Iodine deficiency: Clinical implications

Article Figures & Data

TABLE 1

Clinical manifestations of iodine-deficiency disorder by age group

Age group	Clinical manifestations
Fetus	Abortion Stillbirth Increased risk of perinatal death Cretinism
Infant	Goiter Hypothyroidism Mental retardation Intellectual impairment
Child, adolescent	Goiter Hypothyroidism Intellectual impairment Impaired physical development
Adult	Goiter Toxic multinodular goiter Increased risk of iodine-induced hyperthyroidism Hypothyroidism Intellectual impairment

TABLE 2

Cretinism: Comparative features of neurologic and myxomatous subtypes

	Neurologic cretinism^a	Myxomatous cretinism^a
Period of intrauterine iodine deficiency	Early in pregnancy (maternal hypothyroidism)	Late in pregnancy
Continuing postnatal iodine deficiency	No	Yes
Deaf-mutism	Often present	Absent
Neurologic deficits Gait disturbances Spasticity Squinting	Often present	Absent
Growth	Normal	Growth retardation Epiphyseal dysgenesis
Physical signs of hypothyroidism Coarse, dry skin Hoarseness Delayed relaxation of reflexes	Absent	Present
Effect of thyroid hormone replacement	No effect	Improvement

↵a The features of the two subtypes may overlap, depending on the duration and magnitude of postnatal hypothyroidism.

TABLE 4

Tolerable upper intake levels for iodine^a

Age	Male	Female	Pregnancy	Lactation
Birth to 1 year	Not possible to establish^b	Not possible to establish^b
1–3	200 μg	200 μg
4–8	300 μg	300 μg
9–13	600 μg	600 μg
14–18	900 μg	900 μg	900 μg	900 μg
≥ 19	1,100 μg	1,100 μg	1,100 μg	1,100 μg

↵a These data refer to chronic ingestion of the specified iodine concentrations.
↵b Formula and food should be the only sources of iodine for infants.
Adapted from reference 8.