Subclinical hypothyroidism increases insulin resistance in normoglycemic people

Wanyu Yang; Chenye Jin; Haoyu Wang; Yaxin Lai; Jiashu Li; Zhongyan Shan

doi:10.3389/fendo.2023.1106968

Subclinical hypothyroidism increases insulin resistance in normoglycemic people

Front Endocrinol (Lausanne). 2023 Jul 6:14:1106968. doi: 10.3389/fendo.2023.1106968. eCollection 2023.

Authors

Wanyu Yang¹, Chenye Jin², Haoyu Wang³, Yaxin Lai³, Jiashu Li³, Zhongyan Shan³

Affiliations

¹ Department of Geriatric Medicine, The First Hospital of China Medical University, Shenyang, Liaoning, China.
² Department of Rheumatology Immunology, The First Hospital of China Medical University, Shenyang, Liaoning, China.
³ Department of Endocrinology and Metabolism and The Institute of Endocrinology, National Health Commission (NHC) Key Laboratory of Diagnosis and Treatment of Thyroid Diseases, The First Hospital of China Medical University, Shenyang, Liaoning, China.

Abstract

Objective: To investigate the effect of simple subclinical hypothyroidism (SCH) and type 2 diabetes mellitus (T2DM) combined with SCH on insulin resistance.

Design and methods: A total of 622 people with newly diagnosed T2DM were selected as the study subjects, and 621 normoglycemic people were selected as control subjects. According to the diagnostic criteria of thyroid diseases, the subjects were divided into a normal thyroid function group and a subclinical hypothyroidism group. Both groups received a physical examination, and blood samples were collected. The measurement indexes included FPG, FINS, OGTT2hPG, OGTT2hINS, HbA1c, TC, TG, HDL-C, LDL-C, TSH, FT3 and FT4. HOMA-IR, HOMA-β, and TFQI (thyroid feedback quantile index) were calculated.

Results: There was no significant difference in age or sex distribution between the T2DM group and the normoglycemic group (P>0.05). The prevalence of thyroid dysfunction in the T2DM group was significantly higher than that in the normoglycemic group (16.39% vs. 11.27%, P<0.05), and among the different types of thyroid dysfunction, the prevalence of SCH was the highest at 14.95% (P<0.05). There was no significant difference in BMI, waist-hip ratio, blood lipid profile, HOMA-β, and HOMA-IR values between the T2DM with subclinical hypothyroidism group (T2DM+SCH+ group) and the normal thyroid function group (T2DM+SCH- group) (P>0.05). The BMI, waist-hip ratio and HOMA-IR values of the normoglycemic group with subclinical hypothyroidism (T2DM-SCH+ group) were significantly higher than those of the normoglycemic group with normal thyroid function (T2DM-SCH- group) (P<0.05), and there were no significant differences between the T2DM+SCH- and T2DM+SCH+ groups (P>0.05). HOMA-β values were significantly higher in the T2DM-SCH+ group than in the T2DM-SCH-, T2DM+SCH- and T2DM+SCH+ groups (P<0.05). As the TFQI value increased, the body weight, waist-hip ratio, diastolic blood pressure, FPG, OGTT2hPG and HbA1c values gradually increased in the T2DM group and normoglycemic group (P<0.05). HDL-C, FINS, OGTT2hINS and HOMA-β values gradually decreased (P<0.05).

Conclusion: Subclinical hypothyroidism only increases insulin resistance in normoglycemic people. As the sensitivity of the central thyroid decreases, the risk of developing diabetes increases.

Keywords: diabetes; insulin resistance; subclinical hypothyroidism; thyroid hormone sensitivity; thyroid stimulating hormone.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Diabetes Mellitus, Type 2*
Glycated Hemoglobin
Humans
Hypothyroidism*
Insulin Resistance*
Thyroid Diseases*
Thyrotropin

Substances

Glycated Hemoglobin
Thyrotropin

Grants and funding

This study was funded by the Key Laboratory Project of Thyroid Diseases National Health Commission (2019PT330001),National natural science foundation of China (81970682).