Page 2
questionnaire was used to collect information related to the patterns and attitudes towards the use of cigarettes and e-cigarettes. The Fagerström test for nicotine dependence (FTND) and its adapted version for e-cigarettes were used to analyze nicotine dependence in each of the groups. The nicotine dependence levels measured with FTND were over two times higher among e-cigarette users (mean 3.5) compared to traditional tobacco smokers (mean 1.6; p < 0.001). Similarly, among dual users, nicotine dependence levels were higher when using an e-cigarette (mean 4.7) compared to using traditional cigarettes (mean 3.2; p = 0.03). Habits and behaviors associated with the use of e-cigarettes did not differ significantly (p > 0.05) between exclusive e-cigarette users and dual users. The findings suggest that e-cigarettes may have a higher addictive potential than smoked cigarettes among young adults. Keywords: electronic cigarettes; tobacco; nicotine; addiction; dependence 1. Introduction Nicotine is a highly addictive substance and adolescents and young adults may be at high risk of addiction [1,2]. Nicotine withdrawal effects such as irritability, anxiety, poor concentration, memory impairment, and insomnia can occur after cessation of chronic nicotine use [3]. In addition, exposure to nicotine in adolescence may have adverse affects on the adolescent brain, with postulated risks including impaired memory and attention, increased risk of substance abuse, and addiction and poor academic performance [4–6]. Electronic cigarettes (e-cigarettes) are a relatively new form of nicotine delivery device and the prevalence of their use is rapidly growing in many countries [7–9]. E-cigarettes have been suggested as a way to reduce nicotine dependence and have been reported to be less addictive than traditional cigarettes [10]. However, there have been numerous reports of people who become addicted to Int. J. Environ. Res. Public Health 2019, 16, 2279; doi:10.3390/ijerph16132279 www.mdpi.com/journal/ijerph Int. J. Environ. Res. Public Health 2019, 16, 2279 2 of 10 e-cigarettes and report typical symptoms of nicotine addiction [10–12], including with a dose-response effect [13]. E-cigarette use has even been suggested to lead to an increased risk of addiction, especially among young people [14], with higher exposure to doses of nicotine compared to people who smoke traditional cigarettes, as e-cigarettes are used in times and places where smoking is prohibited [15]. While some suggest e-cigarettes will help to quit smoking or reduce this addiction [16], others have reported that using e-cigarettes has a negative impact on successfully quitting [17–19]. Using e-cigarettes may have little effect on reducing the frequency of nicotine use [20,21]. Due to uncertainty about the dependency potential of e-cigarettes, we decided to carry out a study aimed to: (1) assess the patterns of e-cigarette use by exclusive e-cigarette users and dual users and (2) compare nicotine dependence levels among young adults who use cigarettes or e-cigarettes. We chose to examine the problem in a highly educated group of university students under the assumption that their perception is less biased by commonly held beliefs and stereotypes of e-smoking safety and addiction mechanisms. 2. Materials and Methods 2.1. Participants This study is a continuation of a survey-based and multicentered international project, the YoUng People E-Smoking Study (YUPESS) [22]. From this larger study, we selected a subgroup to be involved in the current study. A cross-sectional survey was performed between January and March 2018. Three fields of study (medical, humanistic, and technical) were randomly selected from a group of 245 different fields of study within Universities in Katowice. The questionnaire was addressed to all the students within each selected field of study. Data were collected from 3002 participants. Out of all the participants, we identified 39 exclusive e-cigarette users and 54 dual users. All subjects who used e-cigarettes (n = 93) were invited to participate in the second part of the study. Exclusion criteria included occurrence of any chronic diseases, history of lung diseases (e.g., asthma or bronchial hyperactivity in childhood), presence of any allergic diseases, any medication intake (current or in the last 2 weeks), acute illnesses or infections in the last 2 weeks, influenza vaccination in the last 2 weeks, and current pregnancy or lactation. Among exclusive e-cigarette users, three met the exclusion criteria and six refused. Finally, 30 exclusive e-cigarette users were included. Among dual users, four met the exclusion criteria. To keep an equal number of participants per group, out of 50 eligible dual users, we randomly selected a group of 30 dual users, using randomization procedures available in the Statistica package. An