title: Selenium levels and hypertension: a systematic review of the literature.
abstract: OBJECTIVE
  Se is an antioxidant micronutrient and has been studied for its potential role in CVD prevention. The purpose of the present study was to conduct a systematic review of the literature on the relationship between Se and hypertension.
  
  
  METHODS
  We conducted a systematic literature search in PubMed and OVID of studies on Se levels and hypertension or blood pressure published in English up to June 2011. Articles meeting inclusion criteria were reviewed and the following information was gathered from each publication: study setting, participant demographics, exclusion criteria, intervention if applicable, medium of Se measure, mean level of Se, outcome definition, relationship between Se and the outcome variable, significance of this relationship, and covariates. In studies that also reported glutathione peroxidase levels, we extracted results on the relationship between glutathione peroxidase and hypertension.
  
  
  RESULTS
  Twenty-five articles were included. Approximately half of the studies reported no significant relationship between Se and hypertension. Of the remaining studies, about half found that higher Se levels were associated with lower blood pressure and the other half found the opposite relationship. The studies varied greatly in terms of study population, study design and Se levels measured in participants.
  
  
  CONCLUSIONS
  Based on the present systematic review, there is no conclusive evidence supporting an association between Se and hypertension. Randomized controlled trials and prospective studies with sufficient sample size in populations with different Se levels are needed to fully investigate the relationship between Se and hypertension.
authors.affiliation: 1 Department of Medicine, Indiana University School of Medicine, 410 West 10th Street, #3000, Indianapolis, IN 46202-2872, USA.
authors.forename: Dulanji
authors.initials: D
authors.lastname: Kuruppu
authors.affiliation: 2 Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA.
authors.forename: Hugh C
authors.initials: HC
authors.lastname: Hendrie
authors.affiliation: 5 Department of Biostatistics, Indiana University School of Medicine, Indianapolis, IN, USA.
authors.forename: Lili
authors.initials: L
authors.lastname: Yang
authors.affiliation: 1 Department of Medicine, Indiana University School of Medicine, 410 West 10th Street, #3000, Indianapolis, IN 46202-2872, USA.
authors.forename: Sujuan
authors.initials: S
authors.lastname: Gao
mesh_terms: D001794:Blood Pressure; D006801:Humans; D006973:Hypertension / Q000097:blood*; D009752:Nutritional Status; D012643:Selenium / Q000097:blood*
chemical_list: D012643:Selenium