title: Relationship between shift work and peripheral total and differential leukocyte counts in Chinese steel workers.
abstract: OBJECTIVE
  Even though shift work has been suspected to be a risk factor for cardiovascular disease, little research has been done to determine the logical underlying inflammation mechanisms. This study investigated the association between shift work and circulating total and differential leukocyte counts among Chinese steel workers.
  
  
  METHODS
  The subjects were 1,654 line workers in a steel plant, who responded to a cross-sectional survey with a questionnaire on basic attributes, life style, and sleep. All workers in the plant received a periodic health checkup. Total and differential leukocytes counts were also examined in the checkup.
  
  
  RESULTS
  Shift workers had higher rates of alcohol use, smoking, poor sleep, poor physical exercise, and obesity than daytime workers. In further analysis, we found that the peripheral total WBC, monocyte, neutrophil, and lymphocyte counts were also greater in shift workers than in daytime workers. When subjects were divided into quartiles according to total WBC, neutrophil, monocyte, and lymphocyte counts, increased leukocyte count was associated with shift work. Using stepwise linear regression analysis, smoking, obesity, and shift work were independently associated with total WBC, monocyte, neutrophil, and lymphocyte counts.
  
  
  CONCLUSIONS
  This study indicates that peripheral total and differential leukocyte counts are significantly higher in shift workers, which suggests that shift work may be a risk factor of cardiovascular disease. Applicable intervention strategies are needed for prevention of cardiovascular disease for shift workers.
authors.affiliation: Division of Cardiac Surgery, Department of Surgery, E-Da Hospital, I-Shou University.
authors.forename: Li-Fen
authors.initials: LF
authors.lastname: Lu
authors.forename: Chao-Ping
authors.initials: CP
authors.lastname: Wang
authors.forename: I-Ting
authors.initials: IT
authors.lastname: Tsai
authors.forename: Wei-Chin
authors.initials: WC
authors.lastname: Hung
authors.forename: Teng-Hung
authors.initials: TH
authors.lastname: Yu
authors.forename: Cheng-Ching
authors.initials: CC
authors.lastname: Wu
authors.forename: Chia-Chang
authors.initials: CC
authors.lastname: Hsu
authors.forename: Yung-Chuan
authors.initials: YC
authors.lastname: Lu
authors.forename: Fu-Mei
authors.initials: FM
authors.lastname: Chung
authors.forename: Mei-Chu Yen
authors.initials: MC
authors.lastname: Jean
mesh_terms: D000328:Adult; D000428:Alcohol Drinking / Q000453:epidemiology; D002681:China; D002940:Circadian Rhythm / Q000502:physiology*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007958:Leukocyte Count; D007962:Leukocytes; D008019:Life Style; D016014:Linear Models; D008297:Male; D008669:Metallurgy; D008875:Middle Aged; D009504:Neutrophils; D009784:Occupational Diseases / Q000097:blood* / Q000503:physiopathology; D012307:Risk Factors; D012890:Sleep / Q000502:physiology; D007319:Sleep Initiation and Maintenance Disorders / Q000453:epidemiology / Q000209:etiology; D012907:Smoking / Q000453:epidemiology; D013232:Steel; D014940:Work Schedule Tolerance / Q000502:physiology*
chemical_list: D013232:Steel