20.500.12556/DiRROS-24022 Interpreting urinary iodine concentration effects of urine dilution and collection timing OBJECTIVES: In population studies, iodine intake estimation relies on median urinary iodine concentration (UIC). However, interpreting UIC measurements can be challenging. METHODS: In our study, we included 772 adult participants from three groups: nationally representative gender-mixed, women of reproductive age, and pregnant women. We measured UIC and urinary creatinine (U-Cr) to calculate the iodine-to- creatinine ratio (I/Cr). U-Cr cut-off value of 0.226 g/L was used for differentiation between diluted and undiluted urine samples. After excluding samples below this cut-off, new median UIC and I/Cr ratios were calculated. We additionally evaluated the influence of urine sample collection time on UIC. RESULTS: Median UICs were 91.8 μg/L for nationally representative group, 58.3 μg/L for women of reproductive age, and 74.9 μg/L for pregnant women, while I/Cr ratios were 91.7, 102.0, and 159.2 μg/g, respectively. After implementing U-Cr cut-off and excluding all data where U-Cr was below cut-off, new median values were 93.4, 76.3, and 95.4 μg/L for UICs, and 88.6, 88.8, and 128.7 μg/g for I/Cr ratios, respectively. In women of reproductive age, median UIC was significantly lower in urine samples collected after 9:30 and after 12:00 as compared to samples collected before 9.30 (53.4, 57.8, and 97.3 μg/L, respectively). CONCLUSIONS: UIC results should be interpreted with caution, considering urine dilution and sample collection timing. U-Cr measurement should be included in population-based iodine intake studies, with corrections applied especially for pregnant women and younger adults, for whom morning is best for single-spot samples. urine dilution urinary iodine concentration true false true Angleški jezik Ni določen © The Author(s) 2024 Neznano 2025-11-07 12:54:22 2025-11-07 14:22:37 2025-11-08 03:43:43 0000-00-00 00:00:00 2024 0 0 Soavtorji: Maša Hribar, Hristo Hristov, Matej Gregorič, Urška Blaznik, Joško Osredkar, Anita Kušar, Katja Žmitek, Živa Lavriša, Tjaša Zaletel, Blaž Krhin, Igor Pravst, Simona Gaberšček, Katja Zaletel; str. 1105-1110 Vol. 78 2024 0000-00-00 Zaloznikova Objavljeno NiDoloceno 0000-00-00 0000-00-00 2024-01-01 616.6 0954-3007 10.1038/s41430-024-01492-y 205173251 https://www.nature.com/articles/s41430-024-01492-y 1 829f9f68-bbd0-11f0-94a7-001a4af901a5 https://dirros.openscience.si/Dokument.php?lang=slv&id=35698 RAZ_Oblak_Adrijana_2024.pdf RAZ_Oblak_Adrijana_2024.pdf 1 CB1D38BF8DFE2140ACC95A129BB55F40 055d04dad805466ece15f3ece1337fe3cfccea184e8c43a4dea5ea6585c7401a 99421bd4-bbdc-11f0-94a7-001a4af901a5 https://dirros.openscience.si/Dokument.php?lang=slv&id=35715 Inštitut za nutricionistiko 0 0 0