Korea: Vitamin D supplementation does not reduce the recurrence of Graves' disease (GD), although having sufficient vitamin D levels did delay the time to recurrence, according to a recent study published in the journal Scientific Reports.

Graves' disease is an autoimmune disease of the butterfly-shaped gland in the throat (thyroid). Major manifestations of the disease are owing to circulating autoantibodies (Ab) that stimulate the thyroid-stimulating hormone receptor (TSH-R) leading to hyperthyroidism and goiter.

Vitamin D regulates bone metabolism and the homeostasis of calcium and phosphorus. Recent literature has reported a higher prevalence of vitamin D deficiency among patients with GD. No study has examined the effect of vitamin D supplementation on the clinical outcomes of Graves’ disease.

Yoon Young Cho and Yun Jae Chung from Korea aimed to evaluate whether daily vitamin D supplementation reduces Graves’ disease recurrence.

The study enrolled subjects who were treated for Graves’ disease at Chung-Ang University Hospital between November 2010 and July 2018. All patients were taking an anti-thyroid drug (ATD) and were followed up for at least one year after ATD discontinuation. During ATD treatment, the researchers measured the serum 25(OH)D level. 25(OH)D < 20 ng/mL was defined as vitamin D deficiency, whereas 25(OH)D ≥ 20 ng/mL was defined as a sufficient vitamin D level.

Finally, the researchers included 210 patients with Graves’ disease who were vitamin D deficient at study enrolment. Patients amenable to supplementation were prescribed vitamin D₃ (cholecalciferol) at a dose of 1000–2000 IU per day. Among 210 individuals, 60 (29%) were supplied with vitamin D, and the others (150 subjects, 71%) were not. All patients started vitamin D supplementation before ATD cessation.

Key findings of the study include:

• Among 210 individuals, 60 (29%) were amenable to taking vitamin D supplements, resulting in sufficient vitamin D levels (from 10.6 to 25.7 ng/mL), whereas the mean vitamin D level was 11.6 ng/mL in the 150 patients who did not take vitamin D supplements.


• The recurrence rate was similar in both groups (38% vs. 49%). However, recurrence occurred earlier in the latter group (7 months vs. 5 months).


• In the multivariate analysis, vitamin D levels and TSH-binding inhibitory immunoglobulin (TBII) titers at ATD discontinuation remained significant factors for recurrence.


• Vitamin D levels and TBII titers at ATD discontinuation exhibited a weak negative correlation (R = −0.143).

Vitamin D supplementation might have a protective effect against Graves’ disease recurrence with a borderline significant recurrence rate reduction.

The study, "Vitamin D supplementation does not prevent the recurrence of Graves’ disease," is published in the journal Scientific Reports.

DOI: https://doi.org/10.1038/s41598-019-55107-9