The effect of thyroidectomy on bone mineral content in perimenopausal women

To examine the effects of total thyroidectomy on skeletal mineral content we performed dual photon densitometry of the spine and hip in 18 patients with well differentiated thyroid cancer treated with total thyroidectomy and post-thyroidectomy 131-I thyroid remnant ablation. Study subjects were 18 Caucasian females, 45-55 years old, no more than 3 years post-menopausal, 4-20 years (mean 9.7) post-thyroidectomy and 131-I ablation. All subjects were free of disease by all criteria and receiving slightly supra-physiological doses of thyroxine. These subjects were compared with 16 carefully age and sex matched controls without thyroid disease. Patients and controls did not differ significantly in: age (mean-range) 50.2 (45-55) vs 48.7 (45-54) years, height 165.1 (152.4-177.8) vs 164.6 (157.5-172.7) cm, or weight 76.7 (49.1-122.7) vs 71.3 (54.5-104.5) kg. Neither did they differ in (mean +/- SEM): serum calcium 9.45 +/- 0.44 vs 9.49 +/- 0.36 mg/dl, serum inorganic phosphate 3.51 +/- 0.67 vs 3.60 +/- 0.43 mg/dl, serum creatinine 0.84 +/- 0.14 vs 0.91 +/- 0.11 mg/dl or PTH 151.7 +/- 71.0 vs 162.4 +/- 52.0 pg/ml. The T12 index was significantly greater in patients on exogenous thyroxine, 12.0 +/- 2.3 vs 8.7 +/- 1.3 (p less than 0.005) although TSH values performed with a standard sensitivity rather than a super sensitive TSH assay were not significantly different 1.8 +/- 0.9 vs 3.2 +/- 1.6 microU/ml. Lumbar vertebral (L2-4) mineral content was not different between patients and controls, 1.245 +/- 0.900 g/cm2 vs. 1.238 +/- 0.166 g/cm2.(ABSTRACT TRUNCATED AT 250 WORDS)