Although electronic cigarettes (ECs) are a much less harmful alternative to tobacco
cigarettes, there is concern as to whether long-term ECs use may cause risks to human
health. We report health outcomes (blood pressure, heart rate, body weight, lung function,
respiratory symptoms, exhaled breath nitric oxide [eNO], exhaled carbon monoxide [eCO],
and high-resolution computed tomography [HRCT] of the lungs) from a prospective 3.5-year
observational study of a cohort of nine daily EC users (mean age 29.7 (±6.1) years) who …

Methods Participants and Study Design. Adult EC users (≥ 18 years old) were identified
amongst a pool of regular Vape Shops customers. Vape shop owners who helped in a
previous study22 were instructed to ask their regular clients a few questions about smoking
history and EC use patterns. Customers who had never smoked or who reported having
smoked less than 100 cigarettes in their lifetime were defined as never smokers23 and
considered for inclusion. They also had to be daily EC users of≥ 3 months. They were …