Fig. 4.

Change in flow-mediated dilation (FMD) in electronic cigarette (EC) vapers after EC vaping or nicotine inhaler (NI). In EC vapers, FMD was unchanged pre-/postacute use of an EC with nicotine (n = 22), EC without nicotine (n = 23), or NI (n = 19) compared with pre-/post-sham control (n = 31), whether reported as percent change (%∆; A), absolute change (mm∆; B), or normalized for shear stress [arbitrary units ∆ (AU∆); C]. Mean postexposure minus baseline differences were compared across electronic cigarette with nicotine (ECN), electronic cigarette without nicotine (EC0), NI, and sham control using a crossover repeated-measure (mixed) analysis of variance model and displayed as mean (25–75%) with whiskers to minimum to maximum of the data.