Thus , regardless of study design , iodine deficiency had a substantial impact on mental development .
Several review s and meta-analyses have examined the effects of iodine on mental development .
None focused on young children , so they were incomplete in summarizing the effects on this important age group .
The current systematic review therefore examined the relationship between iodine and mental development of children 5 years old and under .
Neurological damage to the fetus resulting from severe iodine deficiency during pregnancy.
Abstract Endemic cretinism is characterised by multiple neurological defects including deaf-mutism , diplegia , squint , and mental deficiency . The condition is widely prevalent in the Highl and s of New Guinea in association with severe iodine deficiency . Previous studies have shown that iodised oil provides a very satisfactory correction of severe iodine deficiency in New Guinea . A controlled trial on the use of intramuscular iodised oil in the prevention of endemic cretinism was carried out in the Western Highl and s of New Guinea and involved a population of approximately 8000 . Subsequent follow-up over four years revealed 26 endemic cretins out of a total of 534 children born to mothers who had not received iodised oil ; the mothers of 5 of these cretins were pregnant at the start of the trial . In comparison , 7 cases of endemic cretinism occurred among 498 children born to mothers who had been treated with iodised oil ;  in 6 of these 7 cases , the mother was pregnant when the trial commenced . It is concluded that intramuscular iodised oil is effective in the prevention of endemic cretinism and that , for it to be effective , it should be given prior to conception . This suggests that severe iodine deficiency in the mother produces neurological damage during fetal development
Thus , regardless of study design , iodine deficiency had a substantial impact on mental development .
Several review s and meta-analyses have examined the effects of iodine on mental development .
None focused on young children , so they were incomplete in summarizing the effects on this important age group .
The current systematic review therefore examined the relationship between iodine and mental development of children 5 years old and under .