Consumption of iodized salt may not represent a reliable indicator of iodine adequacy: Evidence from a cross-sectional study on schoolchildren living in an urban area of central Italy.

OBJECTIVE

It has been established that iodine prophylaxis prevents endemic goiter. In this study we reported the amount of iodized salt sold by the retailers of Cassino, a city of central Italy. The aim of the study was to evaluate the effects of an iodine prophylaxis program started in 2005 on urinary iodine concentration (UIC) and thyroid volume (TV), and their correlation with anthropometric parameters in a population of schoolchildren.

METHODS

The study included 234 schoolchildren (119 girls and 115 boys) ages 13 to 14 y. Each student provided a morning urine sample for UIC determination, and TV was evaluated by ultrasonography. Body weight and height also were measured. Each participant completed a questionnaire reporting the presence of thyroid disease and the consumption of iodized salt and iodine-rich food.

RESULTS

The percentage of iodized salt sold by local markets was 42.4%. Median UIC in schoolchildren was 133.9 μg/L (range 33.2-819.5 μg/L), with 71 children having mild (range 50.1-99.9 μg/L) and 10 moderate (range 33.2-48.8 μg/L) iodine deficiency. Eleven children showed excessive iodine intake (range 300.4-819.5 μg/L). Median UIC was higher in children using iodized salt or consuming milk. Goiter prevalence was 3.8%. A positive correlation between TV and body weight, height, and surface was observed.

CONCLUSIONS

The data reported may suggest the presence of an adequate iodine intake in the population of Cassino despite the low percentage of iodized salt sold by local retailers. This indicates that silent iodine prophylaxis through the consumption of iodine-rich or iodine-enriched food is of importance in the prevention of iodine deficiency disorders.