title: Vitamin D deficiency as adverse drug reaction? A cross-sectional study in Dutch geriatric outpatients.
abstract: OBJECTIVE
  Adverse drug reactions as well as vitamin D deficiency are issues of public health concern in older people. However, relatively little is known about the impact of drug use on vitamin D status. Our primary aim is to explore associations between drug use and vitamin D status in older people. Furthermore, prevalences of drug use and vitamin D deficiency are estimated.
  
  
  METHODS
  In a population of 873 community-dwelling Dutch geriatric outpatients, we explored the cross-sectional relationships of polypharmacy (≥5 medications concomitantly used), severe polypharmacy (≥10 medications), and use of twenty-one specific drug groups, with serum 25-hydroxyvitamin D (25(OH)D) by analysis of covariance.
  
  
  RESULTS
  Overall prevalence of polypharmacy was 65 %, of severe polypharmacy 22 %. Depending on the cut-off value, prevalence of vitamin D deficiency was 49 % (<50 nmol/l) or 77 % (<75 nmol/l). Of the patients using a vitamin D supplement, 17 % (<50 nmol/l) or 49 % (<75 nmol/l) were still deficient. In non-users of supplemental vitamin D, after adjustment for age and gender, negative associations were found for severe polypharmacy, metformin, sulphonamides and urea derivatives (SUDs), vitamin K antagonists, cardiac glycosides, loop diuretics, potassium-sparing diuretics, ACE inhibitors, and serotonin reuptake inhibitors; for non-selective monoamine reuptake inhibitors (NSMRIs) the association was positive. The most extreme impacts of drug use on adjusted mean 25(OH)D were -19 nmol/l for SUDs and +18 nmol/l for NSMRIs.
  
  
  CONCLUSIONS
  Drug use should be considered a risk factor for vitamin D deficiency amongst geriatric outpatients.
authors.affiliation: Division of Human Nutrition, Pharmacology and Nutrition, Wageningen University, P.O. Box 8129, 6700 EV, Wageningen, The Netherlands. wout.vanorten-luiten@wur.nl.|Department of Geriatric Medicine, Gelderse Vallei Hospital, Willy Brandtlaan 10, 6716 RP, Ede, The Netherlands. wout.vanorten-luiten@wur.nl.
authors.forename: A C B
authors.identifier: http://orcid.org/0000-0002-5375-4004
authors.initials: AC
authors.lastname: van Orten-Luiten
authors.affiliation: Department of Geriatric Medicine, Gelderse Vallei Hospital, Willy Brandtlaan 10, 6716 RP, Ede, The Netherlands.
authors.forename: A
authors.initials: A
authors.lastname: Janse
authors.affiliation: Division of Human Nutrition, Wageningen University, P.O. Box 8129, 6700 EV, Wageningen, The Netherlands.
authors.forename: R A M
authors.initials: RA
authors.lastname: Dhonukshe-Rutten
authors.affiliation: Division of Human Nutrition, Pharmacology and Nutrition, Wageningen University, P.O. Box 8129, 6700 EV, Wageningen, The Netherlands. renger.witkamp@wur.nl.
authors.forename: R F
authors.initials: RF
authors.lastname: Witkamp
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D003430:Cross-Sectional Studies; D004363:Drug Utilization / Q000706:statistics & numerical data; D064420:Drug-Related Side Effects and Adverse Reactions / Q000453:epidemiology; D005260:Female; D006801:Humans; D008297:Male; D009426:Netherlands / Q000453:epidemiology; D010045:Outpatients; D019338:Polypharmacy; D014807:Vitamin D / Q000031:analogs & derivatives / Q000097:blood; D014808:Vitamin D Deficiency / Q000097:blood / Q000139:chemically induced* / Q000453:epidemiology*
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D
keywords: Adverse drug reaction; Drug-food interaction; Elderly; Polypharmacy; Vitamin D