Surveys for the assessment of the iodine status, carried out between 1997 and 1999 in Turkey showed that the country was severe to moderately iodine deficient. (National median UIC 36 μg/l, goiter prevalence % 31.8). Therefore, a national IDD control program had been implemented and mandatory salt iodization were applied by July 1999 with 5070 mg/kg KI or 2540 mg/kg KIO3 to the household salt.
Objectives: To evaluate the current iodine status by using urinary iodine concentrations (UIC) and household salt iodine content, nation wide.
Methods: A school-based, survey was conducted in 2007 by using multistage proportionate to population size (PPS) cluster sampling method. The study population composed of 900, 612 years old school-age children (SAC) from different centrums, towns, villages. Urine samples, and salt samples that were used for cooking at home were collected. UIC were analyzed using the Sandell-Kolthoff reaction. Iodine content of the salt samples were measured by using iodometric titration method.
Results: Median UIC was 107 μg/l. Severe ID was found in 7.2%, moderate and mild ID in 20.6% and 19.2%, of the SAC respectively. UIC were sufficient in 50%, and excessive (>500 μg/l) in 3%. 662 (73.5%) of the 900 salt samples were iodized. Five hundred and eight samples (56.5%) contained adequately iodized salt (iodine content >15 ppm).
Conclusions: Moderate to severe ID still exists in 27.8% of the Turkish population, which is much better than 1997 and 2002 surveys (i.e. 58, 38.9% respectively). We also conducted a follow-up monitoring study for 30 cities, in 2007, and found that ID have been eliminated in 20. In combination with that data, the present study shows that ID has been eliminated in most of the urban population, however is still an important problem in rural areas, which should be the target of the future program.