Fig. 1.

Baseline flow-mediated dilation (FMD) in the 3 groups. Among the 3 groups, including nonsmokers (n = 47), chronic electronic cigarette (EC) vapers (n = 49), and chronic tobacco cigarette (TC) smokers (n = 40), baseline FMD was not different unadjusted or adjusted for artery diameter, whether reported as percent change (%∆; A), absolute change (mm∆; B), or normalized for shear stress [arbitrary units ∆ (AU∆); C]. Unadjusted means compared between groups using a repeated-measure (mixed) analysis of variance model and displayed as mean (25–75%) with whiskers to minimum to maximum of the data.