Paris (AFP)

What are the effects of vaping on health? This recurring question is rested dramatically by India's decision to ban e-cigarettes, but science can not yet provide a definite answer.

- What do electronic cigarettes contain?

Vaping is the process of inhaling vapors created by high temperature heating of a liquid inside the electronic cigarette.

Most liquids contain nicotine. This highly addictive substance also found in tobacco can affect brain development before age 25 and, according to some studies, have a detrimental effect on that of adults.

On the other hand, vaping fluids do not include many dangerous substances found when smoking tobacco, such as tar (carcinogenic) or carbon monoxide (cardiovascular disease factor).

But the vapor contains fine particles that penetrate the lungs. There are "many potentially toxic substances," concluded a report by the American Academies of Science, published in 2018.

Among them, metals (nickel, lead ...) probably coming from the coil used to heat the liquid. And additives considered safe in the food industry, but related to lung diseases or not studied in their vaporized form.

However, it will be necessary to wait for studies over several decades to be certain of the long-term effects of these substances on the cells of the body.

As for taste, e-liquids exist scented with tobacco, but also with dozens of different flavors, according to the brands: menthol, red fruits, vanilla, mango ... even fanciful tastes like candy or crème brûlée.

- Is Vapoter dangerous?

Researchers have little perspective on electronic cigarettes, sold since the mid-2000s.

For people who already smoke, there is a scientific consensus that it is less harmful to smoke than to smoke tobacco: nicotine remains, but the carcinogenic substances in cigarettes are no longer inhaled.

"Although it is difficult to precisely quantify the long-term toxicity of the electronic cigarette, it is obviously infinitely less than that of the traditional cigarette", concluded in 2015 the French Academy of Medicine.

The World Health Organization (WHO) is more cautious: "NSEs (electronic nicotine delivery systems) are probably less toxic than cigarettes but there is not enough evidence to quantify the exact level of risk, "says the international body in a report released in July.

In any case, "the SEANs are undeniably harmful and will therefore have to be regulated," according to the WHO.

Meanwhile, in the United States, a mysterious epidemic of acute lung disease killed several people this summer and sent hundreds of people to the emergency room.

Most had purchased THC fluids, the psychoactive substance of cannabis, but it is still unclear which ingredient among the many additives may have damaged the lungs.

Vitamin E oil has been cited as a possible cause by New York State, but federal health authorities have not confirmed that this molecule was the culprit.

- Does Vapoter help to stop smoking?

A British study published in February in the New England Journal of Medicine found that e-cigarettes were more effective than patches, gums and other substitutes.

In France, health authorities estimate that 700,000 daily smokers quit smoking with the help of the electronic cigarette between 2010 and 2017.

But we still do not have enough evidence, according to the WHO which quotes three summaries of 2016 and 2017. The possibility that vapers play a role in smoking cessation assistance "is unclear" and probably differs according to types of e-cigarette, concludes the WHO.

For all these reasons, it does not include this device as one of the recommended arsenals for stopping smoking and considers that it should not be promoted as such until more data are available.

This position is making leapfrog manufacturers of e-cigarettes, who talk about "misinformation", but also some specialists in the fight against tobacco, who defend the effectiveness of the electronic cigarette. For these specialists, a ban on e-cigarettes would hurt smokers who want to stop smoking.

- Young people, key to the debate?

One of the questions posed by e-cigarettes is for young people who did not smoke initially and start vaping, encouraged by the aggressive marketing they are targeted by brands.

In addition to nicotine addiction, studies have shown that they are more likely to start smoking tobacco.

The protection of youth is the argument invoked by India to announce Wednesday the ban on electronic cigarettes.

"The decision was made with the impact that e-cigarettes have on youth today," Finance Minister Nirmala Sitharaman told a news conference.

In the United States, authorities speak of epidemic in high schools, with a dominance of fruity aromas, mint and menthol.

On Tuesday, New York became the second US state after Michigan to ban the marketing of flavored electronic cigarettes.

"We help prevent countless young people from becoming addicted to life-long, expensive, unhealthy and potentially life-threatening," Governor Andrew Cuomo said in a statement.

The ban comes just days after President Donald Trump announced on September 11 that a similar measure would be taken in the coming months at the federal level.

© 2019 AFP