Endocrine Abstracts

Background and aim

Autoimmune thyroiditis (AIT) is one of the most common autoimmune diseases, affecting more than 10% of females and 2% of males in the overall population. Clinical evidence suggests that oral supplementation with myo-inositol (MI) and vitamin D (VD) is useful in the treatment of AIT. MI is a carbocyclic polyol precursor of phosphoinositide synthesis. It is involved in cell signaling and, precisely, as a second messenger regulating the activities of Thyroid Stimulating Hormone (TSH). The aim of this study was to investigate the efficacy of a combined administration of MI and VD in patients with AIT.

Patients and methods

74 outpatients (mean age 42.39 ± 8.2 years) with AIT were enrolled in this prospective randomized controlled trial from May to September 2019. A total of 74 patients with AIT having TSH levels between 4.0 and 6.0 µIU/ml, elevated serum thyroid peroxidase antibodies (TPO-Ab) and thyroglobulin antibodies (Tg-Ab), normal free thyroxine (fT₄) and free triiodothyronine (fT₃) levels were randomized into 2 groups: one receiving MI-VD and the other one VD alone. To provide additional information concerning thyroid tissue texture, high-resolution ultrasound scan of the thyroidal area was carried out.

Results

A significant decrease in serum TSH levels was noted in patients of group MI-VD compared prior and after treatment (P < 0.05), showing at baseline 5.18 ± 0.52 µIU/ml and 3.06 ± 0.48 µIU/ml over 6 months treatment. The decrement in control group before vs. post-treatment was not significant (4.93 ± 0.82 µIU/ml and 4.16 ± 0.81 µIU/ml). TSH, thyroid peroxidase antibodies (TPO-Ab) and thyroglobulin antibodies (Tg-Ab) levels were significantly decreased in patients treated with combined MI-VD after six months of treatment. Also, a significant free serum thyroxine (fT₄) increase was observed in MI-VD group. In both groups at baseline plasma VD levels were not different (19.4 ± 3.7 ng/ml group MI-VD; 18.9 ± 2.8 ng/ml group VD). After 6 months treatment, VD values were significantly augmented in each group compared to baseline.

Conclusions

The administration of MI-VD is significantly effective in decreasing TSH, TPO-Ab and Tg-Ab levels. Such treatment restored euthyroidism in patients diagnosed with AIT.

Keywords

Autoimmune thyroiditis, Myo-inositol, Vitamin D.