Using a procedure called bronchoscopy to test for inflammation and smoking-related effects, researchers reported a measurable increase in inflammation after four weeks of e-cigarette use without nicotine or flavours.
The study suggested that even short-term usage could result in inflammatory changes at a cellular level.
"Through the randomised clinical trial of healthy never-smokers over a month, we found that an increase in urinary propylene glycol, a marker of inhalation-e-cig intake, was significantly correlated with increased inflammatory response in the lung," said the study's first author Min-Ae Song from Ohio State University.
For the study, researchers recruited 30 healthy, non-smoking volunteers to directly assess the impact of tobacco and e-cig use on the lungs through bronchoscopy, an outpatient test in which a doctor inserts a thin tube through the nose or mouth to view the airways.
A small sample of lung cells was collected from fluid in the lungs.
Participants were randomised to a four-week intervention with e-cigs containing only 50 per cent propylene glycol (PG) or 50 per cent vegetable glycerine (VG) without nicotine or flavours.
Results from these tests were then compared to a separate control group of never-smokers.
Researchers did not see levels of inflammation higher than the controls, but there was an increase in inflammation among the users who inhaled more of the e-cigarette.
With the recent reports of lung disease and deaths associated with vaping, the effects of vaping nicotine and marijuana oils makes this research more critical, said the researchers.
( With inputs from IANS )