Table 2.

Epidemiological criteria for the evaluation of iodine nutrition in a population, based on the mean urinary iodine levels, on the range of urinary iodine concentration, or both.

Iodine in women and children
Intake amount (µg/L)	Intake status	Nutritional contribution
Pregnant women
<150	Insufficient	N/A
150–249	Adequate	N/A
250–499	More than adequate	N/A
≥500	Excess∗	N/A
Lactating mothers∗∗
<100	Insufficient	N/A
≥100 µg/L	Adequate	N/A
Children <2 years of age
<100	Insufficient	—
≥100	Adequate	—
School-age children
<20	Insufficient	Severe iodine deficiency
20–49	Insufficient	Moderate iodine deficiency
50–99	Insufficient	Mild iodine deficiency
100–199	Adequate	Optimal
200–299	More than adequate	Risk of iodine-induced hyperthyroidism in susceptible populations
>300	Excess	Risk of detrimental health consequences (hyperthyroidism, iodine-induced autoimmune thyroid disease)

N/A: no information available from the evaluation table of the United Nations for the nutritional contribution of iodine in pregnant and lactating women. ^∗Exceeding the amount required to prevent and control an iodine deficit. ^∗∗Levels of mean urinary iodine are lower than the iodine requirements due to iodine excretion in breast milk.