25th May, World Thyroid Day
WHAT WE NEED TO KNOW ABOUT IODINE DEFICIENCY
Iodine deficiency diseases are a group of diseases and developmental disorders that are caused by reduced iodine intake and have an endemic nature due to iodine deficiency and can be prevented by adequate and systemic iodine intake.
The most common manifestation of iodine deficiency is endemic goiter. Disorders occurring in the prenatal and postnatal period are especially significant since iodine intake during pregnancy is crucial for its normal course and in respect of the neuropsychological and physical development of newborns. In adults iodine deficiency can lead to decreased thyroid function (hypothyroidism), memory disorders, depression, infertility, miscarriages and stillbirths.
Iodine deficiency diseases have been a serious problem for Bulgaria too, as iodine deficient mountainous and semi-mountainous areas represent 1/3 of its territory. As a result of the large-scale prevention with iodized table salt as well as the additional prevention with potassium iodide tablets for children and pregnant women, the incidence in Bulgaria dropped significantly from 56% to 12% by 1974.
Daily iodine demands provided from water and food vary across different age groups: about 50 μg in newborns, 90 to 120 μg in children under 10 years of age and about 150 μg in children above 10 years of age and adults. During pregnancy and lactation, the demands increase to 250 μg. Iodine deficiency disorders and diseases are developed when daily iodine intake is below 100 μg.
Some additional external factors mainly related to diet (scarce and/or protein-free diet, intake of natural strumogenic substances contained in some foods - cabbage, beets, etc.) are important to the manifestation of the disorders. The same applies to smoking, some concomitant chronic infections, gastrointestinal diseases, taking medications such as lithium salts, sulfonylureas, etc.
Nitrates, petroleum products, pesticides, artificial fertilizers, etc. have a proven strumogenic effect.
Thyroid malignancies are 2 to 4 times more common in endemic areas than in non-endemic ones. Their incidence increases sharply with radiation as was the case with the Chernobyl accident. In these cases, urgent iodine prevention across the risk contingents is required.
Treatment with iodine-containing preparations is the oldest classic treatment method, which has not lost its relevance to this day and successfully eliminates iodine deficiency. The inorganic iodine compounds, potassium iodide tablets 0.5 mg daily for 6 months, are most commonly used. Giving higher doses carries the risk of hypothyroidism or provoking autoimmune responses. Low-grade short-history goiters reverse or completely disappear, while high-grade ones, those with a long history or with nodules, most often remain without a significant change.
Ioduria is the main criterion of current iodine intake in prevention control, but it is not essential to individual assessment due to significant daily variations.
