INTRODUCTION: Exogenous thyroid hormone usage for thyroid-stimulating hormone (TSH) suppression was found to be risky of bone loss for post-menopausal women (PW) after total thyroidectomy (TT). However, osteoporosis in euthyroid PW was not examined. We aimed to evaluate the frequency and severity of osteoporosis after TT in euthyroid PW.
METHODS: One hundred PW were included and were divided into two groups as the TT group (n=50) and the control group (n=50). The patients were in the post-menopausal period for at least 5 years, were euthyroid, and did not receive any drugs effective on bone metabolism. Age, length of post-menopausal period, and laboratory findings including TSH, triiodothyronine, thyroxine, serum calcium, serum phosphorus, serum magnesium, serum intact parathormone, serum alkaline phosphatase, 24-h urine calcium, and bone mineral density (BMD) of vertebra, femoral neck, trochanteric region, and Wards triangle were analyzed and compared between two groups. BMD was expressed as T-score.
RESULTS: No significant difference was found between the two groups in terms of age, length of postmenopausal period, laboratory findings, and T-scores of L1, L2, and L4 vertebra. The T-scores of the L3 vertebra, femoral neck, trochanteric region, and Wards triangle significantly differed between the groups (p=0.029, p=0.001, p=0.005, and p=0.000, respectively). Osteoporosis was observed in 50% of patients in the TT group, but this rate was only 16% in the control group and this difference was significant (p=0.001).
DISCUSSION AND CONCLUSION: After TT, BMD decreases and the rate of osteoporosis increases in PW, even under replacement dose of exogenous thyroid hormone.