Current iodine status in Turkey.

OBJECTIVES: To evaluate the current nationwide iodine status in Turkey by determining urinary iodine concentrations (UIC) and household salt iodine content. A follow- up monitoring study was also conducted in 30 urban areas. METHODS: A school-based survey was conducted in 2007 by using multistage 'proportionate to population size' (PPS) cluster sampling method. The study population was composed of 900 school-age children (SAC) from different urban, suburban, and rural areas. UIC and iodine content of the table salt used at home were analyzed. RESULTS: Median UIC was 107 microg/l (147 in urban, 42 in suburban and rural areas, p<0.001). There were severe iodine deficiency (ID) in 7.2%, moderate and mild ID in 20.6% and 19.3%, of the SAC, respectively. UIC was sufficient (>100 microg/l) in 50% of the study population, whereas it was excessive (>300 microg/l) in 10.5% of them. Of the 900 salt samples, 662 (73.5%) were iodized and 508 samples (56.5%) contained adequately iodized salt (iodine content >15 ppm). UIC of the study population and salt iodine levels correlated well (r=0.42, p<0.001). CONCLUSIONS: Moderate to severe ID still exists in 27.8% of the Turkish population, which is much better compared to 1997 and 2002 surveys (i.e. 58%, 38.9%, respectively). The follow-up monitoring study (in 2007) demonstrated that ID has been eliminated in 20 of 30 cities surveyed, and median UIC was 130 microg/l. ID has been eliminated in most of the urban population, however, it is still an important problem in rural areas and in particular geographical regions, which should be the target of future programs.