A study from the University of Louisville suggests that nicotine salts in e-cigarettes, especially in high doses, may increase the risk of arrhythmias more easily than previously thought. This challenges the notion that nicotine in e-cigarettes is harmless and highlights the need for careful consideration and possibly stricter regulations to protect public health.
Using e-cigarettes with higher nicotine content is more likely to cause arrhythmias if the concentration is too high.
As the new year begins, people who smoke or vape may have made up their minds to quit or reduce their consumption to improve their health. However, they should err on the side of caution if they intend to switch from traditional cigarettes to e-cigarettes, which some consider to be a safer option.
A new study from the University of Louisville suggests that nicotine in some types of e-cigarettes may be more harmful than others, increasing the risk of irregular heartbeats or arrhythmias.
A popular claim is that the nicotine in e-cigarettes is relatively harmless, while additives and combustion products are largely responsible for the harm of traditional cigarettes. The UOFL study tested the effects of different types and doses of nicotine on e-cigarettes in animal models, and the results showed that nicotine salts in the form of nicotine contained in pod e-cigarettes can cause arrhythmias, especially at high doses.
Comparative analysis of nicotine types
In the study, published in Nicotine and Tobacco Research, researchers compared heart rate and heart rate variability in mice exposed to e-cigarette aerosols containing different types of nicotine. These aerosols either contain the freebase nicotine used in old-fashioned e-cigarettes; nicotine salts for juul and other pod e-cigarettes; or racemic-free base nicotine, which mimics the recently popular synthetic nicotine; And their effects were compared to nicotine-free e-cigarette aerosols or air. In addition, over time, the nicotine concentration provided by the research team became higher and higher, from 1% to 25% and then 5%.
Nicotinic salts have a stronger inducing effect on arrhythmias than free base nicotine, and arrhythmias worsen with the increase of nicotine concentration.
Impact on the regulation and use of e-cigarettes
This suggests that nicotine is harmful to the heart, refuting the popular notion that nicotine itself is harmless," said Alex Carr, an assistant professor in the Department of Physiology at UOFL who led the study. "Our findings provide new evidence that nicotine types and concentrations alter the adverse cardiovascular effects of e-cigarette aerosols, which may have important regulatory implications. ”
The study also revealed that higher levels of nicotine salts increase the activity of the sympathetic nervous system, the so-called "fight-or-flight response", by stimulating the same receptors that are inhibited by receptor blockers (heart medications used for arrhythmias). In the autonomic nervous system, sympathetic innervation enhances the fight-or-flight response in bodily functions, including heart rate.
"Nicotine in e-cigarettes causes irregular heartbeats (arrhythmias) in a dose-dependent manner by stimulating receptors that many heart drugs are designed to inhibit," Carr said. ”
The results of the study suggest that inhalation of e-cigarette aerosols from e-cigarette liquids containing nicotine salts can cause sympathetic innervation and arrhythmias, thereby increasing the risk of cardiovascular disease.
Reflections on the safety of e-cigarettes
The work is part of a growing body of research on the potential toxicity and health effects of e-cigarettes reported by the American Heart Association's Center for Tobacco Control and Addiction, of which the UOFL is its flagship agency. The team's previous study found that exposure to e-cigarette aerosols containing certain flavors or solvent carriers can cause ventricular arrhythmias and other conduction abnormalities in the heart even without nicotine, leading Carl to speculate that arrhythmias may be the result of more than just nicotine, but also the flavors and solvents contained in e-cigarettes.
The researchers concluded that modulating nicotine salts through minimum pH standards or limiting acidic additives in e-cigarette liquids may mitigate the public health risks of e-cigarettes if these results are confirmed in humans.
However, studies have shown that even without regulatory changes, users can reduce potential harm by choosing e-cigarettes that contain freebase nicotine instead of nicotine salts or by using e-cigarettes with lower nicotine content.