Investigation On Iodine Nutritional Condition And The Thyroid Volume And Function Of Children And Women In Areas After Stopping Supply Of Iodized Salt

ObjectiveTo understand the iodine nutritional status and the disease state of the target populations in areas with excess iodine in drinking water after stopping the supply of iodized salt, which can provide scientific bases for developing strategies on control and prevention in iodine excess areas. Then we can discuss the cut-off point of water iodine level where should be defined as iodine excess areas.MethodsAdopted stratified random sampling method,4groups were divided by the concentration of iodine in drinking water, they were50μg/L～(A)、100μg/L～(B)、150μg/L～(C) and300μg/L～(D),2-3villages were randomly selected in each group as investigation spot.200children aged8-10years old and60women (Pregnant, child-bearing and fertile women20respectively) were sampled. Drinking water, edible salt and once random urine samples for each studying object were collected, and the iodine content was measured. The goiter volume of8-10years old children and the thyroid function (FT3,FT4,TSH,Anti-TPO,Anti-Tg) of women were determined. Applied for Excel and SPSS13.0to handle and analyze the dates.Results①The median urine iodine of children was274.3μg/L, and the level of iodine nutrition was more than adequate in A group; But median urine iodine was more than300μg/L and the level of iodine nutrition was possible excess in B, C and D group. The median urine iodine of children was increasing with the increasing of water iodine (H=403.66, v=3, P<0.01).②The median urine iodine of women was238.6and263.0μg/L, the level of iodine nutrition was more than adequate in A and B group. The median urine iodine of women was more than300μg/L and the level of iodine nutrition possible excess in C and D group. The median of women urine iodine was also increasing with the increasing of water iodine (χ2=100.27, v=3,P<0.01).③The goiter rate of children is5.9%、13.0%、14.0%、11.4%for each group; The goiter rate with urine iodine for200～299ug/L was obviously higher than that for100～199μg/L④In A, C, D three groups, FT3and FT4levels during pregnancy are lower than the lactating mothers and other women of childbearing age; and with the increasing of water iodine, FT4hormone levels was decreasing and TSH levels was increasing gradually in womenConclusions①When stopping the supply of iodized salt and water iodine is more than100μg/L, with the increasing of water iodine, people’s iodine nutrition from more than adequate to possible excess, and the same is the goiter rate.②In the different water iodine levels conditions, women’s iodine nutrition can satisfy the need of gravidity and lactation when stopping supply of iodized salt.③The cut-off point of definition and demarcation of iodine excess areas should descend from150μg/L to100μg/L.④We should apply different measures in iodine excess regions to preventing the risk of high iodine, such as changing water or supplying non-iodine salt.