Endocrine Abstracts

Introduction: Increased exposure to sunlight and high serum levels of Vitamin D were reported to relate with decreased risk of various cancer types, such as prostate, breast and colon. Vitamin D receptor and 1α-hydroxylase expression were shown in papillary thyroid carcinoma. In this study, we aimed to evaluate serum 25-OH vitamin D levels in patients with benign and malignant thyroid nodules

Methods: Patients admitted to our thyroid clinic were recruited for the study. Thyroid ultrasonography and serum 25-OH vitamin D measurement were done in all patients and controls. Because serum 25-OH vitamin D levels may change with seasons, blood samples were taken in April–May 2009 and 2010. Results were compared in patients with histopathologically proven thyroid papillary cancer, patients with histopathologically or cytologically proven benign thyroid nodules and patients without thyroid nodules. Patients with diseases related to bone metabolism and thyroid dysfunctions were excluded.

Results: There were 31 patients with histopathologically proven papillary thyroid cancer, 128 patients with cytologically or histopathologically proven benign nodules and 269 patients without any nodule. Of 428 subjects, 360 (84.1%) were female and 68 (15.9%) were male and sex distibution were similar in three groups (P=0.079). Mean serum 25-OH vitamin D levels were 16.91±10.42, 16.35±9.02 and 17.19±10.74 μ/l in malignant, benign and control groups, respectively (P=0.746). Including all subjects, although mean serum vitamin D levels were higher in males compared to females, the difference did not reach statistical significance.

Conclusion: Serum 25-OH vitamin D levels, here in this study, were shown not to differ in patients with benign nodules, malignant nodules and patients without nodules. Possible effect of vitamin D metabolism and receptors on thyroid papillary cancer that was suggested in previous in vitro and in vivo studies seems to be independent from serum 25-OH vitamin D levels.