Popcorn lung is the name given to the medical condition bronchiolitis obliterans. The name came about because it was initially observed among workers in a popcorn factory.
Joseph Allen wants to know why vapers aren’t being warned about the danger of popcorn lung, and uses this as a justification for the investigation. The team used human bronchial epithelial cells in a fluid system to mimic (they claim) actual lung conditions.
The team erroneously claim, “flavouring chemicals are found in over 90%” of eliquids and add, “The most common flavouring compound added to e-cig is diacetyl.”
They base this laughable claim on a 2013 study using 13 brands of cigalikes, and a 2015 study using four different cigalikes. Neither study was set up to test for the presence of diacetyl and both had deeply flawed methodologies.
The Harvard team then exposed the cells to a diacetyl and acetyl propionyl-containing solutions for 24 hours and proved that administering diacetyl in this manner was deleterious to lung cells. It failed to replicate how vaping operates or utilise the diketone-free liquids we now use.
Should we be worried?
Dr Konstantinos Farsalinos did discover the presence of diacetyl in eliquids in a 2014 study – but it prompted a wholesale change in the juice manufacturing industry. Canada removed stocks from shelves and vendors began to test their liquids.
Despite this, Farsalinos pointed out that the risk was small in smokers: “Popcorn lung is very rare even in those exposed to high levels. 1 in 1000 chance of developing an chronic obstructed lung disease, 15% of smokers develop this, and so it is likely diketones are operating in conjunction with other chemicals.”
He concluded that the risk posed to vapers was negligible in comparison.
Public Health England writes in its latest demolition of vaping myths: “One of the most commonly held concerns is that e-cigarettes might cause ‘popcorn lung’. This came about because some flavourings used in e-liquids to provide a buttery flavour contain the chemical diacetyl, which at very high levels of exposure has been associated with the serious lung disease bronchiolitis obliterans.”
“However, diacetyl is banned as an ingredient from e-cigarettes and e-liquids in the UK. It had been detected in some e-liquid flavourings in the past, but at levels hundreds of times lower than in cigarette smoke. Even at these levels, smoking is not a major risk factor for this rare disease.”
This latest study fails to factor in the criticism similar studies raised and offers no new insights. It fails to note that even in diketone-containing eliquids, the levels were far lower than that found in cigarette smoke. It fails to point out that no incidents of bronchiolitis obliterans have been linked to smokers experiencing higher levels of diketones. It fails to appreciate the concept of harm reduction.
There is nothing in this study that should alarm vapers or smokers looking to switch in order to reduce their exposure to tobacco-related harm.
- “Transcriptomic response of primary human airway epithelial cells to flavouring chemicals in electronic cigarettes” by Allen and Lu et al - https://doi.org/10.1038/s41598-018-37913-9
- “Changing patterns of first e-cigarette flavor used and current flavors used by 20,836 adult frequent e-cigarette users in the USA” by Russell, McKeganey, Dickson and Nides - https://harmreductionjournal.biomedcentral.com/articles/10.1186/s12954-018-0238-6
- “Evidence review of e-cigarettes and heated tobacco products 2018” by Public Health England - https://bit.ly/2wpVL7a
- "Clearing up some myths around e-cigarettes” by Public Health England - https://publichealthmatters.blog.gov.uk/2018/02/20/clearing-up-some-myths-around-e-cigarettes/