Mengnan Li,1,2,* Xifeng Yang,1,2,* Ru Li,1,2 Baofeng Wu,1,2 Jinxuan Hao,1,2 Yijie Qi,1,2 Tao Bai,1 Luyang Yang,1 Yi Zhang,3 Yunfeng Liu1,4 

1Department of Endocrinology, First Hospital of Shanxi Medical University, Taiyuan, People’s Republic of China; 2First Clinical Medical College, Shanxi Medical University, Taiyuan, People’s Republic of China; 3Department of Pharmacology, Shanxi Medical University, Taiyuan, People’s Republic of China; 4Clinical Research Center of Endocrine and Metabolic Diseases in Shanxi Medical University, Taiyuan, Shanxi, 030001, People’s Republic of China

*These authors contributed equally to this work

Correspondence: Yunfeng Liu, Department of Endocrinology, First Hospital of Shanxi Medical University, Taiyuan, People’s Republic of China, Email nectarliu@163.com Yi Zhang, Department of Pharmacology, Shanxi Medical University, Taiyuan, People’s Republic of China, Email yizhang313@163.com

Purpose: There is evidence that long-term vascular risk remains increased in patients with hyperthyroidism even after normalization of thyroid function, and the mechanisms that regulate this risk are unclear. The aim of this study was to assess how visceral fat area and subcutaneous fat area change after hyperthyroidism treatment, and to further explore the relationship between thyroid hormones, abdominal fat area (visceral fat area and subcutaneous fat area), and lipids.
Patients and Methods: 50 patients with newly diagnosed Graves’ disease were selected. Anthropometric parameters (weight, height, body mass index, waist circumference, neck circumference), laboratory parameters (thyroid hormones, lipid metabolism indices), abdominal fat area (visceral fat area and subcutaneous fat area), and drug dose were collected. Measurements were made at baseline, 6 and 12 months after treatment. We used linear mixed-effects models for analysis.
Results: The results showed that the following indexes changed significantly at different time points: visceral fat area, subcutaneous fat area, free triiodothyronine, free thyroxine, thyroid stimulating hormone, total cholesterol, high-density lipoprotein, low-density lipoprotein, body weight, neck circumference, body mass index, waist circumference, and drug dose (All P< 0.001). We found that free triiodothyronine and free thyroxine were significantly negatively associated with abdominal fat area (P< 0.01). There was no significant correlation between drug dose and abdominal fat area (P> 0.05). Total cholesterol and low-density lipoprotein were significantly positively associated with abdominal fat area (P< 0.01). However, high-density lipoprotein (P=0.06) was not correlated with abdominal fat area. Moreover, the results showed a significant negative correlation between thyroid hormones and lipids (P< 0.001).
Conclusion: After anti-thyroid medicine treatment, patients had elevated visceral fat area and subcutaneous fat area and altered lipid profiles. These changes may be one of the reasons why metabolic and cardiovascular diseases remain increased after thyroid function is restored.

Keywords: visceral fat area, subcutaneous fat area, thyroid hormones, lipids, Graves’ disease