ESPE Abstracts

Background: Hashimoto thyroiditis (HT) is the most common autoimmune disorder. There are few studies that analysed the relationship between HT and serum vitamin D.

Objective and hypotheses: It has been suggested that vitamin D acts as an immunomodulator in autoimmune diseases such as HT Therefore we planned to investigate vitamin D status in euthyroid girls with HT.

Method: The study group consisted of 66 euthyroid pubertal girls recently diagnosed with HT and 41 subjects as the control group. Parameters of calcium metabolism, thyroid function tests, thyroid antibodies, and 25-hydroxyvitamin D [25(OH)D] levels were measured. Those with 25(OH) D levels of 21–29 ng/ml were characterized as vitamin D insufficiency while those with equal or less than 20 ng/ml were called vitamin D deficiency.

Results: There was no difference between the patients and the control group in thyroid hormone levels. Vitamin D deficiency rate was not higher in the HT group compared with the control subjects (50.8% vs 61%, P> 0.05). Vitamin D insufficiency rate was also not higher in the patient group than in controls (38.5% vs 35.6, P> 0.05). In the HT group, mean 25(OH)D levels were not significantly different compared with the control group (19.9 ng/ml vs 18.7 ng/ml P>0.05), but was inversely correlated with the antithyroglobulin (anti-Tg) levels (r=−0.30, P=0.007). We also found marked higher PTH and lower Ca levels in our patients than in the controls. The inverse correlation among the patient group’s 25(OH)D and PTH levels was worth noting even though it was not statistically significant (r=−0.22; P=0.084; P>0.05). The positive correlation between the patient group’s 25(OH)D and Ca levels was found statistically significant (r=0.30; P=0.016; P<0.05).

Conclusion: In conclusion, We found similarly high rates of vit D insufficiency and deficiency among otherwise healthy controls and girls with HT. In Turkey, clothing habits, lack of vitamin D fortification programs markedly reduce the amount of the vitamin D, which may explain these low levels of vit D. The inverse correlation between vitamin D and anti-Tg suggests that vitamin D deficiency may have a role in the autoimmune process in HT in children.