New research suggests that vaping may cause specific, harmful cardiovascular effects, with the authors pointing out that it is not the harmless alternative to smoking that marketing may have you believe. In addition, due to the unique airway irritation and cardiovascular damage that both smoking and vaping cause, the findings suggest that switching between the two may have an even worse effect than doing either individually.
It now appears that, regardless of the input method, inhaling foreign material is likely to cause airway damage.
“We were surprised to discover that it’s not a specific foreign material being inhaled that causes harmful cardiovascular effects – it’s the fact that some kind of irritant is being inhaled in the first place, regardless of what it was,” said lead researcher Matthew L. Springer, in a statement.
“All inhaled products are likely to have similar harmful effects on vascular function.”
Both cigarette smoking and vaping are known to affect the ability of blood vessels to enlarge enough to supply the heart with adequate blood, which is a precursor to cardiovascular disease, but it was unclear what the common denominator was.
To test how smoking may result in cardiovascular damage and how it may be similar or different to vaping, researchers performed two different studies, one in humans and one in rats. The rat study involved exposing rats to one of four different smoke types, ranging from conventional tobacco to tobacco with reduced nicotine and added menthol, and measuring their blood vessels’ ability to widen. All four smoke types reduced this ability by 20-46 percent, with the worst offenders being the high-nicotine tobacco and the least offending being the low nicotine, added menthol version.
While menthol improved this particular metric, the effects were still substantial, and menthol has other harmful effects that the authors stressed do not result in a net positive over standard tobacco.
“Because flow-mediated dilation was impaired by whole smoke, gas phase components of smoke, and plain carbon particles, with no single constituent uniquely responsible, we then explored whether the mechanism involved a common irritation response from the airway involving the vagus nerve,” Springer said.
In this pursuit, they anesthetized more rats and severed their vagus nerves before exposing them to smoke once more. The results showed that there were no cardiovascular implications with the severed nerves, suggesting that irritation of the airways and sensory nerves in the area may interact with the vagus nerve in some way and cause the cardiovascular effects.
The second study, in humans, looked at 120 people aged 21-50 who either smoked, vaped, or did neither, and followed them over a long period to analyze changes in the blood. After the study period, the researchers discovered that both the smoking and vaping groups had measurable changes in inflammatory markers and other vascular markers, though the effects were often different. Vapers had more instances of “leaky” blood vessels and higher oxidative stress, while smokers had some elevated inflammatory markers and both groups had impaired endothelial cells.
Together, the studies suggest that smoking and vaping may have different but compounding effects, particularly if done together.
“It’s important for regulators, clinicians and the public to realize that vaping is not harmless,” Springer said.
“Smoking and vaping can have similar harmful cardiovascular effects but each condition causes some potentially harmful effects that the other does not. These differences indicate that dual product use, meaning smoking combustible cigarettes and also using e-cigarette products, may actually be worse for vascular health than either smoking or vaping alone.”
Both studies were published in Arteriosclerosis, Thrombosis, and Vascular Biology, and can be found here and here.