Assessment Of Abdominal Fat Distribution In Patients With Newly Diagnosed Hyperthyroidism By Bioelectrical Impedance Analysis

Objective:Thyroid hormone is an important hormone to maintain energy balance,and the increase of its level can lead to metabolic changes and energy imbalance.In order to explore the redistribution of adipose tissue under the condition of hyperthyroidism,this study identified the abdominal visceral fat and subcutaneous fat area of newly diagnosed patients with hyperthyroidism by using bioelectrical impedance analysis,and to analyze the correlation between thyroid hormone levels and lipid metabolism indexes with them in patients.Methods:This study enrolled 80 patients with newly diagnosed hyperthyroidism as the case group,and 42 healthy individuals were selected as the control group.All participants had no medical conditions that might affect the relevant investigation indexes and did not take any drugs affecting thyroid function and lipid levels.All subjects’ anthropometric indicators(body mass index,waist circumference),biochemical parameters(thyroid hormone,lipid metabolism indexes)were collected.At the same time,the distribution of abdominal fat was also measured by using bioelectrical impedance analysis.The differences in visceral fat and subcutaneous fat area between the two groups were compared,and the correlation between thyroid hormone,lipid metabolism indexes and abdominal adipose tissue in hyperthyroidism group was analyzed.All data were statistically analyzed by SPSS 27.0 software.Results:1.Compared with the control group,patients in the hyperthyroidism group showed the significantly decreased levels of abdominal visceral fat and subcutaneous fat area,total cholesterol and low density lipoprotein cholesterol(P<0.05).No significant difference was found in triglyceride and high density lipoprotein cholesterol.2.Spearman correlation analysis showed that subcutaneous fat area in hyperthyroidism group was negatively correlated with free triiodothyronine and free thyroxine(r=-0.354 and-0.263,P=0.001 and0.019),and positively correlated with triglyceride(r=0.349,P=0.002).Visceral fat area was positively correlated with triglyceride(r=0.333,P=0.003).Free triiodothyronine was negatively correlated with total cholesterol and triglyceride(r=-0.231 and-0.253,P=0.039 and 0.024).Pearson correlation analysis showed that subcutaneous fat area in hyperthyroidism group was positively correlated with total cholesterol and low density lipoprotein cholesterol(r=0.293 and 0.274,P=0.008 and 0.014).Visceral fat area was positively correlated with total cholesterol and low density lipoprotein cholesterol(r=0.266 and 0.234,P=0.017 and 0.037),and no correlation was found between abdominal fat area and high density lipoprotein cholesterol.3.Multivariate linear regression analysis showed that subcutaneous fat area was negatively correlated with free triiodothyronine(B=-0.878,P=0.041)and positively correlated with triglyceride(B=18.331,P=0.012).Single factor linear regression analysis showed that free triiodothyronine was an independent influencing factor of triglyceride,and with the increase of 1 pmol/L free triiodothyronine,triglyceride decreased by 0.015 mmol/L.Conclusion:Hyperthyroidism changes the distribution of abdominal adipose tissue in the body.Free triiodothyronine and triglycerides are independent factors affecting abdominal subcutaneous fat.It is recommended to monitor abdominal fat distribution and lipid metabolism indexes in the diagnosis and treatment of patients with hyperthyroidism,so as to discover the abnormal distribution of adipose tissue in time.