title: UV and dietary predictors of serum 25-hydroxyvitamin D concentrations among young shift-working nurses and implications for bone density and skin cancer.
abstract: OBJECTIVE
  In 2011, the U.S. Institute of Medicine updated the definition of vitamin D inadequacy to serum 25-hydroxyvitamin D (25(OH)D) concentration of 30-<50 nmol/l and of deficiency to serum 25(OH)D < 30 nmol/l. We describe the prevalence of these conditions according to these definitions, seasonal variation in 25(OH)D and predictors of serum 25(OH)D concentrations among working, white women.
  
  
  METHODS
  Participants recorded lifestyle factors and dietary intake and provided fasting blood samples for measurement of serum 25(OH)D in both summer and winter. Predictors of serum 25(OH)D variation were analysed using linear regression and generalized linear mixed models.
  
  
  METHODS
  Kingston General Hospital in Kingston, Ontario, Canada, from April 2008 to July 2009.
  
  
  METHODS
  Female premenopausal nurses (n 83) working full-time rotating shifts.
  
  
  RESULTS
  Deficient or inadequate vitamin D status was observed in 9% of participants following summer/autumn and in 13% following winter/spring. Predictors of serum 25(OH)D concentration were vitamin D supplement use, tanning bed use and season. Tanning bed use increased serum 25(OH)D by 23.24 nmol/l (95% CI 8.78, 37.69 nmol/l, P = 0.002) on average.
  
  
  CONCLUSIONS
  According to the 2011 Institute of Medicine bone health guidelines, over 10% of nurses had deficient or inadequate vitamin D status following winter. Higher serum concentrations were associated with use of tanning beds and vitamin D supplements. As health promotion campaigns and legal restrictions are successful in reducing tanning bed use among women, our data suggest that increased prevalence of vitamin D inadequacy and deficiency may be a consequence, and that low vitamin D status will need to be countered with supplementation.
authors.affiliation: 1 Department of Community Health and Epidemiology, Cancer Research Institute, Queen's University, Kingston, ON K7L 3N6, Canada.
authors.forename: Sarah C
authors.initials: SC
authors.lastname: Wallingford
authors.affiliation: 3 Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada.
authors.forename: Glenville
authors.initials: G
authors.lastname: Jones
authors.affiliation: 1 Department of Community Health and Epidemiology, Cancer Research Institute, Queen's University, Kingston, ON K7L 3N6, Canada.
authors.forename: Lindsay C
authors.initials: LC
authors.lastname: Kobayashi
authors.affiliation: 1 Department of Community Health and Epidemiology, Cancer Research Institute, Queen's University, Kingston, ON K7L 3N6, Canada.
authors.forename: Anne
authors.initials: A
authors.lastname: Grundy
authors.affiliation: 1 Department of Community Health and Epidemiology, Cancer Research Institute, Queen's University, Kingston, ON K7L 3N6, Canada.
authors.forename: Qun
authors.initials: Q
authors.lastname: Miao
authors.affiliation: 1 Department of Community Health and Epidemiology, Cancer Research Institute, Queen's University, Kingston, ON K7L 3N6, Canada.
authors.forename: Joan
authors.initials: J
authors.lastname: Tranmer
authors.affiliation: 1 Department of Community Health and Epidemiology, Cancer Research Institute, Queen's University, Kingston, ON K7L 3N6, Canada.
authors.forename: Kristan J
authors.initials: KJ
authors.lastname: Aronson
mesh_terms: D000328:Adult; D015992:Body Mass Index; D015519:Bone Density / Q000187:drug effects*; D002170:Canada / Q000453:epidemiology; D003430:Cross-Sectional Studies; D019587:Dietary Supplements; D005260:Female; D006801:Humans; D008019:Life Style; D008875:Middle Aged; D009726:Nurses; D009752:Nutritional Status; D017697:Premenopause / Q000097:blood; D015995:Prevalence; D012621:Seasons; D012878:Skin Neoplasms / Q000209:etiology / Q000517:prevention & control*; D013472:Sunlight; D014807:Vitamin D / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000097:blood; D014808:Vitamin D Deficiency / Q000150:complications / Q000453:epidemiology; D055815:Young Adult
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D