title: Change of Bone Mineral Density and Biochemical Markers of Bone Turnover in Patients on Suppressive Levothyroxine Therapy for Differentiated Thyroid Carcinoma.
abstract: Untreated hyperthyroidism and high-dose thyroid hormone are associated with osteoporosis, and increased bone mineral density (BMD) has been demonstrated in postmenopausal females with hypoparathyroidism. Studies on the effect of suppressive levothyroxine (LT4) therapy on BMD and bone metabolism after total thyroidectomy in patients with differentiated thyroid carcinoma have presented conflicting results, and few studies in relation to the status of hypoparathyroidism have been studied. One hundred postmenopausal women and 24 premenopausal women on LT4 suppression therapy were included in this study. BMD of lumbar spine and femur and bone turnover markers were measured at the baseline and during the follow-up period up to 18 months using dual energy X-ray absorptiometry. Biochemical marker of bone resorption was measured by urine deoxypyridinoline and bone formation by serum osteocalcin. The age ranged from 36 to 64 years old. Thyroid stimulating hormone (TSH) was suppressed during the study. The results showed that BMD of femur and lumbar spine were not significantly changed in both pre- and postmenopausal women except femur neck in postmenopausal women without hypoparathyroidism. Patients with hypoparathyroidism had higher BMD gain than those without hypoparathyroidism in total hip (1.25 vs. -1.18%, P=0.015). Biochemical markers of bone turnover, serum osteocalcin, and urine deoxypyridinoline did not show significant change. In conclusion, patients with well differentiated thyroid carcinoma are not at a great risk of bone loss after LT4 suppressive therapy. The state of hypoparathyroidism is associated with increased BMD, particularly in postmenopausal women.
authors.affiliation: Department of Endocrinology, Inha University School of Medicine, Incheon, Korea.
authors.forename: Chei Won
authors.initials: CW
authors.lastname: Kim
authors.affiliation: Department of Endocrinology, Inha University School of Medicine, Incheon, Korea.
authors.forename: Seokbo
authors.initials: S
authors.lastname: Hong
authors.affiliation: Department of Endocrinology, Inha University School of Medicine, Incheon, Korea.
authors.forename: Se Hwan
authors.initials: SH
authors.lastname: Oh
authors.affiliation: Department of Endocrinology, Inha University School of Medicine, Incheon, Korea. ; Department of Internal Medicine, Hallym General Hospital, Incheon, Korea.
authors.forename: Jung Jin
authors.initials: JJ
authors.lastname: Lee
authors.affiliation: Department of Endocrinology, Inha University School of Medicine, Incheon, Korea.
authors.forename: Joo Young
authors.initials: JY
authors.lastname: Han
authors.affiliation: Department of Endocrinology, Inha University School of Medicine, Incheon, Korea.
authors.forename: Seongbin
authors.initials: S
authors.lastname: Hong
authors.affiliation: Department of Endocrinology, Inha University School of Medicine, Incheon, Korea.
authors.forename: So Hun
authors.initials: SH
authors.lastname: Kim
authors.affiliation: Department of Endocrinology, Inha University School of Medicine, Incheon, Korea.
authors.forename: Moonsuk
authors.initials: M
authors.lastname: Nam
authors.affiliation: Department of Endocrinology, Inha University School of Medicine, Incheon, Korea.
authors.forename: Yong Seong
authors.initials: YS
authors.lastname: Kim
keywords: Bone density; Hypoparathyroidism; Postmenopause; Thyroid neoplasms; Thyroxine