With the start of the new year, people who smoke or vape may have made the resolution to quit smoking or reduce their tobacco consumption to improve their health. However, they should also proceed with caution if they plan to transition from traditional cigarettes to e-cigarettes, even though some people believe e-cigarettes are a safer option. A study from the University of Louisville shows that nicotine salts in e-cigarettes, especially at high doses, may increase the risk of cardiac arrhythmias that are more serious than previously thought.
This challenges the view that nicotine in e-cigarettes is harmless and highlights the need for careful consideration and potentially stricter regulations to protect public health.
One popular theory 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 University of Los Angeles study tested the effects of e-cigarettes containing different types and doses of nicotine in animal models and showed that nicotine salts, the form of nicotine contained in pod-based e-cigarettes, can cause cardiac arrhythmias, especially at high doses.
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. The aerosols contained free-base nicotine (used in older e-cigarettes), nicotine salts (used in Juul and other e-cigarette cartridges) or racemic free-base nicotine (simulating the recently popular synthetic nicotine), and their effects were compared to nicotine-free e-cigarette aerosols or air. Additionally, the team increased the nicotine concentration over time, from 1% to 2.5% to 5%.
Nicotine salts are more arrhythmogenic than free nicotine, and the higher the nicotine concentration, the more severe the arrhythmias.
"This shows that nicotine is harmful to the heart and refutes the popular belief that nicotine itself is not harmful," said Alex Carll, an assistant professor in the Department of Physiology at the University of Los Angeles who led the study. "Our findings provide new evidence that nicotine type and concentration modify the adverse cardiovascular effects of e-cigarette aerosols, which may have important regulatory implications."
Research has also found that higher levels of nicotine salts increase sympathetic nervous system activity (also known as the "fight or flight" response) because it stimulates the same receptors that are inhibited by beta-blockers, heart drugs that treat arrhythmias. In the autonomic nervous system, sympathetic dominance increases the "fight or flight" response in body functions, including heart rate.
"The nicotine in e-cigarettes causes arrhythmias (arrhythmias) in a dose-dependent manner by stimulating receptors that many heart medications are designed to inhibit," Carll said. The study results concluded that inhalation of e-cigarette aerosols containing nicotine salts may induce sympathetic denervation and cardiac arrhythmias, thereby increasing cardiovascular risk.
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 Tobacco Regulation and Addiction Center, of which the University of Los Angeles is a flagship institute. The team's previous research found that exposure to e-cigarette aerosols containing specific flavors or solvent carriers can cause ventricular arrhythmias and other cardiac conduction irregularities, even in the absence of nicotine, so Carll speculated that the arrhythmias may be caused not just by nicotine, but also by the flavors and solvents in e-cigarettes.
The researchers concluded that if these results are confirmed in humans, regulating nicotine salts through minimum pH standards or limiting acidic additives in e-liquids may mitigate the public health risks of vaping.
However, research shows that even without regulatory changes, users can reduce potential harm by choosing e-cigarettes with free-base nicotine rather than nicotine salts or by using e-cigarettes with lower nicotine content.
Compiled source: ScitechDaily