Sleep Duration and Smoking in the Bandare-Kong Cohort Study: A Cross-sectional Population-Based Study (Findings From the PERSIAN Cohort Study)

Background: Smoking has many deleterious consequences on health, one of which can be sleep-related issues. The aim of this study was to investigate the relationship between smoking and sleep duration in southern Iran. Materials and Methods: This descriptive-analytical cross-sectional study is a part of the Bandare-Kong Non-Communicable Disease cohort study, conducted on 3,736 participants aged 35–70. The data related to sleep and smoking were extracted through a standard questionnaire based on self-reported information and then analyzed by SPSS 26 using the multivariable linear regression model (P<0.05). Results: The mean sleep duration was longer in smokers than in non-smokers (6.04±1.54 vs. 5.92±1.43, P=0.031). Of 893 smokers, 220 slept for 7–8 hours, 618 had a short sleep (<7 hours), and 55 had a long sleep (>8 hours). Of 2843 non-smokers, 639, 2067, and 137 slept for 7–8 hours, had a short sleep (<7 hours), and had a long sleep (>8 hours), respectively. Based on the regression model, among males, the mean sleep duration was 0.4 hours longer in smokers than in non-smokers (B=0.40, 95% confidence interval [CI]: 0.23–0.56, P<0.001). Among females, the mean sleep duration was 1.11 hours longer in smokers than in non-smokers (B=1.11, 95% CI: 0.82–1.40, P<0.001). Conclusion: The findings provide evidence that smoking is associated with longer sleep duration for both genders. Thus, it is recommended that future researchers conduct longitudinal studies to assess the association between sleep quality components, including sleep duration and smoking.