Cigarette Smoking Habit and Subjective Quality of Sleep

Background: Cigarette smoking habit is a physical addiction to nicotine that has long been regarded as one of the most important risk factors of several diseases, especially heart and lung diseases, and particularly lung cancers. Objectives: This study was conducted to assess the effect of cigarette smoking on subjective sleep quality according to Pittsburgh Sleep Quality Index (PSQI) and its components. Patients and Methods: This is a cross-sectional study conducted on 2923 individuals aged between 18 and 98 years in Tehran province, Iran, to evaluate the effect of cigarette smoking on sleep quality. Night-shift workers were not included in the study. Participants were divided into two groups according to the current or noncurrent cigarette smoking habit. Sleep quality was compared between groups using 7 components of Pittsburgh Sleep Quality Index (PSQI) and its global score. Results: Data of 2923 individuals comprised of 1638 (56%) females and 1285 (44%) males with a mean age of 43.68 ± 17.74 years (aged 18-98 years) were analyzed. Out of 2923 participants, 308 cases (10.5%) were current cigarette smokers and 2615 (89.5%) were not current smokers. Three out of seven PSQI components comprising sleep quality, duration, and sedative medication use, in addition to global PSQI score were significantly poorer in the current smokers compared to nonsmokers (P = 0.013, 0.036, 0.001, and 0.010, respectively). Among current smokers, PQSI increased significantly with the number of cigarettes smoked per day (Pearson’s correlation coefficient r = 0.122, P = 0.036). Conclusions: PQSI global score reflecting sleep quality was poorer in the individuals with a history of one-month cigarette smoking. It means that even one month of cigarette smoking could significantly decrease the quality of sleep and still could be worsen with increasing the number of cigarettes smoked per day.