Although positive TPO and/or aTG was more frequent (24/482, 5%) in subjects with thyroid dysfunction (7/11) than in those who remained euthyroid during the study (17/471, χ2 = 69.66, p < 0.0001), thyroid hypoechogenicity had a higher sensitivity than the positivity of thyroid autoantibody tests (100 vs. 63.3%) for diagnosing or predicting thyroid dysfunction (16). Here, TPO is linked to thyroid gland disorder.