Salt iodization prevalence

To evaluate the effectiveness of salt iodization programs, a large-scale study was organized in 1956 for the prevention of Himalayan endemic goiter in India. A follow-up study in 1962 showed a marked decrease in goiter prevalence, while uptake and excretion of urinary iodine had become normal, indicating a state of normal thyroid. 

Urinary iodine excretion and goiter prevalence before and after salt iodization... 

Note Decrease in the prevalence of goiter rate in the National Capital Territory of Delhi after salt iodization. Source Pandav etal., (1980) Sharmaeta/., (1988) Pandavef a/., (1996) Kapil etal., (2004) Gopalakrishnan etal., (2006). 

No national-level data exists in India on the prevalence of Graves disease before or after the salt iodization program. 

Teng et al. (2006) explored the effect of iodine intake on thyroid diseases in China. Baseline characteristics of three populations were estabfished in three communities in 1999 and then again 5 years later. The communities had different levels of iodine nutrition mild deficiency more than adequate and excessive intake. Salt iodization had been implemented in China in 1996. In the general population, median UI increased from 165 pg/1 in 1995 to approximately 300 pg/1 in 1999. The concern was with oversupplementation of iodine to a level that is more than adequate, in a region in which iodine intake was previously mildly deficient, which in turn may accelerate the development of subclinical hypothyroidism to overt hypothyroidism. High levels of iodine intake may increase the incidence and prevalence of autoimmune thyroiditis, making it imperative to tailor supplementation needs to each region. 

Of the 401 municipalities studied, 4 had a moderate prevalence of iodine deficiency, and in 116 the existence of mild iodine deficiency was observed. Since these areas presented mild and moderate levels of deficiency, it became apparent that the endemic disease control policy should focus on addressing the more subtle manifestations of iodine deficiency. The study showed that, despite the salt iodization program, some iodine-deficiency endemic areas still existed in Brazil (Esteves, 1997). 

In 2000, a survey was conducted in 21 cities of 8 Brazilian states. It was called the Thyromobil Project, and aimed at updating IDD data for Brazil, while observing the progress of the salt iodization strategy. The study assessed 2013 male and female schoolchildren aged from 6 to 14 years. For the first time, thyroid volume was assessed by ultrasound. The major studies on goiter prevalence in Brazil are fisted in Table 124.2. 

The Department of Health of the Ministry of Public Health is the main office responsible for implementing intervention programs on IDD alleviation. The pilot project for salt iodization was first launched in 1965 in one of the northern districts where the prevalence of goiter rate had been very high. Later in 1968, the salt iodization program was expanded to all affected areas in the country (Figure 126.3). 

After 5 years of the salt iodization program, the prevalence of goiter decreased substantially. However, the amount of iodized salt produced annually was limited to 20000 metric tons, which was not enough to cover the entire population in the affected areas. IDD was included in the fourth and fifth National Social and Economic Development Plan (1977—1986) as one of the priority health issues to be tackled, and production and distribution of salt iodization was also set as a main strategy. 

Mali is a landlocked country in West Africa, and is one of the poorest countries in the world. Iodine deficiency disorders (IDD) have been prevalent in several areas of the country, especially in the southern part. This chapter provides a historic overview of the changes in IDD over time, and of the various strategies that have been implemented to combat IDD. While the national total goiter rate was estimated to be 30% in 1974, a nationwide survey in 2005 found a total goiter rate of 8%, with 88% of the households using iodized salt. The latest figures indicate that Mali still suffers from iodine deficiency, and that efforts must continue in order to reach the goal of universal salt iodization. 

In February 1922, at the suggestion of the local surgeon Hans Eggenbeiger, the small mountain canton of Appenzell-Aussenhoden allowed the distribution of iodized salt. The results on goiter prevalence in schoolchildren were spectacular and in June 1922 the newly appointed Swiss Goiter Commission recommended to all 25 cantons to introduce salt iodized at 1.9 - 3.75 ppm on a volimtary basis. Being autonomous in health matters and the salt monopoly, only about half of the cantons had complied by 1930. The last two cantons allowed iodized salt in 1952. In 1962, the iodine content of salt was raised ftom 3.75 to 7.5 ppm and in 1980 to 15 ppm. 

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