Supplemental Iodide for Preterm Infants and Developmental Outcomes at 2 Years: An RCT

Research output: Contribution to journalArticlepeer-review

Authors

  • Fiona L R Williams
  • Simon Ogston
  • Robert Hume
  • Jennifer Watson
  • Kayleigh Stanbury
  • Peter Willatts
  • Anita Boelen
  • Edmund Juszczak
  • Peter Brocklehurst
  • I2S2 team

Colleges, School and Institutes

External organisations

  • University of Dundee
  • Nuffield Department of Population Health, NPEU Clinical Trials Unit, National Perinatal Epidemiology Unit, University of Oxford, Oxford, United Kingdom.
  • Neonatal Screening Laboratory, Laboratory of Endocrinology, Academic Medical Centre, Amsterdam, Netherlands; and.

Abstract

BACKGROUND: The recommendation for enteral iodide intake for preterm infants is 30 to 40 μg/kg per day and 1 μg/kg per day for parenteral intake. Preterm infants are vulnerable to iodide insufficiency and thyroid dysfunction. The hypothesis tested whether, compared with placebo, iodide supplementation of preterm infants improves neurodevelopment.

METHODS: A randomized controlled trial of iodide supplementation versus placebo in infants <31 weeks' gestation. Trial solutions (sodium iodide or sodium chloride; dose 30 μg/kg per day) were given within 42 hours of birth to the equivalent of 34 weeks' gestation. The only exclusion criterion was maternal iodide exposure during pregnancy or delivery. Whole blood levels of thyroxine, thyrotropin, and thyroid-binding globulin were measured on 4 specific postnatal days. The primary outcome was neurodevelopmental status at 2 years of age, measured by using the Bayley Scales of Infant Development-III. The primary analyses are by intention-to-treat, and data are presented also for survivors.

RESULTS: One thousand two hundred seventy-three infants (637 intervention, 636 placebo) were recruited from 21 UK neonatal units. One hundred thirty-one infants died, and neurodevelopmental assessments were undertaken in 498 iodide and 499 placebo-supplemented infants. There were no significant differences between the intervention and placebo groups in the primary outcome: mean difference cognitive score, -0.34, 95% confidence interval (CI) -2.57 to 1.89; motor composite score, 0.21, 95% CI -2.23 to 2.65; and language composite score, -0.05, 95% CI -2.48 to 2.39. There was evidence of weak interaction between iodide supplementation and hypothyroxinemic status in the language composite score and 1 subtest score.

CONCLUSIONS: Overall iodide supplementation provided no benefit to neurodevelopment measured at 2 years of age.

Details

Original languageEnglish
Article numbere20163703
JournalPediatrics
Volume139
Issue number5
Publication statusPublished - May 2017

Keywords

  • Brain, Child Development, Child, Preschool, Follow-Up Studies, Humans, Infant, Infant, Premature, Iodides, Parenteral Nutrition, Thyrotropin, Thyroxine, Thyroxine-Binding Globulin, Treatment Outcome, Journal Article, Pragmatic Clinical Trial