Effects of prophylaxis with iodised salt in an area of endemic goitre in north-eastern Sicily

Abstract

In developed countries, the use of iodised salt represents the best prophylaxis of endemic goitre in areas exposed to iodine deficiency. In the present study we re-evaluated goitre prevalence and iodine intake 10 years after the introduction of iodised salt in an area of goitre endemia in north-eastern Sicily (Italy), and we compared these results with those obtained in previous surveys. Three centres with known moderate goitre endemia (Bronte, Nicosia, and Gagliano) and three other smaller ones with severe goitre endemia (Sperlinga, Villadoro, and Maniace) were studied. We surveyed 697 schoolchildren. Goitre prevalence was assessed by thyroid palpation and by a thyroid ultrasound scan. Iodine urinary excretion was also measured. Iodised salt consumption was 44% of total salt consumption. Goitre prevalence assessed by thyroid palpation was significantly decreased in all towns studied compared to previous surveys. However, the persistence of a mild goitre endemia was observed in some small rural centres (5.8% in Sperlinga/Villadoro, and 11.4% in Maniace). Goitre prevalence evaluated by thyroid ultrasound scan was greater than 5% in all centres of the endemic area and was always greater than that assessed by thyroid palpation. Iodine urinary excretion was above 100 microg/l in all localities studied. In conclusion, our studies indicate a progressive reduction in goitre prevalence over a period of about 30 years in schoolchildren in a well-characterised endemic area in northeastern Sicily. The decrease in goitre prevalence was associated with a significant increase in urinary iodine excretion. However, it may be speculated that iodine deficiency is the pre-eminent, but not the exclusive cause of goitre endemia in this area.