title: Nicotine levels, withdrawal symptoms, and smoking reduction success in real world use: A comparison of cigarette smokers and dual users of both cigarettes and E-cigarettes.
abstract: To evaluate how experienced dual users used cigarettes and e-cigarettes in real-world use and under different levels of cigarette availability.
  
  
  
  Dual users (cigarettes+e-cigarettes; n=74) and a smoke-only group (just cigarettes; n=74) engaged in a 26-day study with two ad lib use intervals, a week of 75% cigarette reduction and three days of 100% cigarette reduction. After a week of ad lib use of products, all participants were asked to reduce smoking by 75% (dual users were free to use their e-cigarettes as they wished), followed by another week of ad lib use. All participants were then asked to reduce smoking by 100% (cessation) for three days. Primary outcomes were biological samples (carbon monoxide, urinary nicotine and cotinine). Participants also provided real-time reports of product use, craving, and withdrawal symptoms using a smartphone app.
  
  
  
  Dual users did not smoke fewer cigarettes than smoke-only participants during ad lib periods, but quadrupled their use of e-cigarettes during smoking reduction periods. Dual users were significantly more likely to maintain 100% reduction (97.1% vs. 81.2%). Amongst women, dual use was associated with higher nicotine levels and withdrawal suppression.
  
  
  
  Among a group of experienced dual users, e-cigarettes helped maintain smoking reduction and reduced some withdrawal symptoms, although both withdrawal symptoms and nicotine levels varied as a function of gender.
authors.affiliation: Division of General Internal Medicine, Department of Medicine, University of Wisconsin School of Medicine and Public Health, Center for Tobacco Research and Intervention, 1930 Monroe St., Suite 200, Madison, WI 53711, United States. Electronic address: Dej@ctri.wisc.edu.
authors.forename: Douglas E
authors.initials: DE
authors.lastname: Jorenby
authors.affiliation: Division of General Internal Medicine, Department of Medicine, University of Wisconsin School of Medicine and Public Health, Center for Tobacco Research and Intervention, 1930 Monroe St., Suite 200, Madison, WI 53711, United States.
authors.forename: Stevens S
authors.initials: SS
authors.lastname: Smith
authors.affiliation: Division of General Internal Medicine, Department of Medicine, University of Wisconsin School of Medicine and Public Health, Center for Tobacco Research and Intervention, 1930 Monroe St., Suite 200, Madison, WI 53711, United States.
authors.forename: Michael C
authors.initials: MC
authors.lastname: Fiore
authors.affiliation: Division of General Internal Medicine, Department of Medicine, University of Wisconsin School of Medicine and Public Health, Center for Tobacco Research and Intervention, 1930 Monroe St., Suite 200, Madison, WI 53711, United States.
authors.forename: Timothy B
authors.initials: TB
authors.lastname: Baker
mesh_terms: D000328:Adult; D066249:Craving; D066300:Electronic Nicotine Delivery Systems; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009538:Nicotine / Q000097:blood* / Q000627:therapeutic use; D012907:Smoking / Q000097:blood* / Q000523:psychology; D016540:Smoking Cessation; D013375:Substance Withdrawal Syndrome / Q000097:blood* / Q000188:drug therapy / Q000523:psychology; D062789:Tobacco Products; D014029:Tobacco Use Disorder / Q000097:blood* / Q000523:psychology; D055815:Young Adult
chemical_list: D009538:Nicotine
keywords: Cigarette smoking; Dual use; Gender differences; Nicotine; Nicotine dependence; e-cigarettes