Thursday, March 9, 2017

E-Cigarette Toxic Chemical Exposure Is Same as for Nonsmokers

The new finding from British and U.S. e-cigarette researchers understated the good news for vapers.

“Long-term NRT-only and e-cigarette-only use…is associated with substantially reduced levels of measured carcinogens and toxins relative to smoking only combustible cigarettes,” reported scientists at the University College London; King's College, London; the Roswell Park Cancer Institute in Buffalo, New York; and the U.S. Centers for Disease Control and Prevention (CDC). Their work, with Lion Shahab as lead author, appeared in the Annals of Internal Medicine last month (abstract here). 

“The observed carcinogens and toxins” were a group of volatile organic compounds (VOCs), including acrolein, acrylamide, acrylonitrile, butadiene and a combination of ethylene oxide, acrylonitrile and vinyl chloride.  The researchers actually measured metabolites – products formed when the body breaks down the VOCs – in the urine.

The finding is good news for vapers, who avoid the thousands of toxins in smoke.  But the study and associated media coverage gave the impression that e-cigarette use also resulted in excess exposure to the VOCs.  That may not be true.

People are exposed every day to these VOCs, in the air and in our food and drinks.  Research published by K. Udeni Alwis et al. in 2012 (abstract here) showed that nonsmokers have measurable levels of these chemicals.    

Here are compared results from the Shahab and Alwis studies.  The former did not report absolute levels of the VOC metabolites; rather, it designated smokers as the referent group, and reported levels in vapers as a percentage of levels in smokers.  The Alwis study reported actual levels in smokers and nonsmokers, allowing me to calculate the percentages.       

Percentage Exposures to VOCs in Vapers (Shahab) and NonSmokers (Alwis), Compared to Smokers
VOCPercentage in VapersPercentage in NonSmokers

*ethylene oxide, acrylonitrile and vinyl chloride

The table shows that VOC exposures in vapers were similar to exposures in nonsmokers.  For example, in the Shahab study, vapers’ exposure to acrylamide was 43% of the exposure among smokers, whereas nonsmokers’ exposure was 42% of smokers in the Alwis study.

The authors of the Shahab report, particularly Dr. Alwis (who is at the CDC), should have made the connection between the results of the two studies.  The fact that vapers’ VOC exposures are similar to those of nonsmokers is headline-worthy.

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