Cancer and E-Cigarettes

Question: Is the nicotine delivered via the e-cigarette going to promote cancer in already existing pre-cancerous cells?

Answer. Not likely and not in the next 10 years.

1) Nicotine is not a known carcinogen

Nicotine, inhaled or by any route, is not recognized by the state of California as a known cause of cancer in humans or animals. Hundreds of other chemicals are so recognized, and scores of them are in cigarette smoke. Second hand tobacco smoke is recognized in this way.

2) Careful follow up for 10 years – the Lung Study in the USA has followed thousands of ex-smokers for five years and then for 7.5 years after that,. Risk of cancer of the lung was increased in those who continued to smoke, but not in those using nicotine alone compared with those who quit entirely. That means 10 years of follow-up. If their cells were pre-cancerous to start with, and nicotine was a cause of cancer, new cancers would have been expected to appear within those 10 years.

3) Widespread use of nicotine for 25 years. Since 1984, nicotine has been given to millions of smokers trying to quit smoking, to help them quit smoking, with no reported increase in lung cancer. Over 40,000 were followed for at least 6 months, and some have been followed for 20 years. Some 8% of nicotine gum users become long term users, but no increase in cancers has been reported in long term users of nicotine gum or patch.

Pre-cancerous cervical cells are commoner in smokers. Any smoker so affected, should obtain rigorous follow-up. We have no reason, however, to believe e-cigarettes will increase the risk of the cells becoming cancerous.

E-cigarette use reduces risk of cancer by supplanting the smoking of tobacco cigarettes

Using e-cigarettes INSTEAD of smoking tobacco cigarettes is bound to reduce the risks of lung cancer, because the cancer-causing gases such as 1,3 butadiene found in the smoke of all cigarette brands, are no longer inhaled.

Switching to e-cigarettes with nicotine continued, can be expected to reduce lung cancer risk the same as altogether quitting cigarettes without e-cigarettes.

Complete quitting and complete switching required

100% altogether-quitting or 100% quitting by 100% switching to e-cigarette is required.

Anyone continuing to smoke even one cigarette per day along with e-cigarettes (dual smoking) increases risk of premature death by about half.

Question: If nicotine can cause cancer in specially-bred susceptible mice, how can nicotine e-cigarettes in humans lower cancer risk?

Answer Summary

1) For smokers, nicotine’s danger lies in the fact that nicotine is what smokers smoke for, and the cheapest way to obtain a nicotine hit is still by smoking cigarettes. Over 98% of total inhaled nicotine in NZ is probably in cigarette smoke.

2) Public health argument. Nicotine products including e-cigarettes used as a replacement for smoking, are expected on the basis of the known effects of their respective chemical constituents, to prevent far more cancer than they are likely to ever cause.

3) Health risk for the user. The risk of relapse to smoking remains substantial for the first year after stopping smoking.

4) Human rights argument. Smokers continuing to smoke past age 35 years face a 1 in 2 eventual risk of early death, and so should be entitled, in self-protection, to :

§ buy e-cigarettes for recreational use without the need to quit nicotine

§ use e-cigarettes for so long as they feel the need, to avoid risk of relapsing to smoking. On this point, the smoker is likely to be the best judge, as most doctors have never smoked.

In e-cigarettes, the nicotine inhaled per puff is much less than (about one tenth) in a cigarette puff, and risk of cancer in mice from nicotine in their diet is of great theoretical interest for researchers, but no proven effect for humans.

Cancer risk has been studied in a million Americans, and on follow-up the lung cancer rates were 10-20 times higher for cigarette smokers, compared with never-smokers.

E-cigarettes protect from cancer to the extent that e-cigarette users no longer smoke tobacco cigarettes.

Cancer risk in predisposed mice

The billions of free oxygen radicals and numerous known cancer causing gases in every cigarette smoke puff, substances in smoke besides nicotine, not to mention the solids in the tar, are the cause of increased cancer risk in smokers.

However, in test-tube cancer cell lines and mouse models nicotine itself is known to increase blood supply of some cancers, and may directly stimulate growth of some cancer cells and increase malignancy.  So far this applies to breast and lung cancer in mice.

You suck on it, it smokes, the end glows and it gives you nicotine – but it’s not a cigarette.

Christchurch smokers may get the chance to try the Ruyan e-cigarette, a Chinese smoking substitute that delivers nicotine in a harmless mist through a cigarette-like device, this year.

Christchurch doctor and anti-smoking campaigner Murray Laugesen has been testing the device for its Chinese manufacturers in preparation for a launch in this part of the world.

He is planning clinical trials on the device that would involve “hundreds of people”.

Activated when the smoker sucks on the end, the electronic cigarette glows at the tip, produces harmless theatrical smoke and conveys nicotine from a reloadable cartridge to the smoker’s lungs.

Laugesen has completed the first of several trials for Ruyan to test the product’s efficacy and safety.

The tests found the e-cigarette decreased cigarette cravings as effectively as the Nicorette inhaler already on the market, but most smokers preferred the e-cigarette’s taste and said they would recommend it to a friend, Laugesen said.

The device has been on sale in China since 2004 and in the United States this year, but was only in the first stages of New Zealand testing.

Laugesen’s first impressions of the e-cigarette were positive.

“It’s the first product I’ve seen that looks as if it can compete with tobacco,” he said.

“It’s interesting watching smokers. Usually on about the third puff, a look of surprise comes over their face because they get light-headed.”

The device sells in the US for about $US200 ($NZ256), with refills, which last between one and four days, selling for $US5 ($NZ6.40) each.

It contains a microchip that senses pressure on the mouthpiece and warms the nicotine mist. The nicotine canisters must be certified as a medicine and such aspects as shelf life would have to be tested before it could be sold in New Zealand.

E-cigarettes: harmless inhaled or exhaled – No second hand smoke

Second hand cigarette smoke is a mixture of mainstream and sidestream smoke. It contains the same toxicants as mainstream smoke, but at reduced levels. It is responsible for about 8% of the deaths caused by direct smoking.

Second hand mist from an e-cigarette is not smoke at all, and does not contain any substance known to cause death, short or long term, in the quantities found. It becomes invisible within a few seconds, and is not detectable by smell.

Exhaled breath after e-cigarette use has been tested for CO only. No increase in CO was found.

The e-cigarette does not create side-stream smoke.

Exhaled breath after e-smoking contains even less nicotine per puff, as much of the nicotine inhaled is absorbed. Similarly, propylene glycol is largely absorbed and little is exhaled.

No harm found in e-cigarette mist

Nicotine is not harmful in the quantities mentioned.1

Propylene glycol is harmless – it is used in making theatrical fog and as an ingredient in soaps, personal lubricants and intravenous medicines.


Leading chemicals only Cigarette SMOKE E-cigarette MIST

Nicotine per puff YES 0.1 mg/puff YES 0.01 mg/puff

Propylene glycol NO 0 mg/puff YES 0.7 mg/puff

Carbon monoxide YES NONE

Acrolein YES NONE

Hydrogen cyanide YES NONE

CARCINOGENS 1,3- Butadiene and 20+ others: Trace amounts of a few only:

Acetaldehyde YES TRACE

Acrylonitrile YES NONE

Arsenic YES NONE

Benzalphapyrene YES NONE

Benzene YES NONE

Cadmium YES NONE

NNN, NNK (nitrosamines) YES TRACE

reproduced from Health New Zealand.