Evaluation of Bone Density, Serum Total and Ionized Calcium, Alkaline Phosphatase and 25-hydroxy Vitamin D in Papillary Thyroid Carcinoma, and their Relationship with TSH Suppression by Levothyroxine.

BACKGROUND: This study aimed to evaluate the situation of Bone Mineral Density (BMD), Z score, T score, serum level of corrected and ionized calcium, alkaline phosphatase and 25-hydroxy vitamin D in percutaneous transhepatic cholangiography (PTC) patients and correlation of these variants with thyroid stimulating hormone (TSH) suppression level by levothyroxine.

MATERIALS AND METHODS: Among the patients referred to Esfahan's endocrinology research center, 34 PTC patients (aged 20-50 years) with a history of thyroidectomy and conceived radioactive iodine and suppressive dose of levothyroxine were evaluated in this case-control study, and 38 healthy persons participated as the control group (matched by age and sex, body mass index). Bone density was evaluated with the DEXA method in four areas: Lumbar spine, femoral neck, and trochanter and distal of forearm. A reference laboratory assessed TSH, corrected and ionized calcium, Alkaline phosphatase (ALP) and 25OH vitamin D levels using fasting plasma and evaluated correlation of TSH level with variants by multivariate variance analysis.

RESULTS: There was no significant difference in bone density and laboratory data (unless TSH) between the groups. In the PTC group, there was no significant correlation between TSH and difference values of BMD, Z score or T score, corrected calcium (P value = 0.12), ionized calcium (P = 0.54), ALP (P = 0.22) and 25 OH vitamin D (P = 0.38). There was no significant correlation in the TSH subgroups with BMD. The TSH suppression level has no relation with the elevated prevalence of low BMD, hypocalcemia and vitamin D deficiency. Difference in odds ratio was not significant for osteopenia and osteoporosis between the TSH subgroups (TSH < 0.02, >0.02 and <0.1 and >0.1 mu/L).

CONCLUSION: Suppressive therapy with levothyroxine cannot decrease BMD, Z score and T score in PTC patients.