The long-term health ramifications of electronic cigarettes have become a source of much debate as they become increasingly used as an alternative to cancer-causing cigarettes.
New research from the University of Minnesota's School of Public Health reveals that e-cigs aren't as free from cancer risk as some believe.
E-cigs offer the nicotine hit craved by smokers, but without many of the carcinogenic chemicals you find in your typical cigarette.
But the study led by School of Public Health Associate Professor Irina Stepanov has found that the presence of N-Nitrosonornicotine (NNN) in e-cigarettes increases the risk of contracting throat and mouth cancer.
Previously, the presence of NNN in e-cigarettes hadn't raised much concern, because the nicotine liquid inhaled by users contains an incredibly small quantity of NNN in it.
However, Stepanov found that once the liquid is inhaled, it metabolizes in the body and becomes NNN.
Her study found that 16 out of 20 e-cigarette users had measurable levels of NNN in their saliva compared to non-smokers.
Although this level was lower than in smokers, some did have NNN saliva levels comparable to smokers.
"The finding that some e-cigarette users may be forming substantial amounts of NNN in their bodies is significant when considering the long-term risks of prolonged e-cigarette use," Stepanov said this week.
"For young e-cigarette users who have never smoked, this is particularly bad news, because they are being exposed to a potent carcinogen that most likely is a key contributor to oral and esophageal cancer in tobacco users."
Despite the finding, Stepanov still says that using e-cigarettes reduces a smoker's exposure to NNN "dramatically" compared to regular cigarette smoke.
E-cig use among teens
The use of e-cigarettes is becoming increasingly more common among teenagers, who the National Institute on Drug Abuse say are more likely to use e-cigs than regular cigarettes.
Teen e-cig users are also 30 percent more likely to start smoking within 6 months of starting e-cigarettes.
A study by NIDA found that past month e-cig use among 12th graders was at 16.2 percent, and at 14 percent among 10th graders, and 9.5 percent among 8th graders.