title: The double-edged sword of vitamin D in Ireland: the need for public health awareness about too much as well as too little.
abstract: BACKGROUND
  The Institute of Medicine (IOM) 2011 on dietary references intakes for calcium and vitamin D specified that a 25-hydroxyvitamin D (25OHD) level below 30 nmol/L indicated risk of deficiency and that a level above 125 nmol/L indicated risk of harm.
  
  
  METHODS
  We noted a high prevalence of hypovitaminosis D (23.9 %) and a substantive prevalence of hypervitaminosis D (4.8 %) in a retrospective audit of clinical samples (n = 10,181) obtained over 10 months in 2013.
  
  
  CONCLUSIONS
  Hypovitaminosis D should be corrected by low dose supplementation (5 µg or 200 IU daily) with some at-risk groups needing higher doses (10 µg or 400 IU daily) based on 25OHD levels. Whereas, those taking high-dose vitamin D supplements based on mistaken beliefs about recently authorised claims of benefit for muscle function and misleading unauthorised claims need to be alerted to the potential harms of excessive supplementation.
authors.affiliation: Metabolism Laboratory, St. Vincent's University Hospital, Dublin 4, Ireland, m.kilbane@svuh.ie.
authors.forename: M T
authors.initials: MT
authors.lastname: Kilbane
authors.forename: M
authors.initials: M
authors.lastname: O'Keane
authors.forename: M
authors.initials: M
authors.lastname: Morrin
authors.forename: M
authors.initials: M
authors.lastname: Flynn
authors.forename: M J
authors.initials: MJ
authors.lastname: McKenna
mesh_terms: D000328:Adult; D000368:Aged; D002136:Calcium, Dietary; D019587:Dietary Supplements / Q000009:adverse effects; D005260:Female; D006801:Humans; D007494:Ireland / Q000453:epidemiology; D064747:Lansoprazole; D008297:Male; D008875:Middle Aged; D009748:Nutrition Disorders / Q000453:epidemiology*; D011634:Public Health; D012189:Retrospective Studies; D014807:Vitamin D / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000097:blood; D014808:Vitamin D Deficiency / Q000453:epidemiology; D055815:Young Adult
chemical_list: D002136:Calcium, Dietary; D064747:Lansoprazole; D014807:Vitamin D; C104450:25-hydroxyvitamin D