E-cigarettes Pose CVD Risks Similar to Traditional Cigarettes

The impact of e-cigarettes on cardiovascular disease (CVD) risk factors is similar to effects seen among people who smoked traditional combustible cigarettes; deleterious effects were seen on cholesterol, triglycerides (TGs), and blood glucose as well as on blood flow to the heart.

The findings are reported in 2 studies that will be presented at the American Heart Association’s (AHA) Scientific Sessions 2019, November 16-18, in Philadelphia.

If smokers choose to use e-cigarettes in the effort to quit smoking, they should plan to stop using those, too, noted AHA's deputy chief science and medical officer Rose Marie Robertson, MD, in an AHA press release on the studies. By way of explanation, she points to the paucity of long-term safety data and the expanding body of information describing a range of negative physiologic effects of the devices themselves as well as the chemical compounds used in them. 

Study: E-cigarettes linked to alterations in lipid profiles

Based on knowledge that combustible traditional cigarettes (t-cigarettes) alter human lipid profiles, Sana Majid, MD, a postdoctoral research fellow at Boston University School of Medicine, and colleagues compared cholesterol, triglycerides, and glucose levels in healthy adult nonsmokers, e-cigarette smokers, and dual e- and t-cigarette smokers (dual smokers). (AHA oral presentation Mo3106)

The 476 participants from the Cardiovascular Injury due to Tobacco Use (CITU) study were aged 21-45 years, free of CVD, and taking no daily medications: 

• 94 nonsmokers

• 45 e-cigarettes smokers

• 52 dual smokers

• 285 t-cigarette smokers

Highlights:

• E-cigarette users were predominantly current (dual) or former smokers and were overall younger, with more men and fewer blacks in that group.

• T-cigarette users had lower HDL levels and higher levels of glucose, TCh, LDL, and VLDL vs nonsmokers.

• Sole e-cigarette use remained associated with elevated TCH, TG, and LDL vs nonsmokers (all P<.05) in multivariate regression models adjusted for age, race, and sex.

• Dual cigarette use was associated with lower HDL-C (P<.01).

The findings suggest, the authors write, that t-cigarette smokers who concurrently use or switch to e-cigarettes may not experience appreciable metabolic benefits. "Although primary care providers and patients may think that use of e-cigarettes by smokers makes heart health sense," said lead author Majid in the AHA press release, "...the best option is to use FDA-approved methods...along with behavioral counseling."

The study will be presented on Monday, November 18, 2019, 11:30-12:00, during the oral poster session Smoking, Alcohol Use and other Behavioral Risk Factors for CVD in Zone 3, Science and Technology Hall at the Pennsylvania Convention Center.

Next: E-cigarette impact on coronary endothelial function

Study: Coronary endothelial dysfunction more persistent with e-cigarette use

Coronary vascular dysfunction associated with e-cigarette use may be worse than from smoking traditional cigarettes, according to authors of a second study to be presented at AHA next week (AHA oral presentation Sa3199).

E-cigarettes purportedly deliver a lower dose of nicotine per inhalation vs combustible cigarettes and thus have been marketed as a safer alternative. However, authors write in their abstract:

Each e-cigarette inhalation delivers "an aerosolized bolus of
poorly-characterized ultrafine particles with potential
CV effects that remain unclear."

To assess coronary vascular function, authors analysed change in myocardial blood flow (MBF) after acute exposure among self-reported chronic e-cigarette (n=10) and chronic tobacco cigarette (n=9) users, aged 24-32 years. After overnight abstinence, acute increase in MBF was measured via myocardial contrast echocardiography after exposure to 1 use (15 puffs in 7 minutes) of a popular e-cigarette or 1 cigarette (Camel Filtered) while participants were at rest and again during post-handgrip cuff ischemia. 

Findings

• Traditional cigarette users: MBF increased modestly after inhalation then decreased with subsequent stress

• E-cigarette users: MBF decreased both at rest and after handgrip stress--indicating chronically abnormal coronary vascular function

“We were surprised by our observation of the heart’s blood flow being reduced at rest, even in the absence of stress, following inhalation from the e-cigarette,” said study co-author Susan Cheng, MD, MMSc, MPH, director of Public Health Research at Cedars-Sinai Medical Center, Los Angeles.

“Providers counseling patients on the use of nicotine products will want to consider the possibility that e-cigs may confer as much and potentially even more harm to users and especially patients at risk for vascular disease.”

The study will be presented on Saturday, November 16, 2019, during the oral poster session Markers of Cardiovascular Health, 4:30 PM - 5:00 PM, in Zone 3, Science and Technology Hall at the Pennsylvania Convention Center.