Tobacco smoke exposure and sleep: Estimating the association of urinary cotinine with sleep quality

Abstract

Introduction: A majority of studies on tobacco smoke exposure and sleep quality have relied on self-reported smoking, resulting in potential exposure misclassification and biases related to self-report. The objective of this study was to investigate associations between urinary cotinine, a biological marker of tobacco smoke exposure, and sleep quality measures, including sleep duration, sleep continuity or efficiency, sleep satisfaction and alertness during normal waking hours. Methods: Using data on a national sample of 10 806 adults (aged 18–79 years) from the Canadian Health Measures Survey (2007–2013), we performed binary logistic regression analyses to estimate associations between urinary cotinine concentrations and sleep quality measures, while controlling for potential confounders. Additionally, we performed ordinal logistic regression to assess the association between urinary cotinine concentrations and increased number of sleep problems. Results: Overall, 28.7% of adult Canadian survey respondents had urinary cotinine concentrations above the limit of detection (LOD), and the prevalence of each sleep problem ranged from 5.5% to 35.6%. Elevated urinary cotinine concentrations (quartile 4 vs. < LOD) were associated with significantly higher odds of short or long sleep duration (OR = 1.41; 95% CI: 1.02–1.95; p-trend = .021), trouble falling or staying asleep (OR = 1.71; 95% CI: 1.28–2.27; p-trend = .003), sleep dissatisfaction (OR = 1.87; 95% CI: 1.21–2.89; p-trend = .011), and increased number of sleep problems (OR = 1.64; 95% CI: 1.19–2.26; p-trend = .001). Stronger associations were observed among females compared to males. Conclusion: Using a biological marker of tobacco smoke exposure, our study contributes to the body of literature of toxic environmental exposures on sleep quality by supporting an association between tobacco smoke exposure and poorer sleep quality. To address the limitations of a cross-sectional study design and to better assess the tempo-rality of tobacco smoke exposure and sleep quality, longitudinal studies are recommended.