Role of Thyroid Deficiency on Adiponectin, Leptin, and Metabolic Status in Visceral Obesity: A Cross-Sectional Study

Abstract

Hypothyroidism results in disturbances of metabolism influencing many regulatory systems and active molecules as adipocytokines. Objective of the study was to investigate leptin and adiponectin in patients with visceral obesity and hypothyroidism in relation to metabolic status, insulin resistance and systemic inflammation. A total of 118 patients (59 hypothyroid and 59 euthyroid) were enrolled divided into four age-matched groups according to body wеight (BMI) and thyroid function. Laboratory panel includes TSH, FT4, FT3 (CMIA), adiponectin and leptin (ELISA), IL- 6 (ECLIA), CRP, insulin, glucose, apolipoprotein B and lipoprotein (a) - Lp(a). Hypothyroid patients revealed significant positive correlations of TSH, adiponectin and Lp(a). Their medians of 10.4 mU/l, 12.5 µg/ml and 116.3 mg/l respectively were significantly higher than in euthyroid patients- 1.5 mU/l, 6.26 µg/ml and 32.0 mU/l (p < 0.0001). Leptin in both obese groups was significantly higher than in patients with normal weight. Leptin in hypothyroid patients was lower but not significant to euthyroid ones (9.7 ng/ml vs 13.4 ng/ml respectively, p = 0.16), correlated negatively to TSH and positively to CRP, IL-6, ApoB, Lp(a) and BMI. HOMA-IR and serum insulin at 120 min in OGTT were significantly higher in hypothyroid than in euthyroid patients independent of BMI (p < 0.001). Adiponectin, insulin resistance and chronic inflammation indices in hypothyroid patients correlated positively to TSH, BMI and atherogenic lipoproteins subclasses ApoB/Lp(a). Increased adiponectin in thyroid deficiency could be due to secondary resistance of adiponectin receptors or appeared as a compensatory pathogenetic factor in hypothyroidism.

The role of thyroid hormone in metabolism and metabolic syndrome

“…Serum FT3 or total T3 were also evaluated in some studies. 15,16,22,27,33,35–38,45–47,49,54,57,60,73,74,77–79,81,82,85,86,89,93,96,101,105–110…”

“…However, the NCEPT/ATPIII was the most commonly applied criteria for diagnosis. 14,16,19,25,26,38,48,54,68,69,73,77,92,94,97,98,102 Other authors used the IDF criteria, 42,47,55,56,75,81,93 the World Health Organization or American Heart Association criteria, 45,62,79 or even local/regional or pre-established criteria defined by a joint interim statement. 29,45,52,76,96 Finally, some studies defined MetS by the presence of IR according to an abnormal Homeostatic Model Assessment of Insulin Resistance index (HOMA-IR) or euglycemic clamp result.…”

“…8–14 Sectional studies have shown that the overlap between both diagnoses is common, justifying a high association between them, as shown in Table 2. 14,15…”

Role of Adiponectin in Central Nervous System Disorders

“…. However, another study showed that adiponectin was 2-fold higher in hypothyroid than in healthy patients [ 129 ]. Studies in hypothyroid dogs and guinea pigs show elevated levels of serum adiponectin, as well as their reduction after thyroid hormone replacement therapy [ 130 ].…”

Thyroid Stimulating Hormone Within the Reference Range is Associated with Visceral Adiposity Index and Lipid Accumulation Product: A Population-Based Study of SPECT-China

“…Thyroid hormones affect lipid and glucose metabolism, blood pressure, and obesity, all of which are associated with various cardiometabolic status [1][2][3]. Recent studies have demonstrated that the thyroid stimulating hormone (TSH) levels within the reference range were associated with obesity, lipid profile, and insulin resistance (IR) independent of thyroid function, which potentially modulates the cardiovascular conditions [4][5][6].…”