Reductions in biomarkers of exposure, impacts on smoking urge and assessment of product use and tolerability in adult smokers following partial or complete substitution of cigarettes with electronic cigarettes

Abstract

BackgroundElectronic cigarettes (e-cigarettes) are popular alternatives to conventional cigarettes among adult smokers wishing to reduce their exposure to harmful smoke constituents. However, little information exists on the relative internal exposures resulting from the exclusive or dual use of e-cigarettes.MethodsMeasurements of product use; adverse events; changes in smoking urge; and blood, urine and exhaled breath biomarkers of exposure (BoE) representing toxicants believed to contribute to smoking related diseases were made at baseline and after five days of product use in 105 clinically-confined smokers randomized into groups that partially or completely substituted their usual brand combustible cigarette with commercial e-cigarettes, or discontinued all nicotine and tobacco products.ResultsSubjects switching to e-cigarettes had significantly lower levels (29 %–95 %) of urinary BoEs after 5 days. Nicotine equivalents declined by 25 %–40 %. Dual users who substituted half of their self-reported daily cigarette consumption with e-cigarettes experienced 7 %–38 % reductions, but had increases (1 %–20 %) in nicotine equivalents. Blood nicotine biomarker levels were lower in the cessation (75 %–96 %) and e-cigarette use groups (11 %–83 %); dual users had no significant reductions. All groups experienced significant decreases in exhaled CO (27 %–89 %). Exhaled NO increases (46 %–63 %) were observed in the cessation and e-cigarette use groups; dual users had minimal changes. By Day 5, all groups had greater reductions in smoking urge compared to cessation. However, reductions were larger in the dual use group. No serious adverse events were observed.ConclusionsExposures to harmful smoke toxicants were observed to be lower in smokers who completely or partially replaced their cigarettes with e-cigarettes over five days.

A Review of Pulmonary Toxicity of Electronic Cigarettes in the Context of Smoking: A Focus on Inflammation

“…CO also was substantially reduced. O’Connel et al (219, 220), reported on a five day trial of 105 subjects confined to a clinical facility; they found similar reductions in the urinary biomarkers and CO. Lastly, a one-year clinical trial reported significant reductions in exhaled CO (221). Thus, compared to smoking, there appears to be a significant overall reduction in biomarkers for persons completely switching to e-cigs, but it is not known if these peripheral biomarkers reflect effects in the lung.…”

Carcinogen Biomarkers in the Urine of Electronic Cigarette Users and Implications for the Development of Bladder Cancer: A Systematic Review

“…Of the 22 included studies, four were randomized controlled trials [9,[23][24][25], six were multi-institutional studies [8,[24][25][26], 10 were single-institutional studies, two analyses were of the US Population Assessment of Tobacco and Health [27,28], and one was an analysis of the National Health and Nutrition Examination Survey [29]. In addition, two pairs of studies reported results from common datasets [7,9,23,30] and four were sponsored by the tobacco or ecigarette industry [9,23,25,31]. Aggregation of the 22 studies produced an overall sample size of 1259 study participants, where individual sample study sizes ranged from 6 to 280.…”

“…All 22 included studies were published since 2015. Participant mean/ median age was infrequently reported, but the median age of those reported was 36 yr [1,8,12,23,25,26,[31][32][33][34]. Study designs were primarily cross-sectional and longitudinal studies.…”

Regulations and policies regarding e‐cigarettes

“…Despite the absence of tobacco, many ingredients commonly included in e‐cigarette liquids can have harmful effects when inhaled, although exposure to aerosolized carcinogens and toxins may be decreased among e‐cigarette users compared with conventional cigarette users . Nicotine and other potentially harmful chemicals are also present in the aerosols emitted by e‐cigarettes, which could result in “secondhand” exposures to nonsmokers .…”

“…4 Despite the absence of tobacco, many ingredients commonly included in e-cigarette liquids can have harmful effects when inhaled, 4,33,34 although exposure to aerosolized carcinogens and toxins may be decreased among ecigarette users compared with conventional cigarette users. 35,36 Nicotine and other potentially harmful chemicals are also present in the aerosols emitted by e-cigarettes, which could result in "secondhand" exposures to nonsmokers. 37 Beyond the chemical harms, there are concerns that e-cigarette use will lessen the negative attitudes and prohibitions that have developed in US society regarding cigarette use (ie, the potential to "normalize" cigarette smoking), 38 possibly leading to increased initiation or use of other types of tobacco products.…”