In a trial designed to determine if nicotine content affects study attrition, participant dropout rate was greater for cigarettes with lower nicotine content and less in smokers reporting more favorable subjective ratings of the cigarettes. A total of 246 non-treatment-seeking daily smokers [mean age = 39.52, cigarettes per day (CPD)=20.95, 68.3% white] were recruited. After a 5-day baseline period, participants were randomized to smoke for 3 10-day periods: their preferred brand (control group) or reduced nicotine content (RNC) cigarettes with 3 nicotine levels in a within-subject stepdown fashion (1 group: high–moderate–low) or non-stepdown fashion (5 groups: high–low–moderate, low–moderate–high, low–high–moderate, moderate–low–high, and moderate–high–low). Researchers found:

• Overall attrition was 31.3% (n=77): 24.1% of the control and 25.0% of the stepdown RNC cigarette groups dropped out vs 44.6% of non-stepdown groups.
• Compared with controls, attrition odds were 4.5 and 4.7 times greater among smokers transitioning from preferred and the highest RNC cigarettes to the lowest RNC cigarettes, respectively.