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.”
References
- 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
- Bhatnagar A. Are electronic cigarette users at increased risk for cardiovascular disease? JAMA Cardiol. 1 February 2017. doi: 10.1001/jamacardio.2016.5550
