Health Canada Intense Smoking Regimes Research Articles

Comparative and cumulative quantitative risk assessments on a novel heated tobacco product versus the 3R4F reference cigarette

Novel tobacco products that heat rather than burn tobacco (heated tobacco products or HTPs) have been shown to produce lower levels of harmful and potentially harmful constituents than conventional combusted cigarettes. The present study uses a quantitative risk assessment approach to compare non-cancer and cancer risk estimates for emissions generated by an HTP with smoke from a reference cigarette (3R4F). Fifty-four analytes were evaluated from the HTP aerosol and the 3R4F cigarette smoke. Emissions were generated using the ISO and the Health Canada Intense smoking regimes. The measured values were extrapolated to define a conservative exposure assumption for per day use and lifetime use based on an estimated maximum usage level of 400 puffs per day i.e., approximately 8 HTP tobacco capsules or 40 combustible cigarettes. Non-cancer and cancer risk estimates were calculated using these exposure assumptions for individual and per health outcome domains based on toxicological reference values derived by regulatory and/or public health agencies. The results of this assessment showed a reduction of non-cancer and cancer risk estimates by more than 90 % for the HTP versus the 3R4F cigarette, regardless of the smoking regime.

Heated Tobacco Products: Volatile Emissions and Their Predicted Impact on Indoor Air Quality.

This study characterized emissions from IQOS, a heated tobacco product promoted as a less harmful alternative to cigarettes. Consumable tobacco plugs were analyzed by headspace GC/MS to assess the influence of heating temperature on the emission profile. Yields of major chemical constituents increased from 4.1 mg per unit at 180 °C to 6.2 mg at 200 °C, and 10.5 mg at 220 °C. The Health Canada Intense smoking regime was used to operate IQOS in an environmental chamber, quantifying 33 volatile organic compounds in mainstream and sidestream emissions. Aldehydes, nitrogenated species, and aromatic species were found, along with other harmful and potentially harmful compounds. Compared with combustion cigarettes, IQOS yields were in most cases 1-2 orders of magnitude lower. However, yields were closer to, and sometimes higher than electronic cigarettes. Predicted users' daily average intake of benzene, formaldehyde, acetaldehyde and acrolein were 39 μg, 32 μg, 2.2 mg and 71 μg, respectively. Indoor air concentrations were estimated for commonly encountered scenarios, with acrolein levels of concern (over 0.35 μg m-3) derived from IQOS used in homes and public spaces. Heated tobacco products are a weaker indoor pollution source than conventional cigarettes, but their impacts are neither negligible nor yet fully understood.

Selected Constituent Yield Variation in the Smoke of Commercial Cigarette Brands on the Japanese Market

Summary This study focused on the variation in the yields of constituents in smoke from commercial cigarette brands available on the Japanese market. Nineteen commercial cigarette brands were sampled five times every two months from 2009 to 2010. The target constituents were benzo[a]-pyrene, 1,3-butadiene, benzene, formaldehyde, acetaldehyde, acrolein, N-nitrosonornicotine (NNN), 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), carbon monoxide, “tar”, and nicotine. The results of this study showed that the coefficient of variation (CV) values varied greatly by brands, constituents, and smoking regimes. The yields of NNN and NNK in the smoke were strongly correlated to their yields in the tobacco filler blend for most brands. The yields of benzo[a]pyrene under the International Organization for Standardization (ISO) and the Health Canada Intense (HCI) smoking regimes and 1,3-butadiene under the HCI smoking regime were found to be influenced by the measurement. It was shown that factors for variation were highly varied among constituents. The grand mean of CV values for NNN and formaldehyde associated with cigarette manufacturing over ten months and measurement at the JT laboratory under the HCI smoking regimes were 17.1% and 6.6% respectively. The grand mean of CV values for NNN and formaldehyde associated with both cigarette manufacturing over ten months and measurement at different laboratories under the HCI smoking regimes were 23.7% and 22.9% respectively. This is due to the fact that formaldehyde showed the highest CV values for reproducibility among the constituents. Thus, in order to set realistic and robust confidence intervals, it is very important to take into account the variations associated with cigarette manufacturing and measurement within and between laboratories.

A novel hybrid tobacco product that delivers a tobacco flavour note with vapour aerosol (Part 2): In vitro biological assessment and comparison with different tobacco-heating products

This study assessed the toxicological and biological responses of aerosols from a novel hybrid tobacco product. Toxicological responses from the hybrid tobacco product were compared to those from a commercially available Tobacco Heating Product (c-THP), a prototype THP (p-THP) and a 3R4F reference cigarette, using in vitro test methods which were outlined as part of a framework to substantiate the risk reduction potential of novel tobacco and nicotine products. Exposure matrices used included total particulate matter (TPM), whole aerosol (WA), and aqueous aerosol extracts (AqE) obtained after machine-puffing the test products under the Health Canada Intense smoking regime. Levels of carbonyls and nicotine in these matrices were measured to understand the aerosol dosimetry of the products. The hybrid tobacco product tested negative across the in vitro assays including mutagenicity, genotoxicity, cytotoxicity, tumour promotion, oxidative stress and endothelial dysfunction. All the THPs tested demonstrated significantly reduced responses in these in vitro assays when compared to 3R4F. The findings suggest these products have the potential for reduced health risks. Further pre-clinical and clinical assessments are required to substantiate the risk reduction of these novel products at individual and population levels.

A modified trapping method to quantify hydrogen cyanide in mainstream and sidestream cigarette smoke under ISO and Health Canada intense smoking regimes

Hydrogen cyanide is a toxic compound and plays a critical role in cigarette smoke hazard assessment. Due to its reactivity with other chemicals of cigarette smoke, hydrogen cyanide collection was accomplished by the novel trapping method established in our laboratory using glass-fibre filter pads (GFP) treated by sodium hydroxide. However, the GFP trapping method has not been tested under Health Canada Intense (HCI) smoking regime and the trapping efficiency of GFP versus traditional methods have not been evaluated. The present study employed the two trapping methods to collect hydrogen cyanide in mainstream and sidestream cigarette smoke under ISO and HCI smoking regimes. The causes leading to losses of hydrogen cyanide and effects of smoking parameters used in the traditional trapping method were also investigated in this study. It was found that under both ISO and HCI smoking regimes the amounts of hydrogen cyanide in GFP trapping method were strongly correlated (r>0.99) with those by the traditional trapping method, though the traditional method trapped less hydrogen cyanide in sidestream smoke. Carbonyl compounds, such as formaldehyde, were identified as the contributors for the loss of hydrogen cyanide in the alkaline solution. Puff profile was affected to some extents by the use of impinger. Collectively, the results indicate that the modified trapping method is preferred for the routine analysis of hydrogen cyanide in cigarette smoke under ISO and HCI smoking regimes.

Differences in cadmium transfer from tobacco to cigarette smoke, compared to arsenic or lead

Arsenic, cadmium and lead levels in tobacco filler and cigarette smoke were determined in a 568-sample worldwide survey. Median tobacco levels for arsenic, cadmium and lead were 237, 769 and 397ng/g respectively, comparable to those previously reported albeit somewhat lower for lead and cadmium. Median mainstream smoke yields for arsenic, cadmium and lead were <3.75, 18.2, and <12.8ng/cig. under ISO, and <8.71, 75.1 and <45.7ng/cig. under Health Canada Intense (HCI) smoking regime respectively. In the case of cigarettes with activated carbon, a selective retention of cadmium but not lead or arsenic was observed. This effect was more pronounced under ISO than under HCI smoking regimes. Cadmium selective retention by activated carbon was confirmed by testing specially designed prototype cigarettes and the causes for this selective filtration were investigated. The differences between cadmium, arsenic and lead in terms of their speciation in tobaccos and in cigarette smoke could be related to their distribution in the ash, butt, mainstream (in gas-phase and particulate-phase) and sidestream smoke of a smoked cigarette. The possible formation of organometallic cadmium derivatives in the smoke gas-phase is discussed, the presence of which could adequately explain the observed cadmium selective filtration.

Updates of CORESTA Recommended Methods after Further Collaborative Studies Carried Out under Both ISO and Health Canada Intense Smoking Regimes

Abstract During 2012, three CORESTA Recommended Methods (CRMs) (1-3) were updated to include smoke yield and variability data under both ISO (4) and the Canadian Intense (CI) (5) smoking regimes. At that time, repeatability and reproducibility data under the CI regime on smoke analytes other than “tar”, nicotine and carbon monoxide (6) and tobacco-specific nitrosamines (TSNAs) (7) were not available in the public literature. The subsequent work involved the determination of the mainstream smoke yields of benzo[a]-pyrene, selected volatiles (benzene, toluene, 1,3-butadiene, isoprene, acrylonitrile), and selected carbonyls (acetaldehyde, formaldehyde, propionaldehyde, butyraldehyde, crotonaldehyde, acrolein, acetone and 2-butanone) in ten cigarette products followed by statistical analyses according to the ISO protocol (8). This paper provides some additional perspective on the data variability under the ISO and CI smoking regimes not given in the CRMs.

Estimation of mouth level exposure to smoke constituents of cigarettes with different tar levels using filter analysis

A nicotine part-filter method can be applied to estimate smokers’ mouth level exposure (MLE) to smoke constituents. The objectives of this study were (1) to generate calibration curves for 47 smoke constituents, (2) to estimate MLE to selected smoke constituents using Japanese smokers of commercially available cigarettes covering a wide range of International Organization for Standardization tar yields (1–21mg/cigarette), and (3) to investigate relationships between MLE estimates and various machine-smoking yields. Five cigarette brands were machine-smoked under 7 different smoking regimes and smoke constituents and nicotine content in part-filters were measured. Calibration curves were then generated. Spent cigarette filters were collected from a target of 50 smokers for each of the 15 brands and a total of 780 filters were obtained. Nicotine content in part-filters was then measured and MLE to each smoke constituent was estimated. Strong correlations were identified between nicotine content in part-filters and 41 out of the 47 smoke constituent yields. Estimates of MLE to acetaldehyde, acrolein, 1,3-butadiene, benzene, benzo[a]pyrene, carbon monoxide, and tar showed significant negative correlations with corresponding constituent yields per mg nicotine under the Health Canada Intense smoking regime, whereas significant positive correlations were observed for N-nitrosonornicotine and (4-methylnitrosoamino)-1-(3-pyridyl)-1-butanone.