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Short-term cardiovascular effects of e-cigarettes in adults making a stop-smoking attempt: a randomized controlled trial

Research output: Contribution to journalArticle

Markos Klonizakis, Anil Gumber, Emma McIntosh, Leonie Brose

Original languageEnglish
JournalBMC Medicine
Publication statusIn preparation - 2020

King's Authors


Background: Smoking is a major risk factor for cardiovascular disease and smoking cessation reduces excess risk. E-cigarettes are popular for smoking cessation but there is little evidence on their effect on cardiovascular health.

Objective: To compare short-term cardiovascular effects in smokers who quit smoking using e-cigarettes with or without nicotine or prescription nicotine replacement therapy (NRT).

Design: Single-centre pragmatic three-arm randomised (1: 1: 1) controlled trial with recruitment from May 2017 to June 2019.

Setting: Sheffield, UK.

Participants: Adult smokers of ≥10 cigarettes per day willing to attempt to stop smoking with support (n=284).

Interventions: a) behavioural support and e-cigarettes with 18mg/ml nicotine; b) behavioural support and e-cigarettes without nicotine; c) behavioural support and NRT.

Measurements: Flow Mediated Dilation (%FMD), peak cutaneous vascular conductance (CVC max) responses to acetylcholine (ACh) and sodium nitroprusside (SNP), mean arterial pressure (MAP), recorded at baseline and three days after stopping smoking. General linear model using intention-to-treat approach and adjusting for age, gender, group, Body Mass Index or physical activity, and years smoked.

Results: Adjusting for baseline, at follow-up, all outcomes with the exception of SNP had improved significantly over baseline and there were no differences between the three groups (%FMD F=1.03, p=0.360, df=2,207; ACh F=0.172, p=0.84, df=2,207; SNP F=0.382, p=0.68, df=2,207; MAP F=0.176, p=0.84, df=2,207). For smokers≥ 20 cigarettes per day, benefits were particularly pronounced.

Limitations: 16% loss to follow-up, intervention limited to a single device and liquid manufacturer.

Conclusion: Smoking cessation showed positive cardiovascular impact even after a short, 3-day period and the effects did not differ between nicotine-containing e-cigarettes, nicotine-free e-cigarettes, and NRT.

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