Abstract
Background Type 2 diabetes has an underlying pathology with thyroid dysfunction. However, few
studies have investigated the association between thyroid hormones and diabetic peripheral
neuropathy. Our aim was to evaluate the relationship between thyroid hormones and
electrophysiological properties of peripheral nerves in type 2 diabetes.
Patients and Methods The medical records of 308 patients with type 2 diabetes were enrolled in this study.
Subjects stratified by sex were divided into subgroups based on the diagnosis of nerve
conduction study. The nerve conduction parameters were separately described with the
spectrum of thyroid hormones. Multivariate regression models to analyze the potential
links between thyroid hormones and nerve conduction parameters.
Results The serum free triiodine thyronine levels between normal and abnormal nerve conduction
groups were statistically different in total (4.55±0.65 vs 4.37±0.63, P<0.05) and
female diabetic patients (4.46±0.50 vs 4.14±0.57, P<0.01). Moreover, the summed amplitude
and velocity Z score of female and male increased with free triiodine thyronine levels
(P<0.05). Sex-specific binary logistic regression models showed that free triiodine
thyronine levels were associated with decreased odds of abnormal nerve conduction
diagnosis (odds ratio [95%CI]=0.151[0.047-0.186]) and low tertile of summed amplitude
Z score (odds ratio [95%CI]=0.283[0.099-0.809]) in female. In total patients, free
triiodine thyronine level was negatively associated with odds of abnormal nerve conduction
(odds ratio [95%CI]=0.436 [0.226-0.842]), low tertile of summed velocity (odds ratio
[95%CI]=0.44[0.226-0.858]) and amplitude (odds ratio [95%CI]=0.436[0.227-0.838) Z
score.
Conclusions Serum free triiodine thyronine level is associated with nerve conduction in diabetes.
Low free triiodine thyronine may be a potential risk for diabetic peripheral neuropathy.
Key words
Type 2 diabetes mellitus - Diabetic peripheral neuropathy - Nerve conduction study
- Thyroid hormones - Free triiodine thyronine