Habitual electronic cigarette (e-cigarette) use is associated with an increased cardiovascular risk, according to a study published in JAMA Cardiology.

Roya S Moheimani, BS, from the University of California, Los Angeles, and colleagues evaluated otherwise healthy e-cigarette users between the ages of 21 and 45 years who had used e-cigarettes most days for a minimum of 1 year. Participants who were former tobacco cigarette smokers were eligible for the study if they had quit smoking more than 1 year prior to the study. Healthy volunteers who were not e-cigarette users were eligible to be enrolled as control participants. A total of 42 participants were enrolled, including 23 self-identified habitual e-cigarette users and 19 nontobacco cigarette, non–e-cigarette users.

A cross-sectional, case-controlled study was conducted from 2015 to 2016. Heart rate variability components were analyzed for the high-frequency (HF) component, the low-frequency (LF) component, and the ratio of the LF to the HF. Three parameters of oxidative stress were used to measure plasma: 1) low-density lipoprotein oxidizability; 2) high-density lipoprotein antioxidant/anti-inflammatory capacity; and 3) paraoxonase-1-activity.

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Of the participants, 35% were women, 35% were white, and the mean age was 27.6 years. The HF heart rate variability component was significantly decreased in the e-cigarette users compared with nonuser control participants. The LF component and the LF to HF ratio were significantly increased in the e-cigarette users compared with nonuser control participants, consistent with sympathetic predominance.

Low-density lipoprotein oxidizability was significantly increased in e-cigarette users compared with nonuser participants, consistent with increased oxidative stress. Paraoxonase-1 activity tended to be lower in the e-cigarette users. High-density lipoprotein antioxidant index, inflammatory markers, and C-reactive protein levels were not different between the groups.

“E-cigarette users have heart rate variability components shifted toward sympathetic predominance and decreased vagal tone, and increased oxidative stress, a pattern found in patients with increased cardiovascular risk,” stated the authors.

Editorial comment

In an accompanying editorial, Aruni Bhatnagar, PhD, Department of Medicine, University of Louisville, stated, “Although data from e-cigarette users were not compared with those from smokers of combustible cigarettes, the results of Moheimani et al demonstrate that the use of e-cigarettes is not without consequence and might impose cardiovascular harm and increase CVD risk. Nevertheless, changes in HRV and low-density lipoprotein oxidizability are indirect indices of cardiovascular injury, and it remains unclear to what extent these changes represent an increase in CVD risk.”


  1. Moheimani RS, Bhetraratana M, Yin F, et al. Increased cardiac sympathetic activity and oxidative stress in habitual electronic cigarette users: Implications for cardiovascular risk. JAMA Cardiol. 1 February 2017. doi: 10.1001/jamacardio.2016.5303
  2. Bhatnagar A. Are electronic cigarette users at increased risk for cardiovascular disease? JAMA Cardiol. 1 February 2017. doi: 10.1001/jamacardio.2016.5550