E-cigarette puffing patterns associated with high and low nicotine e-liquid strength: effects on toxicant and carcinogen exposure

Contrary to intuition, use of lower strength nicotine e-liquids might not offer reduced health risk if compensatory puffing behaviour occurs. Compensatory puffing (e.g. more frequent, longer puffs) or user behaviour (increasing the wattage) can lead to higher temperatures at which glycerine and propylene glycol (solvents used in e-liquids) undergo decomposition to carbonyl compounds, including the carcinogens formaldehyde and acetaldehyde. This study aims to document puffing patterns and user behaviour associated with using high and low strength nicotine e-liquid and associated toxicant/carcinogen exposure in experienced e-cigarette users (known as vapers herein)

Daily exposure to formaldehyde and acetaldehyde and potential health risk associated with use of high and low nicotine e-liquid concentrations.

Recent evidence suggests that e-cigarette users tend to change their puffing behaviors when using e-liquids with reduced nicotine concentrations by taking longer and more frequent puffs. Using puffing regimens modelled on puffing topography data from 19 experienced e-cigarette users who switched between 18 and 6 mg/mL e-liquids with and without power adjustments, differences in daily exposure to carbonyl compounds and estimated changes in cancer risk were assessed by production of aerosols generated using a smoking machine and analyzed using gas and liquid chromatography. Significant differences across conditions were found for formaldehyde and acetaldehyde (p < 0.01). Switching from a higher to a lower nicotine concentration was associated with greater exposure regardless of whether power settings were fixed or adjustable which is likely due to increased liquid consumption under lower nicotine concentration settings. Daily exposure for formaldehyde and acetaldehyde was higher for 17/19 participants when using low (6 mg/mL) compared with high (18 mg/mL) nicotine e-liquid concentration when power was fixed. When power adjustments were permitted, formaldehyde and acetaldehyde levels were higher respectively for 16/19 and 14/19 participants with the use of 6 compared with 18 mg/mL nicotine e-liquid

Levels of selected carcinogens and toxicants in vapour from electronic cigarettes.

SignificanceElectronic cigarettes, also known as e-cigarettes, are devices designed to imitate regular cigarettes and deliver nicotine via inhalation without combusting tobacco. They are purported to deliver nicotine without other toxicants and to be a safer alternative to regular cigarettes. However, little toxicity testing has been performed to evaluate the chemical nature of vapour generated from e-cigarettes. The aim of this study was to screen e-cigarette vapours for content of four groups of potentially toxic and carcinogenic compounds: carbonyls, volatile organic compounds, nitrosamines and heavy metals.Materials and methodsVapours were generated from 12 brands of e-cigarettes and the reference product, the medicinal nicotine inhaler, in controlled conditions using a modified smoking machine. The selected toxic compounds were extracted from vapours into a solid or liquid phase and analysed with chromatographic and spectroscopy methods.ResultsWe found that the e-cigarette vapours contained some toxic substances. The levels of the toxicants were 9-450 times lower than in cigarette smoke and were, in many cases, comparable with trace amounts found in the reference product.ConclusionsOur findings are consistent with the idea that substituting tobacco cigarettes with e-cigarettes may substantially reduce exposure to selected tobacco-specific toxicants. E-cigarettes as a harm reduction strategy among smokers unwilling to quit, warrants further study. (To view this abstract in Polish and German, please see the supplementary files online.)

Levels of selected carcinogens and toxicants in vapour from electronic cigarettes

SignificanceElectronic cigarettes, also known as e-cigarettes, are devices designed to imitate regular cigarettes and deliver nicotine via inhalation without combusting tobacco. They are purported to deliver nicotine without other toxicants and to be a safer alternative to regular cigarettes. However, little toxicity testing has been performed to evaluate the chemical nature of vapour generated from e-cigarettes. The aim of this study was to screen e-cigarette vapours for content of four groups of potentially toxic and carcinogenic compounds: carbonyls, volatile organic compounds, nitrosamines and heavy metals.Materials and methodsVapours were generated from 12 brands of e-cigarettes and the reference product, the medicinal nicotine inhaler, in controlled conditions using a modified smoking machine. The selected toxic compounds were extracted from vapours into a solid or liquid phase and analysed with chromatographic and spectroscopy methods.ResultsWe found that the e-cigarette vapours contained some toxic substances. The levels of the toxicants were 9-450 times lower than in cigarette smoke and were, in many cases, comparable with trace amounts found in the reference product.ConclusionsOur findings are consistent with the idea that substituting tobacco cigarettes with e-cigarettes may substantially reduce exposure to selected tobacco-specific toxicants. E-cigarettes as a harm reduction strategy among smokers unwilling to quit, warrants further study. (To view this abstract in Polish and German, please see the supplementary files online.)

Facilitated PCI in patients with ST-elevation myocardial infarction

Background We hypothesized that percutaneous coronary intervention (PCI) preceded by early treatment with abciximab plus half-dose reteplase (combination-facilitated PCI) or with abciximab alone (abciximab-facilitated PCI) would improve outcomes in patients with acute ST-segment elevation myocardial infarction, as compared with abciximab administered immediately before the procedure (primary PCI).Methods In this international, double-blind, placebo-controlled study, we randomly assigned patients with ST-segment elevation myocardial infarction who presented 6 hours or less after the onset of symptoms to receive combination-facilitated PCI, abciximab-facilitated PCI, or primary PCI. All patients received unfractionated heparin or enoxaparin before PCI and a 12-hour infusion of abciximab after PCI. The primary end point was the composite of death from all causes, ventricular fibrillation occurring more than 48 hours after randomization, cardiogenic shock, and congestive heart failure during the first 90 days after randomization.Results A total of 2452 patients were randomly assigned to a treatment group. Significantly more patients had early ST-segment resolution with combination-facilitated PCI (43.9%) than with abciximab-facilitated PCI (33.1%) or primary PCI (31.0%; P = 0.01 and P = 0.003, respectively). The primary end point occurred in 9.8%, 10.5%, and 10.7% of the patients in the combination-facilitated PCI group, abciximab-facilitated PCI group, and primary-PCI group, respectively (P = 0.55); 90-day mortality rates were 5.2%, 5.5%, and 4.5%, respectively (P = 0.49).Conclusions Neither facilitation of PCI with reteplase plus abciximab nor facilitation with abciximab alone significantly improved the clinical outcomes, as compared with abciximab given at the time of PCI, in patients with ST-segment elevation myocardial infarction