How did an abstract from a research paper regarding bladder cancer, presented at a conference, get warp speed global headline coverage and become a statement of fact?

Especially considering… “Research presented at meetings is typically considered preliminary until published in a peer-reviewed journal.” What are we referring to? The latest scare-mongering for vapers. It is no longer the ‘gateway theory’ or ‘teens’, it is now bladder cancer.

Only it isn’t, because this is another click bait scare.

And this article is going to explain to you just why. From the abstract, the study appears to use poor science and should not have gotten the global reach it did.

Vaping and bladder cancer

So, a little more about the ‘study’.

Researchers compared the urine of e-cigarette users 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. The users were mostly male with an average age of 39 years old. The non-smokers had abstained from traditional cigarettes for at least six months prior to the test.”

Results showed:

– Urine from 92 percent of e-cigarette users tested positive for two of the five carcinogenic compounds.
– Further study is needed to clarify the contribution e-cigarettes make to the development of bladder cancer, given the greater concentration of carcinogenic compounds in the urine of e-cigarette users in this study.

They concluded:

“Overall, researchers predicted e-cigarette smokers have a high bladder cancer risk.”

Farsalinos takes a deeper look.

Now, this all sounds probable to the lay person, 92% is concerning, the authors refer to ‘e-cigarette smoke’,  however, that changes when the experts such as Dr Farsalinos take a deeper look. Alongside the published press release of the study, we have not been able to find the actual study, but it seems that Dr Farsalinos has (thankfully) had access to more information.

Vaping and bladder cancer

What he saw was a study that was small – as in only 13 e-cigarette users small. Great for the start of further research, to posit a hypothesis etc… but certainly not headline material.

There was no proof that the non-smokers had abstained for 6 months – they only gave their word. 6 months’ abstinence is not easy if you are giving up cold turkey. We assume they were not using NRT, as this too contains nicotine.

The e-cigarette users were not compared to smokers. Why not? Surely this would have given a more accurate result? Perhaps it would have shown smaller numbers for the e-cigarette users.

Where were the biomarker numbers for the non-smokers? They were not in the press release.

Did they have any biomarkers? Had there been more comparison, then the results might have looked similar to a 2002 review, that showed:

In one study, smokers excreted 6.3 ± 3.7 μg/ 24 h of 2-toluidine while levels in non-smokers were 4.1 ± 3.2 μg/24 h, not significantly different from smokers  with those words being important. A separate review also found in smokers, similar amounts of 2-naphthylamine (84.5 ± 102.7 ng/24 h) as non-smokers (120.8 ± 279.2) (95).

Plus, according to Dr Farsalinos, the biomarkers used in the study are not established for smoking exposure.

Finally, it is not known how or if these biomarkers are in, or produced by vaping.

To explain further the last couple of points.

A biomarker is, “a naturally occurring molecule, gene, or characteristic by which a particular pathological or physiological process, disease, etc. can be identified.”

The biomarkers looked for were O-toluidine and 2-naphthylamine.

Both are used in the dye industry, and indeed it is from the study of workers in dye factories that they realised these biomarkers, when present, increase the risks of bladder cancer.

But, as the review from 2002 shows, the numbers from smokers and non-smokers are fairly similar, which means that the biomarkers could be picked up from the environment. O-toluidine is needed to make the colour magenta,  and is in modern day hair dye. 2-naphthylamine is also used in the dye industry to make yellow, orange and red dyes, known as ‘azo dyes’.

Vaping and bladder cancer

Human biomonitoring (that uses biomarkers), is the direct measurement of people’s exposure to toxic substances in the environment by measuring the substances or their metabolites in human specimens, such as blood or urine.

Exposure leading to absorption, is the key step which is often one of the most difficult to characterize, hence the need in the mentioned study for far more information.”

Here is a list of why sometimes using biomarkers doesn’t give the full picture.

– Biomarkers do not define sources, pathways or duration of exposure
– Cannot define toxic dose
– Susceptible to inferior or unscrupulous analytical laboratories
– Lack of meaningful reference levels
– Lack of toxicological and epidemiological information about the vast majority of environmental chemicals

To give a different example, let’s use coffee.

Over a thousand chemicals have been reported in roasted coffee: more than half of those tested (19/28) are rodent carcinogens. There are more rodent carcinogens in a single cup of coffee than potentially carcinogenic pesticide residues in the average American diet in a year, and there are still a thousand chemicals left to test in roasted coffee. This does not mean that coffee is dangerous but rather that animal cancer tests and worst-case risk assessment, build in enormous safety factors and should not be considered true risks.”

While we cannot say that using e-cigarettes is completely harmless, they are a harm reduction tool.

We as vapers deserve proper science, peer reviewed science so that we know and understand the risks. Click bait headlines in the long run not only undermine a harm reduction tool, but they will eventually undermine science, and then everybody loses.