A Review of Pulmonary Toxicity of Electronic Cigarettes in the Context of Smoking: A Focus on Inflammation

The use of electronic cigarettes ( e-cigs) is increasing rap­idly, but their effects on lung toxicity are largely unknown. Smoking is a well-established cause of lung cancer and respiratory disease, in part through inflammation. It is plau­sible that e-cig use might affect similar inflammatory path­ ways. E-cigs are used by some smokers as an aid for quitting or smoking reduction, and by never smokers ( e.g., adoles­ cents and young adults). The relative effects for impacting disease risk may differ for these groups. Cell culture and experimental animal data indicate that e-cigs have the poten­tial for inducing inflammation, albeit much less than smok­ing. Human studies show that e-cig use in smokers is associated with substantial reductions in blood or urinary bio­ markers of tobacco toxicants when completely switching and somewhat for dual use. However, the extent to which these biomarkers are surrogates for potential lung toxicity remains unclear. The FDA now has regulatory authority over e-cigs and can regulate product and e-liquid design features, such as nicotine content and delivery, voltage, e-liquid formulations, and flavors. All of these factors may impact pulmonary toxicity. This review summarizes current data on pulmonary inflammation related to both smoking and e-cig use, with a focus on human lung biomarkers.

Shields, Peter G., Micah Berman, Theodore M. Brasky, Jo L. Freudenheim, Ewy Mathe, Joseph P. McElroy, Min-Ae Song, and Mark D. Wewers. “A Review of Pulmonary Toxicity of Electronic Cigarettes in the Context of Smoking: A Focus on Inflammation.” Cancer Epidemiology, Biomarkers & Prevention 26, no. 8 (August 1, 2017): 1175–91. https://doi.org/10.1158/1055-9965.EPI-17-0358.