Iodine fortification

We developed a specific register database to prospectively register all new cases of hyper- and hypothyroidism in two areas of Denmark before and during the first years after the implementation of iodine fortification of salt. 

Humans ingest iodine through food. In many countries, iodine fortification, normally through iodized salt, ensures proper iodine intake. The ingested iodine is then absorbed into the bloodstream through the gut. Once absorbed, the major location of iodine storage and utilization is the thyroid. Iodine is transported into the thyroid from the... 

Because a significant amount of iodine is found in relatively few food groups the intake of these foods is important for iodine intake. Many countries iodize household salt and/or salt used by the food industry. The intake of fortified food infiuences iodine intake, depending on the iodization level and the market share of iodized salt. However, even in countries with iodine fortification, the intake of other iodine-rich foods may have a significant impact on total iodine intake. 

Unpublished results from the Danish Investigation of Iodine Intake and Thyroid Diseases before iodine fortification was introduced. Results are median values with 25th and 75th percentiles in parentheses. 

Data from the Danish Investigation of Iodine Intake and Thyroid Diseases based on a FFQ before iodine fortification was introduced in Denmark. Food with a low iodine content was not included, iodine intake from other sources is a little underestimated and iodine from milk, fish and eggs consequently a little overestimated. Rasmussen efa/., (2002). 

Various iodine fortification levels and the market share of iodized salt and other iodized products influence iodine intake. 

Thyroid Size Before and After Introduction of Iodine Fortification... 

Most countries worldwide have some kind of iodine fortification. However, in few countries has the increase in iodine intake following the introduction of an iodine fortification, and the expected effect on thyroid size, been evaluated in a systematical way. In Austria, goiter incidence in schoolchildren was 45.9% in 1964 (assessed by palpation) (Riccabona, 1993). Iodine fortification of salt was introduced by law in 1963, and by 1980 the goiter incidence had fallen to 12% in schoolchildren. The amount of iodine in salt was doubled from 10 to 20 ppm in 1990, and by 1992 the goiter incidence in schoolchildren was 5% (Riccabona, 1993). The iodine excretion in urine, as a measure of iodine intake, increased from 1964... 

Figure 55.1 Thyroid size before and after iodine fortifioation in Aaiborg, Denmark. Thyroid voiume in women in four different age groups and in men 60-65 years of age before and after iodine fortification. Thyroid size decreased significantiy in aii age groups. The number of subjeots is 2101 before fortifioation and 1693 after fortification, y, year of age m, men.

Introduction of iodine fortification in an iodine-deficient population results in lowering thyroid gland volumes. 

Iodine Fortification Some Industrial Initiatives and Concerns... 

This review focuses on iodine fortification as seen in various countries, particularly in India, the initiatives undertaken by the food industry and some bottlenecks in successfully implementing the programs in this area. 

A detailed compilation of (Table 75.4-75.10) several other food products used as vehicles for iodine fortification in... 

Iodine Fortification Some industriai initiatives and Concerns 735... 

Iodine fortification and keeping iodine stable in the food matrix has always been challenging for food and beverage formulation. These challenges include ... 

Mandatory iodine fortification of table salt and salt in bread was initiated in 2000—2001 (Laurberg et ai, 2006), and the Danish National Survey of Dietary Habits and Physical Activity 2000—2002 (Lyhne et al., 2005) subsequently found the median iodine intake among 55—75-year-old subjects to be 153—187 p,g/day (Table... 

In a prospective study performed to evaluate the effect of 4 years of iodine fortification in Denmark, Vejbjerg et al. (2007) found a lower median thyroid volume among 18—65-year-old subjects, independent of age and indicating approximation to the optimal iodine intake in Denmark judged by thyroid volumes. 

Political and societal changes might considerably influence the efficacy of iodine fortification programs (Dunn, 2000). 

Iodine fortification in Germany represents an example of a successfully implemented preventive strategy. The iodine supply is currently in the lower recommended range. A systematic monitoring program should be installed to continuously monitor the efficacy of the iodine fortification program. 

The iodine supply has been optimized in the past decade by a voluntary iodine fortification program. 

Cla The Cl cohort investigated from 1997— 1998 before iodine fortification of salt... 

Before the introduction of iodine fortification (IF) of salt, and iodine supplementation of man and domestic animals, most European countries were more or less affected by iodine deficiency (ID) disorders (Kelly and Snedden, 1960). The countries with the most severe manifestations were, in general, early to introduce preventive programs. However, some countries with only mild-to-moderate ID, such as Denmark, have only introduced programs... 

Figure 119.3 Geographical variations in urinary iodine excretion in Denmark before iodine fortification of salt. Median urinary iodine excretion among inhabitants of various Danish cities before iodine fortification of salt, and the estimated number of people living in areas with different levels of urinary iodine excretion. Values were compiled from different studies of urinary iodine excretion, or estimated from measurements of groundwater iodine content. Geographical variation in iodine intake in Denmark is mostly determined by differences in groundwater iodine content. Pedersen etal., (1999) Rasmussen etal., (2000).

Incidence of Overt Hyperthyroidism after Iodine Fortification of Sait... 

Figure 119.5 Incidence rates of overt hyperthyroidism before and after iodine fortification (IF) of salt. The incidence rate of hyperthyroidism in Aalborg (moderate ID) and Copenhagen (mild ID) before and after the first 6 years of IF of salt. Basic is the time before IF of salt (1997-1998), 1999-2000 is the period of voluntary IF, 2001-2002 is the early, and 2003-2004 is the late period of mandatory IF. The incidence of hyperthyroidism increased significantly in both subcohorts during the study period. In Aalborg, the increase was more pronounced and came before the increase in Copenhagen. Aalborg baseline vs. voluntary IF, P< 0.001 voluntary IF vs. early mandatory IF, P s 0.001 early vs. late mandatory IF, ns. Copenhagen baseline vs. voluntary IF, ns voluntary IF vs. early mandatory IF, P s 0.001 early vs. late mandatory IF, ns. Statistical significance compared with baseline, P < 0.05 P s 0.01 P s 0.001. Data from Pedersen et al., (2006).

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