mirsaeed attarchi department of occupational medicine, school of medicine, tehran university of medical sciences, tehran, ir iran faezeh dehghan department of occupational medicine, school of medicine, aja university of medical sciences, tehran, ir iran taraneh yazdanparast research center of chronic respiratory disease, national research institute of tuberculosis and lung diseases, shahid beheshti university of medical sciences, tehran, ir iran saber mohammadi department of occupational medicine, school of medicine, tehran university of medical sciences, tehran, ir iran mahdie golchin department of occupational medicine, school of medicine, tehran university of medical sciences, tehran, ir iran zargham sadeghi research center of work and environment, petroleum industry health organization (piho), tehran, ir iran