SYDNEY, Feb. 14 (Xinhua) -- A new study directly comparing the effects of various nicotine ingestion methods has shown that heated tobacco devices, vaping and traditional cigarettes can all be toxic to lung cells.

The study by researchers at the University of Technology Sydney (UTS), the University of Tasmania, and Sydney University showed that products which heat solid tobacco, sometimes known as heat-not-burn (HNB), are no less toxic to the cells than ordinary cigarette smoke.

Speaking to Xinhua on Thursday, lead author Dr Pawan Sharma said so far very little research has been done on these devices which are seeing a resurgence in the uptake of nicotine around the world.

"These heated tobacco products are being promoted as a safer alternative to cigarette smoking," Sharma said, "therefore it may attract both current smokers and first time smokers."

Researchers tested the effects of the three nicotine sources on two types of cells taken from the human airways: epithelial cells and smooth muscle cells.

They found that cigarette smoke and heated tobacco vapor were both highly toxic to the cells even at low concentrations, while e-cigarette vapor demonstrated toxicity mainly at higher concentrations, reflecting that of a chronic smoker.

"Our results suggest that all three are toxic to the cells of our lungs and that these new heated tobacco devices are as harmful as smoking traditional cigarettes," Sharma said.

Sharma warned anyone using alternative nicotine devices with the belief they are a healthy alternative, that quitting altogether is the only safe bet.

"It took us nearly five decades to understand the damaging effects of cigarette smoke and we don't yet know the long-term impact of using e-cigarettes," he said.

"These devices that heat solid tobacco are relatively new and it will be decades before we will fully understand their effects on human health."