Econ_Sep_22

The Economist

September 22nd 2018

For daily analysis and debate on science and

technology, visit

Economist.com/science

OR decades, doctors and governments

have been trying towean smokers from

their habit. It is a tricky task. Nicotine is as

addictive as heroin and cocaine. There are

plenty of officially endorsed methods for

quitting. People can try inhalators, gum,

lozenges, patches, nasal sprays and pre-

scription drugs. All can help, but few repli-

cate all the physical and social rituals that

surround cigarettes. That limits how ap-

pealing they are to committed smokers.

It was into this mix that e-cigarettes ar-

rived about a decade ago. Unlike ordinary

cigarettes, which rely on burning tobacco

to deliver their payload, e-cigarettes use an

electric charge to vaporise a dose of nico-

tine (accompanied, often, by various fla-

vouring chemicals). They have proved ex-

tremely popular, particularly in America,

Britain and Japan. Public-health officials

have been quick to conclude that they are

much better than smoking. Consumers,

says RobertWest, a professor ofhealth psy-

chology at University College London, are

“votingwith their lungs”.

Still, not everyone is happy. E-cigarettes

are new, so information about their effects

is still scarce. Others worry about who is

using them. The Food and Drug Adminis-

tration, an American regulator, says it has

data showing an “epidemic” of vaping

among teenagers which it will release in

the coming months. Earlier this month it

put e-cigarette firms on notice that they

must try to combat underage use of their

thought to come mostly from flavourings.

According to work published this January

flavourings such as cinnamon, vanilla and

butter generate themost.

Several studies in mice have confirmed

that the vapour can induce an inflamma-

tory response in the lungs. In June, for ex-

ample, Laura Crotty Alexander at the Uni-

versity of California San Diego and her

colleagues published results which

showed that e-cigarette vapour has a vari-

ety of unpleasant effects, inducing kidney

dysfunction and a thickening and scarring

ofconnective tissue in their hearts calledfi-

brosis. Her data suggest that the vapour

may also be disrupting the epithelial barri-

er that lines the lungs, triggering inflamma-

tion. They speculate that this couldmake it

easier for pathogens like bacteria to take

hold. That would fit with recent work by

Lisa Miyashita at Queen Mary University

of London, which found that vaping

makes cells lining the airways stickier and

more susceptible to bacterial colonisation.

Puffed up

It all soundsworrying. But a dose of scepti-

cism is useful too. One alarming study in

August said that e-cigarette users are more

likely to have been diagnosed with cardio-

vascular disease. But many vapers have

smoked in the past, or still do. The paper

may have been picking up old harms from

smoking, rather than new ones from vap-

ing. Many think that the toxic nature of e-

cigarette vapourmay have been exaggerat-

ed by unrealistic laboratory conditions.

Overheating the fluid creates an unpleas-

ant taste that users actively avoid. Lab tests

may heat the fluid more vigorously than

real vapers do, for example.

The last piece of the puzzle is the nico-

tine. Besides being addictive, it is known to

have an adverse affect all around the body.

But the current source of concern is its ef-

products or face sanction. How worried

should vapers—or their parents—be?

The chemistry is the best place to start.

Cigarette smoke is genuinely nasty stuff. It

contains about 70 carcinogens, as well as

carbon monoxide (a poison), particulates,

toxic heavy metals such as cadmium and

arsenic, oxidising chemicals and assorted

other organic compounds.

The composition of e-cigarette vapour

varies between brands. A best guess sug-

gests that, instead of the thousands of dif-

ferent compounds in cigarette smoke, it

contains merely hundreds. Its main ingre-

dients—propylene glycol and glycerol—are

thought to be mostly harmless when in-

haled. But that is not certain. People with

chronic exposure to special-effect fogs

used in theatres—which contain propylene

glycol—have reported respiratory pro-

blems. Nitrosamines, a carcinogenic fam-

ily of chemicals, have been found in e-ciga-

rette vapour, albeit at levels low enough to

be deemed insignificant. Metallic particles

from the device’s heating element, such as

nickel and cadmium, are also a concern.

Some studies have found that e-ciga-

rette vapour can contain high levels of un-

ambiguously nasty chemicals such as

formaldehyde, acetaldehyde and acrolein,

all derived from other ingredients that

have been exposed to high temperatures.

The vapour also contains free radicals,

highly oxidising substances which can

damage tissue or

DNA

, and which are

Vaping

Smoking without fire

E-cigarettes are farhealthier than smoking. That does notmean theyare benign

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