Supplementary Materials for Association between Free Triiodothyronine and Diabetic Peripheral Neuropathy in Euthyroid Patients with Type 2 Diabetes

A total of 1,422 eligible euthyroid patients with T2DM who underwent electromyography during hospitalization at Zhongshan Hospital, Fudan University, were enrolled from January 2016 to December 2020.These patients were divided into DPN group and non DPN group, and underwent electromyographic examinations, including nerve conduction velocity (NCV), terminal motor and sensor latency (DML and DSL), sensory nerve action potential (SNAP) amplitude, and compound muscle action potential (CMAP) amplitude(Table S2-4). In DPN group and non DPN group, the nerve conduction parameters were regressed with FT3, and age, sex, smoking, drinking, glycosylated hemoglobin, duration of type 2 diabetes, body mass index, systolic blood pressure, serum sodium, potassium, calcium, cholesterol, triglycerides, low-density lipoprotein, high-density lipoprotein, insulin resistance index were gradually corrected (Table S5). The double sample Mendelian randomized analysis method was used to provide evidence for the causal relationship between serum free triiodothyronine level and diabetes peripheral neuropathy through genome-wide association research and the public data of the Thyroidomics Consortium (FT3) and the UK Biobank (ICD10: G63.2) (TableS1, TableS6, Figure S1).

2016年1月至2020年12月期间，共纳入复旦大学附属中山医院住院期间接受肌电图检查（electromyography）的1422例符合条件的甲状腺功能正常的2型糖尿病（T2DM）患者。这些患者被分为糖尿病周围神经病变（DPN）组和非DPN组，并接受肌电图检查，包括神经传导速度（nerve conduction velocity，NCV）、末端运动潜伏期（distal motor latency，DML）及感觉潜伏期（distal sensory latency，DSL）、感觉神经动作电位（sensory nerve action potential，SNAP）振幅以及复合肌肉动作电位（compound muscle action potential，CMAP）振幅（表S2-4）。在DPN组和非DPN组中，将神经传导参数与游离三碘甲状腺原氨酸（free triiodothyronine，FT3）进行回归分析，并逐步校正年龄、性别、吸烟、饮酒、糖化血红蛋白、2型糖尿病病程、体重指数、收缩压、血清钠、钾、钙、胆固醇、甘油三酯、低密度脂蛋白、高密度脂蛋白及胰岛素抵抗指数（表S5）。采用双样本孟德尔随机化分析方法，通过全基因组关联研究及Thyroidomics Consortium（FT3）与英国生物银行（UK Biobank，ICD10：G63.2）的公共数据，为血清游离三碘甲状腺原氨酸水平与糖尿病周围神经病变之间的因果关系提供证据（表S1、表S6、图S1）。