An analysis of the CITU study is shedding light on the impact of e-cigarette use on arterial stiffness and vascular health.
Jessica Fetterman, PhD
While still perceived by many as a healthy or safer alternative to traditional cigarettes, new research is shedding light on the impact e-cigarette use has on vascular health.
An analysis of information from the Cardiovascular Injury due to Tobacco Use (CITU) study, results indicated e-cigarette use resulted in vascular damage similar to that of smokers of combustible cigarettes.
"Many people believe e-cigarettes are safer than combustible cigarettes. In fact, most e-cigarette users say the primary reason they use e-cigarettes is because they think e-cigarettes pose less of a health risk," said study investigator Jessica Fetterman, PhD, assistant professor of medicine at Boston University School of Medicine, in a statement. “Meanwhile, the evidence from scientific studies is growing that e-cigarettes might not be the safer alternative to smoking traditional cigarettes when it comes to heart health. Our study adds to that evidence.”
With a present and growing need to further evaluate the potential harm of e-cigarettes in users, Fetterman and colleagues from the University of Louisville School of Medicine conducted the current study using CITU data to assess impact of use on arteries and blood vessel function. Briefly, CITU was a cross-sectional study of healthy participants between 21-45 years old, with 4 exposure arms examining the impact of combustible cigarettes, e-cigarettes, both, and not smoking.
For this analysis, investigators sought to assess the impact of e-cigarette use through measurements of baseline brachial artery diameter, baseline flow velocity, hyperemic flow very, flow-mediated dilation, and hyperemic shear stress. Before measurements were taken, patients were asked to fast from food and tobacco products overnight. Investigators also sought to assess carotid-femoral pulse wave velocity (PWV), carotid-radial PWV, augmentation index, central systolic blood pressure, central diastolic blood pressure, and heart rate.
More than 400 individuals were included in the investigators analysis, with 94 classified as nonsmokers, 285 as users of combustible cigarettes, 36 as e-cigarette users, and 52 dual users. Of note, combustible cigarette and dual users were typically older than non-smokers and e-cigarette users. Additionally, e-cigarette users were more likely to be younger, male, and white—all e-cigarette users were also former smokers.
Results of an unadjusted analysis revealed measures of arterial stiffness, including carotid-femoral PWV, augmentation index, carotid-radial PWV, and central blood pressures differed across all 4 groups in the study.
Results of the multivariable analysis, which was adjusted for age, sex, race, and study site, indicated combustible cigarette smokers had higher augmentation index than nonsmokers (129.8±1.5 vs 118.8±2.7, P=0.003). Additional analysis of augmentation index revealed similar results for smokers compared with sole e-cigarette users 129.8±1.5 vs 126.2±5.9, P=1.0) and dual users (129.8±1.5 vs 134.9±4.0, P=1.0).
Analysis of differences in endothelial cells between groups suggested users of combustible cigarettes and sole e-cigarette users produced less nitric oxide compared with nonsmokers, which investigators purport is suggestive of impair endothelial nitric oxide synthase signaling in these groups.
“The endothelial cells from e-cigarette users or dual users produced less of the heart-protective compound nitric oxide, compared to non-tobacco users. Their cells also produced more reactive oxygen species, which cause damage to the parts of cells such as DNA and proteins,” Fetterman said, in the aforementioned statement.
This study, “Alterations in Vascular Function Associated With the Use of Combustible and Electronic Cigarettes,” was published in the Journal of the American Heart Association.