MONDAY, May 15, 2017 (HealthDay 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.
Ninety-two percent of e-cigarette users tested positive for two of the five chemicals. More research is needed to investigate the link between e-cigarettes and bladder cancer, the study authors said.
In a second study, researchers examined the effect of nicotine and its chemical compounds -- including nitrosamines and formaldehyde -- on DNA repair in cells lining the bladder.
The researchers found that e-cigarettes triggered cancer-related damage to bladder tissue. The findings also showed that nicotine, nitrosamines and formaldehyde led to damage while blocking DNA repair, boosting cancer risk.
For a separate study, researchers analyzed data on more than 14,000 adults with bladder cancer over three decades. The study compared five-year survival rates of those who smoked less than a pack of cigarettes a day to those who smoked more.
Heavier smokers were at far greater risk of death during the study period than those who smoked less, according to the report. The scientists noted, however, that even a small reduction in smoking could improve survival in the bladder cancer patients.
The studies' findings were scheduled for presentation Monday at the annual meeting of the American Urological Association, in Boston. Research presented at meetings is typically considered preliminary until published in a peer-reviewed journal.
The American Cancer Society has more about bladder cancer.