal gyrus and right orbitofrontal cortex, partly overlapping with functional findings. Within smokers, daily cigarette consumption was positively associated with increased rsFC within the cerebellar network and the default mode network and decreased rsFC within the visual network and the salience network, while carbon monoxide level showed a positive association with increased rsFC within the sensorimotor network. Our results suggest that smoking negatively impacts rsFC within the DAN and that changes within this network might serve as a circuit-based biomarker for structural deficits.

Mouth Level Intake of Nicotine from Three Brands of Little Filtered Cigars with Widely Differing Product Characteristics Among Adult Consumers

Little filtered cigars are tobacco products with many cigarette-like characteristics. However, despite cigars falling under the U.S. Food and Drug Administration regulatory authority, characterizing flavors, which are still allowed in little filtered cigars, and filter design may influence how people use the products and the resulting exposure to harmful and potentially harmful constituents. We estimated nicotine mouth level intake (MLI) from analyses of little cigar filter butt solanesol levels, brand characteristics, carbon monoxide boost, and puff volume in 48 dual cigarette/cigar users during two repeat bouts of ad lib smoking of three little filtered cigar brands. Mean nicotine MLI for the three brands was significantly different with Swisher Sweets (0.1% ventilation) Cherry at 1.20 mg nicotine, Cheyenne Menthol (1.5%) at 0.63 mg, and Santa Fe unflavored (49%) at 0.94 mg. The association between nicotine MLI and puff volume was the same between Cheyenne Menthol and Santa Fe unflavored. However, these were different from Swisher Sweets Cherry. At least five main factors─flavor, ventilation, filter design, nicotine delivery related to tar, and user puff volume─may directly or indirectly impact MLI and its association with other measures. We found that users of little filtered cigars that have different filter ventilation and flavor draw dissimilar amounts of nicotine from the product, which may be accompanied by differences in exposure to other harmful smoke constituents.

Health without filters: the health and environmental impacts of cigarette filters

Tobacco-related diseases kill eight million people worldwide ever year and are responsible for thousands of cases of cancer, cardiovascular disease and other illnesses in Brazil. Cigarette filters are believed by many to reduce the health risks of smoking. This article outlines the history of the technology of filters and discusses the impacts of these cigarette design features and their regulation. We conducted a literature review to assess the impacts of this technology. The results show that filters were initially developed for aesthetic purposes and later improved and marketed as a harm reduction technology. The most widely-used filters are those made of cellulose acetate with or without activated carbon. Despite smokers' beliefs and advertising claims, filters have no health benefits and filter tip ventilation can increase the health risks of smoking. Filters can also make cigarettes more appealing and cause significant environmental impacts. Cigarette filters have no health benefits and lull smokers into a false sense of security and should therefore be banned.

Smokers' awareness of filter ventilation, and how they believe it affects them: findings from the ITC Four Country Survey

BACKGROUND

Filter ventilation creates sensations of 'lightness' or 'smoothness' and is also highly effective for controlling machine-tested yields of tar, nicotine and carbon monoxide. Nearly all factory-made cigarettes (FMC) now have filter ventilation in countries such as Australia, Canada, the UK and the USA. Research conducted before 'light' and 'mild' labelling was banned found low smoker awareness of filter ventilation and its effects. This study explores current levels of awareness of filter ventilation and current understanding of its effects in these four countries.

METHODS

We used data from the 2018 wave of the ITC Four Country Smoking and Vaping Survey with samples from USA, England, Canada and Australia. Analyses were conducted initially on a weighted sample of 11 844, and subsequently on 7541 daily FMC smokers.

FINDINGS

Only 40.3% of all respondents reported being aware of filter ventilation. Among daily FMC smokers, only 9.4% believed their cigarettes had filter ventilation. Believing that their usual cigarettes are smoother was positively associated with believing they are also less harmful. Both these beliefs independently predict believing their cigarettes are ventilated (smoother OR=1.97 (95% CI 1.50 to 2.59) and less harmful OR=2.41 (95% CI 1.66 to 3.49) in relation to those believing each characteristic is average.

INTERPRETATION

Awareness of filter ventilation is currently low, despite decades of public 'education efforts around the misleading nature of 'light' and 'mild" descriptors. Few smokers realise that their cigarettes almost certainly are vented. Smokers who believed their cigarettes have filter ventilation were more likely to believe they were both smoother and less harmful. Awareness of the technology appears to be insufficient to prevent smokers being deceived by it. Filter ventilation is inherently misleading to smokers and it is time to ban it.

Variable Voltage, Tank-Style ENDS Do Not Always Deliver Nicotine

Objective

This study's objective was to characterize the nicotine delivery profile of a variable voltage, tank-style electronic nicotine delivery system (ENDS).

Methods

Ten cigarette smokers (8 men, 2 women) completed this within-subject study assessing effects of 2 device power settings (15 W, 45 W) and 3 liquid nicotine concentrations (0, 3, and 6 mg/ml) using a tank-style ENDS. Participants completed one directed (10 puffs) and one ad libitum use period for each condition, with blood sampled throughout.

Results

Plasma nicotine concentration did not increase significantly at 15 W regardless of liquid nicotine concentration. At 45 W, mean plasma nicotine increased (not significantly compared to 0 mg/ml) from 2.24 ng/ml (SD=0.2) at baseline to 3.4 ng/ml (SD=0.6) in the 3 mg/ml condition. In the 6 mg/ml, 45 W condition, mean plasma nicotine increased significantly (compared to 0 mg/ml) from 2.0 ng/ml (SD=0) at baseline to 5.96 ng/ml (SD=1.3) after 10 puffs. In general, puff duration and volume decreased as device power and nicotine concentration increased.

Conclusions

Despite using a variable wattage, tank-style device, nicotine delivery was minimal. These results, when combined with results from other studies using tank-style devices, highlight ENDS performance heterogeneity. Regulation may play a role in standardizing ENDS nicotine delivery.

Clinical Laboratory Evaluation of Electronic Cigarettes/Electronic Nicotine Delivery Systems: Methodological Challenges

OBJECTIVE

Evaluating electronic cigarettes (ECIGs) in the clinical laboratory is critical to understanding their effects. However, laboratory evaluation of ECIGs can be challenging, as they are a novel, varied, and evolving class of products. The objective of this paper is to describe some methodological challenges to the clinical laboratory evaluation of ECIGs.

METHODS

The authors gathered information about challenges involved in the laboratory evaluation of ECIGs. Challenges were categorized and solutions provided when possible.

RESULTS

Methods used to study combustible cigarettes may need to be adapted to account for ECIG novelty and differences within the class. Challenges to ECIG evaluation can include issues related to 1) identification of ECIG devices and liquids, 2) determination of short -term ECIG abstinence, 3) measurement of use behavior, and 4) assessment of dependence. These challenges are discussed, and some suggestions to inform ECIG evaluation using clinical laboratory methods are provided.

CONCLUSIONS

Awareness of challenges and developing, validating, and reporting methods used to address them aids interpretation of results and replication efforts, thus enhancing the rigor of science used to protect public health through appropriate, empirically-based, ECIG regulation.

Effect of cigarette design on biomarkers of exposure, puffing topography and respiratory parameters

Despite the lack of evidence, many reports exist which have implied that smokers inhale low-yield cigarette smoke more deeply than that of high-yield cigarettes. The objective of this study was to investigate the effect of short-term switching between smoker’s own brand and test cigarettes with different smoke yields on puffing topography, respiratory parameters and biomarkers of exposure. Participants were randomly assigned to smoke either a Test Cigarette-High Tar (TCH), for two days, and then switched to a Test Cigarette-Low Tar (TCL), for two days or the reverse order (n = 10 each sequence). Puffing topography (CReSS microdevice), respiratory parameters (inductive plethysmography) and biomarkers of exposure (BOE, urinary nicotine equivalents – NE and blood carboxyhemoglobin – COHb) were measured at baseline and on days 2 and 4. The average puffs per cigarette, puff volume and puff durations were statistically significantly lower, and inter-puff interval was significantly longer for the TCH compared to the TCL groups. Respiratory parameters were not statistically significantly different between the TCH and TCL groups. Post-baseline NE and COHb were statistically significantly lower in the TCL compared to the TCH groups. Under the conditions of this study, we found no indication of changes in respiratory parameters, particularly inhalation time and volume, between study participants smoking lower versus higher yield cigarettes. Likewise, the BOE provides no indication of deeper inhalation when smoking low- versus high-yield cigarettes. These findings are consistent with the published literature indicating smoking low-yield cigarettes does not increase the depth of inhalation.

Cigarette filter-based assays as proxies for toxicant exposure and smoking behavior--a literature review

BACKGROUND

Cigarettes are being marketed with filters that differ in composition and design. The filters have different toxicant trapping efficiencies, and smoking stains reflect variations in smoking behavior. Presented herein are the results of a structured literature review that was done to identify cigarette filter-based assays that may serve as proxies for mouth-level exposure and assessing smoking methods.

METHODS

A search of the published scientific literature and internal tobacco company documents from 1954 to 2009 was carried out.

RESULTS

The literature search identified diverse schemes for assessing cigarette filters, including visual inspection and digital imaging of smoked-stained spent filters, and quantitative determinations for total particulate matter (TPM), nicotine, and solanesol. The results also showed that: (a) there are sufficient data to link filter-based chemical measures to standardized smoking machine-measured yields of tar and nicotine; (b) TPM eluted from filters or in chemical digest of filters can be used to estimate the efficiency of the filter for trapping smoke solids; (c) visual and digital inspection of spent filters is useful in finding indicators of variations in smoking behaviors; and (d) there is a correlation between solanesol and nicotine measured in filters and exposure biomarkers in smokers.

CONCLUSIONS

The cigarette filter may prove useful in estimating smoking behaviors such as filter vent blocking and puffing intensity, and may have utility as proxy measures of mouth-level smoke exposure in clinical trials. Additional investigations are needed to compare the different proposed assay schemes and the assay results with measurements of human biomarker assays of smoke exposure.

Behavioral filter vent blocking on the first cigarette of the day predicts which smokers of light cigarettes will increase smoke exposure from blocked vents

Filter vent blocking on best-selling light cigarettes increases smoke yield during standard machine testing but not in clinical investigations of smokers. The purpose of the study was to investigate the effect of (a) manipulating cigarette filter vent blocking and (b) blocking status of first cigarette of the day on carbon monoxide (CO) boost. Participants (n = 25; Marlboro Lights nonmenthol cigarette smokers, age range 21-60 years, minimum 15 daily cigarettes, and daily smoking for a minimum 5 years) completed the laboratory-based, within-subject, double-blind, cross-over design of 2 smoking sessions, one utilizing a smoking topography device, one without. Each session consisted of smoking 4 cigarettes; 2 with filter vents blocked and 2 with filter vents unblocked. Spent first daily cigarette filters collected between sessions were scored for evidence of filter vent blocking. Smoking cigarettes with blocked filter vents significantly increased CO boost in both laboratory sessions (p < .001). Those who blocked their first cigarette of the day (n = 10) had significantly greater CO boost when smoking a blocked cigarette, in relation to smoking an unblocked cigarette and in comparison with nonblockers (p = .04). Total puff volume was a significant predictor of CO boost when smoking unblocked and blocked cigarettes (ps < .04). Blocking filter vents significantly increased smoke exposure in relation to when filter vents are not blocked, particularly for those who block filter vents on their first cigarette of the day. Total puff volume predicted CO boost, and results suggest that smokers adjust their smoking behavior by cigarette blocking status. Those smokers who block filter vents may be increasing their exposure by 30%.

Reconciling human smoking behavior and machine smoking patterns: implications for understanding smoking behavior and the impact on laboratory studies

BACKGROUND

Recent Food and Drug Administration legislation enables the mandating of product performance standards for cigarette smoke and the evaluation of manufacturers' health claims for modified tobacco products. Laboratory studies used for these evaluations and also for understanding tobacco smoke toxicology use machines to generate smoke. The goal of this review is to critically evaluate methods to assess human smoking behavior and replicate this in the laboratory.

METHODS

Smoking behavior and smoking machine studies were identified using PubMed and publicly available databases for internal tobacco company documents.

RESULTS

The smoking machine was developed to generate smoke to allow for comparing cigarette tar and nicotine yields. The intent was to infer relative human disease risk, but this concept was flawed because humans tailor their smoking to the product, and chemical yields and toxicologic effects change with different smoking profiles. Although smoking machines also allow for mechanistic assessments of smoking-related diseases, the interpretations also are limited. However, available methods to assess how humans puff could be used to provide better laboratory assessments, but these need to be validated. Separately, the contribution of smoke mouth-holding and inhalation to dose need to be assessed, because these parts of smoking are not captured by the smoking machine. Better comparisons of cigarettes might be done by tailoring human puff profiles to the product based on human studies and comparing results across regimens.

CONCLUSIONS

There are major research gaps that limit the use of smoking machine studies for informing tobacco control regulation and mechanistic studies.

Post-puff respiration measures on smokers of different tar yield cigarettes

The purpose of this study was to determine the effect of different tar yield cigarette brands on the post-puff inhalation/exhalation depth and duration for established smokers of the brands. The study was conducted with 74 established smokers of 1-17 mg Federal Trade Commission (FTC) tar products. The subjects were participating in a five-day inpatient clinical biomarker study during which time they were allowed to smoke their own brand of cigarette whenever they wished. On two separate days, the subjects' breathing pattern was measured using respiratory inductive plethysmography while they smoked one cigarette. This enabled the measurement of the post-puff inhalation volume, exhalation volume, inhalation duration, and exhalation duration for each subject after each puff on two of their own brand of cigarettes. The subjects were grouped according to the FTC tar yield of their product: 1-3 mg; 4-6 mg; 7-13 mg; 14 + mg. The post-puff inhalation volume for the 4-6 mg group was significantly lower than both the 7-13 mg and 14+ mg groups, and the 4-6 mg group exhalation volume was significantly lower than the 14+ mg group (p < 0.05). No other differences were found at the 95% confidence level. When volumes were normalized to resting tidal volume (tidal ratio), there were no differences between the groups for any of the respiratory measures. No significant slope was found for correlations with FTC tar yield for inhalation volume (p = 0.11, mean = 833 mL, R = 0.19), inhalation tidal ratio (p = 0.93, mean = 1.73, R = -0.01) or lung exposure time (p = 0.92, mean = 4.1 s, R = -0.01).

How do different cigarette design features influence the standard tar yields of popular cigarette brands sold in different countries?

OBJECTIVES

To examine the associations among cigarette design features and tar yields of leading cigarette brands sold in the United States, Canada, Australia and the United Kingdom.

METHODS

Government reports and numbers listed on packs were used to obtain data on International Organization for Standardization (ISO)/Federal Trade Commission (FTC) yields for the tar of 172 cigarette varieties sold in the United States, Canada, Australia and the United Kingdom. We used standardised methods to measure the following 11 cigarette design parameters: filter ventilation, cigarette pressure drop, filter pressure drop, tobacco rod length, filter length, cigarette diameter, tipping paper length, tobacco weight, filter weight, rod density and filter density.

RESULTS

Filter ventilation was found to be the predominant design feature accounting for the variations between brands in ISO/FTC tar yields in each of the four countries. After accounting for filter ventilation, design parameters such as overwrap length, tobacco weight and rod density played comparatively minor roles in determining tar yields.

CONCLUSIONS

Variation in ISO/FTC tar yields are predicted by a limited set of cigarette design features, especially filter ventilation, suggesting that governments should consider mandatory disclosure of cigarette design parameters as part of comprehensive tobacco product regulations.

Carboxyhemoglobin and thiocyanate as biomarkers of exposure to carbon monoxide and hydrogen cyanide in tobacco smoke

The determination of biomarkers in human body fluids is a useful tool, which allows the quantitative assessment of the exposure to chemicals or complex mixtures of chemicals and of early biological effects as a result of the exposure. Biomarkers require validation before their successful application in human studies. This review describes some general purposes of human biomonitoring and biomarkers including the requirements for validation. Risk assessment and harm reduction of smoking and tobacco products, respectively, is a very suitable field for the application of biomarkers. A brief historical review shows that the application of biomarkers of exposure and effect in human smoking goes back more than 150 years. Two 'classical' biomarkers of exposure to tobacco, namely carboxyhemoglobin (COHb and its equivalent carbon monoxide in exhalate, COex) and thiocyanate (SCN) in body fluids are discussed in terms of sources of exposure, metabolism, disposition kinetics and influencing host factors. Data on COHb/COex and SCN in nonsmokers and smokers as well as the power to discriminate between smokers and nonsmokers are presented. Both biomarkers are significantly correlated with the daily cigarette consumption. Smoking machine-derived yields of the precursors carbon monoxide and hydrogen cyanide were not correlated with COHb/COex and SCN, respectively. It is concluded that, while COHb/COex is a useful biomarker for assessing the smoke inhalation, preferably in controlled studies, the application of SCN in body fluids as a biomarker for smoking is limited, mainly due to the abundance of other sources for SCN.

The effect of filter vent blocking and smoking topography on carbon monoxide levels in smokers

Two studies were conducted to examine the effect of filter vent blocking and smoking topography on carbon monoxide (CO) levels in smokers. In Study 1, 12 participants smoked two types of cigarettes (Marlboro Light and Carlton 100) under two types of blocking conditions (unblocked and half-blocked) while using a smoking topography device. Participants were restricted to 8 puffs, separated by 45 s. Significant main effects of CO boost for cigarette type and blocking condition replicated previous findings. A significant increase in CO boost for the Marlboro Light blocked condition is a novel finding for this best-selling brand. That result and the finding that topography measures did not predict CO boost made us question the reliability of CO boost. In Study 2, we examined the reliability of CO boost by recruiting 12 participants to smoke three unblocked Carlton 100 cigarettes in one session and three half-blocked in another. CO boost was significantly greater for the blocked sessions compared to the unblocked and CO boost did not differ within session, thus supporting the reliability of the measure. When participants do not switch brands within a session, smoking topography measures are predictive of CO boost.

Analysis of complex mixtures--cigarette smoke

Mainstream cigarette smoke is a complex mixture that is inhaled into the respiratory system. The physical characteristics and chemical composition of mainstream smoke are reviewed and briefly compared with that of sidestream smoke. Special attention is paid to ageing effects and artifact formation during the sampling and testing of cigarette smoke, with specific examples of artifact formation during sampling discussed (nitrogen dioxide, methyl nitrite, etc.). Historically, the generation of cigarette smoke for chemical and biological testing has been based on standard smoke generation procedures that are intended for product comparisons. More recently, emerging global regulations have called for alternative smoke generation methods, with emphasis on results relevant to conditions of product use, e.g., estimates of maximum smoke emissions. Strategies for establishing such alternative smoke generation methods are discussed and the potential effects of alternative smoking conditions on analytical accuracy and precision are addressed. Current regulatory requirements that include Hoffmann analyte analysis (i.e., constituents reported to be associated with the risks of cigarette smoking) are also summarized and the potential effect of alternative smoke generation methods on individual constituent yields considered. Finally, a limited critique of emerging regulation that relates to mainstream cigarette smoke measurements, including a discussion of recent WHO recommendations, is offered.

Smoking Topography Predicts Abstinence following Treatment with Nicotine Replacement Therapy

Objective: Smoking topography refers to how a person smokes a cigarette and includes measures of the number of puffs and puff volume, duration, and velocity. This study examined the relationship between smoking topography and abstinence from cigarettes following nicotine replacement therapy. A secondary objective was to determine the relationship of smoking topography to carbon monoxide (CO) exposure.

Method: Participants (n = 113) smoked one of their preferred brands of cigarette through a smoking topography device prior to participating in an open-label trial of transdermal nicotine versus nicotine nasal spray. A subset of participants (n = 50) provided breath CO samples prior to and following smoking the cigarette.

Results: Mean Vmax [odds ratio (OR), 1.12; 95% confidence interval (95% CI), 1.02-1.24; P = 0.02], mean puff volume (OR, 0.95; 95% CI, 0.91-0.98; P = 0.01), mean interpuff interval (OR, 1.06; 95% CI, 1.00-1.11; P = 0.03), and cigarette type (full flavor versus light/ultralight; OR, 0.35; 95% CI, 0.14-0.89; P = 0.03) were significant predictors of abstinence in a model controlling for treatment group and nicotine dependence. Controlling for time since last cigarette and initial CO level, mean puff velocity (β = 0.171; P = 0.01) was the only significant predictor of CO boost.

Conclusion: These results suggest that smoking topography may be useful to predict abstinence after using nicotine replacement therapy and to assess harm from smoking.

Cigarette filter ventilation is a defective design because of misleading taste, bigger puffs, and blocked vents

OBJECTIVE

To review tobacco industry documents on filter ventilation in light of published studies and to explore the role of filter ventilation in the design of cigarettes that deliver higher smoke yields to smokers than would be expected from standard machine smoked tests (Federal Trade Commission (FTC), International Organization for Standardization (ISO)).

DATA SOURCES

Searched from November 1999 to November 2000 internet databases of industry documents (www.pmdocs.com, www.rjrtdocs.com, www.lorillarddocs.com, www.bw.aalatg.com, www.cdc.gov/tobacco/industrydocs, www.tobaccodocuments.org, www.tobaccopapers.org, www.hlth.gov.bc.ca/Guildford, www.cctc.ca/ncth/Guildford, www.cctc.ca/ncth/Guildford2) for documents related to filter ventilation. Documents found dated from 1955 through 1994.

STUDY SELECTION

Those documents judged to contain the most relevant information or data on filter ventilation related to cigarette taste and compensatory smoking, while also trying to avoid redundancy from various documents deriving from the same underlying data.

DATA SYNTHESIS

Filter ventilation is a crucial design feature creating three main problems for lower tar cigarettes as measured by official smoking machine testing. Firstly, it misleadingly makes cigarettes taste lighter and milder, and, therefore, they appear less dangerous to smokers. Secondly, it promotes compensation mainly by facilitating the taking of larger puffs. Thirdly, for very heavily ventilated cigarettes (that is, > 65% filter air dilution), behavioural blocking of vents with lips or fingers is an additional contributor to compensatory smoking. These three effects are found in industry research as well as published research.

CONCLUSIONS

Filter ventilation is a dangerous, defective technology that should be abandoned in less hazardous nicotine delivery systems. Health interested groups should test cigarettes in a way that reflects compensatory smoking. Lower tar (vented filter) cigarettes should be actively countermarketed.

Smokers' sex and the effects of tobacco cigarettes: subject-rated and physiological measures

Smoking tobacco cigarettes results in characteristic subject-rated and physiological effects in regular tobacco smokers. Few reports have investigated potential sex differences in the physiological and subjective effects produced by tobacco smoking, though previous reports indicate that men and women differ in their tobacco smoking behavior. Sex differences in the subjective and/or physiological effects of smoking may help determine why women find quitting smoking more difficult than men and may help guide gender-specific treatment when planning smoking cessation. This laboratory study investigated sex differences in the subjective and physiological effects of cigarette smoking and smoking behavior in men (n = 38) and women (n = 30) before, during, and after they smoked two of their usual brand of cigarettes through a flowmeter-type puff topography measurement device. Results showed that the reduction in 'desire to smoke' produced by cigarette smoking was greater in women than in men, that the physiological effects of smoking were independent of smokers' sex, and that women take smaller and shorter puffs than men. These results suggest that women may be more sensitive than men to some of the subjective but not the physiological effects of smoking.

Blocking filter vents increases carbon monoxide levels from ultralight, but not light cigarettes

Effect of vent blocking on carbon monoxide (CO) exposure from a best-selling light cigarette was examined in 12 daily cigarette smokers. Mean CO boosts were not different from each other with (a) 0% filter vents blocked (5.0 ppm), (b) vents covered with lips (4.9 ppm), (c) 50% of vents covered with tape (4.8 ppm), and (d) vents covered with a pinch of the fingertips (4.9 ppm). A second study in another 12 smokers was conducted to replicate these findings as well as earlier findings that blocking vents doubles CO intake from 1-mg tar cigarettes. While blocking half the vents with fingers significantly increased CO boost from ultralight cigarettes (2.8 vs. 5.4 ppm, p < 0.001), it did not influence boosts from light cigarettes (6.3 vs. 6.5 ppm, p = 0.8). The lowest yield cigarettes (1 mg tar) may be special. Smoking machine simulations provide poor models of human smoke intake. It is unclear whether tar and nicotine intake from light cigarettes was influenced by vent blocking.

Desire to smoke during spaced smoking intervals

This study examined the detailed time course of desire to smoke self-reports during brief periods of tobacco smoking deprivation to determine how these reports are related to amount and spacing of scheduled smoking. During four independent sessions, subjects (n = 10) smoked cigarettes at 30-, 60-, or 120-min intervals, or only smoked a single cigarette at the end of the 6-h session. At 15-min intervals, subjects answered four analog scale questions measuring their desire to smoke which were averaged to produce a single score. Mean desire to smoke scores were 28, 43, 59 and 71 in the 30-, 60-, 120- and 360-min cigarette spacing conditions, respectively, indicating an orderly relationship with amount of scheduled smoking. Patterns of change were similar across repeated observations and during several different deprivation intervals. Desire to smoke ratings, although temporarily suppressed by smoking, began rising within minutes of smoking and increased to near maximum levels (about 80 on a 100-point scale) after fewer than 3 h of abstinence. The observed rapid escalation in desire to smoke ratings during brief periods of abstinence is consistent with cigarette craving being reported by regular smokers who are not trying to quit. Further, if cravings can be accepted as a feature of tobacco withdrawal, the results support the view that avoidance of withdrawal is an important factor that maintains regular cigarette smoking.

Response to smoking as a function of prior smoking amounts

Smoking patterns are changing to accommodate new environmental smoking restrictions. The current study explored the effects of prior smoking amounts on the behavioral, physiological, and subjective effects of smoking a single cigarette. Ten smokers (six females, four males) each participated in four laboratory sessions of 6 h duration. During each session, they smoked 0, 2, 5, or 11 cigarettes which were evenly spaced throughout the 6-h period at intervals ranging from 30 min (11 cigarettes) to 120 min (2 cigarettes), with condition order determined by a Latin square. At the end of each session, all smoked a final cigarette. Response to the last cigarette of the 6-h session was influenced by pretreatment smoking amounts. Number of puffs drawn from the cigarette (15.0, 14.1, 13.3, and 10.1) was inversely related to prior smoking density, as was heart rate increase (5.8, 4.0, 2.4, and 1.3 bpm). Three physical symptoms of smoking, dizzy, lightheaded and tingling, were significantly greater when preceded by 6 h of no smoking than when preceded by smoking at 30-min intervals. However, these symptoms were rated as mild (19-27 on a 100-point scale) even when no cigarettes had been smoked. These results suggest some dissipation of acute tolerance after 6 h of smoking abstinence. Liking and satisfaction ratings were inversely related to the pretreatment density of smoking. Liking scores for the last cigarette were 85, 71, 68 and 48 (on a 100-point analog scale) when 0, 2, 5 and 11 cigarettes had been smoked. Overall, the study showed that physiological and subjective effects of smoking are modulated by recent histories of smoking.(ABSTRACT TRUNCATED AT 250 WORDS)

Detection of vent-blocking on light and ultralight cigarettes

Trained raters can reliably identify vent-blocking in ultralight cigarettes based on tar stain patterns, yet detection of this phenomenon has not been previously studied in light cigarettes. This study was conducted to extend the research on vent-blocking in ultralight cigarettes to the much more popular light cigarettes. We wanted to find out if individuals could discriminate among stain patterns on cigarette butts with unblocked (0%), partially blocked (50%), and fully blocked (100%) vents using both light and ultralight cigarettes. Subjects were able to use the stain pattern technique to detect vent-blocking in light cigarettes as well as ultralight cigarettes.

Misuse of "light" cigarettes by means of vent blocking

Best-selling "light" cigarettes (9-12 mg tar, by FTC method; Federal Trade Commission, 1990) generally employ filter vents to reduce standard tar and nicotine yields. Earlier research on "ultra light" cigarettes (1-4 mg tar) showed that filter vents were blocked by human smokers leading to dramatic increases in tar and nicotine yields. An objective indicator of vent blocking was applied to a sample of 158 discarded light cigarette butts, and results indicated extreme vent blocking in 47% 27% ( +/- 8, 95% CI), some vent blocking in 26% ( +/- 8), and no vent blocking in 47% ( +/- 8). Cigarette consumers need to be informed of the risks of vent blocking as a countermeasure to the marketing of light cigarettes to health-conscious smokers.

Phase-out filter perforation: effects on human tobacco smoke exposure

Phase-Out is a mechanical device that dilutes the cigarette smoke stream by mechanically perforating cigarette filters. Machine testing of Phase-Out-treated cigarettes suggested that smoke exposure reductions of 90-95% could be achieved with the device. This study evaluated exposure to carbon monoxide (CO) and nicotine when humans (N = 10) smoked Phase-Out-treated cigarettes under controlled laboratory conditions. Using boost (i.e., change from baseline) measures of constituent exposure, reductions ranging from 30-80% were seen for both nicotine and carbon monoxide. Orderly graded reductions in constituent exposure were observed for both nicotine and carbon monoxide as the number of filter perforations increased from zero to six holes, with no further reduction at the eight-hole condition. Percentage reductions in constituent exposure generally corresponded well to those anticipated from machine testing, indicating that the controlled smoking technology was valid and that the Phase-Out device operated as expected in a human smoking assay. The utility of partial constituent-level reductions is discussed both with regard to lowered health risks of smoking and ease of quitting when partial reduction is used as a gradual weaning preparation for quit attempts.

Ultralow-yield cigarettes and type of ventilation: the role of ventilation blocking

Habitual smokers of perforation-ventilated cigarettes and of channel-ventilated cigarettes (18 male and 18 female subjects each; nicotine yield 0.1-0.3 mg, 0.2 mg, respectively) were compared with respect to different smoke exposure indicators and puffing behavior. The role of ventilation blocking was assessed by comparing normal lip contact with smoking through a cigarette holder. The presmoking concentrations (plasma nicotine, cotinine, respiratory CO) were higher for channel-filter than for perforation-ventilated cigarettes, as were the pre- to postsmoking boosts (nicotine, CO) with normal lip smoking. Holder smoking resulted in lower boosts than lip smoking for the channel filter cigarettes, although the puffing behavior was considerably intensified. The boosts for perforation-ventilated cigarettes remained unchanged and were reached with only moderately intensified puffing behavior. The results indicate the importance of ventilation blocking in everyday lip smoking for channel-filter cigarettes, but not for conventional, perforated cigarettes.

Effects of tetrahydrocannabinol content on marijuana smoking behavior, subjective reports, and performance

This study investigated the smoking topography of marijuana and its effect on heart rate, subjective reports, and cognitive/psychomotor task performance. Male subjects (N = 12) with histories of moderate marijuana use smoked ad lib one cigarette containing 0, 1.3, or 2.7% delta 9-THC on separate days. Smoking topography measures revealed smaller puff and inhalation volumes and shorter puff duration for the high marijuana dose compared to the low dose. No other smoking behavior differed between the active doses. Heart rate was increased dose dependently over placebo levels. Active marijuana also increased subjective reports of drug effect over placebo, but not dose dependently. Significant memory impairment was observed on a forward and reverse digit span task, and performance was impaired on the digit symbol substitution task by the high, but not low, dose of marijuana. Performance on a divided attention task was not affected by marijuana. Thus, although subjects adjusted their smoking of cigarettes varying in THC content, dose-related effects of marijuana were obtained on several measures. The observed differences and individual variation in smoking topography measures suggest that precise control of smoking behavior would improve the accuracy of marijuana dose delivery.

Self-selected blocking of vents on low-yield cigarettes

Blockers of vents in ultra-low-yield cigarettes had higher levels of carbon monoxide (CO) and salivary cotinine than did nonblockers. None of the blockers reported that they blocked vents. Exposure differences seemed not to be due simply to vent blocking, but also to be the result of syndromes of heavier (blocking, more cigarettes per day, and starting earlier in the morning) or lighter smoking (not blocking, fewer cigarettes per day, and starting later in the morning). The results are interpreted in light of the boundary model. Cigarette smoking and brand selection should be studied as they occur naturally, as well as in experimentally contrived studies.

Effects of puff number and puff spacing on carbon monoxide exposure from commercial brand cigarettes

Six chronic smokers of mid- to high-carbon monoxide (CO) yield cigarettes smoked ultralow- (1.6 mg CO), low- (5.9 mg CO) and high- (14.3 mg CO) yield commercial cigarettes under controlled smoking conditions in which either puff number or puff spacing was manipulated. CO exposure (pre- to postsmoking increments) was directly related to the number of puffs taken for all cigarette yields. CO exposure from the high- and low-yield cigarettes was equivalent when the number of puffs taken from the low-yield cigarettes was increased by 50% (from 8 to 12 puffs). In contrast, CO exposure from ultralow-yield cigarettes was still marginally lower than exposure from high-yield cigarettes after a 4-fold increase in puff number (8 to 32 puffs). Puff spacing did not affect biological exposure to CO. The study showed that the number of puffs taken during smoking can clearly affect biological exposure to CO, but that compensation for lowered yield using increased puffs is much more difficult when ultralow- as compared with low or "light"- yield cigarettes are smoked.

Prevalence of the misuse of ultra-low-tar cigarettes by blocking filter vents

Evidence from tar-stain patterns in 135 cigarette filters discarded in ashtrays in public areas of shopping malls was used to estimate the prevalence of behaviorally blocked air dilution vents in ultra-low-yield cigarettes. Nineteen per cent (+/- 4, standard errors of the mean) of the filters had been blocked extremely, 39 per cent (+/- 5 SEM) had been blocked to some degree, and 42 per cent (+/- 5 SEM) had not been blocked at all. Smokers, health practitioners, and researchers need to be warned of the risks of vent blocking.