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Vapers beware: 10 things to know about e-cigarettes

With catchy names like Smurf Cake and Unicorn Puke and sweet flavors like bubble gum and strawberry, electronic cigarettes may have special appeal to young people, but that doesn’t mean they are safe.

Evidence is mounting that e-cigarettes are exposing a new generation to nicotine addiction and may be leading users toward a cigarette habit. As a result, the U.S. surgeon general last month issued a report declaring youth e-cigarette use “a major public health concern.”

“All Americans need to know that e-cigarettes are dangerous to youth and young adults,” said Surgeon General Vivek Murthy, in releasing the report. “Any tobacco use, including e-cigarettes, is a health threat, particularly to young people.”

The battery-powered devices heat a liquid typically containing nicotine mixed with the chemicals propylene glycol and glycerin as well as flavorings to deliver an aerosol inhaled by the user. While e-cigarettes deliver nicotine without the tar and smoke of traditional tobacco cigarettes, they still are considered tobacco products.

But their healthy halo has helped propel their popularity: E-cigarettes are now so popular that more American youth vape than smoke cigarettes. In just a decade, e-cigarettes have become a multibillion-dollar business led by multinational tobacco companies with outlets not just online but everywhere from vape shops to convenience stores and retail giants like Wal-Mart.

Ads tout them as a cool, harmless alternative to cigarettes. E-cigarette users, or vapers, have contests to see who can blow the largest cloud of vapor.

But there’s more to e-cigarettes than meets the eye. The surgeon general’s report aligns with increasing scrutiny of e-cigarettes, from new regulations to a growing body of research into health effects.

Here are 10 things to know about e-cigarettes:

E-cigarettes contain nicotine

E-cigarettes contain nicotine, which is addictive and can harm the developing adolescent brain, said UC San Francisco professor of medicine Stanton Glantz.

A lot of the kids who take up vaping are at low risk for smoking, but once they start using e-cigarettes, they are three to four times more likely to start using cigarettes, Glantz said.

“The biggest health concern with e-cigarettes is they are prolonging and expanding the tobacco industry,” Glantz said.

Glantz, director of UCSF’s Center for Tobacco Control Research and Education, said he was initially neutral on e-cigarettes, but now finds them concerning. Among other hazards, e-cigarettes produce ultrafine particles than can trigger inflammatory problems and lead to heart and lung disease.

“The data is just becoming overwhelming,” Glantz said.

E-cigarettes expose people to more than ‘harmless water vapor’

E-cigarettes are billed as producing “harmless water vapor,” but, strictly speaking, the vapor produced when users exhale is actually an aerosol that contains a mixture of nicotine, flavorings and other ingredients that can be toxic.

Stanford University pediatrics professor Bonnie Halpern-Felsher has studied young people’s perceptions of e-cigarettes. In September, she launched a free, downloadable youth tobacco prevention toolkit with an e-cigarette module, funded by the UC Tobacco-Related Disease Research Program (TRDRP) and the California Department of Education.

“Youth are definitely using e-cigarettes because they think they are cool,” Halpern-Felsher said. “Adolescents and young adults don’t know a lot about e-cigarettes. They think it’s just water or water vapor. They don’t understand it’s an aerosol. They don’t understand that e-cigarettes can have nicotine. They don’t understand that flavorants themselves can be harmful.”

The flavors can be toxic

More than 7,000 varieties of flavored e-cigarettes are on the market.

UC Riverside professor of cell biology Prue Talbot screened the cytotoxicity (quality of being toxic to cells) of 36 refill fluids and found that some were highly toxic. The most cytotoxic flavor, Cinnamon Ceylon, contained a chemical called cinnamaldehyde, which gives cinnamon its flavor and whose side effects may include coughing and sore throats. Talbot has been studying more flavors and is building a database to help determine the most dangerous ones.

“Flavors are something that could be potentially regulated,” Talbot said.

Vaping has secondhand and thirdhand effects

Unlike cigarettes, which emit smoke from the lit end, e-cigarettes don’t produce sidestream emissions between puffs, but they still generate secondhand and thirdhand effects when users exhale the mainstream vapor.

In a TRDRP-funded study, Berkeley Lab researcher Hugo Destaillats led a team that found 31 chemicals that include several toxicants at significant levels in e-cigarette vapor. The most toxic chemicals included acrolein, a severe eye and respiratory irritant; and formaldehyde, an irritant and probable carcinogen.

Emissions varied by type of device and voltage.

“The way you heat the liquid drastically determines if you produce a lot of compounds or just a few,” Destaillats said. “As you increase the voltage, toxic byproduct concentrations increase exponentially.”

The batteries can explode

There were 134 reports of e-cigarette batteries overheating, catching fire or exploding between 2009 and January 2016, according to the Food and Drug Administration, which will host a public workshop in April to gather information about e-cigarette battery safety concerns.

E-cigarette batteries “can explode without notice,” Talbot said. “People can be quite severely injured.”

E-liquids are poisonous if swallowed

Calls to poison control centers about e-cigarette exposure in young children have skyrocketed nationally in recent years. In California, the number of calls involving e-cigarettes increased from 19 in 2012 to 243 in 2014, according to the UC-administered California Poison Control System. More than 60 percent of those e-cigarette calls were related to nicotine poisoning in children 5 and under.

E-cigarettes show mixed results in helping smokers quit

While some people have quit smoking with e-cigarettes, on average, adult smokers who use e-cigarettes are about 30 percent less likely to stop smoking cigarettes, Glantz said. Also, e-cigarettes are associated with more, not less, cigarette smoking among adolescents.

“If you are a middle-aged person who has been smoking for 20 years, maybe it is good to switch to e-cigarettes,” Destaillats said. “But if you are a teenager and never have smoked, then it is not a good idea to use e-cigarettes.”

The minimum age has risen

In June, California became the nation’s second state, following Hawaii, to raise the minimum age for tobacco sales to 21, and for the first time added e-cigarettes to the definition of tobacco products. In August, the FDA extended its tobacco oversight to e-cigarettes, banning sales to those under 18.

“It sends a message to youth that e-cigarettes are in the same category of all tobacco products,” Halpern-Felsher said.

E-cigarettes will be taxed

Under Proposition 56, the tobacco tax passed by California voters in November, the state will tax e-cigarettes for the first time, starting April 1. It’s estimated that the price of a typical 30-milliliter bottle of e-liquid could increase to about $30 from $20.

“Anytime you increase the price, people buy less,” Glantz said.

The tax revenue will enhance education efforts by boosting funding for the state Tobacco Control Program. The surgeon general’s report also will make it easier for states to integrate e-cigarettes into tobacco education campaigns and could lead to more regulations, Glantz said.

E-cigarettes may be safer than cigarettes, but unknown risks remain

Expect more information to emerge about e-cigarettes as studies examine long-term effects.

“It’s often assumed that e-cigarettes are safer than cigarettes, but that could be an incorrect assumption,” Talbot said. “We don’t yet know the long-term health effects of e-cigarettes.”

Decades of research have helped scientists determine that cigarette smoke creates more than 7,000 chemicals, at least 69 of which are known to cause cancer and many of which are poisonous.

So, while e-cigarettes deliver fewer cancer-causing chemicals than cigarettes, research has yet to reveal how e-cigarettes fully impact heart and lung health and their cancer-causing potential, Glantz said.

He estimates that e-cigarettes are about one-third to one-half as dangerous as cigarettes.

In other words, they are still plenty dangerous.

“Regular cigarettes are super unhealthy,” Destaillats said. “E-cigarettes are just unhealthy.”

Starting with e-cigs triples odds of starting cigarettes among college students; the evidence just keeps piling up

Tory Spindle and colleagues at VCU recently published a study, “Electronic cigarette use and uptake of cigarette smoking: A longitudinal examination of U.S. college students,” that followed 3757 students at Virginia Commonwealth University for a year to examine the relationship between e-cigarette use among never cigarette smokers at the beginning and whether they were smoking conventional cigarettes a year later. They found, controlling for a wide range of demographic and behavioral variables, that e-cigarette users at baseline were about 3.4 times as likely to be smoking cigarettes a year later as young adults who were not using e-cigarettes.

This effect is consistent with a similar study of young adult males in Switzerland as well as all the studies of adolescents.

Here are the highlights and the abstract:


• E-cig and cigarette use has not been studied in college students longitudinally.
• Ever and current e-cig use increased non-smokers chances of trying cigarettes.
• Historically internalizing/externalizing factors predict cigarette uptake strongly.
• Most internalizing/externalizing factors examined did not predict e-cig uptake.
• Males and marijuana users were more likely to initiate e-cig use.



Electronic cigarette (e-cigarette) use prevalence is increasing among U.S. adolescents and adults but recent longitudinal data for college/university students are scarce.

Furthermore, the extent that e-cigarette use is associated with the onset of cigarette smoking and the factors that lead to the uptake of ecigarettes in college students has not been explored.


3757 participants from a Mid-Atlantic university (women: 66%; White: 45%; Black: 21%; Asian: 19%; Hispanic/Latino: 6%) were surveyed in 2014 and again in 2015.


Among participants reporting never smoking at time 1, those who had ever tried e-cigarettes or were currently using e-cigarettes (at least one use in past 30 days) were more likely to have ever tried cigarettes by time 2 relative to individuals who had not used e-cigarettes. Ever use of e-cigarettes (but not current use) also increased participants’ likelihood of being current cigarette smokers at time 2. Among initial never users of e-cigarettes or cigarettes, males and ever marijuana users had an increased probability of trying e-cigarettes by time 2. Furthermore, less perseverance (an index of impulsivity) and ever use of other tobacco products increased initial never users’ chances of trying both cigarettes and e-cigarettes by time 2.


Given that never-smoking participants who had tried e-cigarettes were more likely to initiate cigarette use later, limiting young adults’ access to these products may be beneficial. As the long-term health implications of e-cigarette use become clearer, predictors of e-cigarette use could help identify future populations likely to use and abuse these products.

Here is the full citation: Spindle, et al. Electronic cigarette use and uptake of cigarette smoking: A longitudinal examination of U.S. college students. Addictive Behaviors 2017; 67:66-72.


High school vapers often become heavy smokers

Also worrisome: Teen vaping rates are skyrocketing, according to a new report by the U.S. Surgeon General’s office

E-cigarette use grew an astounding 900 percent among high school students from 2011 to 2015. That’s according to a report by the U.S. Surgeon General’s office, released December 8. It highlights the harmful effects of e-cigarettes, especially to young people.

E-cigarettes first went on sale in the United States in 2007. Back then, companies advertised them as an aid to help adults give up smoking tobacco. But nonsmokers soon took up e-cigs too . Among them have been teens and even preteens. The Surgeon General’s report says the newly recognized drastic leap in e-cig use could lead many teens to try smoking.

And that would put a new generation of Americans at risk of nicotine addiction, says Thomas Wills. He works at the University of Hawaii at Manoa. He’s also an expert on teen smoking rates.

The Surgeon General’s report and other information about the health effects of e-cigarettes can be found at anew website: Know the Risks: E-cigarettes & Young People.

Two additional new studies back up what the Surgeon General’s office is saying. Both also shine some light on why teens choose to vape — and why some young vapers transition to smoking cigarettes.

Studies had shown that teens who vape are more likely to try cigarette smoking. And that’s disturbing because in the United States alone, the number of teen vapers nearly quadrupled between 2013 and 2015 — to more than 3 million. However, it has not been clear whether these kids who move on to tobacco “are just experimenting with smoking or whether they go on to become regular users,” says Adam Leventhal. He’s an addiction scientist at the University of Southern California, in Los Angeles.

The distinction is important, he says. Teens who become regular smokers during high school are more likely to develop a lifelong addiction to nicotine. According to the Surgeon General’s Report, nine out of 10 adult smokers tried their first cigarettes during adolescence.

To dig into why some teens make this transition, Leventhal and his colleagues recruited more than 3,000 Los Angeles-area 10th graders into a study. The students filled out surveys in the fall and spring. Those questions asked the teens about whether they had vaped or smoked. The researchers then looked at whether the answers had differed between early and late in the school year.

And indeed they did. Vaping seemed to up the likelihood that a teen would start smoking, these data showed.

The researchers broke students into groups, based on their answers in the fall to whether and how often they vaped. One group reported never vaping. A second group said they had tried vaping, but not within the past month. A third group reported vaping on one or two days in the past month. The last group said they had vaped even more than that in the last 30 days.

And the likelihood that a student smoked in the spring doubled in each successive group. For instance, by the spring, students who had previously tried vaping were about two times as likely to use cigarettes as were teens who had never vaped. Each jump to a group that vaped more frequently roughly doubled the likelihood that a student would report frequent, heavy cigarette smoking in the spring. (People who smoked cigarettes on three or more days in the past month were deemed frequent smokers. Lighting up two or more cigarettes on any day was considered heavy use.)

Leventhal’s group published its findings online November 8 in the Journal of the American Medical Association.

The share of teens in this study who reported vaping was slightly lower than the national average. One in three students in the study said they had ever tried vaping. That’s about 4 percentage points lower than the national average for 10th graders. Similarly, about 9 percent of the California kids surveyed said they had vaped in the past month. That’s 5 percentage points lower than the U.S. average 10th graders, according to a February 2016 report. It was conducted by researchers at the University of Michigan in Ann Arbor.

One reason for the lower vaping rate in California could be that kids there also are somewhat less likely to smoke than elsewhere in the country, notes Wills.

It still isn’t clear why some teens make the transition from vaping to smoking, he says. Young people who vape might learn to like the feeling of lighting up, holding a cigarette-like device or inhaling. These are behaviors that are common to both electronic and tobacco cigarettes. That might make it easier for teens to transition to tobacco cigarettes. It’s also possible that kids who use e-cigarettes are getting hooked on nicotine, says Wills. This is the chemical that makes tobacco smoking so addictive. It’s also found in most e-cig liquids.

More research is needed, Wills says, to probe the role of nicotine in teens’ transition from vaping to smoking.

The influence of ads

“Use of e-cigarettes has been rising exponentially among youth,” says Hongying Dai. “Little is known about the factors contributing to this rise,” she adds. Dai is an epidemiologist — a scientist who studies disease risk. She works at the University of Missouri-Kansas City. This researcher wondered whether the number of e-cig advertisements that kids see might affect how likely they were to vape. So she analyzed data from a national survey for clues that might confirm this.

More than 22,000 U.S. middle- and high-school students had filled out the survey about their smoking and vaping habits.

Compared to kids who rarely saw e-cig ads, those who saw them at least “sometimes” were much more likely to vape. Students who frequently ran into ads on the internet were about three times as likely to vape as were teens who reported never seeing such online ads. Kids who vaped also reported high exposure to e-cigarette ads in stores, newspapers and magazines, on TV and at the movies.

Family also seemed to play some role. Kids were more likely to vape if someone in their household used e-cigarettes, the researchers showed.

E-cigarette ads that target teens often portray vaping as glamorous or attractive, notes the Surgeon General’s report. Wills says the tobacco industry used these same tactics to encourage cigarette smoking by young people a generation ago.

Still, some questions remain. For instance, Dai asks, how accurately did the teens report encountering e-cigarette ads? And do all kids notice e-cig ads equally? Or are kids who vape just more likely to pay attention to vape ads?

Dai says she expected to see a link between ads and vaping. Tobacco advertising has been linked to increases in youth smoking rates, she notes. It therefore makes sense that exposure to e-cig advertising could affect teen vaping, she says.

Findings from the second study appear in the August Journal of Adolescent Health.

National view: Lung cancer battle raises concerns about e-cigs, other ‘nicotine-delivery devices’

November has been Lung Cancer Awareness Month and a good time to recall an old saying in the lung cancer community: “If you’ve got lungs, you can get lung cancer.” Lung cancer is everybody’s fight.

It’s the deadliest cancer in America, accounting for 25 percent of all cancer deaths. Lung cancer is also the leading cause of cancer deaths among women. The National Cancer Institute estimates that 71,600 women will die of lung cancer this year. And you may be surprised to learn that of the women who get lung cancer, approximately 1 in 5 are nonsmokers.

Unfortunately, the false stigma that automatically ties smoking to lung cancer has severely hindered life-saving lung cancer research. In fact, of the $5.3 billion the National Cancer Institute receives every year from the federal government, only 6.5 percent is devoted to lung cancer.

That’s a big part of the reason my husband, U.S. Rep. Rick Nolan, is a founder and co-chairman of the bipartisan Congressional Lung Cancer Caucus. For us, and for millions of other families, lung cancer and the need for more federal support for prevention, treatment and, ultimately, a cure, is personal. Our youngest daughter, Katherine, is battling nonsmoking stage 4 small cell lung cancer. And Rick’s father and aunt both had lung cancer.

Of course, the battle against lung cancer is being waged on many fronts, including efforts to discourage young people from smoking. In that regard, experts increasingly are concerned that hard-won progress against lung cancer could be curbed by the growing popularity of “nicotine-delivery devices,” particularly electronic cigarettes, or e-cigarettes, that turn nicotine into an inhalable liquid vapor, and hookah, which are water pipes used to smoke flavored tobacco.

Simply stated, we don’t really know how dangerous these products are or what chemicals and components users are taking into their bodies. For example, we know little about the safety of propylene glycol, a substance contained in many e-cigarettes. And tests have found that some e-cigarettes contain small amounts of nitrosamines and formaldehyde, both cancer-causing agents.

Thankfully, after years of public review and comment, new Food and Drug Administration regulations are being rolled out to address these concerns. Over the next two years, the FDA will be given more authority to require manufacturers to report the content of their products to the public.

Until then, though, the chemicals — and the potential health effects — will remain largely unknown.

Young people are particularly attracted to the exotic and fruity flavors available in e-cigarettes and specialty tobaccos. In fact, a 2014 Minnesota Department of Health survey of more than 70 schools revealed that 13 percent of high school students and 3 percent of middle school students had used e-cigarettes. Those figures are even higher nationwide as these nicotine-delivery devices have become big business. By some estimates, U.S. sales of e-cigarettes and other more-specialized e-smoking products reached $5.5 billion in 2015.

The new FDA regulations will make it harder for children and teenagers to obtain e-cigarettes, hookah tobacco and cigars. Even now, it’s illegal to sell these products to anyone younger than 18 or in vending machines accessible to minors. The FDA also no longer allows stores to give away samples of new tobacco products.

These measures will help in the battle against lung cancer, but we all need to take our own steps to promote tobacco-free families, homes and communities.

Remember, if you’ve got lungs, you can get lung cancer. We’ve all got lungs, so we all have a stake in this fight.

Mary Nolan of Crosby, Minn., is a member of the Congressional Families Cancer Prevention Program of the Prevent Cancer Foundation and is the wife of U.S. Rep. Rick Nolan. She wrote this for the News Tribune

E-cigarette use as a predictor of cigarette smoking

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Beating tobacco starts with going easy on vaping

Stopping smoking has always been a bit of a drag. White-knuckle determination to resist the need to smoke is accompanied by a bewildering variety of inhalers, gums, sprays, patches, tablets and counselling, much of which is associated with modest success and some of which has serious adverse side-effects.

Stopping smoking remains a global health priority since it is still the leading cause of premature death and serious ill health. With the advent of e-cigarettes, quitting smoking has become fun as smokers discover a world of user-modifiable e-cigarette kits and a limitless range of flavours. In a survey of more than 22,000 vapers carried out by researchers in Glasgow, smokers typically started vaping with high-nicotine, tobacco-flavoured e-liquids before progressing to zero-nicotine fruit flavours as they moved further away from the world of smoking.

Although they have helped millions to turn their back on tobacco, e-cigarettes have attracted controversy due to fears that they may attract non-smokers and lead to renormalisation of smoking. Government bodies in Europe and the United States are imposing restrictive regulations on e-cigarette production, sales and use that will limit the range of flavours and reduce access to the modifiable e-cigarette kits that vapers seem to enjoy.

At a World Health Organisation meeting in Delhi this month on tobacco control, delegates were asked to support a worldwide ban on e-cigarettes. Here in the UK, the appetite for regulation is enormous. Almost all council areas within the UK already maintain a ban on the use of e-cigarettes at work, leaving vapers to stand in the cold.

With Brexit, the UK has the opportunity to develop regulations governing e-cigarettes that can ensure that these devices remain widely available for smokers at the same time as their appeal to non-smokers is minimised.

Flavours are important, as are retaining the user-modifiable e-cigarette tanks that allow users to produce the voluminous vaper clouds that have become so characteristic of these devices.

We need to discourage e-cigarette use by non-smokers, not by forcing people to vape in hiding but by recognising what this technology is achieving in saving smokers’ lives.

Dr Neil McKeganey is director of the Centre for Substance Use Research in Glasgow

Big Tobacco wins big with vaping

Big Tobacco, with its legion of lobbyists, and evil geniuses, is almost always a step ahead of regulators and health officials. It wasn’t until May of this year that the FDA finally finalized a rule extending its authority to all nicotine products — including e-cigarettes, cigars, hookah and pipe tobacco, among others. The lack of such authority is why we saw ads for nicotine vaping products on TV, and such products sold legally to teens and kids.

When cigarette smoking rates among teens hit historic lows in the past decade, flavored products (from cigars to vaping) filled the void. When the FDA announced the oversight change, it cited research by the agency and the CDC showing current e-cigarette use among high school students has skyrocketed from 1.5 percent in 2011 to 16 percent in 2015 (an over 900 percent increase) and hookah use has risen significantly. In 2015, 3 million middle and high school students were current e-cigarette users, and data showed high school boys smoked cigars at about the same rate as cigarettes.

A separate study by the FDA and the National Institutes of Health shows that in 2013-2014, nearly 80 percent of current youth tobacco users reported using a flavored tobacco product in the past 30 days – with the availability of appealing flavors consistently cited as a reason for use, the FDA reported.

And now, a new, disturbing study shows just how successfully Big Tobacco is cultivating more nicotine addicts, and how belated the FDA was to take action to oversee the new products. The research, published in the Journal of the American Medical Association, found that teenagers with a regular vaping habit aren’t just more likely to take up smoking — they have higher odds of developing a heavy cigarette habit, Reuters reported.

Vaping devices have been advertised as way to help smokers quit, but the lead author of the study says his findings call that cessation claim into question.

“Our most recent study is the first to show that teenagers who vape not only experiment with cigarettes, but are also more likely to become regular smokers,” said Adam Leventhal, director of the University of Southern California’s Emotion and Addiction Laboratory in Los Angeles.

Rather than keeping kids and teens from smoking, the flavored nicotine products can act as bridge to smoking, said Dr. Brian Primack, a University of Pittsburgh researcher who wasn’t involved in the study.

“… young people who may not have otherwise ended up smoking started with palatable, flavored e-cigarettes — and then after they became accustomed to e-cigarette use, many transitioned to traditional cigarette smoking,” Primack told Reuters. Which is exactly what is happening.

Dozens quit smoking thanks to HKU service hotline

Dozens of smokers have successfully kicked the habit with the help of a hotline set up by the University of Hong Kong.

Altogether, 1,147 people have used the service in the past five years, of whom 233, or 23.5 percent, have stopped smoking, the Hong Kong Economic Journal reports.

The success rate was achieved within six months.

Project director Dr. William Li said the average age of participants was 19.9 years.

Three in five were students including three in 10 who used to smoke more than 10 cigarettes a day.

Just 10 percent of the help seekers have cut down on their tobacco intake.

Li said the situation is “quite worrying” but some cases are promising.

Ah-Tung, 18, started smoking a year ago because of pressure from school and personal relationship issues.

He used to consume half a pack of cigarettes a day.

An avid runner, he decided to seek help after noticing his health had deteriorated.

“I could only complete two laps on the jogging track when I was a smoker, but soon after I quit, I was capable of doing a lot more laps,” he said.

Li said Ah-Tung’s case is typical.

About 43 percent of the people who called the Youth Quitline said they suffer from emotional stress.

Li said those who are emotionally disturbed are more easily influenced by their peers would usually find it more difficult to quit smoking.

HKU School of Nursing also found that 60 percent of young smokers who tried to quit smoking have switched to electronic cigarettes (e-cigarettes), according to Ming Pao Daily.

The percentage was even higher among younger smokers.

Among e-cigarette smokers aged 25 and below, 43 percent are between 15 and 17 while those aged between 18 to 20 make up 35 percent of the group, followed by those from 21 to 25, which makes up 14 percent.

Lam Tai-hing, chair professor of the School of Public Health of the HKU Li Ka Shing Faculty of Medicine, said the success rate among traditional cigarette and e-cigarette smokers is more or less the same.

The figures suggest that e-cigarettes do not help smokers get rid of nicotine addiction, Lam said.

He said more effort is needed to educate the public about the dangers of smoking.

Lam also called for legislation to ban e-cigarettes.

Youth Quitline (5111 4333) targets smokers aged 25 and below.

Vaping raises likelihood of teenagers starting to smoke, study suggests

Research based on teenagers in California tentatively proposes link but experts say it does not prove that one leads to the other

A study of teenagers in California has tentatively suggested a link between vaping and starting to smoke cigarettes, although experts say it does not prove that one leads to the other.

About 37% of teens in the US have tried vaping, and there is widespread anxiety that young people who use e-cigarettes may be more likely to start smoking as a result.

The study, published in the Journal of the American Medical Association (JAMA), looked at vaping and smoking in more than 3,000 teenagers, aged about 15, in the 10th grade of 10 public high schools in Los Angeles county, California.

The numbers who vaped or smoked at all were small – only 26 who had never smoked at the beginning of the study said at the end of the follow-up period, six months later, that they had used e-cigarettes and also smoked in the previous month. Others had previously smoked infrequently or frequently.

But the researchers did find a trend. The more the teenagers said they had vaped, the more likely they were to smoke cigarettes. The more frequent vapers were also likely to smoke more heavily.

The public health community is divided over the pros and cons of e-cigarettes. Some doctors believe they may be the best tool yet for helping established smokers quit the habit, but others are less convinced and warn they could be a means of hooking non-smokers into a tobacco habit.

The authors of the study – Adam Leventhal, of the University of Southern California Keck School of Medicine, and colleagues – acknowledge there are many unknowns but conclude that: “The transition from vaping to smoking may warrant particular attention in tobacco control policy.”

Why can’t scientists agree on e-cigarettes?

Other experts said although the study was well conducted, it could not explain the link. “This study could not tell us if it is something about the young people that vape that predisposes them to smoking or that vaping itself makes smoking more likely,” said Paul Aveyard, professor of behavioural medicine at the University of Oxford. It was well known that teenagers who tried one risky behaviour were more likely to be willing to try another.

“Smoking in young people has fallen in the UK and the US to record lows in the past few years, despite the rise in prevalence of young people experimenting with e-cigarettes,” he said.

“Very few young people who do not smoke cigarettes become regular users of e-cigarettes. In this context, we should not worry unduly about this study’s findings, but it is important to monitor smoking in young people and its relationship with e-cigarette use.”

Prof John Britton, director of the UK centre for tobacco and alcohol studies at the University of Nottingham, said the study “doesn’t tell us whether vaping caused these young people to start smoking, or whether they would have started smoking anyway; or whether vaping prevented some young people who would otherwise have become smokers from progressing to tobacco smoking.”

Children whose parents were smokers and trying to give up would be more likely to have access to e-cigarettes – and also more at risk of starting to smoke in the first place.

“The key question is whether vaping is increasing smoking uptake, over and above that underlying risk,” said Britton. “This study doesn’t answer that question; but it does show that if it does, the proportions of children affected are very small.”

Association of e-Cigarette Vaping and Progression to Heavier Patterns of Cigarette Smoking

E-cigarette vaping is reported by 37% of US 10th-grade adolescents1 and is associated with subsequent initiation of combustible cigarette smoking.2 Whether individuals who vape and transition to combustible cigarettes are experimenting or progress to more frequent and heavy smoking is unknown. In addition, because some adolescents use e-cigarettes as a smoking cessation aid,3 adolescent smokers who vape could be more likely to reduce their smoking levels over time. Therefore, associations of vaping with subsequent smoking frequency and heaviness pattern among adolescents were examined.

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