Normal Anti-Thyroid Peroxidase Antibody (TPO-Ab) Titers and Active Arterial Wall Thickening among Euthyroid Individuals: A Prospective Study

Association between anti-thyroid peroxidase antibody and insufficient sleep in euthyroid population

Background

Low sleep quality induces inflammation. Because anti-thyroid peroxidase antibody (TPO-Ab) is an autoantibody that induces inflammation in the thyroid, insufficient sleep may stimulate the production of TPO-Ab. However, the thyroid function is also associated with sleep. Therefore, to evaluate the association between TPO-Ab positivity and insufficient sleep, the target population should be limited to euthyroid individuals whose free triiodothyronine (T3), free thyroxine (T4), and thyroid-stimulating hormone (TSH) are within the normal ranges.

Method

This cross-sectional study recruited 1324 euthyroid individuals who participated in annual health checkups. Insufficient sleep was assessed by using a questionnaire. Individuals with free T3, free T4, and TSH levels within the normal ranges were defined as euthyroid.

Results

Among the study population, 406 had insufficient sleep, and 242 were TPO-Ab-positive. Insufficient sleep was associated with a higher likelihood of TPO-Ab positivity. Sex and age adjusted odd ratios (95 % confidence intervals, p) of TPO-Ab positive for insufficient sleep was 1.47 (1.08, 2.01, p = 0.014). These associations remained unchanged even after further adjustment for free T4 and TSH, status of body mass index, smoking status, drinking status, mental distress, and physical activity; 1.53 (1.11, 2.10, p = 0.009).

Conclusion

Euthyroid individuals with insufficient sleep may be at risk of autoimmune thyroiditis. Although further investigations are necessary, sleep disorder therapy might reduce the risk of the incidence of autoimmune thyroiditis.

Thyroid peroxidase antibodies were associated with prevalent carotid intima-media thickness in middle-age and older adults: the ELSA-Brasil cohort

PURPOSE

Understanding the relationship between antithyroperoxidase antibodies (TPOAb) and carotid intima-media thickness (cIMT) could provide insights into the mechanisms linking thyroid autoimmunity and cardiovascular disease. We aimed to explore the association of multiple categories of TPOAb with the increased cIMT at baseline and at follow-up in participants from the ELSA-Brasil Study.

METHODS

This prospective cohort study analyzed data from 9,264 participants (51.5 ± 8.9 years old, 55.9% women) without a history of cardiovascular disease. Fasting serum TPOAb levels were determined. Values of cIMT equal to or above one deviation standard of the sample's mean were classified as increased cIMT at baseline. The increased cIMT after the 8-year follow-up was calculated after excluding participants with increased cIMT at baseline. Multivariate analyses were done using binary logistic and Poisson regression models.

RESULTS

The increased cIMT was prevalent in 14.3% of the participants at baseline and its development occurred in 16.8% participants during the cohort. After adjustment for all confounder variables, TPOAb detectability (OR = 1.84, 95%CI = 1.21-2.79), and low detectable (OR = 1.81, 95%CI = 1.18-2.75), high detectable (OR = 2.01, 95%CI = 1.29-3.11) and positive (OR = 1.70, 95%CI = 1.07-2.70) TPOAb were positively associated with increased cIMT at baseline. The associations of low and high detectable TPOAb and increased cIMT at baseline were consistent when excluding those with thyroid dysfunction. There was no statistically significant association between TPOAb levels and increased cIMT at follow-up (p > 0.05), neither for all sample nor for euthyroid individuals.

CONCLUSION

Different levels of TPOAb, including its detectability, were associated with increased cIMT at baseline in the studied sample. We highlight that may be relevant to consider the levels of TPOAb detectability as possible marker of increased cardiovascular risk.

Association between atherosclerosis and height loss among older individuals

Atherosclerosis and height loss are each reportedly associated with cardiovascular disease. However, no studies have found an association between atherosclerosis and height loss. A retrospective study of 2435 individuals aged 60-89 years who underwent annual health check-ups was conducted. Atherosclerosis was defined as carotid intima-media thickness (CIMT) ≥ 1.1 mm. Height loss was defined as being in the highest quintile of height decrease per year, as in our previous studies. Among study participants, 555 were diagnosed as having atherosclerosis. Independent of known cardiovascular risk factors, atherosclerosis was positively associated with height loss. The adjusted odds ratio (OR) was 1.46 (95% confidence interval, 1.15, 1.83). Essentially the same associations were observed for men and women. The adjusted OR (95% CI) was 1.43 (1.01, 2.04) for men and 1.46 (1.07, 1.99) for women. Among older individuals, atherosclerosis is associated with height loss. This result can help clarify the mechanism underlying the association between height loss and cardiovascular disease.

Deciphering thyroid function and CIMT: a Mendelian randomization study of the U-shaped influence mediated by apolipoproteins

Background

Carotid Intima-Media Thickness (CIMT) is a key marker for atherosclerosis, with its modulation being crucial for cardiovascular disease (CVD) risk assessment. While thyroid function's impact on cardiovascular health is recognized, the causal relationship and underlying mechanisms influencing CIMT remain to be elucidated.

Methods

In this study, Mendelian Randomization (MR) was employed to assess the causal relationship between thyroid function and CIMT. Thyroid hormone data were sourced from the Thyroidomics Consortium, while lipid traits and CIMT measurements were obtained from the UK Biobank. The primary analysis method was a two-sample MR using multiplicative random effects inverse variance weighting (IVW-MRE). Additionally, the study explored the influence of thyroid hormones on lipid profiles and assessed their potential mediating role in the thyroid function-CIMT relationship through multivariate MR analysis.

Results

The study revealed that lower levels of Free Thyroxine (FT4) within the normal range are significantly associated with increased CIMT. This association was not observed with free triiodothyronine (FT3), thyroid-stimulating hormone (TSH), or TPOAb. Additionally, mediation analysis suggested that apolipoprotein A-I and B are involved in the relationship between thyroid function and CIMT. The findings indicate a potential U-shaped curve relationship between FT4 levels and CIMT, with thyroid hormone supplementation in hypothyroid patients showing benefits in reducing CIMT.

Conclusion

This research establishes a causal link between thyroid function and CIMT using MR methods, underscoring the importance of monitoring thyroid function for early cardiovascular risk assessment. The results advocate for the consideration of thyroid hormone supplementation in hypothyroid patients as a strategy to mitigate the risk of carotid atherosclerosis. These insights pave the way for more targeted approaches in managing patients with thyroid dysfunction to prevent cardiovascular complications.

Potential Determinants of Thyroid Peroxidase Antibodies and Mortality Risk: Results From the ELSA-Brasil Study

CONTEXT

The presence of thyroid peroxidase antibodies (TPOAbs) may be considered as an indicator of adverse health outcomes.

OBJECTIVE

We aimed to investigate the potential determinants of TPOAb levels and to analyze the association between TPOAb titers and the risk of all- and specific-cause mortality.

METHODS

Baseline and longitudinal data of 13 187 participants from the ELSA-Brasil Study were analyzed. We investigated the association of TPOAb, detectability, positivity, and persistent positivity with sociodemographic and lifestyle factors using logistic regressions. Cox proportional hazards and Fine-Gray subdistribution hazard regression analyses were used to verify the association of TPOAbs with mortality.

RESULTS

The determinants of TPOAb detectability and positivity were younger age, higher body mass index, female sex, and former and current smoking status. Black, mixed, and other self-reported races, intermediate and higher education, and heavy drinking were determinants of detectable and positive TPOAb levels. Female sex, White race, and former smoking were determinants of persistent TPOAb positivity at 2 visits, although only the female sex maintained its association at 3 visits. Moreover, after multivariate adjustment, there were associations between higher levels of TPOAbs and higher risk of cancer-related mortality among men, and TPOAb detectability and mortality by other causes among women.

CONCLUSION

Sociodemographic and lifestyle-related factors were determinants of multiple TPOAb categories. TPOAb levels were associated with mortality risk; however, the low mortality rate in this sample might have compromised this finding. We suggest further studies to explore the clinical importance of detectable TPOAb levels, not only its positivity, as a potential marker of inflammation.

Association between anti-thyroid peroxidase antibody and thyroid stimulating hormone: a cross-sectional study

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.

Height and Active Arterial Wall Thickening in Relation to Thyroid Cysts Status among Elderly Japanese: A Prospective Study

Height is inversely associated with inflammation that stimulates endothelial repair. In our previous study involving elderly men aged 60-69 years, we found that active arterial wall thickening, which is known as the process of endothelial repair, requires CD34-positive cells. As thyroid hormone regulates CD34-positive cell production and as the absence of thyroid cysts might indicate latent damage in the thyroid, the status of thyroid cysts possibly influences the association between height and active arterial wall thickening. We conducted a 2-year follow-up study of Japanese aged 60-69 years. For participants with thyroid cysts, height was significantly inversely associated with active arterial wall thickening (thyroid function and baseline CIMT adjusted odds ratio of active arterial wall thickening for one increment of standard deviation of height (5.7 cm for men and 4.8 cm for women), 0.66 [0.49, 0.89]), while for those without thyroid cysts, a positive tendency between the two parameters was observed (1.19 [0.96, 1.50]). An inverse association between height and active arterial wall thickening was observed only for elderly participants with thyroid cysts possibly because of a supportive role of thyroid hormone, as the absence of thyroid cysts might indicate latent damage in the thyroid.