Effect of vitamin D supplementation on thyroid function in TPO-positive patients with subclinical hypothyroidism and vitamin D deficiency

Kotwal V, Kotwal S, Sharma A

Pdf Page Numbers :- 53-57

Vishali Kotwal^1,*, Suman Kotwal² and Atul Sharma³

¹Department of Medicine, Government Medical College, Jammu, Jammu and Kashmir 180016, India

²Department of Endocrinology, Government Medical College, Jammu, Jammu and Kashmir 180016, India

*Corresponding author: Dr. Vishali Kotwal, Professor, Department of Medicine, Government Medical College, Jammu and Kashmir 180016, India. Email: vishalikotwal@gmail.com

Received 23 December 2025; Revised 12 February 2026; Accepted 25 February 2026; Published 5 March 2026

Citation: Kotwal V, Kotwal S, Sharma A. Effect of vitamin D supplementation on thyroid function in TPO-positive patients with subclinical hypothyroidism and vitamin D deficiency. J Med Sci Res. 2026; 14(2):53-57. DOI: http://dx.doi.org/10.17727/JMSR.2026/14-10

Copyright: © 2026 Kotwal V et al. Published by KIMS Foundation and Research Center. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

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Abstract

Background: Vitamin D deficiency has been implicated in the pathogenesis of autoimmune thyroid disorders. This study evaluated the effect of vitamin D supplementation on thyroid function in patients with mild, thyroid peroxidase (TPO)-positive subclinical hypothyroidism and vitamin D deficiency.

Methods: A total of 100 patients aged 20–60 years with mild subclinical hypothyroidism, vitamin D deficiency, and positive TPO antibodies were enrolled. Fifty patients received oral cholecalciferol 60,000 IU once weekly for 12 weeks, while 50 served as controls. Participants were followed monthly, and serum free triiodothyronine (fT3), free thyroxine (fT4), TSH, and vitamin D levels were assessed at baseline and at 12 weeks.

Results: At 12 weeks, the mean TSH level was lower in the vitamin D supplementation group than in the control group (5.62 vs. 7.06 mIU/L; p < 0.001). The mean vitamin D level was higher in the supplementation group than in the control group (30.18 vs. 20.38 nmol/L; p < 0.001). No significant between-group differences were observed in fT3 or fT4 levels.

Conclusion: Vitamin D supplementation was associated with a reduction in TSH levels in patients with mild, TPO-positive subclinical hypothyroidism and vitamin D deficiency. These findings suggest that correction of vitamin D deficiency may have a beneficial effect on thyroid function in this patient population.

Keywords: subclinical hypothyroidism; vitamin D deficiency; thyroid peroxidase; autoimmune thyroid disease; thyroid-stimulating hormone