High Urinary Iodine, Thyroid Autoantibodies, and Thyroid-Stimulating Hormone for Papillary Thyroid Cancer Risk

Abstract

Thyroid nodules have become a common clinical problem, and the clinical importance of thyroid nodules lies in the determination of thyroid cancer. This study aims to evaluate the risk factors for papillary thyroid cancer (PTC) with regard to urinary iodine concentration (UIC), thyroid-stimulating hormone (TSH), thyroid peroxidase antibody (TPOAb), and thyroglobulin antibody (TGAb) in comparison to thyroid nodular goiter (NG). Among the 2041 patients, 43.8% of which showed more than adequate (UIC 200-299 μg/L) and excessive iodine (UIC ≥ 300.0 μg/L) status. Compared with adequate iodine intake, iodine deficiency (UIC < 100 μg/L) was inversely associated with multifocality (OR 0.59, P = 0.040), while more than adequate iodine intake was independently associated with an increased risk of larger tumor size (OR 1.33, P = 0.002) in female PTC patients but not in males. No significant difference in UIC was observed between patients with PTC and NG, suggesting that high iodine intake may be related with the growth of PTC, but not with its oncogenesis. Besides, positive for TPOAb and TGAb were individually associated with papillary thyroid microcarcinoma (PTMC) risk (OR 2.05 and 1.71, respectively, both P < 0.05) in female patients with tumor foci < 1 cm but not in males. Furthermore, younger age (< 46 years), TGAb positivity and small thyroid nodules in both sexes, higher TSH, TPOAb positivity, and multifocality in females could all predict PTC risk (all P < 0.05). These results might have clinical significance for managing patients with thyroid nodules and those with thyroidectomy.

Iodine status of euthyroid adults: A cross‐sectional, multicenter study

“…Evidence suggests that levels of thyroid hormones will remain within normal range in mild iodine deficiency, while the hormone levels will fall outside the normal ranges only in cases of severe iodine deficiency . Several studies reported the relationship between UIC and thyroid functions . A Korean study reported that the serum TSH and FT4 levels showed statistically significant as UIC .…”

About odide: A Friendly and Necessary Ion

“…Iodine plays a fundamental role in the human species and the ideal plasma concentration of this ion prevents mental retardation/cretinism in fetuses and small children, also causing the thyroid neoplasias expressed by this gland to be less aggressive (papilliferous rather than follicular subtype). Iodine is a friendly and necessary ion at ideal concentrations for the human species (68,69,70,71,72,73,74).…”

Urinary iodine is increased in papillary thyroid carcinoma but is not altered by regional population iodine intake status: a meta-analysis and implications

“…Noteworthy, the extent of the UIC increase in PTC patients was higher than that in BTN patients. Generally, it has been demonstrated a significant association of high urinary iodine with BTN [8,[17][18][19]27]. In fact, BTN is classified as adenomas, colloid nodules, congenital abnormalities, cysts, infectious nodules, lymphocytic or granulomatous nodules, or hyperplasia.…”

“…It has been confirmed that iodine excess-induced thyroid dysfunction may lead to benign thyroid disease, such as autoimmune thyroiditis, benign thyroid nodules (BTN), hypothyroidism and hyperthyroidism [3]. But, it remains considerable controversy about the relationship between high iodine intake and thyroid cancers (TC) risk [4][5][6][7][8][9][10][11][12][13].…”

“…Over the past few decades, TC incidence has rapidly increased, PTC predominated in the histological types of TC after universal salt iodization (USI) [4][5][6]14]. It is considered that increasing iodine intake has contributed to the increase in PTC incidence, whereas it is debatable [4][5][6][7][8][9][10][11][12][13].…”