title: Effect of low-dose selenium on thyroid autoimmunity and thyroid function in UK pregnant women with mild-to-moderate iodine deficiency.
abstract: OBJECTIVE
  Selenium is an essential trace mineral and a component of selenoproteins that are involved in the production of thyroid hormones and in regulating the immune response. We aimed to explore the effect of low-dose selenium supplementation on thyroid peroxidase antibody (TPO-Ab) concentration and thyroid function in pregnant women from a mild-to-moderate iodine-deficient population.
  
  
  METHODS
  Samples and data were from a secondary analysis of Selenium in PRegnancy INTervention (SPRINT), a double-blind, randomized, placebo-controlled study that recruited 230 women with singleton pregnancies from a UK antenatal clinic at 12 weeks of gestation. Women were randomized to receive 60 µg/day selenium or placebo until delivery. Serum thyroid peroxidase antibodies (TPO-Ab), thyrotropin (TSH) and free thyroxine (FT4) were measured at 12, 20 and 35 weeks and thyroglobulin antibodies (Tg-Ab) at 12 weeks.
  
  
  RESULTS
  93.5% of participants completed the study. Se supplementation had no more effect than placebo in decreasing TPO-Ab concentration or the prevalence of TPO-Ab positivity during the course of pregnancy. In women who were either TPO-Ab or Tg-Ab negative at baseline (Thy-Ab(-ve)), TSH increased and FT4 decreased significantly throughout gestation (P < 0.001), with no difference between treatment groups. In women who were Thy-Ab(+ve) at baseline, TSH tended to decrease and was lower than placebo at 35 weeks (P = 0.050). FT4 fell more on Se than placebo supplementation and was significantly lower at 35 weeks (P = 0.029).
  
  
  CONCLUSIONS
  Low-dose selenium supplementation in pregnant women with mild-to-moderate deficiency had no effect on TPO-Ab concentration, but tended to change thyroid function in Thy-Ab(+ve) women.
authors.affiliation: Department of Nutritional Sciences, Faculty of Health and Medical Sciences, University of Surrey, Guildford, GU2 7XH, UK.|Department of Endocrinology and Metabolism, The First Hospital of China Medical University, Shenyang, China.
authors.forename: Jinyuan
authors.initials: J
authors.lastname: Mao
authors.affiliation: Department of Clinical Health Psychology, Tilburg University, Tilburg, The Netherlands.
authors.forename: Victor J
authors.initials: VJ
authors.lastname: Pop
authors.affiliation: Department of Nutritional Sciences, Faculty of Health and Medical Sciences, University of Surrey, Guildford, GU2 7XH, UK.
authors.forename: Sarah C
authors.initials: SC
authors.lastname: Bath
authors.affiliation: Clinical Laboratories, Máxima Medical Center Eindhoven, Veldhoven, The Netherlands.
authors.forename: Huib L
authors.initials: HL
authors.lastname: Vader
authors.affiliation: Nuffield Department of Obstetrics and Gynaecology, John Radcliffe Hospital, University of Oxford, Oxford, UK.
authors.forename: Christopher W G
authors.initials: CW
authors.lastname: Redman
authors.affiliation: Department of Nutritional Sciences, Faculty of Health and Medical Sciences, University of Surrey, Guildford, GU2 7XH, UK. m.rayman@surrey.ac.uk.
authors.forename: Margaret P
authors.initials: MP
authors.lastname: Rayman
mesh_terms: D001323:Autoantibodies / Q000097:blood; D015992:Body Mass Index; D019587:Dietary Supplements; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007455:Iodine / Q000097:blood* / Q000172:deficiency; D011247:Pregnancy; D012643:Selenium / Q000008:administration & dosage* / Q000097:blood; D013961:Thyroid Gland / Q000187:drug effects* / Q000276:immunology*; D013972:Thyrotropin / Q000097:blood; D013974:Thyroxine / Q000097:blood; D006113:United Kingdom
chemical_list: D001323:Autoantibodies; C006606:anti-thyroglobulin; C056626:thyroid microsomal antibodies; D013972:Thyrotropin; D007455:Iodine; D012643:Selenium; D013974:Thyroxine
keywords: Iodine; Pregnancy; Selenium; Thyroid autoimmunity; Thyroid function; Thyroid peroxidase antibodies