Heat-not-burn is smoke and mirrors

Heated tobacco devices, vaping and traditional cigarettes are all toxic to human lung cells, says a new study.[1]

The study, led by Dr Pawan Sharma, a researcher at the University of Technology Sydney and the Woolcock Institute of Medical Research, Sydney, suggests the new heat-not-burn devices that heat solid tobacco instead of an e-liquid, are no less toxic to the cells than ordinary cigarette smoke, adding to existing findings that these newer electronic nicotine delivery devices may not be a safer substitute for cigarette smoking.

“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,” he said. “If the current trend continues, tobacco use will cause more than eight million deaths annually by 2030 around the world.

“The latest addition in this emerging trend is the planned and vigorous introduction of heat-not-burn products. We knew very little about the health effects of these new devices, so we designed research to compare them with cigarette smoking and vaping.”

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.

Dr Sharma and his team exposed the cells to different concentrations of cigarette smoke, e-cigarette vapour and vapour from a heated tobacco device. They measured whether this was damaging to cells and whether it affected the cells’ normal functions.

They found 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. They say these concentrations represent the levels of nicotine found in chronic smokers.

“The introduction and vigorous marketing of new devices is very tempting to smokers who want to stop smoking and mistakenly believe they can switch to another harmless tobacco product,” Dr Sharma said. “It is also opening another avenue for attracting young people to use and become addicted to nicotine.This study adds to evidence that these new devices are not the safe substitute to cigarette smoking they are promoted to be.”


  1. ‘IQOS exposure impairs human airway cell homeostasis: direct comparison with traditional cigarette and e-cigarette’. ERJ Open Research,2019; 5: 00159-2018.

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