Epicardial Fat Thickness in Children with Subclinical Hypothyroidism and Its Relationship to Subclinical Atherosclerosis: A Pilot Study.

Background/aims: Thyroid hormones (TSH) play a key role in the working of the cardiovascular system, with direct effects on cardiac function, vascular system, and atherosclerotic factors. Epicardial adipose tissue, the visceral fat of the heart, has emerged as a new cardiometabolic risk marker because of its close anatomical proximity to the myocardium and coronary artery. This study aimed to evaluate epicardial fat thickness (EFT) in children with subclinical hypothyroidism (SH) and its relation to early atherosclerotic changes.

Methods: The study included 32 children with SH due to autoimmune thyroiditis and 32 healthy children matched for age and gender as control group. Patients and controls underwent anthropometric evaluation and measurement of fasting lipids, glucose, insulin, homeostasis model assessment for insulin resistance and high-sensitivity C-reactive protein (hs-CRP). TSH, free thyroxine (FT4 and FT3) and antithyroid autoantibodies (antithyroid peroxidase and thyroglobulin antibodies) were also measured. Conventional echo-cardiography was used to assess EFT. Noninvasive ultrasound was used to measure carotid intima-media thickness and brachial artery flow-mediated dilation (FMD) responses.

Results: Compared to controls, patients had higher atherogenic index (AI) and hs-CRP (p = 0.001 for each). Conventional echocardiography revealed that patients with SH had higher EFT (p = 01) and significantly lower FMD response compared with the control (p = 0.001). In multivariate analysis, EFT values were significantly correlated with TSH (OR 1.2; 95% CI 1.04-1.34; p = 0.01), hs-CRP (OR 1.1; 95% CI 1.09-1.14; p = 0.001, AI (OR 1.6; 95% CI 1.17-2.03; p = 0.001), and FMD response (OR 2.4; 95% CI 1.14-2.53; p = 0.01).

Conclusions: Our study demonstrated that EFT is higher in children with SH compared with controls and associated with FMD responses. Measurement of EFT by echocardiography in children with SH may help to identify those at high risk of developing subclinical atherosclerosis.