Abstract Background E-cigarettes (EC) are the most used tobacco product among young adults. Although there are limited data on the long-term respiratory effects of ECs, evidence suggests EC use may contribute to increased risk of chronic obstructive pulmonary disease (COPD). Prior work has shown changes in pulmonary perfusion early in COPD development; We sought to test if EC use was associated with differences in pulmonary small vessel volume in healthy young adults. Methods The VapeScan Study is a single-site, observational study that recruited young adults 18 to 50 years from around New York City. Exclusion criteria included pregnancy, cardiovascular disease, and diagnosis of bronchiectasis, emphysema, or COPD. Enrollment groups were defined by self-reported EC and cigarette use: no history of EC or cigarette use (controls), exclusive EC use, current EC use with former cigarette use, and dual EC / cigarette use. Full-lung, low-dose CT was performed at total lung capacity (TLC). Total pulmonary vascular volume (TPVV) was defined as the volume of detectable pulmonary arteries and veins, small vessel volume (SVV) was defined as the blood volume in vessels 0.75mm radius, and the SVV/TPVV ratio was calculated. Pre-bronchodilator spirometry defined the ratio of the forced expiratory volume in one second to forced vital capacity (FEV1/FVC). Analyses were adjusted for demographics and body size. Results Among 296 participants (mean age 28 years, 50% male), 87 were controls, 75 had exclusive EC use, 52 had current EC use with former cigarette use, and 82 had dual EC / cigarette use. Forty-five (15%) reported a history of asthma, 51 (17%) had FEV1/FVC0.70, and 110 (37%) reported cannabis use. After adjustment for age, gender, and body size, exclusive EC use was associated with a non-significant increase in TPVV (+7.53mL, 95%CI -0.33, 15.40) and significantly higher SVV (+3.80mL, 95%CI 0.55, 7.04) and SVV/TPVV (+0.01, 95%CI 0.00, 0.03) compared with controls. EC use with former cigarette use was also associated with greater SVV than the control group (+6.27, 95%CI 2.62, 9.92). The figure shows differences in predicted SVV across enrollment groups. Results were similar with further adjustment for cannabis use, and after excluding participants with asthma or FEV1/FVC0.7. Conclusions EC use was associated with greater SVV in otherwise healthy young adults, a finding which may reflect peripheral vascular inflammation and represent a risk factor for subsequent lung injury and development of chronic cardiopulmonary disease. This abstract is funded by: NIH R01HL155576, R01ES029967
Hermann et al. (Fri,) studied this question.