title: Determinants of vitamin D levels in men receiving androgen deprivation therapy for prostate cancer.
abstract: OBJECTIVE
  Studies found an association between decreased 25-OH vitamin D blood level and prostate cancer progression. Vitamin D supplementation is controversial and dosage recommendations inconsistent. This study identified factors associated with 25-OH vitamin D levels and whether vitamin D supplementation with 800 IU/day raised vitamin D levels in prostate cancer patients receiving androgen deprivation therapy (ADT).
  
  
  METHODS
  We recruited 108 men treated with ADT for ≥9 months from eight cancer and urology practices. Sections of the NHANES 2005-2006 questionnaire and Canadian Fitness Survey were completed identifying age, ethnicity, length of ADT use, calcium supplementation ≥1000 IU mg/day, body mass index, exercise, alcohol and tobacco use, and vitamin D supplementation ≥800 IU/daily. Blood was collected for 25-OH vitamin D analysis.
  
  
  CONCLUSIONS
  The majority of men (66%) had blood levels of 25-OH vitamin D <32 ng/mL. Regression analysis showed vitamin D supplementation (β = 6.556, CI 1.463, 11.650; p = .012) and African American ethnicity (β = -7.816, CI -12.996, -2.635; p = .003) is associated with 25-OH vitamin D level after controlling age and tobacco use.
  
  
  CONCLUSIONS
  Findings support current recommendations for supplementation with ≥800 IU vitamin D/day for men receiving ADT. Nurse practitioners caring for prostate cancer patients receiving ADT should include vitamin D monitoring and supplementation.
authors.affiliation: LIED Outpatient Clinic, University Medical Center of Southern Nevada, Las Vegas, Nevada.
authors.forename: Lori J
authors.initials: LJ
authors.lastname: Mennen-Winchell
authors.forename: Victor
authors.initials: V
authors.lastname: Grigoriev
authors.forename: Patricia
authors.initials: P
authors.lastname: Alpert
authors.forename: Hildemar
authors.initials: H
authors.lastname: Dos Santos
authors.forename: Serena
authors.initials: S
authors.lastname: Tonstad
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000726:Androgen Antagonists / Q000627:therapeutic use*; D002170:Canada; D019587:Dietary Supplements; D006801:Humans; D008297:Male; D008875:Middle Aged; D011471:Prostatic Neoplasms / Q000150:complications / Q000188:drug therapy*; D014807:Vitamin D / Q000032:analysis / Q000097:blood* / Q000378:metabolism
chemical_list: D000726:Androgen Antagonists; D014807:Vitamin D
keywords: 25-Hydroxyvitamin D; androgen ablation therapy; cancer; male; prevention