title: Occupational Exposure and Health Impairments of Formaldehyde on Employees of a Wood Industry.
abstract: BACKGROUND
  Occupational exposure to formaldehyde may decrease white blood cell counts and change blood concentration. In this study, the influences of occupational exposure to formaldehyde on the number of white blood cells and blood concentrations were studied.
  
  
  METHODS
  This case-control study was conducted in June of 2012 at North Wood Factory, Golestan Province, Iran. The US-NIOSH method No. 2541 was used to determine the occupational exposure of 30 workers of the production line (case group) and 30 administrative staffs (control group) to formalde-hyde. The number of white blood cells and blood concentration were determined using the normal blood count method and related indices. Demographic features as well as the symptoms of being exposed to formaldehyde were collected using a standard questionnaire.
  
  
  RESULTS
  The occupational exposure of case group ranged from 0.50 ppm to 1.52 ppm. The prevalence of all studied symptoms from formaldehyde exposure in workers (2<median<5; range 1 to 5) was signifi-cantly different (P<0.001) towards the administrative staffs (median 1; range 1 to 4). The number of white blood cells in production line workers was not significantly different from those in administra-tive staff. The average blood concentration in the case group was significantly different from the con-trol group (mean difference= 0.9 [95% CI: 0.40-1.39];P=0.007).
  
  
  CONCLUSIONS
  Occupational exposure to formaldehyde changed the blood concentration of the studied workers but did not change the number of their white blood cells.
authors.affiliation: Occupational Health Engineering Department, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Mohammad Javad
authors.initials: MJ
authors.lastname: Jafari
authors.affiliation: Department of Environment and Energy, Science and Research Branch, Islamic Azad University, Tehran, Iran.
authors.forename: Abolfazl
authors.initials: A
authors.lastname: Rahimi
authors.affiliation: Occupational Health Engineering Department, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Leila
authors.initials: L
authors.lastname: Omidi
authors.affiliation: Department of Statistics, Science and Research Branch, Islamic Azad University, Tehran, Iran.
authors.forename: Mohammad Hassan
authors.initials: MH
authors.lastname: Behzadi
authors.affiliation: Doctorate of Laboratory Sciences, Golestan University of Medical Sciences, Gonbad, Iran.
authors.forename: Mohammad Hassan
authors.initials: MH
authors.lastname: Rajabi
keywords: Blood Cell; Formaldehyde; Occupational Exposure; Symptoms; Wood Industry