A new study by researchers at the University of California, Los Angeles’ David Geffen School of Medicine has found that certain markers for heart disease risk were higher in e-cigarette users than in non-users. Said markers include higher levels of adrenaline in their hearts, compared with non-users, and elevated levels of inflammation and oxidative stress in their bodies.
Study co-author Dr. Holly Middlekauff said, ““This suggests that e-cigarettes have a more complicated effect than just the direct pharmacological effect of nicotine,” and that nicotine and other e-cigarette compounds “may set in motion a constellation of physiologic effects that persist, even when nicotine is out of the system.”
In the study, 16 e-cigarette users (defined as those who had been using e-cigarettes for at least one year) and 18 non-users were studied. Study participants were ages 21 to 45 and included both men and women. None of them smoked tobacco cigarettes at the time.
Researchers took the participants to a quiet, temperature-controlled room, and measured the participants’ heartbeats for 5 minutes while they rested and for another 5 minutes while they practiced controlled breathing. Also, a separate blood test looked at markers of oxidative stress and inflammation, which told researchers how well the body was responding to harmful toxins.
Study results indicated that the e-cigarette users showed increased adrenaline levels in their hearts, as well as higher levels of oxidative stress. The researchers said that both increased adrenaline levels in the heart and oxidative stress are ways in which tobacco cigarettes can contribute to increased cardiovascular risk. However, the study had some limitations. First, it relied on self-reporting for behaviors such as e-cigarette use and tobacco cigarette use, which can be an unreliable method, even though the researchers tested users’ blood to confirm whether they had recently smoked tobacco cigarettes.
Also, the researchers were unable to quantify just how many e-cigarettes the e-cig users had smoked, given the difficulty of measuring the liquid used by each per day. Plus, more former smokers of tobacco cigarettes were in the e-cigarette-user group than in the nonuser group, although the researchers noted that they did not believe this explained the difference in their findings. Most importantly, the researchers cautioned that they cannot confirm a cause-effect relationship between e-cigarette use and cardiovascular risk based on this single, small study.
They are also still unsure of how the effects of e-cigarettes on the heart compare to the effects of tobacco cigarettes on the heart, and future research is needed to determine this.