Lung injuries linked to vaping are most likely caused by toxic chemical fumes, a new study suggests.
Researchers looked at lung biopsies from 17 patients who had vaped and were suspected to have vaping-associated lung injury.
They found no evidence of tissue injury caused by a build up of lipids — fatty substances such as mineral oils.
It had been suspected these were a possible cause of the lung injuries associated with vaping.
Instead injuries from vaping most likely are caused by direct toxicity or tissue damage from noxious chemical fumes, scientists say.
This is a public health crisis, and a lot of people are working frantically around the clock to find out what the culprit or culprits could be – and what chemicals may be responsible
Professor Brandon Larsen, a surgical pathologist at the Mayo Clinic, Arizona, said: “While we can’t discount the potential role of lipids, we have not seen anything to suggest this is a problem caused by lipid accumulation in the lungs.
“Instead, it seems to be some kind of direct chemical injury, similar to what one might see with exposures to toxic chemical fumes, poisonous gases and toxic agents.”
The small study, published in The New England Journal of Medicine, acknowledges that research into the pathology of vaping-associated lung injury is in its early stages.
Of the 17 biopsies that were examined, two were from Mayo Clinic patients, and the others were from hospitals across America.
All of the patients had vaped, and 71% had vaped with marijuana or cannabis oils.
Researchers say they all showed acute lung injury, including pneumonitis – inflammation of the lung tissue – and two of the patients died.
Senior author Prof Larsen added: “We were not surprised by what we found, regarding toxicity.
“We have seen a handful of cases, scattered individual cases, over the past two years where we’ve observed the same thing, and now we are seeing a sudden spike in cases.
12 Deaths linked to electronic cigarette use, or vaping, in 10 US states
Our study offers the first detailed review of the abnormalities that may be seen in lung biopsies to help clinicians and pathologists make a diagnosis in an appropriate clinical context.”
He said that unless clinicians and pathologists have the information in advance, diagnosing vaping-associated injury can be difficult.
Prof Larsen continued: “This is a public health crisis, and a lot of people are working frantically around the clock to find out what the culprit or culprits could be – and what chemicals may be responsible.”
He called for people to recognise that vaping is not without potential risks, and said that it would appear wise to explore better ways to regulate the industry and better educate people.
Public Health England say the number of young people trying vaping rose for a number of years as the popularity of e-cigarettes increased, over recent years it has plateaued.
The report, led by researchers at King’s College London, looked at surveys relating to e-cigarette use among young people, the most recent of which was the Action on Smoking and Health YouGov survey of more than 2,000 children aged 11 to 18 in 2018.
In April, Martin McKee, professor of European public health at the London School of Hygiene and Tropical Medicine, said the UK was “out of step” with other parts of the world when it came to messages around the safety of vaping.
Some American states have imposed a temporary ban on the sale of e-cigarettes or flavoured liquids used in them while researchers investigate health-related issues.
According to the Centres for Disease Control and Prevention, more than 800 lung injury cases are associated with electronic cigarette use, or vaping, and 12 deaths have been confirmed in 10 states.
Professor John Britton, director of the UK Centre for Tobacco & Alcohol Studies and consultant in respiratory medicine at the University of Nottingham, said: “This helpful study of samples of lung tissue from people affected by vaping show signs of acute damage, suggesting that the vapour they are inhaling includes something causing direct irritation and inflammation of the lung.
“That these samples do not show evidence of lipid accumulation indicates that the cause is not lipid per se, but something else in the vapour.
“This is a small number of cases so we don’t know how representative it is, but the findings are helpful.
“As in all disease outbreaks, it takes time to narrow down on the underlying cause: and in this example it is clearly something to do with vaping, something that often – but not exclusively – occurs in people who vape THC or other oils, and something that isn’t occurring in countries outside the USA.
“So it is something in US vape fluids, or something about the particular e-cigarettes used by those affected, but remains something separate from vaping more generally and particularly from vaping nicotine.”