Denmark iodine deficiency

Over the years, people living with iodine deficiency tend to develop multifocal thyroid autonomy, and multinodular toxic goiter is a common cause of hyperthyroidism. The difference in relative distribution of the four most common causes of hyperthyroidism in Iceland, with high iodine intake, and Judand, Denmark, with mild-to-moderate iodine deficiency, is shown in Figure 47.3. In Iceland, Graves ... 

Figure 47.3 Nosological types of hyperthyroidism with different iodine intake levels. Relative frequency of the four most common nosological types of hyperthyroidism in Iceland, with relatively high iodine intake from consumption of fish and high iodine content of dairy products, and from East Jutland, Denmark, with mild-to-moderate iodine deficiency. MNTG, multinodular toxic goiter GD, Graves disease STA, solitary toxic thyroid adenoma SAT, subacute thyroiditis. Data from Laurberg et al., (1991).

In Denmark, we studied the incidence of overt hypothyroidism before the Danish iodine program in two areas with a small difference in iodine intake caused by different iodine contents of groundwater. The population hv-ing in the area with only mild iodine deficiency had a considerably higher incidence of overt hypothyroidism than the population with moderate iodine deficiency, whereas the lower iodine intake was associated with more hyperthyroidism (Figure 47.5) (Billow Pedersen et aL, 2002). Subtyping of disease revealed that the difference in hypothyroidism was caused by 50% more cases of spontaneous autoimmune hypothyroidism in the area with the highest iodine intake (Carld et ai, 2006). 

In a cross-sectional study from a borderline iodine-deficient area in Denmark (Copenhagen), Knudsen et al. included 2656 randomly selected subjects aged 41—71 years. The prevalence rate of TPO-Ab, measured by ELISA, was high at 22.8% (Knudsen et al.y 1999). 

In the same group of women, the incidence of hyperthyroidism was 1.3 cases/1000/year and of hypothyroidism 1.0 cases/1000/year. These data can be compared to data from studies from Denmark (Laurberg et ai, 2006), which show that only a small difference in iodine intake is associated with a large difference in incidence of overt hyper- and hypothyroidism. Thus, the incidence rate of hyperthyroidism for women in a region with moderate iodine deficiency (urinary iodine 45 lig/1) was higher than in a region with mild iodine deficiency (urinary iodine 61pg/l) 1.5 cases/1000/year compared to 1.0 cases/1000/year. In... 

A Danish study of iodine intake in elderly men and women was made in 1988 after a number of studies had suggested that the iodine intake in Denmark has been stable and relatively low for the last 30 years (Pedersen et ai, 1995). AH subjects were born in 1920 and were thus 68-years old at the time of the study. Iodine was measured in a spot urine sample collected in the morning. Careful investigation of the intake of supplementary iodine was taken into account, which none of the previous studies had done. The median urine excretion was 42p,g/l, which indicates moderate iodine deficiency (see Table 116.1). Analyses among users and nonusers of daily iodine supplements indicated that the basic level of iodine intake was overestimated if individual iodine supplementation was not taken into account. About half of the population took no supplements. 

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... 

Judged from internationally recommended levels of iodine intake Denmark is an area of mild to moderate iodine deficiency. The basic levels of urinary iodine excretion have not changed much during the last 30 years, but part of the population take individual iodine supplementation in the form of vitamin/mineral tablets containing 150 Mg iodine. The basic levels of iodine excretion in tuine found in the studies cited above corresponds well to the intake levels calculated from analyses of food and beverage (10). 

---