As part of the CITU (Cardiovascular Injury due to Tobacco Use) study, researchers performed noninvasive vascular function testing in individuals without known cardiovascular disease or cardiovascular disease risk factors who were nonsmokers (n=94), users of combustible cigarettes (n=285), users of e‐cigarettes (n=36), or dual users (n=52). In unadjusted analyses, measures of arterial stiffness including carotid‐femoral pulse wave velocity, augmentation index, carotid‐radial pulse wave velocity, and central blood pressures differed across the use groups. In multivariable models adjusted for age, sex, race, and study site, combustible cigarette smokers had higher augmentation index compared with nonusers (129.8±1.5 versus 118.8±2.7, P=0.003). The augmentation index was similar between combustible cigarette smokers compared with sole e‐cigarette users (129.8±1.5 versus 126.2±5.9, P=1.0) and dual users (129.8±1.5 versus 134.9±4.0, P=1.0). Endothelial cells from combustible cigarette smokers and sole e‐cigarette users produced less nitric oxide in response to A23187 stimulation compared with nonsmokers, suggestive of impaired endothelial nitric oxide synthase signaling.