Analysis of thyroid function under different iodine nutritional status

Abstract

Objective \nTo understand the iodine nutritional status of medical examination people and the thyroid dysfuction rates under different urinary iodine. \n \n \nMethods \nA total of 2 650 medical examination people from Inner Mongolia National Examination Medical Center from March to December of 2018 were selected. The average age was (46.2 ± 12.5) years old, including 697 males and 1 953 females. Blood samples were collected for determination of thyroid function [thyroid stimulating hormone (TSH), thyroid peroxidase antibody (TPOAb), thyroglobulin antibody (TgAb), free thyroxine (FT4), and free triiodothyronine (FT3)], and according to the results of the examination, people were divided into normal thyroid function, subclinical hypothyroidism, subclinical hyperthyroidism, hypothyroidism, hyperthyroidism, autoimmune antibody abnormalities, and other abnormal groups. Urine samples were collected to detect urinary iodine levels, to analyze the thyroid dysfuction rates of each group people and different urinary iodine. The thyroid function was detected by automatic electrochemiluminescence immunoassay analyzer, the urinary iodine was determined by arsenic cerium catalytic spectrophotometry. \n \n \nResults \nAmong the 2 650 medical examination people, there were 1 270 patients with abnormal thyroid function, and the total abnormal rate was 47.92%. The abnormal rates of males and females were 28.84% (201/697) and 54.74% (1 069/1 953), respectively, and the abnormal rate of females was higher than that of males (χ2 = 376.19, P < 0.05). The urinary iodine medians of each group were 145.38, 152.60, 103.21, 176.31, 134.17, 138.92, and 127.00 μg/L, all in the appropriate range of iodine (100 - 199 μg/L). Thyroid abnormal rates [55.56% (125/225), 50.86% (445/875)] of urinary iodine ≥300 μg/L (iodine excess) group and < 100 μg/L (iodine deficiency) group were higher than that of 100 - 199 μg/L group [44.70% (460/1 029), χ2 = 12.65, 12.61, P < 0.05]. Among thyroid abnormal people, autoimmune antibody abnormalities people was the most, accounting for 69.61% (884/1 270). Urinary iodine was positively correlated with FT4 and FT3 (r = 0.04, 0.05, P < 0.05); FT4 was negatively correlated with TSH and TgAb (r = - 0.20, - 0.73, P < 0.05), and it was positively correlated with FT3 (r = 0.52, P < 0.05); TPOAb was positively correlated with TgAb (r = 0.64, P < 0.05). \n \n \nConclusions \nUrinary iodine of medical examination people is in the appropriate range of iodine, indicating that the overall iodine nutritional status is good. However, some people still have iodine excess and iodine deficiency, both of which lead to an increase in thyroid abnormal rate. \n \n \nKey words: \nThyroid gland;\xa0Iodine;\xa0Hypothyroidism;\xa0Hyperthyroidism