DIAGNOSTIC VALUE OF THYROID HORMONES IN PATIENTS WITH OBESITY

Abstract

Introduction. According to the WHO, obesity is not merely an aesthetic issue but a serious medical condition that triggers a cascade of complications: cardiovascular, metabolic, inflammatory, thrombotic, and renal. Its role as a triggering factor in the development of arterial hypertension, coronary heart disease, heart failure, stroke, and type 2 diabetes mellitus is well established. Despite its clinical significance, obesity is often underestimated by both patients and healthcare providers. The main focus is typically on treating comorbid conditions, while weight correction remains outside the scope of systematic medical support. Therefore, increasing awareness of obesity as a key factor in the development and progression of noncommunicable diseases (NCDs), as well as the search for effective approaches to prevent and treat this condition, is of great relevance. An important direction in current research is the assessment of endocrine regulation of metabolism, particularly the influence of thyroid hormones on energy balance, metabolic processes, and body weight. Patients with obesity often have thyroid dysfunctions, which may either cause excessive body weight or result from it. Determining levels of thyroid-stimulating hormone (TSH), triiodothyronine (T3), and thyroxine (T4) is a necessary step in the evaluation of such patients to timely detect subclinical or overt hypothyroidism. This allows for optimizing treatment strategies for obesity and preventing its complications. Aim of the study. To conduct a comparative analysis of thyroid hormone levels in patients with and without obesity. Methods. Sixty patients receiving outpatient treatment were examined. Among them, 20 were practically healthy, 20 had hypothyroidism, and the remaining 20 had hypothyroidism combined with obesity. The average age of patients was 55±3 years. The levels of free triiodothyronine (FT3; reference interval: 1.3–3.1 nmol/L) and free thyroxine (FT4; reference range: 66.9–160.9 nmol/L) in plasma were measured using the Cobas 6000 immunoassay analyzer with Roche Diagnostics test kits (Switzerland). Results and discussion. According to the study results, the T4 level in patients of group 1 (65.3 ± 0.44 nmol/L) was 1.07 times lower than in the control group (70.2 ± 0.35 nmol/L, p<0.05). The mean serum concentration in group 2 was 50.1 ± 0.46 nmol/L, which was 2.3 times lower than the control value. T4 levels in group 2 were also 1.3 times lower than in group 1 (p<0.05) (Figure 1). T3 levels in group 1 patients (1.9 ± 0.54 nmol/L) were 1.1 times lower than those in the control group (2.1 ± 0.11 nmol/L, p<0.05). In group 2, the mean serum T3 concentration was 0.9 ± 0.25 nmol/L, which was 2.3 times lower than the control value. T3 levels in group 2 were 2.1 times lower than in group 1 (p<0.05) (Figure 2). Conclusions. In patients with obesity, a negative correlation is observed between BMI and free T3 and T4 levels. A decrease in thyroid hormones, even with normal TSH, may represent an adaptive response, thyroid hormone resistance, or impaired leptin signaling. Monitoring thyroid function in obese patients is essential for early detection of subclinical hypothyroidism and correction of metabolic disturbances.