title: Frequency of E-Cigarette Use and Cigarette Smoking by American Students in 2014.
abstract: High school students' electronic cigarette (e-cigarette) use rose rapidly in 2014, to levels higher than cigarette smoking, which declined significantly. This study assesses how frequency of e-cigarette use is associated with students' smoking status.
  
  
  
  Using Monitoring the Future data in 2015, this study evaluated the association between students' smoking and frequency of 30-day e-cigarette use in 2014, focusing on high school seniors. Previous research has considered only whether e-cigarettes were used at all during the past month.
  
  
  
  Non-smokers were far less likely than smokers to have used an e-cigarette (p<0.001). E-cigarette use frequency rose with the amount of ever smoking (p<0.001). However, among current smokers, there was no difference in e-cigarette use by very light smokers (<1 cigarette/day); light smokers (1-5 cigarettes/day); and heavy smokers (≥1/2 pack/day) (p=0.99). Because most students have never smoked, never smokers constituted 25% of all seniors who used an e-cigarette. Among tenth- and eighth-graders, 43% and 48% of past-month e-cigarette users had never smoked.
  
  
  
  Non-smoking high school students are highly unlikely to use e-cigarettes; among those who do, most used them only on 1-2 of the past 30 days. By contrast, current smokers are likely to use e-cigarettes and on many more days. It is unclear whether students' e-cigarette use represents short-term experimentation or future sustained use, and whether it will eventually increase or decrease youth smoking and nicotine addiction. More sophisticated research methods, employing better data, will be essential to unravel the mystery that is the e-cigarette phenomenon.
authors.affiliation: Department of Health Management and Policy, School of Public Health, University of Michigan, Ann Arbor, Michigan. Electronic address: kwarner@umich.edu.
authors.forename: Kenneth E
authors.initials: KE
authors.lastname: Warner
mesh_terms: D000293:Adolescent; D000073865:Cigarette Smoking / Q000453:epidemiology*; D066300:Electronic Nicotine Delivery Systems / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D008297:Male; D013334:Students / Q000706:statistics & numerical data*; D011795:Surveys and Questionnaires; D014481:United States / Q000453:epidemiology