Danish iodization programs

It has often been hypothesized that the factor involved in goitrogenesis, when iocfine intake is below the recommended level, is an increase in serum TSH caused by insufficient thyroid hormone production. However, at the level of iocfine deficiency observed in Denmark before the Danish iodization program we found no evidence of a high TSH in the population. On the contrary, serum TSH was on average lower in people with moderate than in people with only mild iocfine deficiency (Knudsen et ai, 2000b). The low TSH pattern developed gradually over the years, as illustrated in Figure 47.2. 

The Danish iodization program has led to a decrease in thyroid size and frequency of thyroid enlargement in practically all groups investigated. 

The intake of iodized salt by this program was estimated to be around 4g/day, and the iodization level was set to 13 ppm. Bread is a staple food in Denmark, and simulation studies performed by the Danish National Food Agency based on Danish food surveys had shown that iodized salt in bread, in combination with iodized table salt, would distribute the iodine nearly as evenly in the population as iodization of all salt used by the food industry. 

---