Day-to-Day Variability in Self-Reported Cigarettes Per Day

Area of Science:

• Addiction research
• Behavioral science
• Public health

Background:

• Nicotine addiction theory suggests minimal day-to-day variability in cigarettes per day (CPD).
• Social learning theory predicts significant day-to-day variability in CPD.
• Limited data exists on the extent of daily CPD fluctuations.

Purpose of the Study:

• To describe the day-to-day variability in CPD among daily smokers.
• To compare variability predictions from nicotine addiction and social learning theories.
• To identify factors influencing CPD variability.

Main Methods:

• Secondary analysis of two natural history studies involving daily smokers.
• Ecological Momentary Assessment (EMA) via palm-top computer for smokers not intending to quit.
• Interactive Voice Response (IVR) system via phone for smokers intending to quit within 3 months.
• Analysis focused on smokers averaging ≥10 CPD on days without cessation attempts.

Main Results:

• On average, smokers exhibited small day-to-day changes in CPD (mean changes of 2.2 and 2.9).
• A minority of smokers (7-11%) averaged ≥5 CPD change daily.
• A substantial proportion (8-31%) frequently varied CPD by ≥5 on at least 10 days.
• Smoking restrictions, dependence, stereotypy, and quitting interest did not predict variability.

Conclusions:

• Daily CPD variability is greater than previously suggested.
• A significant minority of smokers display considerable day-to-day fluctuations in CPD.
• The causes of this observed variability remain undetermined.