Endocrine Abstracts

JOINT2664

Introduction: Hyperthyroidism reduces bone mass and increases fracture risk. These changes are clearly demonstrated in cases of frank thyrotoxicosis in postmenopausal women. Thyroid hormone treatment has a limited effect on bone. Clinical studies show contradictory results. Thyroid hormone treatment should be considered as an additional osteoporotic risk factor in postmenopausal women.

Observation: 76-year-old postmenopausal patient, followed for papillary thyroid microcarcinoma operated and irradiated in 2014, initially put on braking treatment with TSH target <0.1 for the first year, given the good biological and morphological response, the TSH target was redefined between 0.5-2 with a dose of 62.5ug levothyroxine. An osteodensitometry was ordered as part of the work-up, and came back in favour of femoral and lumbar osteopenia with radial osteoporosis. The patient was referred to rheumatology for treatment and follow-up.

Discussion: A literature review analyzed 11 significant studies. All provided information on gender, menopause, bone density measured at different sites and a match to control subjects. All patients had received five or more years of hormone-reducing therapy. One limited cross-sectional study found a significant reduction in lumbar density of 2-6% per year since initiation of thyroxine therapy in postmenopausal women, while a single cross-sectional study found a reduction in femoral neck density, with no changes in lumbar or forearm density compared to control subjects. Of nine studies involving postmenopausal women only, six found no difference in bone density between thyroid cancer patients treated with hormone-braking therapy and controls. One study showed only a slight decrease in bone density at the distal end of the radius. In the work by Kung et al. thyroxine results in complete TSH suppression in all patients and a decrease in bone density at all sites evaluated in postmenopausal women. These contradictory results do not allow us to confirm or deny the deleterious effect of hormone replacement therapy on bone mass in postmenopausal women It is reasonable to consider hormone replacement therapy as an additional osteoporotic risk factor.

Bibliography: G. Weryha et al./Revue du rhumatisme monographies 78 (2011) 114–118