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Approaches for the design of reduced toxicant emission cigarettes.

ABSTRACT: Cigarette smoking causes serious diseases through frequent and prolonged exposure to toxicants. Technologies are being developed to reduce smokers' toxicant exposure, including filter adsorbents, tobacco treatments and substitutes. This study examined the effect of modifications to filter ventilation, variations in cigarette circumference and active charcoal filter length and loading, as well as combinations of these features in a reduced-toxicant prototype (RTP) cigarette, on the yields of toxicants in cigarette smoke. An air-dilution mechanism, called split-tipping, was developed in which a band of porous paper in the centre of the filter tipping functions to minimise the loss of effective filter ventilation that occurs at the high flow rates encountered during human-smoking, and to facilitate the diffusional loss of volatile toxicants. As compared with conventional filter ventilation cigarettes, split-tipping reduced tar and volatile smoke constituent emissions under high flow rate machine-smoking conditions, most notably for products with a 1-mg ISO tar yield. Furthermore, mouth level exposure (MLE) to tar and nicotine was reduced among smokers of 1-mg ISO tar cigarettes in comparison to smokers of cigarettes with traditional filter ventilation. For higher ISO tar level cigarettes, however, there were no significant reductions in MLE. Smaller cigarette circumferences reduced sidestream toxicant yields and modified the balance of mainstream smoke chemistry with reduced levels of aromatic amines and benzo[a]pyrene but increased yields of formaldehyde. Smaller circumference cigarettes also had lower mainstream yields of volatile toxicants. Longer cigarette filters containing increased levels of high-activity carbon (HAC) showed reduced machine-smoking yields of volatile toxicants: with up to 97% removal for some volatile toxicants at higher HAC loadings. Split-tipping was combined with optimal filter length and cigarette circumference in an RTP cigarette that gave significantly lower mainstream (up to ~90%) and sidestream (predominately 20%-60%) smoke yields of numerous toxicants as compared with a commercial comparator cigarette under machine-smoking conditions. Significantly lower mainstream and sidestream smoke toxicant yields were observed for an RTP cigarette comprising several toxicant reducing technologies; these observations warrant further evaluation in clinical studies where real-world relevance can be tested using biomarkers of exposure and physiological effect.

SUBMITTER: Dittrich DJ

PROVIDER: S-EPMC4125608 | biostudies-literature | 2014

REPOSITORIES: biostudies-literature

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Approaches for the design of reduced toxicant emission cigarettes.

Dittrich David J DJ Fieblekorn Richard T RT Bevan Michael J MJ Rushforth David D Murphy James J JJ Ashley Madeleine M McAdam Kevin G KG Liu Chuan C Proctor Christopher J CJ

SpringerPlus 20140722

Cigarette smoking causes serious diseases through frequent and prolonged exposure to toxicants. Technologies are being developed to reduce smokers' toxicant exposure, including filter adsorbents, tobacco treatments and substitutes. This study examined the effect of modifications to filter ventilation, variations in cigarette circumference and active charcoal filter length and loading, as well as combinations of these features in a reduced-toxicant prototype (RTP) cigarette, on the yields of toxi ...[more]

PMID: 25110628

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Project description:ImportanceUse of electronic cigarettes (e-cigarettes) is increasing. Measures of exposure to known tobacco-related toxicants among e-cigarette users will inform potential health risks to individual product users.ObjectivesTo estimate concentrations of tobacco-related toxicants among e-cigarette users and compare these biomarker concentrations with those observed in combustible cigarette users, dual users, and never tobacco users.Design, setting, and participantsA population-based, longitudinal cohort study was conducted in the United States in 2013-2014. Cross-sectional analysis was performed between November 4, 2016, and October 5, 2017, of biomarkers of exposure to tobacco-related toxicants collected by the Population Assessment of Tobacco and Health Study. Participants included adults who provided a urine sample and data on tobacco use (N = 5105).ExposuresThe primary exposure was tobacco use, including current exclusive e-cigarette users (n = 247), current exclusive cigarette smokers (n = 2411), and users of both products (dual users) (n = 792) compared with never tobacco users (n = 1655).Main outcomes and measuresGeometric mean concentrations of 50 individual biomarkers from 5 major classes of tobacco product constituents were measured: nicotine, tobacco-specific nitrosamines (TSNAs), metals, polycyclic aromatic hydrocarbons (PAHs), and volatile organic compounds (VOCs).ResultsOf the 5105 participants, most were aged 35 to 54 years (weighted percentage, 38%; 95% CI, 35%-40%), women (60%; 95% CI, 59%-62%), and non-Hispanic white (61%; 95% CI, 58%-64%). Compared with exclusive e-cigarette users, never users had 19% to 81% significantly lower concentrations of biomarkers of exposure to nicotine, TSNAs, some metals (eg, cadmium and lead), and some VOCs (including acrylonitrile). Exclusive e-cigarette users showed 10% to 98% significantly lower concentrations of biomarkers of exposure, including TSNAs, PAHs, most VOCs, and nicotine, compared with exclusive cigarette smokers; concentrations were comparable for metals and 3 VOCs. Exclusive cigarette users showed 10% to 36% lower concentrations of several biomarkers than dual users. Frequency of cigarette use among dual users was positively correlated with nicotine and toxicant exposure.Conclusions and relevanceExclusive use of e-cigarettes appears to result in measurable exposure to known tobacco-related toxicants, generally at lower levels than cigarette smoking. Toxicant exposure is greatest among dual users, and frequency of combustible cigarette use is positively correlated with tobacco toxicant concentration. These findings provide evidence that using combusted tobacco cigarettes alone or in combination with e-cigarettes is associated with higher concentrations of potentially harmful tobacco constituents in comparison with using e-cigarettes alone.

Project description:BackgroundThere is considerable debate about the benefits and risks of electronic cigarettes (ECs). To better understand the risk-benefit ratio of ECs, more information is needed about net nicotine consumption and toxicant exposure of cigarette smokers switching to ECs.MethodsForty cigarette smokers (?1 year of smoking) interested in switching to ECs but not necessarily quitting smoking were enrolled in a 4-week observational study and provided an e-Go C non-variable battery and refillable atomizers and choice of eight flavors in 12 or 24 mg nicotine dosage. Measurement of urinary cotinine (metabolite of nicotine), 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL; a pulmonary carcinogen), and eight volatile organic compounds (VOCs) that are toxic tobacco smoke constituents was conducted at baseline and week 4.ResultsAll participants with follow-up data (92.5%) reported using the study EC. Of the 40 smokers, 16 reported no cigarettes at week 2 (40%) and six continued to report no cigarettes at week 4 (15%). Change in nicotine intake over the 4 weeks was non-significant (p = .90). Carbon monoxide (p < .001), NNAL (p < .01) and metabolites of benzene (p < .01) and acrylonitrile (p = .001) were significantly decreased in the study sample. Smokers switching exclusively to ECs for at least half of the study period demonstrated significant reductions in metabolites of ethylene oxide (p = .03) and acrylamide (p < .01).ConclusionSmokers using ECs over 4 weeks maintained cotinine levels and experienced significant reductions in carbon monoxide, NNAL, and two out of eight measured VOC metabolites. Those who switched exclusively to ECs for at least half of the study period significantly reduced two additional VOCs.ImplicationsThis study extends current literature by measuring change in smoking dependence and disease-associated biomarkers, NNAL and a panel of eight common VOCs that are toxic tobacco smoke constituents in smokers who switch to ECs. The findings support the idea of harm reduction, however some levels of toxicant exposure are still of clinical concern, particularly for dual users. Extrapolation of these results must be careful to separate the different toxic exposure results for exclusive switchers versus dual cigarette + EC users, and not to equate harm reduction with the idea that using ECs is harmless.

Project description:BackgroundPlastic filters on cigarette butts are a widespread source of nonbiodegradable, toxic environmental waste. State and local legislation to ban the sale of single-use cigarettes may be considered to prevent this waste, but scientific evidence on the impact of switching smokers to unfiltered cigarettes on smoking behavior and toxicant exposures is needed to inform this policy. We have designed an open-label, randomized, 9-week, crossover clinical trial of adult filtered-cigarette smokers who switch to unfiltered cigarettes.ObjectiveOur objective is to understand the impact of switching smokers of filtered cigarettes to unfiltered cigarettes on smoking behavior and toxic exposures.MethodsThis trial involves a 1-week baseline period; a 2-week period of smoking filtered or unfiltered cigarettes, where groups are randomly assigned; a 3-week washout period; another 1-week baseline period; and a 2-week crossover period of smoking the opposite condition (ie, filtered or unfiltered cigarettes) for a sufficient sample size of 40 participants. We will determine changes in (1) observed topography (ie, puff count, interpuff interval, and puff volume) and cigarettes smoked per day, via butt counts and self-report, (2) expired carbon monoxide and excretion of urinary cotinine, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol, and volatile organic compounds, and (3) participants' knowledge and attitudes toward unfiltered cigarettes, satisfaction with smoking, and intention to quit if they were not able to smoke filtered cigarettes.ResultsThis study was funded in June 2018 and approved by the relevant Institutional Review Boards in July 2018. This study has enrolled 37 participants as of October 2020. Data analysis is currently underway, and trial results are expected to be published in spring 2021.ConclusionsThis pilot proof-of-principle study will inform the design of a larger, future research project that can provide robust scientific evidence on our research question. Such a large study could inform possible state or local legislation to ban the sale of single-use filtered cigarettes in order to mitigate the environmental impact of discarded single-use plastic filters.Trial registrationClinicalTrials.gov NCT03749876; https://clinicaltrials.gov/ct2/show/NCT03749876.International registered report identifier (irrid)DERR1-10.2196/19603.

Project description:The Food and Drug Administration can set standards that reduce the nicotine content of cigarettes.We conducted a double-blind, parallel, randomized clinical trial between June 2013 and July 2014 at 10 sites. Eligibility criteria included an age of 18 years or older, smoking of five or more cigarettes per day, and no current interest in quitting smoking. Participants were randomly assigned to smoke for 6 weeks either their usual brand of cigarettes or one of six types of investigational cigarettes, provided free. The investigational cigarettes had nicotine content ranging from 15.8 mg per gram of tobacco (typical of commercial brands) to 0.4 mg per gram. The primary outcome was the number of cigarettes smoked per day during week 6.A total of 840 participants underwent randomization, and 780 completed the 6-week study. During week 6, the average number of cigarettes smoked per day was lower for participants randomly assigned to cigarettes containing 2.4, 1.3, or 0.4 mg of nicotine per gram of tobacco (16.5, 16.3, and 14.9 cigarettes, respectively) than for participants randomly assigned to their usual brand or to cigarettes containing 15.8 mg per gram (22.2 and 21.3 cigarettes, respectively; P<0.001). Participants assigned to cigarettes with 5.2 mg per gram smoked an average of 20.8 cigarettes per day, which did not differ significantly from the average number among those who smoked control cigarettes. Cigarettes with lower nicotine content, as compared with control cigarettes, reduced exposure to and dependence on nicotine, as well as craving during abstinence from smoking, without significantly increasing the expired carbon monoxide level or total puff volume, suggesting minimal compensation. Adverse events were generally mild and similar among groups.In this 6-week study, reduced-nicotine cigarettes versus standard-nicotine cigarettes reduced nicotine exposure and dependence and the number of cigarettes smoked. (Funded by the National Institute on Drug Abuse and the Food and Drug Administration Center for Tobacco Products; ClinicalTrials.gov number, NCT01681875.).

Project description:BackgroundThe U.S. Food and Drug Administration and the government of New Zealand have proposed a reduction of the nicotine content in cigarettes to very low levels. This study examined the potential effects of this regulation in smokers with affective disorders.MethodsIn a randomized controlled parallel group trial conducted at two sites in the USA (Penn State University, Hershey, PA and Massachusetts General Hospital, Boston, MA) 188 adult smokers with a current (n = 118) or lifetime (n = 70) anxiety or unipolar mood disorder, not planning to quit in the next 6 months, were randomly assigned (1:1) to smoke either Usual Nicotine Content (UNC) (11.6 mg nicotine/cigarette) research cigarettes, or Reduced Nicotine Content (RNC) research cigarettes where the nicotine content per cigarette was progressively reduced to 0.2 mg in five steps over 18 weeks. Participants were then offered the choice to either receive assistance to quit smoking, receive free research cigarettes, or resume using their own cigarette brand during a 12-week follow-up period. Main outcomes were biomarkers of nicotine and toxicant exposure, smoking behavior and dependence and severity of psychiatric symptoms. The pre-registered primary outcome was plasma cotinine.ResultsA total of 143 (76.1%) randomized participants completed the randomized phase of the trial, 69 (73.4%) in the RNC group and 74 (78.8%) in the UNC group. After switching to the lowest nicotine content cigarettes, compared to smokers in the UNC group, at the last randomized visit the RNC group had significantly lower plasma cotinine (metabolite of nicotine): difference between groups, -175.7, 95% CI [-218.3, -133.1] ng/ml. Urine NNAL (metabolite of NNK, a lung carcinogen), exhaled carbon-monoxide, cigarette consumption, and cigarette dependence were also significantly lower in the RNC group than the UNC group. No between-group differences were found on a range of other biomarkers (e.g. 8-isoprostanes) or health indicators (e.g. blood pressure), or on 5 different psychiatric questionnaires, including the Kessler K6 measure of psychological distress. At the end of the subsequent 12-week treatment choice phase, those randomized to the RNC group were more likely to have quit smoking, based on initial intent-to-treat sample, n = 188 (18.1% RNC v 4.3% UNC, p = 0.004).ConclusionReducing nicotine content in cigarettes to very low levels reduces some toxicant exposures and cigarette addiction and increases smoking cessation in smokers with mood and/or anxiety disorders, without worsening mental health.Trial registrationTRN: NCT01928758, registered August 21, 2013.

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Approaches for the design of reduced toxicant emission cigarettes.

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Approaches for the design of reduced toxicant emission cigarettes.

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