The association between cotinine-measured smoking intensity and sleep quality

Area of Science:

• Sleep Medicine
• Public Health
• Biomarkers

Background:

• Cigarette smoking is a known risk factor for various health issues, including potential sleep disturbances.
• Objective verification of smoking intensity is crucial for accurate health assessments.

Purpose of the Study:

• To quantitatively assess the association between smoking intensity, verified by urinary cotinine levels, and sleep quality.
• To investigate sleep quality in relation to different smoking intensities using the Pittsburgh Sleep Quality Index (PSQI).

Main Methods:

• A cross-sectional study involving 189,970 participants from the Kangbuk Samsung Health Study (2016-2018).
• Logistic regression analysis was used to evaluate the association between quartiles of urinary cotinine levels and poor sleep quality (global PSQI score >5).
• Adjustments were made for relevant covariates in the analysis.

Main Results:

• Elevated urinary cotinine levels were significantly associated with increased odds of poor sleep quality.
• The odds ratio for poor sleep quality was 1.23 overall, 1.19 for males, and 1.55 for females when comparing the highest cotinine quartile to non-smokers.
• Cotinine-verified smokers who self-reported as never smokers showed higher odds (OR: 1.26) of poor sleep quality compared to cotinine-verified never smokers.

Conclusions:

• Urinary cotinine levels indicating higher smoking intensity are associated with poor sleep quality in young and middle-aged South Korean adults.
• Objective cotinine measurement revealed higher odds of poor sleep quality in individuals misreporting their smoking status.
• Further prospective research is recommended to establish a definitive cause-effect relationship between smoking and sleep quality.