Time to first cigarette after waking predicts cotinine levels

Area of Science:

• Biomedical and Health Sciences
• Addiction Research
• Nicotine and Tobacco Research

Background:

• Significant variability exists in cotinine levels per cigarette smoked.
• Nicotine dependence assessment often focuses on smoking frequency, potentially overlooking other behavioral markers.
• Understanding factors influencing nicotine uptake is crucial for effective smoking cessation interventions.

Purpose of the Study:

• To investigate the association between behavioral measures of nicotine dependence, specifically time to first cigarette after waking, and plasma/urinary cotinine levels.
• To determine if time to first cigarette is a significant predictor of nicotine exposure, independent of smoking frequency.
• To identify distinct nicotine dependence phenotypes based on smoking behavior.

Main Methods:

• A community-based study involving 252 daily cigarette smokers (black and white).
• Measurement of plasma and urinary cotinine levels.
• Assessment of smoking frequency and time to first cigarette after waking to define dependence phenotypes.

Main Results:

• Plasma cotinine levels showed a 74-fold difference among smokers smoking one pack per day.
• Two nicotine dependence phenotypes were identified: 'low' (smoked >30 minutes after waking) and 'high' (smoked ≤30 minutes after waking).
• Time to first cigarette was a strong predictor of cotinine levels, with earlier times associated with significantly higher levels, even after adjusting for cigarette frequency. A plateau effect was observed in heavy smokers.

Conclusions:

• Time to first cigarette after waking is a robust predictor of nicotine uptake.
• This behavioral measure should be incorporated into the assessment of nicotine dependence and the design of smoking interventions.
• Findings highlight the complexity of nicotine metabolism and dependence beyond simple cigarette consumption.