title: Determinants of vitamin d status among Jordanian employees: Focus on the night shift effect.
abstract: OBJECTIVE
  To assess the association between night work and 25-hydroxy vitamin D (25OHD) levels, and to evaluate effect of potential risk factors on 25OHD levels.
  
  
  METHODS
  A total of 140 adult Jordanian employees were recruited. Demographic, lifestyle and working patterns data were documented through a well-structured questionnaire. Vitamin D status was assessed by measuring circulating concentrations of 25OHD.
  
  
  RESULTS
  Mean 25OHD level was 23.8 ng/ml. No significant difference was found in 25OHD levels between the summer and winter (p = 0.46), or between males and females (p = 0.35). The female night workers had significantly lower serum 25OHD levels compared to the female day workers (p = 0.01). No significant difference in serum 25OHD levels was found between the night and day male workers (p = 0.25). The number of night shifts/month was negatively correlated with 25OHD levels in both the males and females (p = 0.01 and p = 0.007, respectively). Age was positively correlated with 25OHD levels in both the males and females (p = 0.02 and p = 0.001, respectively). Body mass index was negatively associated with 25OHD levels in the whole sample (p = 0.03), but not within each gender group (p = 0.21 for the males and p = 0.09 for the females). Smoking had no significant association with 25OHD levels (p = 0.99 for the males and p = 0.22 for the females).
  
  
  CONCLUSIONS
  Our results suggest that women working night shifts are at higher risk of 25OHD deficiency, and, consequently, of other health problems linked to 25OHD deficiency. Int J Occup Med Environ Health 2016;29(5):859-870.
authors: The University of Jordan, Amman, Jordan (Faculty of Pharmacy, Department of Biopharmaceutics and Clinical Pharmacy). e.alefishat@ju.edu.jo.
authors: Eman
authors: E
authors: Alefishat
authors: Applied Science Private University, Amman, Jordan (Faculty of Pharmacy, Department of Clinical Pharmacy and Therapeutics). ranaabufarha@ju.edu.jo.
authors: Rana
authors: R
authors: Abu Farha
mesh_terms: D000328:Adult; D015992:Body Mass Index; D002940:Circadian Rhythm / Q000502:physiology*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007597:Jordan; D008019:Life Style; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D012621:Seasons; D012907:Smoking; D011795:Surveys and Questionnaires; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D014940:Work Schedule Tolerance / Q000502:physiology*
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D
keywords: Jordan; night shift work; risk assessment; vitamin D; vitamin D deficiency; working conditions