I2S2

A randomised controlled trial of iodine supplementation in preterm infants with follow-up at 2 years.

Trial started: 2010  Trial ended: 2015 

Summary

Objectives

To determine whether iodide supplementation in preterm infants improves neurodevelopmental outcomes at 2 years of age.

Methods

A randomised controlled trial conducted in 21 UK neonatal units involving infants born at <31 weeks' gestation. Infants were randomised to receive either sodium iodide supplementation (30 ?g/kg/day) or placebo, starting within 42 hours of birth and continuing until 34 weeks' equivalent gestational age.

Outcome measures

Primary outcome: Neurodevelopmental status at 2 years of age, assessed using the Bayley Scales of Infant and Toddler Development-III, including cognitive, motor and language scores.

Results

A total of 1273 infants were included, with 637 allocated to iodide supplementation and 636 to placebo. Of these, 131 infants died, and neurodevelopmental assessments were completed for 498 infants in the iodide group and 499 in the placebo group. There were no significant differences between the groups in cognitive scores (mean difference –0.34, 95% confidence interval –2.57 to 1.89), motor composite scores (mean difference 0.21, 95% confidence interval –2.23 to 2.65) or language composite scores (mean difference –0.05, 95% confidence interval –2.48 to 2.39). There was weak evidence of an interaction between iodide supplementation and hypothyroxinaemic status for the language composite score and one subtest score.

Conclusions

Overall, iodide supplementation did not improve neurodevelopmental outcomes at 2 years of age in preterm infants.

Summary based on: Williams FLR, Ogston S, Hume R, et al. Supplemental Iodide for Preterm Infants and Developmental Outcomes at 2 Years: an RCT. Pediatrics. 2017;139(5):e20163703. https://doi.org/10.1542/peds.2016-3703.