Baolan Ji,1,* Shuwei Shi,1,2,* Hongyan Zhao,1,2 Xuan Ma,1,2 Jie Sheng,1,2 Bo Ban,3 Guanqi Gao1 

1Department of Endocrinology, Linyi People’s Hospital, Linyi, Shandong, 276034, People’s Republic of China; 2School of Clinical Medicine, Shandong second Medical University, Weifang, Shandong, 261000, People’s Republic of China; 3Department of Endocrinology, Affiliated Hospital of Jining Medical University, Jining, Shandong, 272029, People’s Republic of China

*These authors contributed equally to this work

Correspondence: Guanqi Gao, Department of Endocrinology, Linyi People’s Hospital, North Side of the Intersection of Wohushan Road and Wuhan Road in Lanshan District, Linyi, Shandong, 276034, People’s Republic of China, Email guanqi_gao@yeah.net Bo Ban, Department of Endocrinology, Affiliated Hospital of Jining Medical University, 89 Guhuai Road, Jining, Shandong, 272029, People’s Republic of China, Email banbo2011@163.com

Aim: Diabetes is an independent risk factor for thyroid nodules (TNs), however, the influencing factors of TNs have not been fully clarified under the condition of diabetes. Previous studies have shown a connection between pituitary-thyroid hormone (TH) functions and TNs in different populations. However, the potential link in euthyroid patients with diabetes is unclear. We aimed to explore the correlates of TNs in euthyroid type 2 diabetes (T2D) patients.
Methods: This cross-sectional study included 1965 euthyroid adults with T2D. Clinical and biochemical data, including TH and relevant covariates were collected. TNs were evaluated using ultrasound. Univariate and multivariate logistic regression analyses were performed to identify factors associated with TNs, with analyses stratified by sex.
Results: The overall prevalence of TNs was 51.9%. The prevalence of TNs was higher in females. Stratified by sex, the results from univariate and further logistic regression analyses showed that free triiodothyronine (FT3) (OR: 1.381; 95% CI: 1.066– 1.790) and thyroid-stimulating hormone index (TSHI) (OR: 0.740; 95% CI: 0.584– 0.937) were independently correlated with TNs only in females, while no TH-related indicators entered the regression model in males.
Conclusion: The relationship between TH and related indices with TNs exhibited sex differences. Specifically, FT3 and TSHI were independently associated with TNs in females. These findings underscore the importance of evaluating TH and related indices for early monitoring and management of TNs, particularly in euthyroid female T2D patients.

Keywords: pituitary-thyroid hormone, type 2 diabetes, thyroid nodules, correlates