Factors Associated With Electronic Cigarette Users' Device Preferences and Transition From First Generation to Advanced Generation Devices.

INTRODUCTION Electronic cigarettes (e-cigs) are becoming increasingly popular but little is known about how e-cig users' transition between the different device types and what device characteristics and preferences may influence the transition. METHODS Four thousand four hundred twenty-one experienced e-cig users completed an online survey about their e-cig use, devices, and preferences. Participants included in analysis were ever cigarette smokers who used an e-cig at least 30 days in their lifetime and who reported the type of their first and current e-cig device and the nicotine concentration of their liquid. Analyses focused on transitions between "first generation" devices (same size as a cigarette with no button) and "advanced generation" devices (larger than a cigarette with a manual button) and differences between current users of each device type. RESULTS Most e-cig users (n = 2603, 58.9%) began use with a first generation device, and of these users, 63.7% subsequently transitioned to current use of an advanced generation device. Among users who began use with an advanced generation device (n = 1818, 41.1%), only 5.7% transitioned to a first generation device. Seventy-seven percent of current advanced generation e-cig users switched to their current device in order to obtain a "more satisfying hit." Battery capabilities and liquid flavor choices also influenced device choice. CONCLUSION E-cig users commonly begin use with a device shaped like a cigarette and transition to a larger device with a more powerful battery, a button for manual activation and a wider choice of liquid flavors.