In a randomised Peruvian trial, women of childbearing
age from Andean villages in an area of severe
iodine deficiency with a 1–3% cretinism rate were
studied.18,19 The treatment group received iodised oil
injection either before conception or during pregnancy;
the control group did not receive an injection.
Cognitive development scores were done in a subsample
of their children between 1 and 4 years of age.
The initial publication did not find a statistical difference
in cognitive outcomes.18 A subsequent reanalysis
reassigned children to two groups, iodine-deficient
or iodine-sufficient at time of cognitive testing, based
on their UIC and T4. This analysis found a significant
higher IQ score in the iodine-sufficient group compared
with the iodine-deficient group (85.6 13.9 vs.
74.4 4.8).19