title: Association between vitamin B12 deficiency and long-term use of acid-lowering agents: a systematic review and meta-analysis.
abstract: BACKGROUND
  Vitamin B12 (cobalamin) deficiency can result in irreversible structural brain changes if not treated appropriately. Long-term use of acid-lowering agents (ALA) has been linked to vitamin B12 deficiency, but results are inconsistent.
  
  
  OBJECTIVE
  To evaluate the association between prolonged ALA use and vitamin B12 deficiency by performing a meta-analysis.
  
  
  METHODS
  A systematic search was conducted using MEDLINE, PubMed, EMBASE, Current Contents, Cochrane Library, Google Scholar, Science Direct and Web of Science. Original data were abstracted from each study and used to calculate a pooled odds ratio and 95% confidence interval (95% CI).
  
  
  RESULTS
  Of the articles reviewed, four case-control studies (4254 cases and 19,228 controls) and one observational study met full criteria for analysis. The long-term ALA use was significantly associated with development of vitamin B12 deficiency (hazard ratio 1.83, 95% CI: 1.36-2.46, P-value 0.00).
  
  
  CONCLUSIONS
  Chronic use of ALA is a risk factor for developing vitamin B12 deficiency. Judicious prescribing of ALA and regular monitoring of vitamin B12 in patients who are inevitably on long-term ALA therapy are recommended.
authors.affiliation: Prince of Wales Hospital, Sydney, Australia; University of New South Wales, Sydney, Australia.
authors.forename: S B
authors.initials: SB
authors.lastname: Jung
authors.forename: V
authors.initials: V
authors.lastname: Nagaraja
authors.forename: A
authors.initials: A
authors.lastname: Kapur
authors.forename: G D
authors.initials: GD
authors.lastname: Eslick
mesh_terms: D000863:Antacids / Q000008:administration & dosage* / Q000009:adverse effects*; D016022:Case-Control Studies; D005764:Gastroesophageal Reflux / Q000097:blood / Q000188:drug therapy; D006801:Humans; D014806:Vitamin B 12 Deficiency / Q000097:blood* / Q000139:chemically induced* / Q000175:diagnosis
chemical_list: D000863:Antacids
keywords: acid lower/suppress; cobalamin deficiency; histamine receptor antagonist; proton pump inhibitor; vitamin B12 deficiency