The influence of changing nicotine to tar ratios on human puffing behaviour and perceived sensory response

Characteristic Human Individual Puffing Profiles Can Generate More TNCO than ISO and Health Canada Regimes on Smoking Machine When the Same Brand Is Smoked

Human smoking behavior influences exposure to smoke toxicants and is important for risk assessment. In a prospective observational study, the smoking behavior of Marlboro smokers was measured for 36 h. Puff volume, duration, frequency, flow and inter-puff interval were recorded with the portable CReSSmicro™ device, as has often been done by other scientists. However, the use of the CReSSmicro™ device may lead to some registration pitfalls since the method of insertion of the cigarette may influence the data collection. Participants demonstrated consistent individual characteristic puffing behavior over the course of the day, enabling the creation of a personalized puffing profile. These puffing profiles were subsequently used as settings for smoking machine experiments and tar, nicotine and carbon monoxide (TNCO) emissions were generated. The application of human puffing profiles led to TNCO exposures more in the range of Health Canada Intense (HCI)-TNCO emissions than for those of the International Standardization Organization (ISO). Compared to the ISO regime, which applies a low puff volume relative to human smokers, the generation of TNCO may be at least two times higher than when human puffing profiles were applied on the smoking machine. Human smokers showed a higher puffing intensity than HCI and ISO because of higher puffing frequency, which resulted in more puffs per cigarette, than both HCI and ISO.

Differences in vaping topography in relation to adherence to exclusive electronic cigarette use in veterans

Background

Understanding vaping patterns of electronic cigarette (EC) use is important to understand the real-life exposure to EC vapor. Long term information on vaping topography in relation to tobacco cigarette (TC) smoking cessation success has not been explored.

Methods

Observational non-blinded study where active TC smokers were asked to replace TC with EC over 4 weeks (replacement phase, RP) followed by exclusive EC use for an additional 12 weeks (maintenance phase, MP). TC use and EC compliance was monitored weekly. Subjects were classified as success or failure whether or not they completed the protocol. Vaping information was stored and downloaded directly from the EC device and averaged per calendar day for analysis.

Results

From 25 subjects that followed the protocol, sixteen succeeded in completing the RP and 8 the MP (32%). No significant differences in baseline characteristics were noted between subjects in the success and failure groups including markers of nicotine addiction, plasma cotinine levels or smoking history. Success subjects showed significantly longer puff duration (seconds per vape) and total overall vapor exposure (number of vapes x average vape duration or vape-seconds) in both study phases. Furthermore, subjects in the success group continued to increase the number of vapes, device voltage and wattage significantly as they transitioned into the MP. After an initial drop, subjects in the success group were able to regain plasma cotinine levels comparable to their TC use while subjects in the failure group could not. Cotinine levels significantly correlated with the average number of daily vapes and vapes-seconds, but not with other vaping parameters.

Conclusion

The topography of smokers who adhere to exclusive EC use reflects a progressive and dynamic device adaptation over weeks to maintain baseline cotinine levels. The higher inhaled volume over time should be considered when addressing the potential toxic effects of EC and the variable EC adherence when addressing public health policies regarding their use.

Validation of selected analytical methods using accuracy profiles to assess the impact of a Tobacco Heating System on indoor air quality

Studies in environmentally controlled rooms have been used over the years to assess the impact of environmental tobacco smoke on indoor air quality. As new tobacco products are developed, it is important to determine their impact on air quality when used indoors. Before such an assessment can take place it is essential that the analytical methods used to assess indoor air quality are validated and shown to be fit for their intended purpose. Consequently, for this assessment, an environmentally controlled room was built and seven analytical methods, representing eighteen analytes, were validated. The validations were carried out with smoking machines using a matrix-based approach applying the accuracy profile procedure. The performances of the methods were compared for all three matrices under investigation: background air samples, the environmental aerosol of Tobacco Heating System THS 2.2, a heat-not-burn tobacco product developed by Philip Morris International, and the environmental tobacco smoke of a cigarette. The environmental aerosol generated by the THS 2.2 device did not have any appreciable impact on the performances of the methods. The comparison between the background and THS 2.2 environmental aerosol samples generated by smoking machines showed that only five compounds were higher when THS 2.2 was used in the environmentally controlled room. Regarding environmental tobacco smoke from cigarettes, the yields of all analytes were clearly above those obtained with the other two air sample types.

Cigarettes with different nicotine levels affect sensory perception and levels of biomarkers of exposure in adult smokers

INTRODUCTION

Few clinical studies involving cigarettes have provided a comprehensive picture of smoke exposure, test article characterization, and insights into sensory properties combined. The purpose of these pilot studies was to determine whether cigarettes with different levels of nicotine but similar tar levels would affect sensory experience or smoking behavior so as to significantly alter levels of selected biomarkers of exposure (BOE).

METHODS

In 2 confined, double-blind studies, 120 adult smokers switched from Marlboro Gold cigarettes at baseline to either 1 of 2 lower nicotine cigarettes or 1 of 2 higher nicotine cigarettes and then to the other cigarette after 5 days. Urinary excretion of exposure biomarkers (nicotine equivalents [NE], total and free 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol [NNAL], 1-hydroxypyrene, and 3-hydroxypropyl mercapturic acid) as well as carboxyhemoglobin and plasma cotinine were measured at baseline, Day 5, and Day 10. Daily cigarette consumption was monitored and sensory characteristics were rated for each cigarette.

RESULTS

With higher nicotine yield, urine NE, urine total NNAL, and plasma cotinine increased while nonnicotine BOE decreased without changes in cigarette consumption. In contrast, with lower nicotine yield, urine NE, urine total NNAL, and plasma cotinine dropped while nonnicotine BOE and cigarettes per day increased. Higher nicotine cigarettes were rated harsher and stronger than at baseline while lower nicotine cigarettes were less strong. All 4 test cigarettes were highly disliked.

CONCLUSIONS

These studies demonstrate that abrupt increases or decreases in nicotine and the resulting sensory changes impact BOE through changes in intensity or frequency of smoking.

Limitations in the characterisation of cigarette products using different machine smoking regimes

It is recognised that no single machine smoking regime can represent the different behaviours of individual human smokers. It has been argued that the current ISO standard regime provides machine yields that are somewhat low for certain cigarette designs compared to human intake. Various cigarette machine smoking regimes have been proposed as options for regulatory use to provide data that reflect "average" or "maximum" yields as related to human intake. Some public health representatives have proposed that the intense regime mandated for testing in Canada with 100% of the ventilation holes in the cigarette filter blocked, should be used for product characterisation and that it is not necessary that it should reflect general human smoking behaviour. We believe that this is a flawed approach because our studies and those of other workers demonstrate that the conditions generated in the cigarette when using this intense machine smoking regime are extreme in comparison to the conditions found for regimes based more realistically on human smoking. In this paper, we provide data to show that smokers modify their smoking intensity over the course of smoking in response to changes in draw resistance, smoke concentrations and smoke temperatures. We compare changes in and interactions between these parameters during puffing when smoking cigarettes of different designs. Cigarettes were smoked using various machine smoking regimes previously proposed for smoke testing as well as a regime based on human smoking data from an 'in-house' study. Puffing parameters were derived from this study to represent the 'average smoker' under laboratory conditions and equivalent to the 90th percentile when the studied smokers smoked under natural conditions. Biomarker data from human uptake studies have shown that ventilation is an effective cigarette design tool to reduce total smoke constituent uptake in humans so demonstrating that any blocking of filter ventilation is far from 100%. Likewise, this current work also shows how smokers modify their smoking behaviour in ways not well reflected by the 100% ventilation blocking regime. It seems logical that any machine smoking regime chosen for future product regulation should reflect these findings for it to have valid public health relevance. In addition, it seems misguided to discourage product design features, such as ventilation, which clearly can provide products with reduced human smoke exposure, just to maintain the dogma, counter to the scientific evidence, that there must be a regulatory regime with 100% ventilation blocking.

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%.

Reduced-nicotine content cigarettes: Is there potential to aid smoking cessation?

INTRODUCTION

Current smoking cessation treatments largely address pharmacological dependence on nicotine. New approaches are needed that address both nicotine dependence and psychological dependence on cigarettes as the source of nicotine. One such approach is the use of cigarettes with reduced nicotine content.

METHODS

We reviewed the available literature on the use of reduced-nicotine content cigarettes as a cessation aid.

RESULTS

One case series study and trial data indicate that reduction in the level of nicotine in cigarette tobacco can reduce the level of nicotine dependence in smokers and do so without adverse effects on cardiovascular biomarkers or significant compensatory smoking. We identified three clinical trials (total n = 489) that suggest that smokers can dissociate nicotine delivery from the act of smoking if they use reduced-nicotine content cigarettes in combination with nicotine replacement therapy.

DISCUSSION

The identified studies point to a benefit but involved only a small number of participants and provide only limited data on long-term abstinence. More definitive evidence from larger trials with longer follow-up is needed to clarify the role of reduced nicotine cigarettes as an aid to smoking cessation.

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.

A review of the influence of particle size, puff volume, and inhalation pattern on the deposition of cigarette smoke particles in the respiratory tract

Ventilation of the cigarette was designed to allow dilution of the cigarette smoke and thereby reduce the dose delivered to the smoker. Following the toxicological principle of dose response, a lower concentration of cigarette smoke should be associated with a lower toxicological response. However, there have been many studies reporting on the phenomenon of compensation whereby the smoker increases puff volume and/or frequency in order to obtain higher volumes of smoke This article reviews studies of the particle size of cigarette smoke and examines, based on available literature, the associated differences in the tobacco smoke and smoking behavior and their relationship to deposition patterns in the lung. The data available indicate that particle size of the cigarette smoke does not significantly change as a function of cigarette type or smoking behavior. The cigarette smoke particle size is in the same range as the minimum deposition particle size in the lung. While varying concentrations of particles are taken into the mouth, the subsequent inhalation pattern has been reported as remaining constant and also does not appear to change significantly under different smoking types and conditions. The dynamics of what happens to the smoke in the short time it is retained in the mouth have not been studied, and this perhaps should be the subject of future investigations. The current data therefore suggest that the particle deposition pattern of the smoke within the lung would not change significantly if compensation occurs.