Effect Of TSH Suppression Therapy On Bone Density And Bone Metabolism In Patients With Differentiated Thyroid Carcinoma: A Prospective Cohort Study

Objective:To investigate the effect of postoperative TSH suppression therapy on bone mineral density and bone metabolic turnovers in patients with differentiated thyroid carcinoma after 1-2 years of treatment.Subjects and methods:In this study,29 cases of DTC patients undergoing thyroidectomy in the First Affiliated Hospital of China Medical University from 2013 to2014 were selected and divided into three groups:male(5),premenopausal women(16)and postmenopausal women(8),the control group were selected from the community with age,gender and BMI matching the DTC group,the ratio is 1:2.The baseline bone mineral density(g/cm~2)of the patients in the DTC group before thyroidectomy were measured.The bone mineral density(BMD)of the lumbar vertebrae,hip and femoral neck were measured as the evaluation indexes and the bone metabolic turnovers(?-crosslaps and P1NP)were measured.After one year TSH suppression therapy,the above-mentioned indexes were revisited,and the difference of baseline and 1 year follow-up was taken as the change value of each index.The comparison of related indexes and its changes of value were done between the two groups at the follow-up of 1year.19 patients in the DTC group were followed up for 2 years after surgery,bone mineral density and bone metabolic turnovers were compared with baseline after 2 years of follow-up.Results:1.Comparison of baseline characteristics:there is no significant difference among DTC group and control group on age,BMI,BMD at each site and bone metabolic turnovers at the baseline level.2.At 1 year follow-up,the BMD of lumbar vertebrae,hip and femoral neck in premenopausal women in DTC group were significantly higher than those in control group.There were no significant differences in BMD and bone metabolic turnovers among men and postmenopausal women compared with control group.3.(1)For men,there was no significant difference between the DTC group and the control group on BMD and bone metabolic turnovers.(2)For premenopausal women,after one year TSH suppression therapy the change of lumbarBMDwas0.002±0.043g/cm~2,whilethecontrolgroupwas-0.037±0.037g/cm~2,which has significant difference between the two groups(p=0.002).The change of femoral neck BMD was 0.009±0.053g/cm~2 in DTC group,and the control group was-0.031±0.044g/cm~2,which has significant difference between the two groups(p=0.008).(3)For postmenopausal women,the change of lumbar BMD was-0.004±0.029 g/cm~2and the control group was-0.058±0.042g/cm~2,which has significant difference between the two groups(p=0.004).4.At 2-year follow-up,the BMD of the lumbar and femoral neck and?-crosslaps in the DTC group was significantly decreased compared with baseline.Conclusion:Differentiated thyroid carcinoma after TSH suppression therapy for 1 year did not have significant negative effect on BMD and bone metabolic turnovers;1 year after TSH suppression therapy,in premenopausal women,lumbar and femoral neck BMD increased;in postmenopausal women,lumbar BMD did not obviously decrease and bone absorption reduced.