Bone mineral density in treated at a young age for differentiated thyroid cancer after Chernobyl female patients on TSH-suppressive therapy receiving or not Calcium-D3 supplementation

Long-term management of patients with differentiated thyroid cancer (DTC) commonly includes TSH-suppressive therapy with L-T4 and, in case of postsurgical hypoparathyroidism, Calcium-D3 supplementation, both of which may affect skeletal health. Experience with female patients treated for DTC at a young age and who were then receiving long-term therapy with L-T4 and Calcium-D3 medication is very limited to date. This cross-sectional study set out to investigate effects of Calcium-D3 supplementation and TSH-suppressive therapy on bone mineral density (BMD) in 124 young female patients treated for DTC at a mean age of 14 years and followed-up for an average of 10 years. BMD was found to be significantly higher in patients receiving Calcium-D3 medication than in patients not taking supplements. The level of ionized calcium was the strongest factor determining lumbar spine BMD in patients not receiving Calcium-D3 supplementation. Pregnancy ending in childbirth and HDL-cholesterol were associated with a weak adverse effect on spine and femoral BMD. No evidence of adverse effects of L-T4 and of radioiodine therapies on BMD was found. We conclude that Calcium-D3 medication has a beneficial effect on BMD, and that TSH-suppressive therapy does not affect BMD in women treated for DTC at young age, at least after 10 years of follow-up.