title: Rotating night shift work and polymorphism of genes important for the regulation of circadian rhythm.
abstract: OBJECTIVE
  People living in industrialized societies have developed specific working schedules during the day and at night, including permanent night shifts and rotating night shifts. The aim of this study was to examine the association between circadian polymorphisms and rotating night shift work.
  
  
  METHODS
  This cross-sectional study comprised 709 nurses and midwives (348 current rotating and 361 current day workers). Genetic polymorphism of selected clock genes BMAL1 (rs2279287), CLOCK (rs1801260), PER1 (rs2735611), PER2 (rs2304672), PER3 (rs10462020), CRY1 (rs8192440), CRY2 (rs10838527, rs10838527) was determined using real-time polymerase chain reaction (PCR) assays.
  
  
  RESULTS
  There were no differences in BMAL1, CLOCK, CRY2, PER1, PER2, and PER3 genotypes among nurses and midwives working rotating night and day shifts. The frequency of women with rare CRY1 TT genotype was higher in the group of rotating night shift than day workers (17.0% versus 13.9%, P=0.06). Moreover, CRY1 TT genotype was associated with the total rotating shift-work duration, compared to women rarely working night shifts.
  
  
  CONCLUSIONS
  These results suggest that CRY1 (rs8192440) polymorphism may influence the adaptation to the rotating night shift work among nurses and midwives.
authors.affiliation: Department of Toxicology and Carcinogenesis, Nofer Institute of Occupational Medicine, 8 Teresy Street, Lodz, Poland. edyta@imp.lodz.pl
authors.forename: Edyta
authors.initials: E
authors.lastname: Reszka
authors.forename: Beata
authors.initials: B
authors.lastname: Peplonska
authors.forename: Edyta
authors.initials: E
authors.lastname: Wieczorek
authors.forename: Wojciech
authors.initials: W
authors.lastname: Sobala
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Bukowska
authors.forename: Jolanta
authors.initials: J
authors.lastname: Gromadzinska
authors.forename: Jenny-Anne
authors.initials: JA
authors.lastname: Lie
authors.forename: Helge
authors.initials: H
authors.lastname: Kjuus
authors.forename: Wojciech
authors.initials: W
authors.lastname: Wasowicz
mesh_terms: D000222:Adaptation, Physiological; D000328:Adult; D002940:Circadian Rhythm / Q000235:genetics*; D056925:Circadian Rhythm Signaling Peptides and Proteins / Q000235:genetics*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008875:Middle Aged; D009726:Nurses / Q000706:statistics & numerical data; D011110:Polymorphism, Genetic; D014940:Work Schedule Tolerance / Q000502:physiology*
chemical_list: D056925:Circadian Rhythm Signaling Peptides and Proteins