Endocrine Abstracts

Introduction: Graves’ disease (GD) is an autoimmune thyroiditis frequently associated with development of Graves’ orbitopathy (GO). GD patients have lower vitamin D levels compared to the general population. Whether low vitamin D levels are associated with GO is still controversial. The aim of our study was to assess the vitamin D levels in patients with GO and the clinical outcome.

Methods: This is a single-center observational study in an outpatient clinic of autoimmune endocrinopathies at a Tertiary, General, University Hospital. Patients with GO and increased levels of thyroid-stimulating immunoglobulin (TSI >1.75 IU/l) were included in the study. Clinical activity score (CAS) was evaluated according to the European Consensus Report. Patients were divided in two groups according to CAS (inactive CAS<3 and active CAS≥ 3). Laboratory tests for TSH, T3, FT4, TSI, TgAbs, TPOAbs, complete blood count, liver enzymes and 25OHvitamin D levels were performed in all patients.

Results: A total of 78 patients (71.8 % females) with a mean age of 53.9±13.33 years were analyzed. The mean follow-up was 3±9.04 years. The median TSI levels were 5.65 IU/l and the mean CAS was 3±1.42. 47% (37/67) and 26.9% (21/70) of the patients had positive anti-TPO and anti-Tg antibodies, respectively. 23.1% (18/78) of the patients had undergone total thyroidectomy, 10.3% (8/78) had thyroid cancer, 29.5% (23/78) had other autoimmunities, and 69.2% (54/78) had smoking history. Overall, mean 25OHVitamin D levels were 21.98±1.38 ng/ml. When analyzed based on disease activity, mean 25OHVitamin D levels were 21.05±7.8 ng/ml in patients with inactive GO (CAS<3) and 22.51 ± 10.72 ng/ml in patients with active GO (CAS≥3). Overall, CAS was significantly associated with TSI levels, diplopia and years of the disease (P=0.011, P=0.025 andP=0.035, respectively). 25OHvitamin D levels were significantly associated with anti-TPO and the disease duration in patients with active GO (P=0.05).

Conclsion: In our study, we found a correlation of vitamin D levels with anti-TPO and disease duration in patients with active GO. However, further prospective studies are needed to confirm whether there is a correlation between GO activity and vitamin D levels.