title: Selenium levels in rice samples from high and low risk areas for esophageal cancer.
abstract: OBJECTIVE
  To assess the relationship between selenium (Se) concentration in rice and the incidence of esophageal cancer (EC) in a high risk area in Northern Iran.
  
  
  METHODS
  This ecological study was conducted in Golestan province of Iran in 2012. In this area, 45714 acres of land are cultivated by rice. A total of 69 rice samples were taken. We investigated Se concentrations by the voltammetric method. Statistical analysis was performed using the Pearson correlation test and Mann-Whitney U test.
  
  
  RESULTS
  The mean (+/-SD) Se level in rice samples was 0.229 (+/-0.145) mg/kg. The Se concentration was significantly higher in rice samples from high EC rate areas (0.35 mg/kg) compared with low risk areas (0.16 mg/kg) (p<0.001). There was a significant positive correlation between the levels of Se in rice and the incidence rate of EC (p=0.03).
  
  
  CONCLUSIONS
  We found a high rice Se concentration and a significant positive relationship between rice Se levels and EC rates in the Golestan province of Iran. High soil and rice Se levels may play a possible role in the pathogenesis of EC in this area.
authors.affiliation: Environmental Health Research Center, Golestan University of Medical Sciences, Gorgan, Iran.
authors.forename: Hadi
authors.initials: H
authors.lastname: Rahimzadeh-Barzoki
authors.forename: Hamidreza
authors.initials: H
authors.lastname: Joshaghani
authors.forename: Somayeh
authors.initials: S
authors.lastname: Beirami
authors.forename: Morteza
authors.initials: M
authors.lastname: Mansurian
authors.forename: Shahryar
authors.initials: S
authors.lastname: Semnani
authors.forename: Gholamreza
authors.initials: G
authors.lastname: Roshandel
mesh_terms: D004938:Esophageal Neoplasms / Q000453:epidemiology*; D006801:Humans; D007492:Iran / Q000453:epidemiology; D012275:Oryza / Q000737:chemistry*; D012307:Risk Factors; D012643:Selenium / Q000032:analysis*
chemical_list: D012643:Selenium