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Medical Files

Increased cancer risk with electronic cigarettes

The controversy on electronic cigarettes or e-cigs continues to rage. We previously presented the pros and cons of e-cigs in this column (“Take 2 on electronic cigarettes,” 10/4/13; “Score on electronic cigarettes,” 01/31/15); and our bottom line in both was that the jury was still out whether or not

e-cigs could do more harm than good.

E-cigs heat liquid nicotine from cartridges, converting the addictive substance into inhalable vapor; hence, it’s also called “vaping.” There’s a small device inside the e-cig that heats up the liquid nicotine, turning it into a vapor that smokers inhale and exhale. Since it does not contain tar and other chemicals found in traditional cigarettes, its manufacturers claim that using it is a lot safer than tobacco smoking.

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That may be true if it’s only used temporarily for a short period of time as a smoking-cessation tool. However, if one uses it indefinitely as an “alternative lifestyle” to tobacco smoking, then, health experts have raised concerns on its long-term safety.

Previously published scientific data finding it safe were biased researches, coming from studies initiated or funded by e-cig manufacturers. We only found one credible study published in the journal Lancet two years ago showing that e-cigs could be as beneficial for smoking cessation as nicotine patches, but it was not recommended for long-term, indefinite use—as an alternative to actual smoking.

Desire to quit

In the study, around 650 adult smokers who expressed desire to quit were randomly assigned to one of three treatments, to be taken as needed for 12 weeks. These three treatment regimens are: 16-milligram nicotine e-cigarettes, 21-mg nicotine patches, or placebo e-cigarettes that did not contain nicotine.

After six months, the three groups had similar quit rates (4 percent to

7 percent). But there were significantly more people in the nicotine e-cig group than the patch group who were able to reduce by half their cigarette consumption in six months (57 percent vs 41 percent). There were no red flags to alert the researchers on any possible adverse side effect of e-cigs compared to nicotine patches after using them for six months.

Personally, I have no strong objections if patients ask me if they could use e-cigs to help them quit smoking; but I tell them I still think that a nicotine patch is more advisable because it also weans the smoker off the habit of lighting a cigarette, holding it with one’s forefinger and middle finger and lifting it to one’s lips to suck in the smoke or vapor.

Using e-cigs is still virtually smoking. And for an effective smoking cessation regimen to work and be sustained, one must also avoid the behavioral simulation of the vice—like the act of holding a cigarette, or what looks like it, and gently inhaling the smoke or vapor.

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Why are e-cigs not advisable for long-term use?  Based on fairly recent research data, its potential to cause cancer could also be quite high.

In a paper published several months ago in the New England Journal of Medicine, Doctors Paul Jensen, Wentai Luo, James Pankow, Robert Strongin and David Peyton from Portland State University in the United States warned that harmful substances in the form of formaldehyde-containing hemiacetals may be formed during the heating and vaporization process of e-cigs. These hemiacetals come from the e-cig liquids including nicotine, propylene glycol, glycerol, or both; and other flavorant chemicals commonly used.

Formaldehyde-releasing agents including hemiacetals, injure the respiratory tract causing a severe form of inflammation of the small airways in the lungs (bronchiolitis). These agents have also been identified by the International Agency for Research on Cancer as a group 1 carcinogen, meaning they can increase the risk of cancers. And in the case of e-cigs, lung cancer risk could be unduly increased just like tobacco smoking, probably worse.

Cancer-risk calculations

Based on their cancer-risk calculations, long-term vaping with e-cigs can be associated with an incremental lifetime cancer risk of 4.2×10-3. For perspective, this risk is around five times as high as the risk associated with long-term smoking.

The researchers explained that an e-cig user vape an average of 3 milliliters per day, which would make him/her inhale 14.4±3.3 mg of formaldehyde daily in the form of formaldehyde-releasing hemiacetals.

An average pack of cigarettes (20 sticks) deliver around 3 mg of formaldehyde to the smoker. So the average e-cig smoker inhales the same amount of formaldehyde, which a smoker consuming nearly five packs of cigarettes would get.

Doing their math, the researchers calculated that the increased lifetime risk of cancer for a tobacco cigarette averaging one pack per day is about 900 out of a million. This means that in a population of 1 million people, 900 more smokers would eventually develop cancer compared to a nonsmoking population.

And for e-cigs? Based on the same mathematical calculation, inhaling

3 ml of e-cig liquid in aerosol form would lead to a lifetime risk of cancer of around 4,200 in a population of 1 million. This is almost five times the risk in those who smoke tobacco.

So you still think electronic cigarettes are cool? Think again.

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TAGS: cancer, electronic cigarettes, Health, Science
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