Poland, a country with mild/moderate iodine deficiency introduced an obligatory iodination salt system in 1996.
Aim: To compare the results of radioiodine (131I) uptake after 5 h and 24 h with the activity of radioiodine used in the treatment of hyperthyroid patients with Graves' disease in the years 1995 and 2003.
Patients, methods: The marker of iodine content in the diet was urinary iodine excretion. 1000 randomly chosen patients (average age: 46 +/- 12 years) were included in the study. Every patient had routinely estimated radioiodine uptake after 5 h and 24 h and the activity of 131I was calculated using scintigraphy and ultrasonography of the thyroid gland. Urinary iodine excretion in samples from year 1995 and 2003 was also determined in some patients and healthy volunteers.
Results: The iodine load in the diet increased from 66 microg (average) in the year 1995 to 115 microg in the year 2003. Thyroid radioiodine uptake was 40% lower in comparison with the results from 1995. The average activity of 131I given in the year 2003 (10 mCi) was about 40% higher than in the year 1995 (7 mCi).
Conclusion: There was significant negative correlation between higher iodine content in the diet and lower values of radioiodine uptake, which led to the application of the higher activity of 131I during treatment.