A new study from the Duke University School of Medicine has found chemicals in vapes can mix to form "unexpectedly toxic compounds" that can trigger heart, breathing and blood vessel issues.
Researchers looked at what happened when cells lining the main airway from the trachea to the lungs came into contact with flavouring chemicals such as vanilla, berry/fruit, and cinnamon.
They also looked into the effects of new compounds that form as a result of flavouring chemicals and solvents; propylene glycol, and vegetable glycerine (the main solvents in vapes) mixing.
They were surprised by the results.
"We consistently observed that the new chemicals formed from the flavours and e-liquid solvents were more toxic than either of their parent compounds," said Sven-Eric Jordt, associate professor of anesthesiology, pharmacology and cancer biology at Duke.
The new compounds, formed by the collision of solvents and flavourings, activated specific irritant receptors in the airways that are responsible for a plethora of inflammatory responses.
"Activation of sensory irritant receptors can increase the heart rate and, in predisposed people, can lead to an irregular heartbeat and higher blood pressure," said Jordt
"More than 40 percent of flavour chemicals are converted into new chemicals in e-cigarettes, almost nothing was known about their toxicity until now."
It was also found that the new compounds can kill cells in the airways.
The compounds did this by affecting the cells' ability to consume oxygen and produce ATP, the chemical used to provide energy to the cell.
Compounds formed from berry/fruit and cinnamon flavourings turned out to be more toxic and harmful than chemicals formed from vanilla flavourings.
Jordt said the findings suggest "regulators need to be made aware that these compounds can form so that toxicology studies can be initiated to evaluate their safety".
The study has not yet been peer-reviewed so there is a possibility findings could be altered.
