Subclinical Thyroid Dysfunction and the Risk of Cardiovascular Disease

The Impact of Thyroid Hormone Imbalance on Cardiovascular Health: A Population-Based Study

INTRODUCTION

Thyroid hormone imbalances are known to significantly affect cardiovascular health, contributing to conditions such as arrhythmias, dyslipidemia, and hypertension. Given the increasing prevalence of thyroid dysfunction and its potential impact on cardiovascular outcomes, early diagnosis and intervention are crucial, particularly within specific regional populations.

OBJECTIVE

This study aimed to evaluate the impact of thyroid hormone imbalance on cardiovascular health outcomes in patients at Lady Reading Hospital, Peshawar, over a 24-month period.

MATERIALS AND METHODS

A prospective cohort study was conducted between October 2022 and September 2024, involving 150 adult patients diagnosed with thyroid dysfunction, categorized into subclinical, hyperthyroid, and hypothyroid groups. The study assessed key cardiovascular health indicators, including blood pressure, lipid profiles, heart rate, and electrocardiograms (ECGs), at baseline and during follow-up visits at 6, 12, and 24 months. Participants were included if they met the biochemical criteria for thyroid dysfunction and had no significant pre-existing cardiovascular disease. Data were collected through medical records and standardized questionnaires. The Institutional Review Board at Lady Reading Hospital approved the study.

RESULTS

Dyslipidemia was found in 90 participants (60%), hypertension in 99 participants (66%), and hypothyroidism in 76 participants (72%). Arrhythmias were observed in 14 individuals (46%) with hyperthyroidism. ECG findings revealed sinus bradycardia in 32 participants (30%) with hypothyroidism and sinus tachycardia in 23 participants (76%) with hyperthyroidism. Multivariate analysis showed that hypothyroidism significantly increased the odds of hypertension (OR = 3.2, p = 0.001), dyslipidemia (OR = 2.9, p = 0.003), and arrhythmias (OR = 4.3, p < 0.001).

CONCLUSION

Thyroid hormone imbalance has a profound impact on cardiovascular health, with hyperthyroidism linked to arrhythmias and hypothyroidism associated with hypertension and dyslipidemia. Subclinical thyroid dysfunction also increases cardiovascular risks, emphasizing the need for early detection and region-specific management strategies. This study provides valuable insights into the long-term cardiovascular effects of thyroid dysfunction in the Khyber Pakhtunkhwa (KPK) region, supporting the importance of routine screening and timely intervention.

Glucagon-modified Liposomes Delivering Thyroid Hormone for Anti-obesity Therapy

BACKGROUND

Thyroid hormones (active form T3) are naturally potent compounds that influence energy expenditure, cholesterol metabolism, and fat oxidation. T3 would be an effective anti-obesity drug if it would not be delivered to the heart and bones, which leads to serious side effects, such as cardiovascular and bone thyrotoxicity, muscle wasting, and so on.

METHODS

In this study, we designed a targeted drug delivery system that is a glucagon-modified liposome to deliver T3 to the liver and adipose tissues.

RESULTS

The liposomes exhibited excellent properties, including uniform nanoscale particle size, good physicochemical stability, and adequate drug release behavior. More importantly, the glucagon-modified liposomes were enriched in the liver, which minimized the undesired bone and cardiovascular thyrotoxicity of T3. Compared to the control group, T3-loading glucagon-modified liposomes could effectively decrease body weight, reverse hepatic steatosis, and correct hyperlipidemia and hyperglycemia in ob/ob mice, without the undesired cardiovascular and bone thyrotoxicity.

CONCLUSION

These findings indicate that delivery of thyroid hormone by glucagon-modified liposomes may provide an effective strategy for anti-obesity therapy.

Type 2 Diabetes Mellitus Coincident with Clinical and Subclinical Thyroid Dysfunctions Results in Dysregulation of Circulating Chemerin, Resistin and Visfatin

The alterations of circulating adipocytokines have been reported in thyroid diseases or type 2 diabetes mellitus (T2DM), but such data in T2DM coincident with clinical and subclinical thyroid-dysfunctions are limited, and remain to be investigated. We studied the changes in serum chemerin, resisitin and visfatin in T2DM patients with thyroid dysfunctions, and their association with inflammatory and insulin resistance-markers. A total of 272 female and male Iranian participants were selected and divided into six groups: the euthyroid group, T2DM, T2DM coincident with clinical and sub clinical hypothyroidism (SC-HO, and C-HO), and T2DM coincident with clinical and sub clinical hyperthyroidism (SC-HR, C-HR).Demographic characteristics, serum levels of adipocytokines, thyroid hormones, inflammatory factors (IL1-β, IL-6 and CRP) and insulin resistance-markers were determined in all participants. T2DM patients with clinical thyroid dysfunctions showed higher levels of circulating resistin, visfatin, chemerin and inflammatory factors, compared with the T2DM group and T2DM coexisted with subclinical thyroid diseases. No significant differences were observed in circulating adipocytokines and inflammatory markers between T2DM coexisting with subclinical thyroid diseases and those without thyroid dysfunctions. Our results revealed that clinical thyroid dysfunction in T2DM patients was associated with elevated levels of circulating resistin, chemerin, visfatin and inflammatory factors, while no such alteration was detected in T2DM coincident with subclinical thyroid dysfunction.

The Impact of Subclinical Hyperthyroidism on Cardiovascular Prognosis in Patients Undergoing Percutaneous Coronary Intervention

CONTEXT

Limited studies have focused on the impact of subclinical hyperthyroidism (SHyper) on poor prognosis in patients with known coronary artery disease (CAD).

OBJECTIVE

We implemented the present study to explore the association between SHyper and adverse cardiovascular events in CAD patients who underwent drug-eluting stent implantation.

METHODS

We consecutively recruited 8283 CAD patients undergoing percutaneous coronary intervention (PCI). All subjects were divided into 2 groups according to their thyroid function: group 1 (euthyroidism group, n = 7942) and group 2 (SHyper group, n = 341). After 1:4 propensity score (PS) matching, 1603 patients (332 SHyper group and 1271 euthyroidism group) were selected. The primary endpoint was major adverse cardiovascular events (MACEs), a composite of cardiac mortality, nonfatal myocardial infarction (MI), and target vessel revascularization (TVR).

RESULTS

Kaplan-Meier (K-M) survival analyses suggested that there was no significant difference in the primary endpoint and secondary endpoints (MACE: 11.4% vs 8.8%, log-rank P = .124; cardiac death: 1.2% vs 0.9%, log-rank P = .540; nonfatal MI: 5.7% vs 4%, log-rank P = .177; and TVR: 6% vs 4.7%, log-rank P = .303) in the PS-matched population. Cox regression analysis indicated that SHyper was not an independent risk factor for MACEs (HR 1.33, 95% CI 0.92-1.92, P = .127).

CONCLUSION

SHyper is not independently associated with adverse cardiovascular events in CAD patients undergoing PCI. More studies should be implemented in the future to assess the long-term predictive value of SHyper with thyrotropin levels <0.1 mIU/L for CAD patients undergoing PCI.

Ultra-processed food consumption and risk of subclinical thyroid dysfunction：A prospective cohort study

Background: Prospective cohort studies linking Ultra-processed foods (UPF) and subclinical thyroid dysfunction (SCTD) are limited, especially in Chinese adults. Objective: We designed a large-scale cohort study to examine whether UPF...

Association of Thyroid-Stimulating Hormone (TSH) Levels With the Prognosis of Patients Undergoing Heart Transplantation: A Retrospective Study

Purpose: To investigate the impact of TSH levels using a more stringent cutoff of subclinical hypothyroidism (i.e., TSH > 2.5 mIU/L) on the short-term complications and long-term prognosis in patients who underwent heart transplantation (HTx). Methods: This is a retrospective study of consecutive patients with end-stage heart failure (HF) who underwent HTx. They were divided into three groups: thyroid-stimulating hormone (TSH) ≤ 2.50 mIU/L (L-TSH), 2.50 < TSH ≤ 4.91 mIU/L (M-TSH), and TSH > 4.91 mIU/L (H-TSH). The outcomes are all-cause death and cardiogenic death. Results: There are 63 (70%) males and 27 (30%) females. Nine (10%) patients died within 1 month after surgery, including five cardiogenic deaths. By 1 year, a total of 19 patients total were dead. The survival rate in the M-TSH group was significantly higher than that of the L-TSH group (P = 0.017). After adjusted by variables of sex, age, BMI, diabetes history, hypertension history, the multivariable Cox analysis showed that body mass index (HR = 0.804, 95%CI: 0.680-0.951, P = 0.011), and L-TSH (HR = 8.757, 95%CI: 1.786-42.948, P = 0.007 vs. M-TSH), and H-TSH (HR = 6.427, 95%CI: 1.137-36.327, P = 0.035 vs. M-TSH) were independently associated with all-cause death. The multivariable Cox analysis showed that body mass index (HR = 0.703, 95%CI: 0.564-0.878, P = 0.002), and L-TSH (HR = 17.717, 95%CI: 1.907-164.607, P = 0.011 vs. M-TSH) were independently associated with cardiogenic death. Conclusion: For patients with end-stage HF undergoing HTx, low and high baseline TSH levels are independently associated with 1-year all-cause death and low baseline TSH levels with cardiogenic death.