This paper (with two others I'm conveying) has studied the truly longterm effects of TSH suppression in cancer patients (to prevent a recurrence of the problem) What it shows is that long term there is no effect on bone density in the large majority of patients. They term the state subclinical hyperthyroidism - ie low TSH but normal FT4. So it shows that doctors need not get worried about OP effects over a longterm TSH- supressive dose of T4. A minority may be affected but it is individual not widespread. I don't think FT3 was included. This finding can obviously apply to patients on T4 or T4/T3 who have low or no TSH, with normal FT4/3. Article behind paywall
Thyroid Vol. 31, No. 11
Thyroid Cancer and Nodules
Bone Mineral Density in Adult Survivors of Pediatric Differentiated Thyroid Carcinoma: A Longitudinal Follow-Up Study
Bernadette L. Dekker, Anneke C. Muller Kobold, Adrienne H. Brouwers, Graham R. Williams, Marloes Nies, Mariëlle S. Klein Hesselink, Anouk N.A. van der Horst-Schrivers, Bas Havekes, Marry M. van den Heuvel-Eibrink, Heleen J.H. van der Pal, John Th. M. Plukker, Cecile M. Ronckers, Hanneke M. van Santen, …et al
Published Online:10 Nov 2021doi.org/10.1089/thy.2021.0179
Abstract
Background: Survivors of pediatric differentiated thyroid carcinoma (DTC) receive thyrotropin-suppressive therapy to minimize disease recurrence. However, knowledge about long-term effects of subclinical hyperthyroidism on bone mineral density (BMD) in pediatric DTC survivors is scarce, as is the information regarding long-term consequences of permanent hypoparathyroidism on BMD. We evaluated BMD in pediatric DTC survivors and investigated if BMD was affected by subclinical hyperthyroidism and/or permanent hypoparathyroidism during long-term follow-up.
Methods: In this nationwide longitudinal study, we determined BMD in the lumbar spine and femur by dual energy X-ray absorptiometry in 65 pediatric DTC survivors. Measurements were repeated after minimal 5 years of follow-up in 46 pediatric DTC survivors. BMD results were evaluated according to the recommendations of the International Society for Clinical Densitometry (ISCD) and WHO. At both visits, we determined biochemical parameters and markers of bone resorption (C-terminal telopeptide of type I collagen [β-CTX]) and formation (N-propeptide of type I collagen [PINP] and osteocalcin).
Results: First and second BMD measurements were done after a median follow-up of 17.0 (interquartile range [IQR] 8.0–25.0) and 23.5 (IQR 14.0–30.0) years after diagnosis, respectively. Median age at diagnosis was 15 years (IQR 13.0–17.0). Twenty-nine percent of the survivors had subclinical hyperthyroidism. In most survivors, BMD T- and Z-scores were within the reference range during both BMD evaluations. However, after 23.5 years of follow-up, a low BMD was found in 13.0%. In the 13 survivors with permanent hypoparathyroidism, BMD values did not differ after 5 years of follow-up compared with baseline values or in comparison with the 33 survivors without permanent hypoparathyroidism. During follow-up, turnover markers β-CTX and PINP remained stable.
Conclusions: This longitudinal study of pediatric DTC survivors demonstrated normal and stable median lumbar spine and femur BMD values after a median time of 17 and 23.5 years after diagnosis. However, compared with controls, a lower BMD was still found in 13.0% after prolonged follow-up despite intensive follow-up. Based on the studied follow-up period, these data do not provide convincing evidence in support of standard monitoring of bone mass among DTC survivors, but may be restricted to individual cases at low frequency.
Trial Registration: This follow-up study was registered in The Netherlands Trial Register under no. NL3280 (trialregister.nl/trial/3280).
Hyperthyroidism Breaking News
