More information on how ecigs increase cardiovascular disease risk

The evidence that e-cigarette use is associated with increased cardiovascular disease keeps accumulaing, together with studies on the specific pathophysiological mechanisms through which e-cigarette use increases disease risk. The recent review by Huiqi Zong, Zhekai Hu and colleagues, Electronic cigarettes and cardiovascular disease: epidemiological and biological links, is the most recent summary of this evidence.

Here is their summary of the epidemiology:

In a National Health Interview Survey (NHIS) in America, Alzahrani et al. [80, 81], using years 2014 (n=36,697), 2015 (updated in a subsequent letter to the editor), and 2016 (n=33,028) data, reported an odds ratio (OR) of 1.49 (95% confidence interval (CI), 1.06–2.09) for occasional e-cigarette users and 2.14 (95% CI, 1.41–3.25) in those vaping daily, which indicates high cumulative risk estimates for MI. They concluded that daily e-cigarette use was independently associated with increased odds of having had a MI. Similarly, Vindhyal et al. [82], analyzing the NHIS data of 2014 (n=36,697), 2016 (n=33,028), and 2017 (n=26,742), found e-cigarette users have an over 50% higher risk of developing MI (OR, 1.56; 95% CI, 1.45–1.68) and even a 30% higher risk of developing stroke (OR, 1.30; 95% CI, 1.20–1.40) when compared with nonusers. In addition, Osei et al. [83] found dual users were associated with 36% higher odds of CVD (OR, 1.36; 95% CI, 1.18–1.56) compared with smoking alone in a large cross-sectional telephone survey. A composite of self-reported coronary heart disease, MI, or stroke was regarded as the main outcome. They also found the odds of CVD gradually increased with increasing frequency of e-cigarette exposure in current tobacco cigarette smokers.

They then go on to summarize the evidence how the components of e-cigarette aerosol (nicotine, polypropylene glycol, flavorings, and metals) impact oxidative stress, inflammation, endothelial dysfunction, atherosclerosis, hemodynamic effects, and platelet function mediate the increases in risk (chart above).

This paper should be read in the context of earlier reviews of the biological effects of e-cigarettes on CVD as well as our recent meta-analysis that shows that cardiovascular disease risk associated with e-cigarettes is similar to cigarettes.

Here is the abstract:

Electronic cigarettes (e-cigarettes), as alternative nicotine delivery methods, has rapidly increased among youth and adults in recent years. However, cardiovascular safety is an important consideration regarding e-cigarettes usage. e-cigarette emissions, including nicotine, propylene glycol, flavorings, nitrosamine, and metals, might have adverse effects on cardiovascular health. A large body of epidemiological evidence has indicated that e-cigarettes are considered an independent risk factor for increased rates of cardiovascular disease occurrence and death. The incidence and mortality of various types of cardiovascular disease, such as cardiac arrhythmia, hypertension, acute coronary syndromes, and heart failure, have a modest growth in vapers (users of e-cigarettes). Although the underlying biological mechanisms have not been fully understood, studies have validated that oxidative stress, inflammation, endothelial dysfunction, atherosclerosis, hemodynamic effects, and platelet function play important roles in which e-cigarettes work in the human body. This minireview consolidates and discusses the epidemiological and biological links between e-cigarettes and various types of cardiovascular disease.

The full citation is: Zong H, Hu Z, Li W, Wang M, Zhou Q, Li X, Liu H. Electronic cigarettes and cardiovascular disease: epidemiological and biological links. Pflugers Arch. 2024 Feb 20. doi: 10.1007/s00424-024-02925-0. Epub ahead of print. PMID: 38376568. It is available here.