title: Anti-clockwise rotating shift work and health: would you prefer 3-shift or 4-shift operation?
abstract: BACKGROUND
  We explored the association between work schedules involving nightshifts and selected measures of health and whether these associations differed among those working in either 3- or 4-shift cycles.
  
  
  METHODS
  Employees at a German industrial company who worked on a fixed daytime schedule or on one involving nightshifts were invited to participate in this cross-sectional study. Work schedules involving a nightshift were organized into either 3 or 4 shifts rotated anti-clockwise on a weekly basis. Health characteristics included a range of clinical and physiological measures and self-reported data on stress and sleep quality. We assessed the independent association of work schedules involving any nightshift and these health characteristics in separate regression analyses, adjusting for age, gender, smoking, and alcohol consumption.
  
  
  RESULTS
  Nightshift work (N = 133) in general and 3-shift-work (N = 53) in particular was associated with decreased sleep quality (P < 0.001). Compared to those working daytime (N = 632), employees working on a 3-shift cycle had higher adjusted odds of meeting the definition of metabolic syndrome (OR = 2.56 [1.38, 4.75]). Employees working 4-shift cycles were somewhat less likely to have metabolic syndrome (OR = 1.22 [0.73, 2.05]) and had higher parasympathetic activity measured by heart rate variability (OR = 2.20 [1.04, 4.63]).
  
  
  CONCLUSIONS
  Our data suggest important relationships between shift schedule and a selected group of objective and subjective health measures. Additional research that further clarifies potential mechanisms underlying these relationships is needed.
authors: Mannheim Institute of Public Health, Social and Preventive Medicine, Mannheim Medical Faculty, Heidelberg University, Mannheim, Germany. daniel.mauss@allianz.de
authors: Daniel
authors: D
authors: Mauss
authors: David
authors: D
authors: Litaker
authors: Marc N
authors: MN
authors: Jarczok
authors: Jian
authors: J
authors: Li
authors: Jos A
authors: JA
authors: Bosch
authors: Joachim E
authors: JE
authors: Fischer
mesh_terms: D000328:Adult; D015992:Body Mass Index; D002097:C-Reactive Protein / Q000032:analysis; D005260:Female; D005858:Germany; D006442:Glycated Hemoglobin / Q000032:analysis; D006304:Health Status; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008074:Lipoproteins / Q000097:blood; D008297:Male; D024821:Metabolic Syndrome / Q000453:epidemiology; D016272:Occupational Health; D010561:Personnel Staffing and Scheduling / Q000458:organization & administration*; D012890:Sleep / Q000502:physiology; D020178:Sleep Disorders, Circadian Rhythm / Q000517:prevention & control; D013315:Stress, Psychological / Q000453:epidemiology; D013997:Time Factors; D055105:Waist Circumference
chemical_list: D002097:C-Reactive Protein; D006442:Glycated Hemoglobin; D008074:Lipoproteins