International Journal of Preventive Medicine (Int J Prev Med)2008-78021342022072726722672ENIndustrial Diseases Research Center, Shahid Sadoughi University of Medical Sciences, YazdDepartment of Occupational Medicine, Shahid Sadoughi University of Medical Sciences, YazdIndustrial Diseases Research Center, Shahid Sadoughi University of Medical Sciences, YazdDepartment of Occupational Medicine, Shahid Sadoughi University of Medical Sciences, YazdDepartment of Community Medicine, Monitoring of Health Research Center, Shahid Sadoughi University of Medical Sciences, YazdDepartment of Occupational Medicine, Shahid Sadoughi University of Medical Sciences, YazdYazd Cardiovascular Research Center, Shahid Sadoughi University of Medical Sciences, Yazd20220725<strong>Context</strong>: Fractional exhaled nitric oxide can be used as a biomarker of some respiratory diseases. Aims: This study was conducted to compare exhaled nitric oxide in cigarette and water‑pipe smokers with nonsmokers. <strong>Methods</strong>: This cross‑sectional study was conducted on 549 adult subjects as a sub‑study of Shahedieh cohort in Yazd. Participants were divided into 5 groups according to their smoking habits: non‑smokers (n = 202), cigarette smokers (n = 121), water‑pipe smokers (n = 129), cigarette ex‑smokers (n = 58), water‑pipe and cigarette smokers (n = 39). The smokers were also categorized into heavy and light smokers. Fractional exhaled nitric oxide was compared between the groups. <strong>Statistical Analysis Used</strong>: The data were analyzed by SPSS (ver. 20) using Kolmogorov‑Smirnov, Kruskal‑Wallis, and Mann‑Whitney U tests. <strong>Results</strong>: Fractional exhaled NO was lower in all smokers than nonsmokers, but cigarette smokers showed the least level of NO than other groups. Fractional exhaled NO was not significantly lower in water‑pipe smokers than nonsmokers. <strong>Conclusions</strong>: Cigarette smoking significantly affect fractional exhaled NO, but water‑pipe smoking did not significantly affect exhaled NO level.http://ijpm.mui.ac.ir/index.php/ijpm/article/view/2672http://ijpm.mui.ac.ir/index.php/ijpm/article/download/2672/717718513