The American Urological Association announced these presentations to the world with a press release carrying the heading: “2 Studies Link E-Cigarettes to Potential Increased Bladder Cancer Risk”. The first problem with this is that the studies have not undergone any peer-review process as, to date, they remain unpublished. Therefore, presenting the findings from these two pieces of work (whether they agree or not) as if they support each other and are therefore valid and factual is erroneous.
The scientists justified the need for their research: “While traditional cigarette smoking is a clear cause of bladder cancer, much less has been studied about the bladder cancer risk associated with e-cigarettes.”
Researchers compared the urine of vapers to that of non-smokers; “urine samples were examined for five known bladder carcinogens that are either present in traditional cigarettes or common solvents believed to be used in some e-cigarette liquids. “
“Urine from 92 percent of e-cigarette users tested positive for two of the five carcinogenic compounds.”
"These studies raise new concerns about the harmful impact of e-cigarettes on bladder cancer," said Dr. Chang. "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 to e-cigarette smoke and bladder cancer. This research underscores the importance of smoking cessation (of both traditional and e-cigarettes) for people with bladder cancer, and people looking to avoid it."
Doctor Konstantinos Farsalinos commented: “It is all over the news today that e-cigarette use is associated with bladder cancer. This is an impressive statement that would certainly raise concerns if any such association was [sic] really shown in any study. First, this is based just on a conference abstract, not a published study.”
“Second, the abstract did not measure any association between e-cigarette use and bladder cancer. It evaluated chemicals linked with bladder cancer in the urine of 13 e-cigarette users compared 10 non-users as controls. No smokers were recruited for comparison. The authors of the abstract found higher levels of o-toluidine and 2-naphthylamine in e-cigarette users compared to controls.”
He stated that the problems with this abstract are: “Very low sample size, non-verified smoking cessation in e-cigarette users (history taking only, no verification with exhaled carbon monoxide), no inclusion of smoking controls for comparison, it is unknown if and how these compounds are formed in the e-cigarette aerosol, and the biomarkers measured are not established biomarkers of smoking exposure.”
Then upshot is that the studies failed to isolate the environmental impact and previous studies have shown similar levels of the measured chemicals in both smokers and non-smokers. Farsalinos feels an investigation is warranted to discover if the chemicals even exist in vapour.