OBJECTIVES: This study aimed to evaluate the association of iodine nutritional status with TNs, and papillary thyroid carcinoma (PTC) in women attending an outpatient clinic at a university hospital in an iodine-sufficient region of Brazil. Additionally, the urinary iodine status was evaluated in patients with PTC and BRAF mutation.
METHODS: Cross-sectional study including 133 women who underwent thyroid ultrasound and urinary iodine concentration (UIC) measurement. The diagnosis of PTC was confirmed by histopathology, and the BRAF V600E mutation was assessed through immunohistochemistry in patients with classical PTC.
RESULTS: A UIC > 300 µg/L was an independent risk factor for the presence of TNs (odds ratio [OR] 3.42, 95 % confidence interval [CI] 1.10-10.66 p = 0.033) and for the occurrence of PTC (OR 3.90, 95 % CI 1.00-15.42, p = 0.05). The BRAF V600E mutation was present in 50 % of the analyzed PTCs, with frequencies of 33.3 %, 50.0 %, and 75.0 % among participants with insufficient, adequate, and more than adequate iodine levels, respectively. The median UIC was higher in patients with the follicular subtype of PTC compared with those with the classical subtype (318.1 µg/L vs. 207.1 µg/L, respectively; p = 0.048). A high frequency of UIC values ≥ 300 µg/L also was found in patients with the follicular subtype of PTC (83.3 %).
CONCLUSION: In an iodine-sufficient area, UIC values ≥ 300 µg/L suggested an association with the presence of TNs and PTC. A high frequency of iodine excessive status was observed in patients with follicular subtype. However, none of the patients with presence of the BRAFV 600E mutation presented excessive iodine status.