The use of electronic nicotine delivery systems (ENDS), also known as ecigarettes or vaping, has rapidly risen across the globe. In recent years, adolescents seem to be taking up the habit at alarming rates. Many claim that the additive flavorings are a big reason teens are drawn to these devices. Much debate exists around the use of ecigarettes, or vaping. Many claim that it is safe, while others say at least safer than traditional cigarettes. Still others argue that vaping can be a gateway to smoking cessation. But, what does the science show? As doctors, we are expected to practice evidence-based medicine (no hidden conspiracies with tobacco companies here).

Smoking Cessation

While it is true that vaping has helped some smokers quit, researcher published in July showed that only 10% of nearly 1,300 former smokers who turned to vaping to help quit were successful in doing so. In the study, smokers who switched from smoking to vaping were followed for 1 year. The study authors “found no evidence that ENDS use, within context of the 2015–2016 US regulatory and tobacco/vaping market landscape, helped adult smokers quit at rates higher than smokers who did not use these products. Absent any meaningful changes, ENDS use among adult smokers is unlikely to be a sufficient solution to obtaining a meaningful increase in population quit rates.” Another study, published in August, investigated the smoking/vaping trajectories and quit-smoking success rates of smokers deciding to start vaping for the first time and buying their e-cigarette in brick-and-mortar vape shops in Belgium. The study found that “around one in five smoking customers buying their first e-cigarette in a brick-and-mortar vape shop had quit smoking completely after 6 months.” Many studies replicate these findings.

eCigarette Ingredients

While we may not know the full extent of the dangers ENDS pose, the research clearly demonstrates there are a multitude of harmful effects that come along with vaping. The flavoring additives, so popular with teenagers, have come under scrutiny. Study findings published in July in an American Heart Association journal suggest that e-cigarette flavorings may damage blood vessels and the heart. One study quantified six different pyrazine additives in ecigarettes. Pyrazines have previously been found to have synergistic effects on nicotine addiction by increasing appeal, easing smoking initiation, and discouraging cessation. Also, they are known as potentially toxic to the reproductive tract. It has also been demonstrated that fruit flavorings and other additives are frequently used by teens and young adults who vape, potentially putting them at risk.

Among the toxic chemicals found in ecigarettes are aldehydes. One study looked at the respiratory uptake of formaldehyde and acetaldehyde specifically. The results showed that both were increased during vaping.

Many harmful trace metals have also been discovered in ecigarettes. Nickel, chromium, cadium, tin, aluminum, and lead have all been observed and are potential carcinogens, leading to both lung and sinonasal cancer and potentially oral cancer.



While many argue that vaping is not addictive like smoking regular cigarettes, they fail to acknowledge that the same addictive ingredient is present in both: nicotine. In fact, it’s possible that higher levels of nicotine are present in the serum of vapers. This in turn increases cancer risks by stimulating nicotinic acetylcholine receptors (nAchRs).

And while many may claim ecigarettes don’t contain nicotine, the truth is that virtually all contain some amount, with high-nicotine ecigarettes flooding the US market. In one randomized, single blind, 3-period crossover design study, researchers found that vaping products that contained nicotine impaired acetylcholine mediated vasodilatation, increased indices of arterial stiffness, increased both diastolic and systolic blood pressure as well as heart rate, and raised plasma myeloperoxidase. Another study demonstrated changes in peripheral and central blood pressure as well as heart rate and pulse rate velocity in those who vaped products containing nicotine. Other research found “a single session of e-cig use, approximating nicotine exposure of one tobacco cigarette, induces significant inhibition of cough reflex sensitivity. Exploratory analysis of a subgroup of subjects suggests that nicotine is responsible for this observation. Our data, consistent with previous studies of nicotine effect, suggest a dual action of nicotine: an immediate, peripheral protussive effect and a delayed central antitussive effect.”


Other Affects on the Lungs

The pro-inflammatory effects smoking can play on the endothelium in the lungs, leading to a host of pulmonary diseases, have long been known. While ecigarette liquid (ECL) is not cytotoxic by itself, it becomes so once it is vaped. It appears vaped ECL is toxic to alveolar macrophage function. It creates excessive amounts of reactive oxygen species, inflammatory cytokines, and chemokines, leading to an inflammatory state in the alveolar macrophages. It has further observed that there is a nicotine-dependent inhibition of phagocytosis, suggesting that vapers may suffer an inhibited clearance of bacteria that places them at risk of lung infections. One interesting case showed lipoid pneumonia caused by vaping.

There are many case studies in the literature showing ecigarettes causing bronchiectasis, eosinophilic pneumonia, pleural effusion, and possible hypersensitivity pneumonia. In another case, a young man suffered subacute respiratory failure due to diffuse alveolar hemorrhage caused by vaping.

While it is clear from these studies that much more research needs to be done, there is enough science to be concerned that ecigarettes are not safe like many claim. In fact, they appear to have many hazards that are still being discovered. Are they safer than cigarettes? That remains to be determined. No one can make that claim without more large-scale clinical trials. Until that time, hedge your bets where you will.


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Cases of Severe Lung Injury After Vaping Reported in Three States

Teen vaping tied to marijuana use

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Vaping may aid smoking cessation but also boost relapse risk

Flavored tobacco use rising in U.S. kids as vaping takes off