E-cigarette users are exposed to increased concentrations of potentially harmful levels of metals that are linked to elevated oxidative DNA damage a new study has found. For the study published in the journal BMJ Open Respiratory Research researchers found that the biomarkers which reflect exposure effect and potential harm are both elevated in e-cigarette users compared to the other groups and linked to metal exposure and oxidative DNA damage. Our study found e-cigarette users are exposed to increased concentrations of potentially harmful levels of metals -- especially zinc -- that are correlated to elevated oxidative DNA damage said the study's