title: A randomized trial of selenium supplementation and risk of type-2 diabetes, as assessed by plasma adiponectin.
abstract: BACKGROUND
  Evidence that selenium affects the risk of type-2 diabetes is conflicting, with observational studies and a few randomized trials showing both lower and higher risk linked to the level of selenium intake and status. We investigated the effect of selenium supplementation on the risk of type-2 diabetes in a population of relatively low selenium status as part of the UK PRECISE (PREvention of Cancer by Intervention with SElenium) pilot study. Plasma adiponectin concentration, a recognised independent predictor of type-2 diabetes risk and known to be correlated with circulating selenoprotein P, was the biomarker chosen.
  
  
  METHODS
  In a randomized, double-blind, placebo-controlled trial, five hundred and one elderly volunteers were randomly assigned to a six-month intervention with 100, 200 or 300 µg selenium/d as high-selenium or placebo yeast. Adiponectin concentration was measured by ELISA at baseline and after six months of treatment in 473 participants with one or both plasma samples available.
  
  
  RESULTS
  Mean (SD) plasma selenium concentration was 88.5 ng/g (19.1) at baseline and increased significantly in the selenium-treatment groups. In baseline cross-sectional analyses, the fully adjusted geometric mean of plasma adiponectin was 14% lower (95% CI, 0-27%) in the highest than in the lowest quartile of plasma selenium (P for linear trend = 0.04). In analyses across randomized groups, however, selenium supplementation had no effect on adiponectin levels after six months of treatment (P = 0.96).
  
  
  CONCLUSIONS
  These findings are reassuring as they did not show a diabetogenic effect of a six-month supplementation with selenium in this sample of elderly individuals of relatively low selenium status.
authors.affiliation: Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom. m.rayman@surrey.ac.uk
authors.forename: Margaret P
authors.initials: MP
authors.lastname: Rayman
authors.forename: Gabrielle
authors.initials: G
authors.lastname: Blundell-Pound
authors.forename: Roberto
authors.initials: R
authors.lastname: Pastor-Barriuso
authors.forename: Eliseo
authors.initials: E
authors.lastname: Guallar
authors.forename: Holger
authors.initials: H
authors.lastname: Steinbrenner
authors.forename: Saverio
authors.initials: S
authors.lastname: Stranges
mesh_terms: D052242:Adiponectin / Q000097:blood*; D000368:Aged; D015415:Biomarkers / Q000097:blood; D003924:Diabetes Mellitus, Type 2 / Q000097:blood; D019587:Dietary Supplements; D004311:Double-Blind Method; D004334:Drug Administration Schedule; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D010919:Placebos; D012306:Risk; D012643:Selenium / Q000008:administration & dosage / Q000097:blood*; D051149:Selenoprotein P / Q000097:blood*
chemical_list: D052242:Adiponectin; D015415:Biomarkers; D010919:Placebos; D051149:Selenoprotein P; D012643:Selenium