Search

To maintain normal level of thyroid hormone, especially for free thyroxine (FT4), individuals with latent thyroid gland damage might have required higher thyroid stimulating hormone (TSH) than those without latent thyroid gland damage. Anti-thyroid peroxidase antibody (TPO-Ab) is a main cause of auto-immune thyroiditis, and therefore euthyroid individuals positive for TPO-Ab might have latent damage to the thyroid gland. Therefore, the association between TSH values and TPO-Ab positivity may be useful to determine the influence of latent thyroid gland damage on requirement of TSH. Furthermore, because latent damage of thyroid might elevate TSH level but not FT4 level, those associations should be observed independent from FT4. This cross-sectional study analyzed 1431 Japanese with normal ranges of free triiodothyronine (FT3) and FT4. Since TPO-Ab is associated with atherosclerosis in euthyroid individuals, cardiovascular risk factors might underlie the association between TPO-Ab and TSH values. After adjusting for FT4 and known cardiovascular risk factors, the adjusted odds ratio (95% confidence interval) of TPO-Ab positivity for logarithmic value of TSH was 1.53 (1.20, 1.95). Essentially the same association was observed when the analysis was restricted to individuals without subclinical hypothyroidism (1.54 [1.15, 2.13]). Euthyroid individuals with latent thyroid gland damage might have increased the requirement of TSH., (© 2023. Springer Nature Limited.)

Background: High normal levels of thyroid-stimulating hormone (TSH) have been reported to be associated with chronic kidney disease (CKD) among euthyroid individuals. However, there has been only limited research on the association between TSH and proteinuria, a major risk factor for the progression of renal disease., Methods: A cross-sectional study of 1595 euthyroid individuals was conducted. All participants were within the normal range for free triiodothyronine (T3), free thyroxine (T4), and TSH. Analyses were stratified by thyroid cyst status to test the hypothesis that the absence of thyroid cysts, an indicator of latent thyroid damage, is associated with declining ability to synthesis thyroid hormone., Results: For participants with thyroid cysts, a significant inverse association between TSH and proteinuria was observed (adjusted odds ratio (95% confidence intervals) of log-transformed TSH for proteinuria 0.40 (0.18, 0.89)). In participants without thyroid cysts, a significant positive association between those two factors was observed (2.06 (1.09, 3.90))., Conclusions: Among euthyroid individuals in the general population, being in the normal range of TSH was found to have an ambivalent association with proteinuria. Thyroid cyst status could be an effect modifier for those associations., (© 2021. The Author(s).)

Background: The absence of thyroid cysts may indicate latent thyroid damage, as demonstrated in our previous study. However, the association between the absence of thyroid cysts and latent functional damage of the thyroid is unknown. At low thyroid hormone productivity, which may be associated with latent functional damage of the thyroid, the association between thyroid-stimulating hormone (TSH) and hypertension might be enhanced. Therefore, we evaluated the association between TSH level and hypertension stratified by thyroid cyst status., Methods: We conducted a cross-sectional study of 1724 euthyroid Japanese individuals aged 40-74 years who participated in an annual health checkup in 2014., Results: In the study population, 564 and 686 participants had thyroid cysts and hypertension, respectively. A significant positive association was observed between TSH and hypertension in subjects without a thyroid cyst but not in subjects with thyroid cysts. There was a significant positive association between hypertension and TSH in subjects without a thyroid cyst (odds ratio [OR] 1.27; 95% confidence intervals [CI] 1.01, 1.61) but not in subjects with thyroid cysts (OR 0.79; CI 0.57, 1.09) in the model fully adjusted for known confounding factors. The correlation between the TSH and free triiodothyronine (fee T3) levels (simple correlation coefficient [r] = - 0.13, p < 0.01) was stronger in the subjects without thyroid cysts than in those with thyroid cysts (r = - 0.03, p = 0.525)., Conclusions: TSH is positively associated with hypertension only in individuals without thyroid cysts. The correlation between the TSH and free T3 levels was stronger in the subjects without thyroid cysts than in those with thyroid cysts. Therefore, the absence of thyroid cysts could be related to the association between TSH level and hypertension, possibly by indicating that the subjects without thyroid cysts had limited thyroid hormone reserves. Therefore, the absence of thyroid cysts could indicate the latent functional damage of the thyroid.

Anti-thyroid peroxidase antibody (TPO-Ab) is revealed to be inversely associated with thyroid cysts among euthyroid population. TPO-Ab causes autoimmune thyroiditis by bolstering thyroid inflammation. Therefore, at least partly, absence of thyroid cysts could indicate latent thyroid damage. Since participants with subclinical hypothyroidism are reported to have higher HbA1c than normal healthy controls, HbA1c could be inversely associated with thyroid cysts through a mechanism reflecting latent thyroid damage. To investigate the association between HbA1c and thyroid cysts among a euthyroid population, a cross-sectional study was conducted on 1,724 Japanese individuals who were within the normal range of thyroid function [i.e., normal range of free triiodothyronine (T3) and free thyroxine (T4)] and aged 40–74 years. Among this study population, 564 were diagnosed with thyroid cysts. Independently of thyroid related hormones [thyroid stimulating hormone (TSH), free T3, and free T4] and known cardiovascular risk factors, HbA1c was found to be significantly inversely associated with the presence of thyroid cysts. This association remained significant even after this analysis was limited to participants within a normal range of TSH. The fully adjusted odds ratios (ORs) of thyroid cysts for 1 standard deviation (SD) increment of HbA1c were 0.84 (0.74, 0.95) for total participants and 0.80 (0.70, 0.92) for participants within a normal range of TSH. Among participants with normal thyroid function, HbA1c was inversely associated with the presence of thyroid cysts. The absence of thyroid cysts and higher levels of HbA1c could indicate the latent functional damage of the thyroid. [ABSTRACT FROM AUTHOR]