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

Switching people who smoke to unfiltered cigarettes: Effects on smoking topography

Introduction

Smoking topography (ST) describes smoking behavior and patterns. Removal of the cigarette filter and subsequent impact on ST has not been investigated. This is the first clinical trial comparing ST for filtered and unfiltered cigarettes in a naturalistic experiment.

Methods

We conducted a crossover clinical trial following established people who smoke cigarettes (n = 32) for two weeks under filtered and unfiltered smoking experimental conditions. Participants (50 % female, mean age 38.3 yr.) smoked in each experimental condition followed by a 3-week post-washout period. ST (puff count, volume, duration, peak and average flow) was measured at six time-points. Statistical analysis included a linear repeated mixed-effects model of smoking experimental conditions by visit number and sex.

Results

Average flow (ml/sec) was significantly less for filtered smoking (-6.92 lower (95 % CI: -13.44 to -0.39), p < 0.05), thus demonstrating more resistance on inhalation. No significant differences were found between filtered or unfiltered experimental conditions for other ST variables. However, average volume and average peak flow were somewhat higher in unfiltered smoking, and lower mean puff counts/cigarette were observed for unfiltered compared to filtered smoking.

Conclusion

Lower average flow rates were associated with filtered cigarette smoking. No significant differences were found for other ST variables between smoking experimental conditions. ST measurements comparing cigarette smoking conditions may determine if product regulatory changes, such as removing the cigarette filter could impact smoking behavioral patterns among people who smoke. This proof-of-principle study measuring ST may be replicated in larger trials to determine potential behavioral changes in smoking unfiltered cigarettes.

Characterisation of a smoke/ aerosol exposure in vitro system (SAEIVS) for delivery of complex mixtures directly to cells at the air-liquid interface

In vitro testing is important to characterise biological effects of consumer products, including nicotine delivery products such as cigarettes, e-cigarettes and heated tobacco products. Users' cells are exposed to these products' aerosols, of variant chemical compositions, as they move along the respiratory tract. In vitro exposure systems are available to model such exposures, including delivery of whole aerosols to cells, and at the air-liquid interface. Whilst there are clear advantages of such systems, factors including time to aerosol delivery, aerosol losses and number of cell cultures that can be exposed at one time could be improved. This study aimed to characterise a custom-built smoke/ aerosol exposure in vitro system (SAEIVS) using 1R6F reference cigarette smoke. This system contains five parallel smoking chambers and delivers different dilutions of smoke/ aerosol to two separate cell culture exposure chambers in <10 s. Using two dosimetry measures (optical density 400 nm [OD⁴⁰⁰ ]; mass spectrometric nicotine quantification), the SAEIVS demonstrated excellent linearity of smoke dilution prior to exposure (R²  = 0.9951 for mass spectrometric quantification; R²  = 0.9965 for OD⁴⁰⁰ ) and consistent puff-wise exposures across 24 and 96 well plates in cell culture relevant formats (e.g., within inserts). Smoke loss was lower than previously reported for other systems (OD⁴⁰⁰ : 16%; nicotine measurement: 20%). There was good correlation of OD⁴⁰⁰ and nicotine measurements, indicating that OD was a useful surrogate for exposure dosimetry for the product tested. The findings demonstrated that the SAEIVS is a fit-for-purpose exposure system for the reproducible dose-wise exposure assessment of nicotine delivery product aerosols.

Naturalistic Topography Assessment in a Randomized Clinical Trial of Smoking Unfiltered Cigarettes: Challenges, Opportunities, and Recommendations

Smoking topography (ST) is a set of measures profiling the behavioral characteristics of smoking in various settings. The CReSS portable device can measure ST in the natural environment. No standard protocol exists for measuring ST longitudinally with the CReSS. This study examined the utilization of the CReSS to measure ST and highlights challenges and opportunities in a naturalistic setting. This study is part of a randomized cross-over clinical trial of smoking filtered or unfiltered cigarettes. Participants (n = 43) smoked in each study condition for two weeks using the CReSS device for five days in their naturalistic smoking setting. The devices were calibrated and cleaned during the washout period, and data were downloaded every visit. Five test puffs were administered to calibrate each device. Moderate compliance rates (74.1%) were found with device usage, and the issues encountered were overheating/clogging, incorrectly registered date/time-stamped data, and device repair/replacement. Routine inspection/cleaning and training in device usage were instrumental in mitigating device malfunctioning. The CReSS device proved to be a feasible tool to examine naturalistic smoking topography and the potential impact of changes in tobacco product design on smoking unfiltered cigarettes. This is the first study to examine ST variables longitudinally, measured at multiple time points, and using unfiltered cigarettes.

Study on the daily Ad Libitum smoking habits of active Korean smokers and their effect on urinary smoking exposure and impact biomarkers

INTRODUCTION

Understanding interactions of smoking topography with biomarkers of exposure to tobacco is essential for accurate smoking risk assessments.

METHODS

In this study, the smoking topography and the levels of tobacco smoke exposure urinary biomarkers of a sample of active Korean smokers were quantified and measured. The results were used to investigate the effect of daily activities and smoking time on the smoking topography. Moreover, correlations between the smoking topography parameters and biomarkers were assessed.

RESULTS

No significant effect of either the daily activities or time on the smoking topography of the subjects were observed. Synchronic correlations of the cigarette consumption per day (CPD) and the average flow per puff with both urinary cotinine and trans-3'-hydroxycotinine were significant. For the urinary nicotine metabolites, the peak levels appeared when the CPD was over 19 cigarettes per day and the average puff velocity was between 35 and 45 ml/s. Nevertheless, when the average flow was over 60 ml/s, the levels of cotinine and trans-3'-hydroxycotinine significantly dropped.

CONCLUSIONS

The findings of this study may be beneficial for further smoking risk assessments with contributions of both the smoking topography and biomarkers to provide current smokers with applicable cession programs.Clinical significanceSmoking habits and levels of urinary biomarkers of Korean smokers are investigated.People with a higher dependency on nicotine smoke cigarettes with slower puffs.Effects of daily activities or time on smoking topography were not significant.Correlations between smoking topography and urinary biomarkers were significant.Peak biomarker levels were observed under certain smoking topography conditions.

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.

Smoking Topography among Korean Smokers: Intensive Smoking Behavior with Larger Puff Volume and Shorter Interpuff Interval

The difference of smoker’s topography has been found to be a function many factors, including sex, personality, nicotine yield, cigarette type (i.e., flavored versus non-flavored) and ethnicity. We evaluated the puffing behaviors of Korean smokers and its association with smoking-related biomarker levels. A sample of 300 participants was randomly recruited from metropolitan areas in South Korea. Topography measures during a 24-hour period were obtained using a CReSS pocket device. Korean male smokers smoked two puffs less per cigarette compared to female smokers (15.0 (13.0–19.0) vs. 17.5 (15.0–21.0) as the median (Interquartile range)), but had a significantly larger puff volume (62.7 (52.7–75.5) mL vs. 53.5 (42.0–64.2) mL); p = 0.012). The interpuff interval was similar between men and women (8.9 (6.5–11.2) s vs. 8.3 (6.2–11.0) s; p = 0.122) but much shorter than other study results. A dose-response association (p = 0.0011) was observed between daily total puff volumes and urinary cotinine concentrations, after controlling for sex, age, household income level and nicotine addiction level. An understanding of the difference of topography measures, particularly the larger puff volume and shorter interpuff interval of Korean smokers, may help to overcome a potential underestimation of internal doses of hazardous byproducts of smoking.

Cigarette Filter Ventilation and its Relationship to Increasing Rates of Lung Adenocarcinoma

The 2014 Surgeon General's Report on smoking and health concluded that changing cigarette designs have caused an increase in lung adenocarcinomas, implicating cigarette filter ventilation that lowers smoking machine tar yields. The Food and Drug Administration (FDA) now has the authority to regulate cigarette design if doing so would improve public health. To support a potential regulatory action, two weight-of-evidence reviews were applied for causally relating filter ventilation to lung adenocarcinoma. Published scientific literature (3284 citations) and internal tobacco company documents contributed to causation analysis evidence blocks and the identification of research gaps. Filter ventilation was adopted in the mid-1960s and was initially equated with making a cigarette safer. Since then, lung adenocarcinoma rates paradoxically increased relative to other lung cancer subtypes. Filter ventilation 1) alters tobacco combustion, increasing smoke toxicants; 2) allows for elasticity of use so that smokers inhale more smoke to maintain their nicotine intake; and 3) causes a false perception of lower health risk from "lighter" smoke. Seemingly not supportive of a causal relationship is that human exposure biomarker studies indicate no reduction in exposure, but these do not measure exposure in the lung or utilize known biomarkers of harm. Altered puffing and inhalation may make smoke available to lung cells prone to adenocarcinomas. The analysis strongly suggests that filter ventilation has contributed to the rise in lung adenocarcinomas among smokers. Thus, the FDA should consider regulating its use, up to and including a ban. Herein, we propose a research agenda to support such an effort.