A Laboratory Method to Measure Skin Surface Staining by Cigarette Smoke, Tobacco Heating Products and E-Cigarettes

Summary Exhaled or side-stream cigarette smoke (CS) may visually stain a consumer's skin over time. Tobacco heating products (THPs) and e-cigarettes (ECs) have reduced staining potential because they do not produce side-stream aerosols and their exhaled aerosols have significantly reduced levels of toxicants, particles and odour. Here we assess discolouration of porcine skin in vitro after exposure to particulate matter (PM) or aerosols from CS (3R4F), two THPs (glo and glo sens) and an EC (iSwitch Maxx). PM was prepared by capturing aerosols on Cambridge filter pads and eluting with dimethyl sulfoxide (DMSO). Abattoir-obtained porcine skin samples were incubated with PM or DMSO control at 37 °C between 0 and 6.0 h. For aerosol assessment, porcine skin samples were exposed to between 50 and 400 puffs of the products, or air control, using a smoking machine. Colour profiles and staining levels of each skin sample were measured at different timepoints and puff thresholds using a spectrophotometer. Staining increased with time and dose, the greatest changes being observed following exposure to aerosols and PM from CS. THP, EC and control values were significantly different from CS after 0.5 h exposure to PM or 50 puffs of aerosols. The minimal staining induced by THPs and EC was comparable to controls. These data suggest that THPs and ECs could offer hygiene benefits to consumers who switch from smoking cigarettes. Further studies are required to assess the longer-term effects of THPs and ECs on skin discoloration. [Contrib. Tob. Nicotine Res. 30 (2021) 158–166]

The Effects of Cigarette Filter Ventilation on Delivery and Retention of Organic Acids

Summary A method for simultaneous identification and quantitative determination of 30 organic acids was established. The smoke yields and filter retentions of organic acids and routine smoke components, total particulate matter (TPM), nicotine-free dry particulate matter (NFDPM), nicotine and carbon monoxide (CO) at different filter ventilation levels were determined under both International Organization for Standardization (ISO) and Health Canadian Intense (HCI) smoking regimes. As a result of smoke dilution during filter ventilation, the yields of all organic acids were reduced in mainstream cigarette smoke. The spatial distribution pattern of the concentration of each organic acid in the filter was investigated at different ventilation levels and their filter retention determined. On one hand, the concentration of organic acids with a lower boiling point (BP) and lower molecular weight (MW) was relatively higher at the smoking end and the periphery part of the filter and spatial concentration distributions within the filter were significantly affected by smoke diffusion. On the other hand, those acids with high BPs and high MW were mainly distributed at the tobacco rod end and central part of the filter and spatial concentration distributions were only slightly influenced by their smoke diffusion within the filter whilst air compression around the filter vents also led to less change. This way, different acids in mainstream cigarette smoke were reduced to different extents which can also influence the acid-base equilibrium and sensory quality of the smoke. Compared with ISO smoking regime, the vent blocking and more intense smoking HCI regime led to different extents of yield increase for each of the studied acids. The effect of filter ventilation in the HCI smoking regime was not investigated, as the HCI smoking regime requires blocked ventilation holes. [Contrib. Tob. Nicotine Res. 30 (2021) 199–211]

Intake and Uptake of Chemicals Upon Use of Various Tobacco/Nicotine Products: Can Users be Differentiated by Single or Combinations of Biomarkers?

Summary With increasing use of new generation tobacco/nicotine products (TNPs) instead or in addition to conventional cigarettes (CCs), the question arises, whether the user of these new TNPs and CCs can be distinguished on the basis of their exposure in terms of intake and uptake of specific chemicals. For this purpose, the exposure to chemicals for users of 5 product types including CCs, HNB (heat-not-burn products), electronic cigarettes (ECs), oral tobacco products (OT, with the focus on snus), nicotine replacement therapy (NRT) products (only nicotine gum (NG) was considered in this study) was evaluated on the basis of published data. For both intake and biomarker-based uptake, 4 relative exposure levels with the assigned values from 1 (lowest exposure) to 4 (highest exposure) were defined resulting in exposure level patterns. Unique single-biomarker-based exposure levels were found for smokers (11 chemicals), vapers (1 chemical) and non-users (NU, 1 chemical). A few selected biomarkers (usually with relative levels of 3–4) were found to be sufficient for unequivocal differentiation of one user/NU group from the other 5 groups. The impact of dual-product use is also briefly discussed. [Contrib. Tob. Nicotine Res. 30 (2021) 167–198]

Determination of Benzoic Acid and Benzyl Alcohol in E-Liquids (JUULTM Pods) by Isotopic Dilution High-Performance Liquid Chromatography and Tandem Mass Spectrometry

Summary The new pod devices like JUULTM, Vuse AltoTM, mybluTM, and other “pod-mod” related products had a huge impact on the e-cigarette market, especially among teens and young adults due in particular to aggressive marketing on social media, wide availability, and discrete use due to their special design. These pod devices are designed to deliver nicotine levels per puff comparable to combustible cigarettes while producing smaller amounts of visible exhaled aerosol from the heating of e-liquids. Some of these liquids contain high concentrations of acids, such as benzoic acid, to allow higher nicotine deliveries with less harshness and throat irritation. Benzoic acid is a potential source of the human carcinogen benzene and a chemical of concern. Besides acids, flavoring agents such as benzyl alcohol, a local anesthetic that could facilitate tobacco smoke inhalation are also common in these devices. Both benzoic acid and benzyl alcohol in e-liquids might be of relevance for the health risk of vapers. An isotope dilution high-performance liquid chromatography-tandem mass spectrometry (ID-HPLC-MS/MS) method has been developed for the detection of benzoic acid and benzyl alcohol in the JUULTM brand e-liquids. The sample preparation consisted of a simple dilution followed by a mechanical stirring process. ID-HPLC-MS/MS was used to separate, identify, and quantify the benzoic acid and/or benzyl alcohol in diluted extracts. Detection limits were 0.11 and 9.05 ng/μL for benzyl alcohol and benzoic acid, respectively. Product variability estimated from the analysis of seven different e-liquids in triplicates (n = 21) yielded relative standard deviations ranging from 4.3% to 16.0% for benzyl alcohol and 6.3% to 11.1% for benzoic acid. The amount of benzoic acid (32.8 ± 2.8 mg/g; 3.3 ± 0.3%, w/w) and the nicotine-benzoic acid molar ratio (1.15 ± 0.02) remained relatively consistent among pod flavors. [Contrib. Tob. Nicotine Res. 30 (2021) 212–220]

Robustness of HPHC Reduction in THS 2.2 Aerosol Relative to 3R4F Reference Cigarette Smoke under Extreme Climatic Conditions

Summary In order to assess robustness for the reduction of harmful and potentially harmful constituent (HPHC) levels generated by the Tobacco Heating System 2.2 (THS 2.2), a heated tobacco product, we compared the aerosol of this product with mainstream smoke from the 3R4F reference cigarette under different conditions of temperature and humidity. The desired climatic conditions were achieved by using an air-conditioning system coupled with the smoking-machine housing. Two extreme climatic conditions were selected, representing a “Hot and Dry” climate (30 °C and 35% relative humidity RH) and a “Hot and Very Humid” climate (30 °C and 75% RH). In addition, aerosol and smoke were generated using the standard conditions recognized for smoking-machine analyses of tobacco products (22 °C and 60% RH), which were close to the climatic conditions defined for “Subtropical and Mediterranean” environments (25 °C and 60% RH). The experimental conditions were chosen to simulate the use of THS 2.2 and cigarettes under extreme conditions of temperature and humidity. HeatSticks and cigarettes taken from freshly opened packs were subjected to short-term conditioning from two to a few more days under the same experimental conditions. We analyzed 54 HPHCs in THS 2.2 aerosol and 3R4F cigarette smoke, generated in accordance with the Health Canada Intense (HCI) standard, using modified temperature and humidity conditions for sample conditioning and machine-smoking experiments. We used a volume-adjusted approach for comparing HPHC reductions across the different climatic conditions investigated. Although a single puffing regimen was used, the total puff volume recorded for the 3R4F cigarette smoke varied due to the influence of temperature and humidity on combustion rate, which justified the use of a volume-adjusted approach. Volume-adjusted yields were derived from HPHC yields expressed in mass-per-tobacco stick normalized per total puff volume. The results indicated that, regardless of the considered climatic conditions, the HPHC levels investigated in THS 2.2 aerosol were reduced by at least 90%, on average, when compared with the concentrations in 3R4F cigarette mainstream smoke. This confirmed the robustness in performance for THS 2.2 to deliver reduced levels of HPHCs under the extreme climatic conditions investigated in this study. In order to further characterize the robustness of these reductions, the lowest reduction performance achieved for individual HPHCs across all climatic conditions was used to define the threshold for a robust reduction. The majority of the 54 HPHCs investigated in THS 2.2 aerosol showed more than 90% reduction. Calculations derived from nicotine-adjusted yields also confirmed robust reductions for all investigated HPHCs. The small differences in absolute reduction between the volume- and nicotine-adjusted approaches were predominantly attributed to a combination of the differences in both nominal nicotine deliveries and total puff volumes between THS 2.2 and 3R4F cigarettes; however, this did not influence the determination of robustness. Our findings confirm the value of this approach for assessing the robustness of a product’s performance under different climatic conditions.

Machine Vaping of Electronic Cigarettes - A Comparison of Puffing Regimes#

Summary Several machine-based puffing regimes for collection of e-cigarette aerosol were evaluated with the objective of recommending one regime for standardization. The study involved a comparison of several candidate regimes for which puff volume, duration, interval, profile shape, and puff number were defined and varied. Testing was conducted at four laboratories using seven e-cigarette test products. Each participating laboratory generated and analyzed aerosol from the test products for glycerin, propylene glycol, water, and nicotine using the candidate regimes. Results were compared within each product’s data set to understand the impact of the regimes on product yield, consistency of results, and reliability of the testing equipment. Each of the regimes evaluated was determined to be fit for purpose for the range of products tested. Based on specific selection criteria, the recommended collection parameters are a square-shaped 55-mL puff of 3 s duration with a puff frequency of one puff every 30 s. Standardized reporting parameters include aerosol collected mass (ACM), puff count, and e-cigarette weight loss along with analyte yield on a per-puff basis and total-puffs basis.

A Cross-Sectional Study of Electronic Cigarette Use Among Chinese Adult Populations in Four Cities of China. Part II. Puffing Topography

Summary With the rapid popularity and increasing numbers of E-cigarette (EC) users, debates on possible health risks and regulation of EC products have attracted attention in public. As a useful means to help assessing the risks of EC consumers, puffing topography studies have come to be an important tool globally. In this paper, a cross-sectional epidemiological study on puffing topography of 511 EC consumers in four cities of China was conducted in January 2018. Data acquisition was based on a questionnaire and a Clinical Research Support System (CReSS) Pocket device for the smoking behavior recording. The results showed that EC consumers in the four cities were mainly young males, most of whom preferred tank systems with zero or low nicotine concentrations (1–5 mg/mL) in the liquid. The average puff volume, puff duration and inter-puff interval (IPI) were 87.2 mL, 1.97 s and 22.0 s, respectively. The factors that may have affected puffing topography such as product type, nicotine concentration, using time, smoking status and battery power were studied. The results suggest that the EC product type and the concentration of nicotine in EC liquids were the main factors that affected the puffing topography of the users. This study was the first study on the puff topography of Chinese EC consumers with a large number of participants. The results may not only help to more deeply understand smoking behavior and to better assess the potential risks for the EC users, but they may also supply useful information for the development of smoking machine regimes for ECs.

A Cross-Sectional Study of Electronic Cigarette Use Among Chinese Adult Populations in Four Cities of China. Part I. Questionnaire Survey

Summary The use of electronic cigarettes (ECs) has grown exponentially over the past few years in China. To obtain the basic information of Chinese EC users, a questionnaire survey was performed to collect the data that describe characteristics of study populations, including daily usage, consumption preference, and risk perception. Volunteers were recruited from Beijing, Shanghai, Guangzhou, and Shenzhen cities of China. In total, among the 511 participants that were included in the analysis, 491 participants (95%) used refillable ECs in the past 3 months. There was a strong association between EC use and traditional cigarette smoking. The majority of participants were dual users and the number of cigarettes smoked decreased with the use of ECs. After using an EC, 20.7% of conventional cigarette smokers attempted to quit smoking. Young people were the primary users across all geographic locations. Specifically, the daily usage for the participants who were 18–39 years old, was higher than those over 40 years old. The majority of participants (59.9%) preferred fruit flavors and 57.8% of them used 1–5 mg/mL nicotine-concentration liquids. Most EC users are motived to quit smoking, and 74.6% claimed that the ECs had no irritant effect on the oral cavity. A total of 50.5% of family members of the study participants reported an improvement of health status while the participants used ECs instead of traditional cigarettes. Overall, the results of this Chinese survey indicate that the per-day cigarette consumption of the dual users decreased whereas their proportion of smokers of low-“tar” cigarettes increased.

Evidence From the Scientific Assessment of Electronic Cigarettes and Their Role in Tobacco Harm Reduction

Summary While smoking remains a main global cause of preventable morbidity and mortality, a potential inflection point has arrived where it could become possible for non-combustible nicotine products to displace cigarettes and reduce risk for smokers who transition completely from smoking. These have proven consumer satisfaction and are now widely and increasingly available globally. One of the most prominent of these nicotine products are electronic cigarettes (ECs), which are used daily by millions of current and former smokers. The category is not without controversy as these products are not risk free and can cause nicotine dependence. The differing interpretation of science assessing ECs has transpired into inconsistent regulation and product standards, providing an environment for its fragmented manufacturing base which allows for variable product quality and in turn, product quality variability has impacted on how they are viewed. In this review, we assess published scientific evidence to evaluate whether, on balance, ECs fulfil a tobacco harm reduction role by reducing health risks relative to smoking and providing a viable alternative for smokers while having limited appeal to non-smokers.