The Greek Population Is Iodine Sufficient and Not at Risk of Iodine-Induced Hyperthyroidism

In the April issue of The Journal of Nutrition, Andersson et al. (1) published a paper entitled “Global iodine status in 2011 and trends over the past decade,” in which they discuss the status of global daily iodine intake. In this paper, both in Table 1 and in the global map of Figure 5, Greece is incorrectly listed as a country at risk of iodine-induced hyperthyroidism (i.e., median urinary iodine concentration of 202 mg/L). Indeed, in the 1960s, several areas in Greece were iodine deficient. However, since then, the situation has significantly improved. To begin with, in 1996, studies in a representative area of southwestern Greece indicated that 5 out of 7 areas had a sufficient iodine intake and a median urinary iodide concentration of 114 mg/L (2). In 1999, studies were conducted in 17 villages near Athens that were previously iodine deficient; in 13 of them the urinary iodine concentration reached 109–164 mg/L and in the remaining 4 it ranged from 43 to 70 mg/L (3). In 1994, in another area of northwestern Greece, research among schoolchildren showed that the median urinary iodine concentration was 84 mg/L, which is indicative of borderline iodine deficiency. In the same area, 7 y later (2001), the median urinary iodine concentration of 300 children was 202 mg/L, which is indicative of sufficient iodine intake (4). In addition, we recently studied 134 first-trimester pregnant women residing in the greater Athens area and found that the median urinary excretion was 120 mg/L (range 28–538 mg/L) (5). In today’s Greece we conclude that the population as a whole has an adequate daily dietary intake of iodine. These changes are due to the improvement of socioeconomic conditions and an increased use of iodized salt. Even if cases of iodine deficiency are still recorded, we can conclude that Greece is not a country at risk of iodine-induced hyperthyroidism.