The prevalence of UIE 200 µg/L was 30-40% for both boys and girls. A shift in distribution of UIE was observed wherein the prevalence of UIE 200 µg/L decreased with age. It is possible
that young children who attended day care centers and primary schools received lunch and milk programs which used or contained iodized salt. Furthermore, iodization of drinking water in these schools in some areas may have provided higher amounts of iodine to young children.