Aims: High-but-normal thyrotropin (TSH) is associated with visceral obesity, hyperlipidemia, insulin resistance in patients with type 2 diabetes (T2DM), which may lead to the occurrence of nonalcoholic fatty liver disease (NAFLD). This study aimed to investigate the association between TSH levels and the incidence of NAFLD in euthyroid T2DM patients.
Methods: A total of 2289 T2DM patients with euthyroid function were included in this cross-sectional study conducted at the Third Affiliated Hospital of Sun Yat-sen University from January 2016 to December 2018. NAFLD was diagnosed by ultrasound. Thyroid function parameters, including the levels of TSH, free triiodothyronine (FT3) and free thyroxine (FT4) were analyzed. Multivariate logistic regression analyses were performed to evaluate the effect of TSH levels on the risk of NAFLD in T2DM patients.
Results: NAFLD was diagnosed in 940 subjects with T2DM (41.1%). The subjects were divided according to the inter-quartile of thyroid function parameters. The NAFLD prevalence rates show a positive correlation with the increasing TSH quartiles(Q1 to Q4: 34.8%, 37.5%, 44.9% and 47.0%, P<0.01), but not with the FT3 or FT4 quartiles. In the multivariate logistic regression analysis, the highest TSH quartile (OR=1.610, 95% CI=1.131-2.289, P=0.008) was independently associated with the risk of NAFLD in patients with T2DM, after adjusting for multiple confounding factors. After additionally stratified by HbA1c levels, the highest TSH quartile level was still independently associated with the risk of NAFLD in euthyroid T2DM patients.
Conclusion: High-but-normal serum TSH is a significant independent risk factor for increased incidence of NAFLD in T2DM patients with euthyroid function, thus providing a novel insight for treating NAFLD.
X. Tang: None. Y. Tan: None. M. Li: None. Y. Nie: None. Y. Chen: None.
Research and Development Plans in Key Areas of Guangdong Province (2019B020227003); National Natural Science Foundation of China (81770826); National Key Research and Development Program of China (2017YFA0105803)