Most adult cigarette smokers who use e-cigarettes are dual cigarette and e-cigarette (CC-EC) users, yet little is known about relative consumption of cigarettes to e-cigarettes and any associated harm reduction. Rate of substitution from cigarettes to e-cigarettes at week 6 and change in biomarkers of exposure and potential harm were examined among dual dual cigarette and e-cigarette users [64/114 (56%); 35 Black, 29 Latino] in an e-cigarette switching randomized trial. Dual users averaged 79% substitution of cigarettes for e-cigarettes at week 6, resulting in a reduction from baseline of 70.0 ± 54.1 cigarettes per week (p < .001). Total nicotine consumption remained stable (baseline: 1160.5 ± 1042.1 pg/mL of cotinine, week 6: 1312.5 ± 1725.9 pg/mL of cotinine, p = .47), while significant reductions were seen in the potent lung carcinogen 4-(methylnitrosamino)-1-(3-pyridul)-1-butanol (NNAL) (-55.9 ± 88.6 ng/ml, p < .001), carbon monoxide (-6.3 ± 8.6 ppm, p < .001), and self-reported respiratory symptoms (−3.3 ± 8.0, p = .002). No significant changes were found in blood pressure or spirometry. Greater substitution from cigarettes to e-cigarettes was associated with larger reductions in NNAL (r = −.29, p = .02). The predominant dual-use pattern was characterized by regular e-cigarette and intermittent cigarette use. Findings demonstrate the short-term harm reduction potential of this dual-use pattern in Black and Latino smokers and suggest that the greatest benefit, aside from cessation of both products, is achieved by higher substitution of e-cigarettes for cigarettes. Findings need confirmation in a larger sample with longer follow-up in dual users with greater variability in the rate of substitution. NCT03511001 Findings suggest short-term harm reduction potential of dual cigarette-e-cigarette use for Black and Latino smokers. Results also demonstrate the heterogeneity of dual-use, with the greatest harm reduction seen in dual users with higher rates of substitution from cigarettes to e-cigarettes. Study results should be confirmed in a full clinical trial with long-term follow-up to evaluate maintenance of dual-use patterns and associated harm reduction potential over time.

Introduction One possible reason for the rapid proliferation of waterpipe (WP) smoking is the pervasive use of flavoured WP tobacco. To begin to understand the impact of WP tobacco flavours, the current study examined the impact of a preferred WP tobacco flavour compared with a non-preferred tobacco flavoured control on user’s smoking behaviour, toxicant exposure and subjective smoking experience. Method Thirty-six current WP smokers completed two, 45-minute ad libitum smoking sessions (preferred flavour vs non-preferred tobacco flavour control) in a randomised cross-over design. Participants completed survey questionnaires assessing subjective smoking experience, exhaled carbon monoxide (eCO) testing, and provided blood samples for monitoring plasma nicotine. WP smoking topography was measured continuously throughout the smoking session. Results While participants reported an enhanced subjective smoking experience including greater interest in continued use, greater pleasure derived from smoking, increased liking and enjoyment, and willingness to continue use after smoking their preferred WP tobacco flavour (p values <0.05), no significant differences were observed in nicotine and carbon monoxide boost between flavour preparations. Greater average puff volume (p=0.018) was observed during the non-preferred flavour session. While not significant, measures of flow rate, interpuff interval (IPI), and total number of puffs were trending towards significance (p values <0.10), with decreased IPI and greater total number of puffs during the preferred flavour session. Discussion The current study is the first to examine flavours in WP smoking by measuring preferred versus control preparations to understand the impact on subjective experience, smoking behaviour and toxicant exposure. The pattern of results suggests that even this relatively minor manipulation resulted in significant changes in subjective experience. These results indicate a possible need for regulations restricting flavours in WP tobacco as with combustible cigarettes.

Background: Monitoring trends and perceptions of new nicotine salt-based electronic cigarettes (ECs), like JUUL, is important to identify associations with product experimentation and use. Understanding harm perceptions of these new devices will inform prevention and intervention efforts. The current study assesses perceptions of the absolute harmfulness of JUUL use in addition to comparing it to other tobacco products. Methods: Participants (N = 839, 52% male) reporting ever use of JUUL were recruited from Amazon’s Mechanical Turk from January to March 2018. Respondents completed questionnaire items assessing demographics, co-use of non-JUUL products, JUUL use status (i.e., daily users (10.8%), non-daily users (29.4%), and triers (59.9%)), and JUUL and other tobacco products absolute harm perceptions. Results: Overall, participants rated JUUL as significantly less harmful than all other tobacco products (p < 0.001), except other ECs. Daily JUUL users rated JUUL as less harmful compared to non-daily JUUL users and JUUL triers (p < 0.05). JUUL was rated as more harmful by women compared to men (p < 0.05). Conclusions: Increased frequency of JUUL use was associated with decreased harm perceptions. JUUL was associated with reduced perceptions of absolute harm compared to most other tobacco products, except other ECs. Public health practitioners should develop public health interventions that increase harm perceptions of ECs.

To examine whether changes in select measures of e-cigarette puffing topography are associated with changes in smoking behavior. Sixteen current cigarette smokers were instructed to completely switch from smoking combustible cigarettes to using e-cigarettes over a 2-week period. The study was completed in the Southern Midwestern region of the United States. Measures included demographics, smoking history, and cigarette dependence, as well as baseline and 2-week follow-up self-reported cigarettes per day, cigarette craving and urges, exhaled carbon monoxide readings, and e-cigarette usage data (puff number, puffing time, and average puff duration) collected via the e-cigarette built-in puff counter. Over the 2-week switching period, participants significantly reduced their cigarettes per day (~80% reduction, p < .0001). Although the number of e-cigarette puffs/day remained relatively stable (p > .05), the average total e-cigarette daily puffing time increased significantly (p = .001). Users’ average puff duration increased by 91 ms/puff/d (p < .001). The percentage decrease in cigarettes smoked per day was significantly and directly related to the slope of subjects’ average puff duration over time (r(13) = .62, p = .01), such that as cigarettes per day decreased, puff duration increased. Self-reported smoking urges remained relatively stable from baseline to the end of the 2-week period (p > .05). Among smokers switching to an e-cigarette, greater increases in e-cigarette puff duration was associated with greater reductions in cigarette smoking. The current study is one of the first to examine changes in smokers’ e-cigarette puffing behavior and associated changes in cigarette consumption as they attempt to completely switch to e-cigarettes. During a 2-week switching period, participants reduced their cigarettes per day. Moreover, although e-cigarette puffs per day remained relatively stable, users’ average puff duration increased significantly. Greater increases in e-cigarette puff duration were associated with greater reductions in cigarette smoking. Understanding how to effectively use an e-cigarette to best reduce and eventually quit smoking will be necessary as smokers increasingly turn to these products to facilitate possible cessation.