Acute cardiovascular effects of electronic cigarettes: a systematic review and meta-analysis

Electronic cigarette (EC) is widely advertised as a safe alternative to traditional cigarette (TC). We aimed to investigate the cardiovascular effect of EC with/without nicotine compared with TC. We systematically searched PubMed/MEDLINE, EMBASE, and Cochrane CENTRAL for randomized controlled trials that compared the effect of different smoking modalities on cardiovascular function up to 1 October 2024. Analysis used the weighted mean difference (WMD) with a 95% confidence interval (CI) via Comprehensive Meta-Analysis software, version 3.0. The study evaluated key cardiovascular parameters, including pulse wave velocity (PWV), augmentation index at 75 beats/min (AIx75), flow-mediated dilation (FMD), heart rate (HR), systolic blood pressure, and diastolic blood pressure. We analysed 9 trials involving 370 participants. Acute exposure to EC with nicotine (ECN) compared with nicotine-free EC (EC0) increased PWV (WMD = 0.26; 95% CI: 0.14-0.38, P < 0.001), AIx75 (WMD = 4.29; 95% CI: 2.07-6.51, P < 0.001), and HR (WMD = 5.06; 95% CI: 2.13-7.98, P = 0.001), significantly. In contrast, comparison between ECN and TC revealed no significant differences in FMD (WMD = 0.80; 95% CI: -0.09-1.70, P = 0.08). Our meta-analysis suggests that ECN acutely increases arterial stiffness more than EC0 does. Additionally, we found that the acute effect of ECN on endothelial dysfunction is not different from TC. Therefore, our study suggests that vaping cannot be considered as a safe substitute for TC. Further investigation is needed to explore the long-term cardiovascular effects of vaping and its modalities.