Our study aims to clarify the population nutrient status in locations with different levels of
iodine in the water in China; to choose effective measurements of water improvement(finding other
drinking water source of
iodine not excess) or non-
iodised salt supply or combinations thereof; to classify the areas of elevated water
iodine levels and the areas with
endemic goiter; and to evaluate the risk factors of water
iodine excess on pregnant women, lactating women and the overall population of women. From Henan, Hebei, Shandong and Shanxi province of China, for each of 50 ∼ 99 µg/L, 100 ∼ 149 µg/L, 150 ∼ 299 µg/L, and ≥ 300 µg/L water
iodine level, three villages were selected respectively. Students of 6-12 years old and pregnant were sampled from villages of each water-
iodine level of each province, excluded
iodized salt consumer. Then the children's
goiter volume, the children and pregnant's urinary
iodine and water
iodine were tested. In addition, blood samples were collected from pregnant women, lactating women and other women of reproductive age for each water
iodine level in the Shanxi Province for thyroid function tests. These indicators should be matched for each person. When the water
iodine exceeds 100 µg/L; the
iodine nutrient of children are
iodine excessive, and are adequate or more than adequate for the pregnant women. It is reasonable to define elevated water
iodine areas as locations where the water
iodine levels exceed 100 µg/L. The supply of non-
iodised salt alone cannot ensure adequate
iodine nutrition of the residents, and water improvement must be adopted, as well.
Iodine excess increases the risk of certain
thyroid diseases in women from one- to eightfold.