From US News:
Although many people think "vaping" is safer than smoking, research suggests that both e-cigarettes and traditional cigarettes are tied to an increased risk for bladder cancer.
"We've known traditional smoking raises bladder cancer risk, and given the surge in popularity of e-cigarettes, it's imperative we uncover any potential links" between e-cigarettes and bladder cancer, Dr. Sam Chang said in an American Urological Association news release.
Chang is a professor of urologic surgery at Vanderbilt-Ingram Cancer Center in Nashville.
Most inhaled nicotine is excreted in the urine. For the study, the researchers compared the urine of people who use e-cigarettes with that of nonsmokers. The investigators looked for five chemicals known to cause bladder cancer and may be found in e-cigarette liquid.