123 HUBUNGAN DEFISIENSI SELENIUM DENGAN THYROID STIMULATING HORMONE (TSH), TRIIODOTHYRONIN (T3), DAN FREE THYROXINE (fT4) PADA ANAK SEKOLAH DASAR DI DAERAH ENDEMIK GAKI Selenium Defciencies Association with Thyroid Stimulating Hormone (TSH), Triiodothyronin (T3) and Free Thyroxine (fT4) Levels in Endemic IDD Areas Primary School Children Nur Ihsan *1 , Yusi Dwi Nurcahyani 1 1 Balai Litbang GAKI Magelang Kavling Jayan, Borobudur, Magelang *e-mail: nur.ihsan1@gmail.com Submitted: March 5, 2015, revised: March 24, 2015, approved: June 1, 2015 ABSTRACT Background. Iodine and selenium are essential micronutrients in the formation of thyroid hormones. Selenium plays a role in the conversion of T4 to T3, that its defciency can affect thyroid hormone metabolism and exacerbate iodine defciency.This study aimed to determine the relationship between selenium status and thyroid hormone status of primary school children in the endemic iodine defciency areas. Methods. This is a cross sectional design study conducted in Candiroto, Temanggung district. The subjects were 70 students of the fourth, ffth and sixth grade of three elementary schools which were randomly selected.The selenium concentration in the serum were determined using atomic absorption spectrophotometry while the TSH, fT4 and T3 were measured using enzyme linked immunosorbent assay (ELISA) method. The data were analysed using spearman correlation and linear regression. Result. It was found that selenium status on all subjects were below standard, with a median of 21.2 (13.7 to 30.1) ug/L.Thyroid status were in the normal range, with the fT4 median and TSH mean of 8.5 (4.5 to 15.3) mg/L and 3.6 (± 2.0) mIU/L respectively. T3 levels were in the category below normal on 92.9 percent subjects with median of 0.7 (0.4 to 1.9) nmol/L. Almost 90 percent of the subjects consumed substandard iodized salt (> 30 ppm). There is signifcant correlation between selenium levels with TSH levels (r = 0.384; p = 0.001), however there are no signifcant correlation between selenium with fT4 and T3. Increased in TSH levels can predict increase in selenium levels after considering other variables (R 2 = 0,133). Conclusion. In this study, selenium defciency is positively associated with TSH, but not signifcantly associated with fT4 and T3. Keywords: free T4, IDD, selenium, schoolchildren, T3. ABSTRAK Latar Belakang. Iodium dan selenium merupakan mikronutrien yang penting dalam pembentukan hormon tiroid. Selenium berperan dalam konversi T4 ke T3, sehingga defsiensi selenium dapat mempengaruhi metabolisme hormon tiroid dan memperberat GAKI. Penelitian ini bertujuan untuk mengetahui hubungan status selenium dan status hormon tiroid anak sekolah dasar di daerah endemik GAKI. Metode. Desain penelitian menggunakan rancangan cross sectional. Lokasi penelitian di Kecamatan Candiroto salah satu daerah endemik berat GAKI di Kabupaten Temanggung. Sebanyak 70 sampel serum darah diambil dari siswa kelas 4, 5, dan 6 pada 3 sekolah dasar yang dipilih secara acak. Kadar Selenium diukur dengan menggunakan metode atomic