If all traditional cigarette smokers switched to electronic cigarettes, lives would be saved and overall public health would improve, scientists and doctors say.

But UCSF researchers, in a paper published Monday, say a growing body of research shows that people who take up e-cigarettes aren't necessarily giving up conventional cigarettes, and on top of that, the devices are being heavily marketed to young people, creating a potential new market for the nicotine and tobacco industry.

"Our bottom line is, at the moment, it doesn't seem like e-cigarettes are having a big impact on the population in terms of quitting," said UCSF's Dr. Neal Benowitz, a leading nicotine researcher and a co-author of the scientific review published in Circulation, a journal of the American Heart Association.

E-cigarettes, battery-operated devices that vaporize a nicotine solution, have been sold in the U.S. only since the mid-2000s, but their popularity is exploding, particularly among teenagers.

The percentage of U.S. middle and high school students who said they've tried e-cigarettes was 3.3 percent in 2011 but rose to 6.8 percent by the following year, according to a survey by the U.S. Centers for Disease Control and Prevention.

Health effects unclear

Some manufacturers claim the devices help people stop smoking and some users agree, but researchers in the study say that's unclear. The paper cites studies that show people tend to use e-cigarettes with combustible cigarettes, rather than as an alternative.

Little is known about the long-term health effects of e-cigarette use because the $1.5 billion U.S. industry is so young. But the researchers say that while emissions from the devices are less toxic than those from burning cigarettes, they are not "harmless water vapor" as some manufacturers claim.

"As we're getting better and better understanding of the chemistry of these things, they're looking worse and worse," said Stanton Glantz, director of UCSF's Center for Tobacco Control Research and Education and a co-author of the Circulation paper.

The researchers described how e-cigarettes deliver nicotine by creating an aerosol of ultra-fine particles. There's not enough evidence to determine the health consequences of those particles, but they noted that previous research has shown frequent low- or short-term exposure to similar fine particles from tobacco or air pollution contribute to systemic inflammatory processes in the body that increase the risk of heart and respiratory disease.

"You can be a lot less bad as a cigarette and still be pretty bad," Glantz said.

Bans enacted

It may take years or even decades for clinical trial data to determine the firsthand and secondhand effects of exposure to the particles, but an increasing number of cities and states aren't waiting to find out.

San Francisco, Chicago, New York and Los Angeles have implemented bans on e-cigarette use in areas where smoking has been banned. New Jersey, Utah and North Dakota, as well as 172 other municipalities around the country, have enacted similar laws, according to Americans for Nonsmokers' Rights in Berkeley.

Last month, the U.S. Food and Drug Administration announced plans to regulate e-cigarettes for the first time. The agency's action has been both welcomed as a first step and criticized for failing to curb the way the products are marketed to appeal to youths and sold in a variety of e-liquid flavors, ranging from gummy bears to Belgian waffles, something that young people might find attractive.

Oliver Kershaw, who founded the online E-Cigarette Forum in 2007, said he supports the responsible use of e-cigarettes either as a substitute for standard cigarettes or a way to help kick the nicotine habit. Kershaw had not yet seen the UCSF paper.

"It's smoking that is the danger. Everything else pales in comparison," said Kershaw, who traded conventional cigarettes for e-cigarettes five years ago.

But he objects to the wave of anti-e-cigarette legislation that treats the devices like regular cigarettes.

"You're far more likely to be exposed to dangerous compounds from an air freshener than you are from an e-cigarette," Kershaw said. Exposure to diesel fuel fumes and other environmental air pollutants is harmful, he noted.

Safety debated

Dr. Robert Jackler, a professor at the Stanford School of Medicine and researcher on the hazards and marketing of tobacco who was not involved in the study, said he also doesn't want e-cigarettes to go away because the devices could be useful to help people transition from regular cigarettes.

But until the science is better known, he said, e-cigarettes should be treated the same as regular cigarettes when it comes to public use and marketing.

"The burden should be proving it's safe," he said, "not that it's unsafe after hurting hundreds of thousands of people."
