Study: E-cigarettes may increase cardiovascular risk

A new study suggests e-cigarette smokers may be increasing their risk of cardiovascular problems by smoking the electronic alternative to conventional cigarettes.

Although widely perceived by the public to be a safer option, e-cigarettes still come with an FDA warning because they deliver "detectable levels of known carcinogens and toxic chemicals to which users could be exposed."

Now a research team from the David Geffen School of Medicine at the University of California in Los Angeles is saying e-cigarettes may cause heart problems for users. According to their study, which was published this week in JAMA Cardiology, individuals that routinely use e-cigarettes have increased oxidative stress and an imbalance in their cardiac autonomic tone.

The study, which was led by Dr. Holly R. Middlekauff, included 23 healthy e-cigarette smokers between the ages of 21 and 45. The participants did not smoke traditional cigarettes and did not take prescription medication. A control group of 19 healthy individuals also participated in the study. Those in the control group, however, were not e-cigarette smokers or traditional cigarette smokers. They also were not taking any prescription medications.

The research team measured each participant’s heart rate variability during quiet rest and controlled breathing using an an electrocardiogram. They measured 3 spectral components: high frequency, low frequency, and very low frequency. They also conducted blood tests to analyze for oxidative stress.

They found that participants who used e-cigarettes had a shift in their cardiac autonomic balance towards sympathetic predominance. The body’s sympathetic nervous system takes control of the cardiovascular system in critical situations– causing the "fight or flight" response when an individual is in danger by increasing the adrenaline levels in the heart.

With regard to the oxidative stress markers, researchers found an increased level of low-density lipoprotein oxidizability among e-cigarette smokers. This indicates that lipoproteins containing the apolipoprotein B are prone to oxidation.

Researchers say their findings reveal that e-cigarette smokers are more prone to increased cardiac sympathetic activity and increased oxidative stress, which are both signs of tobacco-related cardiovascular risk.

"Nicotine, which is the major bioactive ingredient in e-cigarette aerosol, with its metabolites, may harbor unrecognized, sustained adverse physiologic effects that lead to an increased cardiovascular risk profile in habitual e-cigarette users," the researchers say.

To learn more, read the full study.