US researchers suggest that an outbreak of vaping-associated lung injuries (EVALI) in 2019 was because the vapers were using cannabis oil containing vitamin E acetate. This substance is used as a cutting or thickening agent when cannabis oil containing tetrahydrocannabinol (THC) is smoked in an e-cigarette cartridge. However, the lung injury seen in the US is not related to the nicotine rep-lacement e-cigarettes sold in the UK.
In the study, a team led by Benjamin Blount of the US Centers for Disease Control and Prevention (CDC) compared the lung fluid of 51 patients with EVALI with 99 healthy people (New Engl. J. Med., doi: 10.1056/NEJMoa1916433). They found vitamin E acetate in the lung fluid from 48 of the 51 samples, but not in the healthy participants, including 18 e-cigarette users. In addition, they say the absence of other toxicants – plant oils, medium-chain triglyceride oil, coconut oil, petroleum distillates, and diluent terpenes – in lung fluids from nearly all patients with EVALI provides further evidence that vitamin E acetate is the main culprit.
A surveillance study led by CDC’s Kathleen Hartnett reports that the first cases of EVALI were reported to CDC in August 2019 (New Engl. J. Med., doi: 10.1056/NEJMsr1915313). By December, the total had risen to over 2500. Most patients were men younger than 35 years of age and adolescent boys. Around 80% reported using e-cigarette products containing THC.
Hartnett’s team notes that the outbreak coincided with the increased use of CBD oil in e-cigarettes. However, the team also points out that newer-generation e-cigarettes use nicotine salts, which allow more nicotine to be inhaled with less irritation. They note that nicotine salts may increase the risk of adverse effects to the lungs, as inhalation tends to be more frequent and deeper.
John Britton, director of the UK Centre for Tobacco & Alcohol Studies at the University of Nottingham, says: ‘These studies provide further evidence that the outbreak of serious lung disease among vapers in the US this year was caused by vaping THC, and may particularly be due to vaping THC solutions containing vitamin E acetate. The conclusions provide strong reassurance that people vaping nicotine as an alternative to tobacco smoking are unlikely to be affected, and should continue to vape instead of smoke.’
This view is echoed by Jacob George, professor of cardiovascular medicine and therapeutics at the University of Dundee: ‘The key message is that the comparative risks of tobacco cigarettes – with more than 7000 different chemicals in each cigarette – are still significantly higher than e-cigarettes. Non-smokers should not try e-cigarettes but tobacco smokers could switch to e-cigarettes as a harm reduction measure.’