Since thyroglobulin plays an important role in synthesizing thyroid hormone , thyroid cysts could possess beneficial effects on thyroid hormone synthesized by pooling thyroglobulin. Thyroid cysts were defined as those using a maximum diameter of 2.0 mm, containing no sound component. TPO-Ab (+) was positively associated with SCH with hypertension (adjusted odds ratio [OR] and 95% confidence interval [CI], 2.62 [1.40, 4.89]) but not with SCH without hypertension (0.84 [0.37, 1.89]), respectively. Moreover, among participants without thyroid cysts, SCH was positively associated with hypertension (2.15 [1.23, 3.76]) but ICA-110381 not among participants with thyroid cysts (0.58 [0.16, 2.16]), respectively. TPO-Ab ICA-110381 was positively associated with SCH with hypertension, but not with SCH without hypertension. In addition, status of thyroid cysts might act as a determinant factor around the association between SCH and hypertension. These findings are efficient tools to clarify the background mechanism that underlies SCH. Introduction Anti-thyroid peroxidase antibody (TPO-Ab) causes autoimmune thyroid disease  by bolstering thyroid inflammation . In addition, high prevalence of TPO-Ab ICA-110381 (+) is usually reported in subclinical hypothyroidism (SCH) [3,4]. Since both low-grade inflammations and hypothyroidism are known factors that are associated with hypertension [5,6], status of hypertension among SCH could act as a determinant factor of the association between TPO-Ab and SCH. Therefore, TPO-Ab (+) could be positively associated with SCH with hypertension but not with SCH without hypertension. In addition, high concentration of thyroglobulin in the fluid from thyroid cysts was reported by a previous study . Since thyroglobulin plays an important role in synthesizing thyroid hormone , thyroid cysts could possess beneficial effects on thyroid hormone synthesized by pooling thyroglobulin. Our previous study also reported a positive association between TPO-Ab titer and absence of thyroid cysts . Since TPO-Ab injures thyroid, the absence of thyroid cysts might indicate latent thyroid damage. Moreover, since hypothyroidism is known to be associated with hypertension , this study speculated that SCH with absence of thyroid cysts could be associated with hypertension by ICA-110381 indicating latent thyroid damage. Furthermore, if the presence of thyroid cysts has a beneficial influence on thyroid hormone synthesis, thyroid cysts could be positively associated with isolated systolic hypertension because hyperthyroidism is known to be a common cause of isolated systolic hypertension . Clarifying those associations by using multi-faceted analysis in a simple population is an efficient tool to clarify the background mechanism that underlies the JAM3 association between TPO-Ab and SCH among eu-thyroid populace. We conducted a cross sectional study of 1483 eu-thyroid Japanese aged 40C74 years who participated in annual health check-up in 2014. Methods Study population The methods that relate to the present risk survey including thyroid function have been described elsewhere . We ensured that participants comprehended the objective of the study and informed consent was obtained. This ICA-110381 study was approved by the Ethics Committee of Nagasaki, University Graduate School of Biomedical Sciences (Project registration number: 14051404). In 2014, the total number of residents aged 40C74 years in Saza Town (estimated by the National Institute of Populace and Social Security Research in March 2013) was 6,207 . The study populace comprised 1,883 Japanese individuals between the ages of 40 and 74 years from Saza town in the western a part of Japan who underwent an annual medical checkup in 2014, as recommended by the Japanese government. The follow-up rate for this annual health check-up is usually high; more than 80% of individuals who underwent medical health check-up in 2014 also underwent.