The Relation between Frequency of E-Cigarette Use and Frequency and Intensity of Cigarette Smoking among South Korean Adolescents.
The prevalence of adolescent electronic cigarette (e-cigarette) use has increased in most countries. This study aims to determine the relation between the frequency of e-cigarette use and the frequency and intensity of cigarette smoking. Additionally, the study evaluates the association between the reasons for e-cigarette use and the frequency of its use.



Using the 2015 Korean Youth Risk Behavior Web-Based Survey, we included 6655 adolescents with an experience of e-cigarette use who were middle and high school students aged 13-18 years. We compared smoking experience, the frequency and intensity of cigarette smoking, and the relation between the reasons for e-cigarette uses and the frequency of e-cigarette use.



The prevalence of e-cigarette ever and current (past 30 days) users were 10.1% and 3.9%, respectively. Of the ever users, approximately 60% used e-cigarettes not within 1 month. On the other hand, 8.1% used e-cigarettes daily. The frequent and intensive cigarette smoking was associated with frequent e-cigarette uses. The percentage of frequent e-cigarette users (≥10 days/month) was 3.5% in adolescents who did not smoke within a month, but 28.7% among daily smokers. Additionally, it was 9.1% in smokers who smoked less than 1 cigarette/month, but 55.1% in smokers who smoked ≥20 cigarettes/day. The most common reason for e-cigarette use was curiosity (22.9%), followed by the belief that they are less harmful than conventional cigarettes (18.9%), the desire to quit smoking (13.1%), and the capacity for indoor use (10.7%). Curiosity was the most common reason among less frequent e-cigarette users; however, the desire to quit smoking and the capacity for indoor use were the most common reasons among more frequent users.



Results showed a positive relation between frequency or intensity of conventional cigarette smoking and the frequency of e-cigarette use among Korean adolescents, and frequency of e-cigarette use differed according to the reason for the use of e-cigarettes.
Department of Family Medicine, ASAN Medical Center, University of Ulsan College of Medicine, Seoul 05505, Korea. junga_lee@amc.seoul.kr.
Jung Ah
JA
Lee
National Evidence-Based Healthcare Collaborating Agency, Seoul 100705, Korea. wwwvince77@gmail.com.
Sungkyu
S
Lee
Department of Family Medicine, ASAN Medical Center, University of Ulsan College of Medicine, Seoul 05505, Korea. hjcho@amc.seoul.kr.
Hong-Jun
HJ
Cho
D000293:Adolescent; D066300:Electronic Nicotine Delivery Systems / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D033182:Intention; D008297:Male; D009042:Motivation; D015995:Prevalence; D056910:Republic of Korea / Q000453:epidemiology; D012907:Smoking / Q000453:epidemiology*; D011795:Surveys and Questionnaires; D062789:Tobacco Products / Q000706:statistics & numerical data*; D000072137:Vaping / Q000453:epidemiology*
adolescent; e-cigarette; electronic cigarette; frequency; smoking; tobacco