Vitamin D status including 3-epi-25(OH)D3 among adult patients with thyroid disorders during summer months.

INTRODUCTION: In the context of pleiotropic vitamin D effects its role has also been investigated in thyroid pathology, in particular autoimmune thyroid diseases (AITD). However, available data concerning vitamin D status among Polish adult population are inconclusive.

AIM: In the study we investigated vitamin D status and adequacy of supplementation, as well as sunlight exposure during summer months among adult patients with thyroid diseases.

MATERIALS AND METHODS: Adults with diagnosed or suspected thyroid disease were recruited almost entirely in an ambulatory setting from June through September in Northern Poland. Questionnaire examinations were performed; serum concentrations of 25(OH)D2, 25(OH)D¬¬3, 3-epi-25(OH)D3, 24,25(OH)2D3 were determined by LC-MS/MS.

RESULTS: 30 men and 194 women participated in the study, mean age +/-standard deviation (SD): 42 +/-15 years, mean +/-SD body mass index (BMI) 26 +/-6 kg/m sq. Among participants 133 declared L-thyroxine treatment, 44 - Hashimoto's thyroiditis, 40 -nodular goiter, 20 - hyperthyroidism and/or Graves' disease. Mean+/-SD 25(OH)D level was 26.9 +/-8.2 ng/ml, deficiency (< 20 ng/ml) was stated in 12%, insufficiency (20 ≤ 25(OH)D <30 ng/ml) in 50.4% of study participants. Calcidiol was significantly higher in subjects who declared supplementation, mean±SD: 29.4 ±7.5 versus 25.2 ±8 ng/ml. Among participants without vitamin D supplementation sunlight exposure correlated with 25(OH)D. The C3 epimer of C3 25(OH)D3 was detected in all subjects; its concentration correlated strongly with that of 25(OH)D3. 24,25(OH)2D3 levels also strongly correlated with those of 25(OH)D.

CONCLUSIONS: To our knowledge in the current study for the first in Poland vitamin D status was examined in summer months among patients with thyroid diseases, as well as serum 3-epi-25(OH)D3 and 24,25(OH)2D3 concentrations were analyzed. Data presented here indicate vitamin D sufficiency is not attained even in summer months in patients with thyroid diseases.