(Reuters Health)

Even though the U.S. Surgeon General has concluded e-cigarette vapor may expose children to nicotine and other harmful chemicals, a new study finds that one in three adults aren’t sure if the devices are dangerous to use around kids.

Big U.S. tobacco companies are all developing e-cigarettes, battery-powered gadgets with a heating element that turns liquid nicotine and flavorings into a cloud of vapor that users inhale. Some previous research suggests vapor from e-cigarettes may be less toxic than traditional cigarette smoke, but the electronic alternatives still release chemicals that aren’t normally in the air and the long-term health effects of the ingredients and flavorings in e-cigarettes are unclear.

Overall, just 5.3 percent of adults who participated in a 2015 online survey thought exposure to secondhand e-cigarette vapor caused "no harm" to kids, the study from the U.S. Centers for Disease Control and Prevention found. Another 40 percent of adults thought it caused "little harm" or "some harm" to children.

"The bottom line is that kids should not be exposed to the emissions from any type of tobacco product, irrespective of whether that product is smoked, smokeless or electronic," said senior study author Brian King, a researcher with the CDC Office on Smoking and Health in Atlanta.

"Although e-cigarette aerosol generally contains less harmful ingredients than secondhand smoke, it is not harmless; safer is not the same thing as safe," King said by e-mail. "It’s important for users of these products, particularly parents, to know the dangers of secondhand exposure to e-cigarette aerosol and to protect kids from this preventable health risk."

To assess how adults thought about the risk of exposing kids to e-cigarettes, CDC researchers examined data from a survey of 4,127 adults 18 or older. The survey asked people to consider the potential harms of all electronic vapor products including e-cigarettes as well as e-hookahs, hookah pens, vape pens and e-cigars.

Current e-cigarette users were almost 18 times more likely than people who never tried the devices to think the secondhand vapors caused no harm to children, and former e-cigarette users were more than seven times more likely to have this opinion, according to the results published in the CDC journal Preventing Chronic Disease.

Compared with people who never smoked traditional cigarettes, current smokers were more than four times more likely to consider secondhand e-cigarette vapor harmless for kids, and former smokers were about twice as likely to have this opinion, the study found.

Men were more than twice as likely as women to think secondhand e-cigarette fumes were harmless for kids.

Adults aged 45 to 64 were less likely to be uncertain about the risk of exposing kids to second-hand e-cigarette smoke than younger adults aged 18 to 24, the study also found.

One limitation of the study is that researchers didn’t have detailed data to determine how often current or former e-cigarette users and cigarette smokers had used these products, the authors note. That means responses from heavy users were included in the same categories as people who only smoked or vaped occasionally.

Still, the findings underscore the need to raise awareness about the potential harms as researchers continue to investigate the long-term health effects of e-cigarettes, said Dr. Alexander Prokhorov, director of the tobacco outreach education program at MD Anderson Cancer Center in Houston.

"The products simply have not been in existence long enough to investigate their long-term effects" Prokhorov, who wasn’t involved in the study, said by e-mail.

"It took us decades to fully understand the devastating consequences of conventional cigarettes and we are regularly discovering more and more illnesses and disorders attributable to active and passive smoking," Prokhorov said. "I would not be surprised if ongoing studies will soon report additional facts on first- and second-hand vaping and health."

SOURCE: Preventing Chronic Disease, online May 31, 2017.