Effect of calcitonin deficiency on bone density and bone turnover in totally thyroidectomized patients

Abstract

To investigate the influence of calcitonin deficiency on bone turnover and density we studied 25 premenopausal female and 12 male patients (age 23 to 49 years) who had undergone total thyroidectomy for differentiated thyroid cancer 1 to 15 years previously. Basal and calcium stimulated extractable calcitonin, representing the monomeric, biologically active form of the hormone, was lacking or markedly decreased in all patients. There was a relative increase of urine hydroxyproline excretion (an index of osteoclastic bone degradation) in relation to serum osteocalcin (an index of osteoblastic bone formation) indicating an imbalance of bone turnover with a tendency to increased degradation in all patients. Total and trabecular bone density, measured with quantitative computed tomography at the distal forearm were significantly decreased in the male and normal in the female patients, without a relation to the duration of the calcitonin deficiency. The study indicates that patients with calcitonin deficiency, suppressive thyroid hormone treatment, or both may have a higher risk of increased bone degradation and osteopenia. Whether the effect is more due to calcitonin deficiency or thyroid hormone therapy, cannot be concluded from this study design. The fact that only the male patients had a decreased bone density may be due to a lower parathyroid activity in our female patients and the greater thyroidectomy-induced decrement of monomeric calcitonin in our male patients compared with male controls.

Prospective study of bone loss in pre‐ and post‐menopausal women on L‐thyroxine therapy for non‐toxic goitre

“…Several prospective studies have reported accelerated bone loss in lumbar and/or hip sites in thyroidectomized patients (Pioli et al, 1992) or in hypothyroid patients (Ribot et al, 1990;Krolner et al, 1983;Stall et al, 1990) on L-T4 suppressive or replacement therapy, respectively. In thyroidectomized patients with carcinoma, a highly suppressive L-T4 dosage is given; furthermore, it may be difficult to evaluate the effect on bone of deficit of the main calciotrophic hormones (PTH and calcitonin) (Schneider et al, 1991). In 15 pre-menopausal women treated with a suppressive L-T4 dose for 12-36 months after thyroidectomy Pioli et al (1992) found a more marked loss of spinal bone mineral content than in controls.…”

Sexual Influence on Bone Metabolism in Uremic Patients on Regular Dialytic Treatment

“…This could suggest a greater sensitivity of male skeleton to the protective action of CT. According to this hypothesis, Schneider et al [40], studying the effect of CT deficiency on bone density in totally thyroidectomized pa tients, failed to demonstrate any variation of bone density in females, but found a significant decrease in males. For these reasons it is difficult to strengthen that CT is really effective in protecting the female skeleton.…”

Impact of Parathyroid Status and Ca and Vitamin-D Supplementation on Bone Mass and Muscle-Bone Relationships in 208 Belarussian Children after Thyroidectomy because of Thyroid Carcinoma

“…It was difficult to predict what would have been the skeletal impact of the parathyroid status of the children in this study. In a previous study we had demonstrated that thyroidectomized adult patients tended to loose bone density, showing higher urinary Ca/creatinine excretion ratios compared to normal controls (Schneider et al, 1991). This observation suggests that the low serum Ca values of some of our children could be explained by a raise in urinary Ca excretion resulting from impaired tubular resorption.…”

“…In a previous study we had reported no remarkable effects on bone mineral densitiy (DXA-assessed BMD) and serum calcitonin levels in thyroidectomized adults who had subnormal total and serum ionized Ca levels (Schneider et al, 1991), presumably due to alternative sources of calcitonin. In this study we investigated the bone mass in 208 Belarussian children and adolescents who had undergone total thyroidectomy because of papillary thyroid carcinoma (Reiners et al, 2000).…”