Iodine status in schoolchildren living in northeast Italy: the importance of iodized-salt use and milk consumption.

Background: The aims of the study were: (i) to determine iodine status of schoolchildren living in northeast Italy; (ii) to assess dietary habits and iodine status and (iii) to investigate the level of knowledge concerning iodine sufficiency and ways to ameliorate iodine status.

Methods: One thousand three hundred seventy-five consecutive 12-13 year-old completed questionnaires collecting demographic data and information about the use of iodized salt and food frequency habits. Iodine concentration in urine samples (UIC) and in commercially available milk samples has been measured.

Results: The median UIC was found to be 81 μg/l (95% confidence interval (CI) 74-87); 40% of the subjects had an UIC of ≥ 100 μg/l. Iodine deficiency was prevalent in subjects living in hilly areas. Median iodine concentration in milk was 264 μg/l. Only the combined use of iodized salt plus daily milk normalized UIC, resulting into a median value of 108 μg/l. A logistic regression model confirmed independent associations between low UIC and low intake of milk, use of non-iodized salt and geographical location (P<0.0001). Only 45% of the subjects were aware of the importance of iodine.

Conclusions: Northeast Italy is still characterized by mild iodine deficiency. An adequate iodine status was achieved only when iodized salt was combined with daily milk intake. The national iodine prophylaxis program has led to greater consumption of iodized salt and, it is now used in 60-70% of the Italian households. The low level of awareness highlights the need for public programs to promote knowledge and efforts to improve iodine status.