Issues

The cover is adapted from Figure 1 in the article, “Biomarkers of Exposure and Effect in the Lungs of Smokers, Nonsmokers, and Electronic Cigarette Users,” by Song and colleagues. To address the need for data regarding effects of electronic cigarettes (e-cigs) on the lung and to inform policy determination, Song and colleagues conducted a cross-sectional bronchoscopy study of never-smokers, exclusive e-cig users, and cigarette smokers to assess group differences, examining inflammatory infiltrates, cytokines, and genome-wide DNA methylation and gene expression in the lung. There were statistically significant differences among never-smokers, e-cig users, and smokers for inflammatory cell counts and cytokines. E-cig users were found to be intermediate between smokers and never-smokers for biomarkers of inflammation and for gene methylation and expression, including known smoking-related pathways. While these findings are cross-sectional and therefore cannot be extrapolated with regard to temporality or causality, the findings are consistent with the hypothesis that e-cigs may be less harmful than smoking, at least for the smoking-related biomarkers measured herein. For more information, see the article beginning on page 443.