The use of iodine salt has become a public concern these days. It is known that iodine is a micro-nutrient element indispensable for the synthesis of thyroid hormones. A certain level of thyroid hormone is required to secure the normal development and vitality of the human body, especially the liver, kidney, muscles, heart, and the brain. Insufficient intake of iodine element would lead to a poor iodine nutrition, and therefore cause the iodine deficiency disorders.

The iodine deficiency disorders are a syndrome of hypothyroidism and other minor pathogenesis, which is a result of insufficient intake of iodine due to a lack of iodine in the external environment. The most common diseases related include endemic goiter, endemic cretinism, congenital hypothyroidism, birth deformities, simple deaf/mute, preterm delivery, abortion, stillbirth, etc. As a chief harm, it causes various cerebral dysgenesis.

Iodine deficiency disorders as a universal disease have appeared in 118 countries out of the 154 countries in the world. All countries have made use of salt iodization to prevent iodine deficiency disorders.

China is among the countries most afflicted by the disease. There is a prevalence of the disease in the 30 provinces, autonomies and municipalities directly under the Central Government except for Shanghai, and the population of the diseased area amounts to as many as 425 million, about 40% of that of the whole world, and 60% of that in Asia. Presently, we still have seven million endemic goiter sufferers and 190,000 cretinism patients; and those with a mental disability total 10.17 million, among whom over 80% get the disease due to iodine deficiency. It has therefore become a major issue concerning public health that influences population quality of China. And more mentally disabled children are to be born if no proper prevention measures are effected.

Beijing is one of the regions where there is a lack of iodine in the external environment. In the 1970s, over 30% of the population get endemic goiter due to iodine insufficiency, and it is not unusual to find cretinism sufferers in the mountainous areas in the north.
Salt iodization is the most convenient, most economic and safest measure recognized internationally for the prevention of iodine deficiency disorders. The Beijing Municipal Government has adopted the method ever since the 1970s and has now obtained a great achievement. Presently, coverage of iodized salt has covered over 90% of the population, and cretinism is found nowhere. Less than 1% of the school children get goiter. The monitoring results in 2008 show that, in the eight areas that are heavily diseased in the past, including Yanqing and Huairou districts, 0.64% of the school children get goiter, a level complying with the criteria for iodine deficiency disorders eradication (goiter proportion to be less than 5%); the urinary iodine test of women of childbearing age and lactation women also shows that Beijing residents have enjoyed a proper iodine nutrition.

Besides the prevention measures, Beijing Municipal Government has also developed several projects in the areas such as Yufa Town of Daxing District, where the water resources are of high iodine values. Such projects are meant to annihilate high-iodine water by changing the drinking water wells. Now there is neither high-iodine area nor iodine-excess area in Beijing.

Presently, salt iodization remains the chief measure for the prevention of the disease in Beijing. In the future, iodine concentration in salt will reduce by an appropriate amount as dietary pattern changes. Such reduction, however, must be implemented only when a large amount of monitoring data constantly shows that the iodine nutrition is maintained at a proper level for the residents.