Tehran University of Medical Sciences Journal of Sleep Sciences 2476-2938 1 2 2016 07 27 51 58 EN Amir Houshang Mehrparvar Department of Occupational Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran Masoud Rahimian Department of Internal Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran Mahmoud Vakili Department of Social Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran Behrouz Moghbelolhossain Department of Occupational Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran Mohammad Javad Zare Sakhvidi Department of Industrial Hygiene, Shahid Sadoughi University of Medical Sciences, Yazd, Iran Mojahedeh Salmani Nodoushan Department of Occupational Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran Leila Jahani Department of Occupational Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran 2016 06 18 2016 06 18 Background and Objective: Obstructive sleep apnea (OSA) syndrome is a kind of sleep-related disorder with complex features and may lead to daytime sleepiness. This study aimed to find the differences between smokers and non-smokers regarding the parameters of polysomnography. Materials and Methods: This was a cross-sectional study conducted on consecutive patients referred to a sleep lab to perform polysomnography for sleep-related breathing disorders in Shahid Sadoughi University of Medical Sciences in 2014. For all participants, overnight polysomnography study was performed for at least 6 hours. Then, parameters of polysomnography were compared between smokers and non-smokers. Data were analyzed by SPSS using chi-square test, Student’s t-test, Mann–Whitney U-test, and logistic regression analysis. Results: In total, 228 subjects were enrolled in the study (155 non-smokers). Obstructive apnea number and index,total apnea number, apnea-hypopnea index (AHI), baseline and average saturation by pulse oximeter, snore, and snore arousal were significantly different between smokers and non-smokers (P < 0.050). Severe OSA was the most commonly observed among smokers, but AHI was not significantly correlated with pack-years of smoking. Conclusion: The results of this study showed that smokers suffer from severe OSA more frequent than nonsmokers; obstructive apnea is more common among smokers with higher AHI. https://jss.tums.ac.ir/index.php/jss/article/view/29 https://jss.tums.ac.ir/index.php/jss/article/download/29/25