The study has compared new heated tobacco devices, which heat solid tobacco instead of an e-liquid, with vaping and traditional cigarettes showing that all the three are toxic to the cells.
In addition, these newer electronic nicotine delivery devices can destroy lung tissue leading to fatal diseases such as chronic obstructive pulmonary disease, lung cancer and pneumonia, and can increase the risk of developing asthma.
"Smoking is the leading cause of preventable death, and with the introduction of e-cigarettes in the last decade, the trend of nicotine uptake is not going to slow down in the near future," said Pawan Sharma, a researcher at the University of Technology Sydney.
"The latest addition in this emerging trend is the planned and vigorous introduction of heated tobacco devices. They are commonly called next generation or heat-not-burn products. We know very little about the health effects of these new devices, so we designed this research to compare them with cigarette smoking and vaping," added Sharma.
For the study, researchers tested the effects of all three nicotine sources on two types of cells taken from the human airways: epithelial cells and smooth muscle cells.
In healthy lungs, epithelial cells act as the first line of defence to any foreign particles entering the airway while smooth muscle cells maintain the structure of the airway. However, smoking can lead to difficulty in breathing primarily by hampering the normal functions of these cells.
The team exposed the cells to different concentrations of cigarette smoke, e-cigarette vapour and vapour from a heated tobacco device, and measured whether this was damaging to cells and whether it affected the cells' normal functions.
The findings, published in ERJ Open Research, showed that cigarette smoke and heated tobacco vapour were highly toxic to the cells both at lower and higher concentrations while e-cigarette vapour demonstrated toxicity mainly at higher concentrations.
Importantly, the review of the European Respiratory Society's Tobacco Control Committee's own data on these devices has shown that, in rats, there is evidence of lung inflammation, and there is no evidence of improvement in lung inflammation and function in smokers who switch to heated tobacco, said Professor Charlotta Pisinger from the varsity.
"If the current trend continues, tobacco use will cause more than eight million deaths annually by 2030 around the world," noted Sharma.