Addiction journal article summarizes findings
Given the whirlwind of debate around electronic cigarettes, it is difficult to know which data set to rely upon. Each point of view presents its own statistics, and headlines proclaim utterly divergent messages, proving either their complete safety or their dreadful dangers, or a wide variety of in-between positions.
A group of scientists, at Virginia Commonwealth University and the Health Sciences Center of the University of Texas at Houston, has presented an article, in the current issue of the Journal of Addiction Medicine, that tries to give an overview of what is known, while also noting the uncertainties that remain. Given the lag time in scientific publication – the time needed for peer review and editing before an article is accepted and published – the article already seems out of date. It was submitted in December 2013, Accepted in April 2014, and published in the July/August issue, 2014. Nonetheless, it is likely to be quite helpful as a fairly unbiased overview of the knowns and unknowns.
After reviewing the basic types of electronic cigarettes, the article notes that nicotine concentrations and flavorings tend to be inconsistent and variable from one brand to another, or even within brand, and dutifully notes the potential adverse effects of the "psychomotor stimulant" nicotine, including tiny levels of cytotoxicity by comparison with tobacco smoking. Cytotoxicity is the level of genetic mutation that a substance can induce when applied to cells, and since cancer is basically cellular mutation run amok, cytotoxicity refers to the substance's likelihood of producing cancer.
The article's section on e-liquid poisonings does note that these events primarily induce vomiting, which ejects the poisons effectively. On "humectants" such as propylene glycol and vegetable glycerin, it is noted that the long term effects of inhaling their vapors is simply unknown.
No cytotoxicity is noted for the nicotine component of e-liquid, but some flavorings are implicated at trace levels, cinnamon being the highest. So think twice before having that second slice of cinnamon toast at breakfast tomorrow morning. The article notes that differences in methods of measurement from one study to another make it difficult to compare published results.
Vapor, in any case, is much less cytotoxic than the liquid itself, and vapor is of course the form in which users ingest the substance. The hazards common to vapor and cigarette smoke are 9-450 times lower, according to the article. Only one vapor in 21 was found to have any cytotoxicity, and all "fibroblasts" (tissue structures that aid in the healing of damaged tissue) were found to be much more "viable" after exposure to vapor than after exposure to smoke. Indeed the cytotoxicity levels noted were comparable to trace elements in a licensed nicotine inhaler.
Air quality after vaping is less damaged than after smoking, with far lower levels of particulate matter and toxicants, according to the article.
The article notes that "acute lung effects" (physiological) are comparable to those of cigarette smoking, and include airway resistance and/or impedance. In other words, "throat hit". Like duh!
On the question of e-cigs as a smoking cessation method, the article discusses studies on "tobacco abstinence syndromes", a fancy way of saying that when you're trying to quit, sometimes ya just really wanna smoke, and it's a bitch! The question is, does the nicotine in e-cigs reduce those cravings, or is it the behavioral aspects of vaping that do it. It appears that e-cigs sometimes reduce the "cognitive function" problems that go along with quitting (when you want a smoke so bad you can't think straight). For some abstinence syndromes, men respond more to the nicotine, while women respond more to the behavioral aspects.
One study looked at "abuse potential" by offering smokers either money or their cigarette/e-cig. The amount of money at the "cross-over level" (the point at which they would take the money instead of the smoke/vape) was $1.06 for a vape, $1.50 for a cig, indicating that e-cigs have less addiction potential, by 46 cents.
No one in the vaping community will be particularly surprised by any of this, but it's good to see that science marches on, making the product better known, and thus eventually safer, even safer than it already is, in fact.