The overall objective of this study is to develop a reliable method to obtain habitual iodine intakes from spot urinary iodine concentration (UIC) and to assess the prevalence of inadequate iodine intake in school-age children and women of reproductive age. We will evaluate different methods to estimate iodine intake from UIC and estimate the prevalence of inadequate and excess iodine intake in UIC studies conducted in populations with low, adequate and high iodine intakes using the the established estimated average requirement (EAR)/Tolerable Upper Intake Level (UL) cut-point method.

Inclusion Criteria:

• lived in study area >= 12 months
• no reported intake of Amiodarone
• no history of thyroid dysfunction / goiter (past & present)
• no exposure to iodine containing contrast agents within the last 12 months

Second arm: Women aged 18 - 49, exclusion / inclusion criteria apply, plus non-pregnant, non-lactating.

Apparently healthy school-age children and women of reproductive age