Effect of Vit D Replacement in Patients With Subclinical Hypothyroidism

Replacing vitamin D has a significant impact on improving subclinical hypothyroidism
Replacing vitamin D has a significant impact on improving subclinical hypothyroidism

This article is written live from the American Association of Clinical Endocrinologists (AACE) 2017 Annual Meeting in Austin, TX. MPR will be reporting news on the latest findings from leading experts in endocrinology. Check back for more news from AACE 2017.


A significant decrease in thyroid stimulating hormone (TSH) level and anti TPO titre was seen when patients with autoimmune subclinical hypothyroidism (SCH) and vitamin D deficiency received vitamin D replacement, according to a study presented at the AACE 2017 Annual Meeting. 

To date, there have been no studies assessing the outcome of vitamin D replacement on SCH. Study authors from King Fahad Medical City and King Abdualziz Medical City, led by Naji Aljohani, MD, SBIM, FACE, FACP, hypothesized that replacing vitamin D in deficient patients with SCH would result in reduced TSH levels and anti TPO titres. To test this, they performed an observational, prospective study in Saudi patients with SCH and vitamin D deficiency. 

At baseline, the mean TSH was 6.0mIU/L, mean Free T4 was 14.4pmol/L, mean anti TPO antibody titre was 343.4 IU/mL, and mean vitamin D level was 25.2nmol/L. 

After 3 months of treatment with vitamin D, the researchers found a significant increase in serum vitamin D to 59.6nmol/L (P=0.0001) as well as significant reductions in TSH to 4.9mIU/L (P=0.001) and anti TPO titre to 125.1IU/mL (P=0.057). 

"We showed that replacing vitamin D has a significant impact on improving SCH, measured by a significant reduction in both TSH and anti TPO antibody titre after 3 months of treatment," said Dr. Aljohani. A subgroup stratified by vitamin D status, however, indicated that the reduction was only significant for those with vitamin D deficiency. 

Due to the small sample size, the authors acknowledge that bigger randomized controlled trials are needed to validate these findings.

For continuous endocrine news coverage from the AACE 2017 Annual Meeting, check back to MPR's AACE page for the latest updates.