Urinary Iodine Concentration and Thyroid Peroxidase Antibodies in the Korean Population Using Korea National Health and Nutrition Examination Survey VI

ABSTRACT

Background and Objectives@#This study was planned to investigate the relationship between iodine intake and thyroid peroxidase antibody in Korean population. @*Materials and Methods@#We used the data of the 6th Korea National Health and Nutrition Examination Survey from 2013 to 2015. A total of 6564 subjects who had the data of thyroid function test were included. We analyzed urinary iodine concentration and thyroid peroxidase antibody using the complex sample method. Univariate and multivariate analysis were performed according to clinical factors and thyroid function tests. @*Results@#In the multivariate analysis, the thyroid peroxidase antibody positivity was not related to urinary iodine concentration in the total group (p=0.102), male group (p=0.245) and female group (p=0.098). The urinary iodine concentration was associated with thyroid stimulating hormone (TSH) (p=0.001) and free T4 (p=0.001) but not associated with thyroid peroxidase antibody (p=0.218). When high TSH group was divided into the positive and negative thyroid peroxidase antibody, high TSH group with negative thyroid peroxidase antibody increased according to increasing urinary iodine concentration (p＜0.001).But there was no difference in the high TSH group with positive thyroid peroxidase antibody (p=0.826). @*Conclusion@#This study did not show a statistically significant relationship between urinary iodine concentration and thyroid peroxidase antibody. As urinary iodine concentration increased, thyroid function was decreased only in the negative thyroid peroxidase antibody group. This confirmed that the increased urinary iodine concentration caused hypothyroidism which was not associated with thyroid peroxidase antibody.