title: The association between serum selenium and gestational diabetes mellitus: a systematic review and meta-analysis.
abstract: BACKGROUND
  Results of the studies about association between serum selenium concentration and gestational hyperglycemia are inconsistent. Some studies have demonstrated that women with gestational diabetes mellitus (GDM) have lower Se concentrations while contrary results are reported in other studies.
  
  
  OBJECTIVE
  The aim of this study is to compare the serum Se concentration in women with GDM and normoglycemic pregnant women via a systematic review and meta-analysis.
  
  
  METHODS
  A computerized literature search on four databases (PubMed, Cochrane register of control trials, Scopus and Google scholar) was performed from inception through August 2013. Necessary data were extracted and random effects model was used to conduct the meta-analysis.
  
  
  RESULTS
  Six observational studies (containing 147 women with GDM and 360 normoglycemic pregnant women) were found, which had compared serum Se concentration in women suffering from GDM with normal pregnant ones. Our meta-analysis revealed that serum Se concentration was lower in women with GDM compared to normoglycemic pregnant women (Hedges=-1.34; 95% CI: -2.33 to -0.36; P<0.01). Stratified meta-analysis demonstrated that concentration of Se in the sera of women with GDM was lower than normal pregnant women both in second and third trimesters, but the result was not significant in second trimester (second trimester: Hedges=-0.68; 95% CI: -1.60-0.25; P=0.15, third trimester: Hedges=-2.81; 95% CI: -5.21 to -0.42; P<0.05). It was also demonstrated that serum Se status was lower in pregnant women with impaired glucose tolerance (IGT) compared to normoglycemic pregnant women (Hedges=-0.85; 95% CI: -1.18 to -0.52).
  
  
  CONCLUSIONS
  The available evidences suggest that serum Se concentration is significantly lower in pregnant women with gestational hyperglycemia compared to normal pregnant women.
authors.affiliation: Food Security Research Center and Department of Community Nutrition, School of Nutrition and Food Sciences, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Gholamreza
authors.initials: G
authors.lastname: Askari
authors.affiliation: Isfahan Endocrine and Metabolism Research Center, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Bijan
authors.initials: B
authors.lastname: Iraj
authors.affiliation: Department of Nutrition, Faculty of Health, Shahid Sadoughi University of Medical Sciences, Yazd, Iran; Nutrition and Food Security Research Center, Shahid Sadoughi University of Medical Sciences, Yazd, Iran.
authors.forename: Amin
authors.initials: A
authors.lastname: Salehi-Abargouei
authors.affiliation: Department of Food Hygiene and Quality Control, Faculty of Veterinary Medicine, Shahrekord University, Shahrekord 34141, Iran.
authors.forename: Aziz A
authors.initials: AA
authors.lastname: Fallah
authors.affiliation: Food Security Research Center and Department of Community Nutrition, School of Nutrition and Food Sciences, Isfahan University of Medical Sciences, Isfahan, Iran. Electronic address: tinajafari15@yahoo.com.
authors.forename: Tina
authors.initials: T
authors.lastname: Jafari
mesh_terms: D016640:Diabetes, Gestational / Q000097:blood*; D005260:Female; D005951:Glucose Tolerance Test; D006801:Humans; D011247:Pregnancy; D011264:Pregnancy Trimesters; D012643:Selenium / Q000097:blood*
chemical_list: D012643:Selenium
keywords: Gestational diabetes mellitus; Impaired glucose tolerance; Meta-analysis; Selenium