E cigarette smoke damages DNA and reduces repair activity in mouse lung, heart, and bladder as well as in human lung and bladder cells PNAS E cigarettes damage DNA in lab study Toxicological Effects of E Cigarettes on Cells, Animals, and Humans and Mechanisms of Toxicity Springer Nature Link Comparison of the in vivo genotoxicity of electronic and conventional cigarettes aerosols after subacute, subchronic and chronic exposures. ScienceDirect