SAT-276 Vitamin D Deficiency In Hashimoto's Thyroiditis

Background: Vitamin D (25OHD) deficiency is associated with the presence of antithyroid antibodies and abnormal thyroid function tests, suggesting that vitamin D may be involved in the pathogenesis of autoimmune thyroid disease (1). Some have described an inverse association between 25OHD levels and thyroid antibody titers as well as thyroid stimulating hormone (TSH) in patients with Hashimoto’s Thyroiditis (HT) (2). Objective: To study vitamin D deficiency in children and young adults with Hashimoto’s thyroiditis and to assess the relationship between 25OHD levels and thyroid antibody titers (thyroid peroxidase/TPO Ab and thyroglobulin/Tg Ab) in our center. Methodology: An IRB-approved study consisting of 20 patients, ages 1- 21 years with HT was conducted in endocrinology clinic and vitamin D status was assessed. Fifteen had 25OHD deficiency defined as <20 ng/ml (group 1) and 5 had levels ≥20 ng/ml (group 2). T-tests and Spearman’s correlation were performed. Results: Among the whole group, mean age was 16 ± 2.6 (S.D.) years, 80% female, and 45% African American, 25% Asian, 15% Caucasian and 10% Hispanic. Mean 25OHD level was 11.91 ± 4.23 ng/ml in group 1 vs 29.98 ± 4.03 ng/ml in group 2 (p <0.05). Mean TSH was 5.06 ± 3.80 mIU/ml in group 1 vs 2.07 ± 1.61 mIU/ml in group 2 (p=0.02), while mean FT4 was 1.14 ± 0.30 ng/dl in group 1 vs 1.07 ± 0.22 ng/dl in group 2 (p=0.62). TPO antibody titers were 1907 ± 3497 IU/ml in group 1 vs 305 ± 264 IU/ml in group 2 (p=0.09). Thyroglobulin antibody titers were 263 ± 508 IU/ml in group 1 vs 87 ± 157 IU/ml in group 2 (p=0.29). Spearman’s correlation analysis was performed to assess the association between the variables TSH, FT4, TPO Ab titers, Tg Ab titers against 25OHD levels. A significant negative correlation was found between TSH and 25OHD (r= -0.51, p=0.013) as well as between TPO Ab titers and 25OHD (r= -0.47, p=0.035). Conclusion: Small sample size was a limitation in our study. However, this is the first study as far as we know in a minority group of children and adolescents in the United States. Seventy-five percent of our group had 25OHD deficiency. We found a significant negative correlation between TSH and 25OHD as well as TPO Ab and 25OHD. This suggests that there may be a significant role of vitamin D in the pathogenesis of Hashimoto thyroiditis. Further studies will be needed to evaluate the role of treatment of vitamin D deficiency and its effects on Hashimoto’s thyroiditis. References1. Kivity, S., et al.,Vitamin D and autoimmune thyroid diseases. Cell Mol Immunol, 2011. 8(3): p. 243-7. 2. Shin, D.Y., et al., Low serum vitamin D is associated with anti-thyroid peroxidase antibody in autoimmune thyroiditis. Yonsei Med J, 2014. 55(2): p. 476-81