en Occupational Medicine Occupational Medicine Original Research Original Research <span style="font-size:13pt"><span style="text-justify:kashida"><span style="text-kashida:0%"><span style="text-autospace:none"><span style="font-family:&quot;Times New Roman&quot;,serif"><span style="font-style:italic"><b><span style="font-size:9.0pt"><span style="font-style:normal">Background: </span></span></b><span style="font-size:9.0pt"><span style="font-style:normal">Many people are exposed to cigarette smoke actively or passively. We aimed to determine the effect of active and passive smoking on hearing thresholds and hearing loss noise-exposed workers. </span></span></span></span></span></span></span></span><br> <span style="font-size:13pt"><span style="text-justify:kashida"><span style="text-kashida:0%"><span style="text-autospace:none"><span style="font-family:&quot;Times New Roman&quot;,serif"><span style="font-style:italic"><b><span style="font-size:9.0pt"><span style="font-style:normal">Methods: </span></span></b><span style="font-size:9.0pt"><span style="font-style:normal">This cross-sectional study was conducted on 929 metal workers. We divided the workers into 3 groups according to smoking status&mdash;current smokers, nonsmokers, and passive smokers. Audiometric testing was recorded for both ears. Hearing loss was defined by 3 models. The SPSS software Version 24 was used to analyze the collected data. We used an independent t test, chi-square, Fisher exact, and analysis of variance tests and logistic regression, and the significance level was set at P ˂0.05 to interpret the relationships between variables.</span></span></span></span></span></span></span></span><br> <span style="font-size:13pt"><span style="text-justify:kashida"><span style="text-kashida:0%"><span style="text-autospace:none"><span style="font-family:&quot;Times New Roman&quot;,serif"><span style="font-style:italic"><b><span style="font-size:9.0pt"><span style="font-style:normal">Results:</span></span></b><span style="font-size:9.0pt"><span style="font-style:normal"> The hearing threshold levels at 4000 Hz, high frequencies, and low frequencies were significantly higher in smokers than nonsmokers (</span></span><span style="font-size:9.0pt">P </span><span style="font-size:9.0pt"><span style="font-style:normal">< 0.05). Also, and hearing loss at the 4000 Hz (</span></span><span style="font-size:9.0pt">P</span><span style="font-size:9.0pt"><span style="font-style:normal"> = 0.002; odds ratio [OR] = 1.96; 95% CI = 1.27-3.03) and high frequencies (</span></span><span style="font-size:9.0pt">P</span><span style="font-size:9.0pt"><span style="font-style:normal"> = 0.001; OR = 2.15; 95% CI = 1.36-3.4) had a significant correlation with smoking. Hearing loss was significantly correlated with passive smoking at 4000 Hz (</span></span><span style="font-size:9.0pt">P </span><span style="font-size:9.0pt"><span style="font-style:normal">< 0.001; OR = 5.87; 95% CI = 3.29-10.47), high frequencies (</span></span><span style="font-size:9.0pt">P </span><span style="font-size:9.0pt"><span style="font-style:normal">< 0.001; OR = 7.16; 95% CI = 3.97-12.89) and low frequencies (</span></span><span style="font-size:9.0pt">P</span><span style="font-size:9.0pt"><span style="font-style:normal"> = 0.021; OR = 4.16; 95% CI = 1.12-15.43). </span></span></span></span></span></span></span></span><br> <span style="font-size:13pt"><span style="text-justify:kashida"><span style="text-kashida:0%"><span style="text-autospace:none"><span style="font-family:&quot;Times New Roman&quot;,serif"><span style="font-style:italic"><b><span style="font-size:9.0pt"><span style="font-style:normal">Conclusion:</span></span></b><span style="font-size:9.0pt"><span style="font-style:normal"> The findings show that active and passive smokers who work in noisy environments are at higher risk for noise-induced hearing loss. Therefore, smoking cessation in smoker workers and reduction of environmental exposure to cigarette smoke is necessary to reduce the exacerbation of hearing loss. Moreover, more attention should be paid to passive smokers and they should be given priority in the same programs.</span></span></span></span></span></span></span></span> Passive smoker, Noise, Hearing loss 596 601 http://mjiri.iums.ac.ir/browse.php?a_code=A-10-282-4&slc_lang=en&sid=1 Saber Mohammadi mohammadi.s@iums.ac.ir 200319475328460078338 200319475328460078338 No Occupational Medicine Research Center, Department of Occupational Medicine, School of Medicine, Iran University of Medical Sciences, Tehran, Iran Marjan Amini omrc@iums.ac.ir 200319475328460078339 200319475328460078339 No Occupational Medicine Research Center, Department of Occupational Medicine, School of Medicine, Iran University of Medical Sciences, Tehran, Iran Fatemeh Shidfar iranomrc@gmail.com 200319475328460078340 200319475328460078340 No Occupational Medicine Research Center, Department of Occupational Medicine, School of Medicine, Iran University of Medical Sciences, Tehran, Iran Elahehe Kabir-Mokamelkhah Kabir.e@iums.ac.ir 200319475328460078341 200319475328460078341 Yes Occupational Medicine Research Center, Department of Occupational Medicine, School of Medicine, Iran University of Medical Sciences, Tehran, Iran