Introduction: Electronic cigarettes (e-cigs) are becoming increasingly popular, but little is known about their dependence potential. This study aimed to assess ratings of dependence on electronic cigarettes and retrospectively compare them with rated dependence on tobacco cigarettes among a large sample of ex-smokers who switched to e-cigs. Methods: A total of 3,609 current users of e-cigs who were ex-cigarette smokers completed a 158-item online survey about their e-cig use, including 10 items designed to assess their previous dependence on cigarettes and 10 almost identical items, worded to assess their current dependence on e-cigs (range 0-20). Results: Scores on the 10-item Penn State (PS) Cigarette Dependence Index were significantly higher than on the comparable PS Electronic Cigarette Dependence Index (14.5 vs. 8.1, p < .0001). In multivariate analysis, those who had used e-cigs longer had higher e-cig dependence scores, as did those using more advanced e-cigs that were larger than a cigarette and had a manual button. Those using zero nicotine liquid had significantly lower e-cig dependence scores than those using 1-12 mg/ml, who scored significantly lower than those using 13 or greater mg/ml nicotine liquid (p < .003). Conclusions: Current e-cigarette users reported being less dependent on e-cigarettes than they retrospectively reported having been dependent on cigarettes prior to switching. E-cig dependence appears to vary by product characteristics and liquid nicotine concentration, and it may increase over time.

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.

Background/Objectives Weight gain after quitting smoking is a common concern for smokers and can discourage quit attempts. The purpose of this analysis was to describe the long term weight gain, smoking cessation attributable (SCA) weight gain and describe their relationship to cigarette consumption and body mass index (BMI) 10 years ago in a contemporary, nationally representative sample of smokers who continued to smoke and those who quit. Subjects/Methods 12,204 adults ≥ 36 years old were selected from the 2003-2012 National Health and Nutrition Examination Survey (NHANES). Ten year weight gain for never, continuing and former smokers (who quit 1-10 years ago) was calculated by body mass index (BMI) 10 years ago and cigarettes per day (CPD). SCA weight gain was calculated by taking the difference between the adjusted mean ten year weight gain of former smokers and that of continuing smokers. Results Mean ten year weight gain among continuing smokers was 3.5 kg versus 8.4 kg among former smokers; 4.9 kg of SCA weight gain. After Bonferroni correction, there was no significant difference in overall weight gain between continuing and former smokers of 1-14 CPD and SCA weight gain was lowest in this group (2.0 kg, CI: 0.3, 3.7). SCA weight gain was highest for former smokers of ≥25 CPD (10.3 kg, CI: 7.4, 13.2) and for those who were obese (7.1 kg, CI: 2.9, 11.3) mostly due to lower than average weight gain or weight loss among continuing smokers in these groups. Conclusions In a current, nationally representative sample, baseline BMI and CPD were important factors that contributed to the magnitude of long term weight gain following smoking cessation. Light to moderate smokers (<15 CPD) experienced little SCA weight gain while heavy smokers (≥25 CPD) and those who were obese prior to quitting experienced the most.