January 29, 2018

expert reaction to e-cigarettes and DNA damage

E-cigarette smoke damages DNA and reduces repair activity in mouse lung, heart, and bladder as well as in human lung and bladder cells, reports a new study, published in PNAS.

Dr Ed Stephens, Senior Research Fellow at the University of St Andrews, said:

“This new research is a valuable contribution to understanding the mechanisms of DNA damage caused by nicotine-bearing aerosols inhaled by smoking cigarettes or vaping. By measuring indicators of DNA damage in various mouse organs the authors observed significant differences between experiments using nicotine-bearing e-cigarette vapour and those using filtered air.

“Unfortunately, no direct comparisons were made with tobacco smoke; instead the authors cite another study¹ that found a key biomarker related to such genetic damage to be present in very much smaller quantities (97% less) in the urine of vapers compared with smokers.

“That study and this new research are both consistent with the widely-held view that vaping is not without risk of cancer and other diseases, but that risk is usually considerably lower than smoking.”

¹ Shahab et al. 2017

Prof. Peter Hajek, Director of the Tobacco Dependence Research Unit, Queen Mary University of London (QMUL), said:

“Human cells were submerged in nicotine and in off-the-shelf bought carcinogenic nitrosamines. It is not surprising of course that this damaged the cells, but this has no relationship to any effects of e-cigarettes on people who use them.

“In the other part of this study, animals were exposed to what for them are extremely large doses of nicotine and this also generated some damage, but this too has unclear relevance for effects of vaping.

“No comparison with conventional cigarettes was made, but in the text of the article, the authors acknowledge the key bit of information that is of crucial relevance in this story: Vapers show a reduction in these chemicals of 97% compared to smokers. They should have added that his may well be the level that non-smokers obtain from their environment.”

* ‘E-cigarette smoke damages DNA and reduces repair activity in mouse lung, heart, and bladder as well as in human lung and bladder cells’ by Hyun-Wook Lee et al. published in PNAS on Monday 29 January. 

Declared interests

None to declare.