title: Trace elements in hemodialysis patients: a systematic review and meta-analysis.
abstract: BACKGROUND
  Hemodialysis patients are at risk for deficiency of essential trace elements and excess of toxic trace elements, both of which can affect health. We conducted a systematic review to summarize existing literature on trace element status in hemodialysis patients.
  
  
  METHODS
  All studies which reported relevant data for chronic hemodialysis patients and a healthy control population were eligible, regardless of language or publication status. We included studies which measured at least one of the following elements in whole blood, serum, or plasma: antimony, arsenic, boron, cadmium, chromium, cobalt, copper, fluorine, iodine, lead, manganese, mercury, molybdenum, nickel, selenium, tellurium, thallium, vanadium, and zinc. We calculated differences between hemodialysis patients and controls using the differences in mean trace element level, divided by the pooled standard deviation.
  
  
  RESULTS
  We identified 128 eligible studies. Available data suggested that levels of cadmium, chromium, copper, lead, and vanadium were higher and that levels of selenium, zinc and manganese were lower in hemodialysis patients, compared with controls. Pooled standard mean differences exceeded 0.8 standard deviation units (a large difference) higher than controls for cadmium, chromium, vanadium, and lower than controls for selenium, zinc, and manganese. No studies reported data on antimony, iodine, tellurium, and thallium concentrations.
  
  
  CONCLUSIONS
  Average blood levels of biologically important trace elements were substantially different in hemodialysis patients, compared with healthy controls. Since both deficiency and excess of trace elements are potentially harmful yet amenable to therapy, the hypothesis that trace element status influences the risk of adverse clinical outcomes is worthy of investigation.
authors.affiliation: Department of Medicine, University of Alberta, Edmonton, Alberta, Canada. mtonelli-admin@med.ualberta.ca
authors.forename: Marcello
authors.initials: M
authors.lastname: Tonelli
authors.forename: Natasha
authors.initials: N
authors.lastname: Wiebe
authors.forename: Brenda
authors.initials: B
authors.lastname: Hemmelgarn
authors.forename: Scott
authors.initials: S
authors.lastname: Klarenbach
authors.forename: Catherine
authors.initials: C
authors.lastname: Field
authors.forename: Braden
authors.initials: B
authors.lastname: Manns
authors.forename: Ravi
authors.initials: R
authors.lastname: Thadhani
authors.forename: John
authors.initials: J
authors.lastname: Gill
mesh_terms: D001774:Blood Chemical Analysis; D006801:Humans; D010949:Plasma / Q000737:chemistry*; D006435:Renal Dialysis / Q000009:adverse effects*; D044967:Serum / Q000737:chemistry*; D014131:Trace Elements / Q000032:analysis* / Q000494:pharmacology*
chemical_list: D014131:Trace Elements