Rubin MR et al. (2008) Dynamic and structural properties of the skeleton in hypoparathyroidism. J Bone Miner Res [doi:10.1359/jbmr.080803]

A few small studies have reported that patients with hypoparathyroidism have atypical bone structure and skeletal dynamics. Rubin et al. have conducted the largest study to date of bone parameters in patients with hypoparathyroidism in order to establish the features of the skeleton in this setting.

This study enrolled 33 patients who had been affected with hypoparathyroidism for at least 3 years and were receiving calcium and vitamin D supplementation, and 33 age-matched and sex-matched healthy individuals. Mean BMD at key skeletal points was determined by dual-energy X-ray absorptiometry scans. All patients also underwent a percutaneous iliac crest bone biopsy.

BMD was above average or in the normal range in the lumbar spine, hip, femoral neck and distal third of the radius in patients with hypoparathyroidism (Z scores +2.2 ± 2.2, +1.1 ± 1.3, +1.3 ± 1.3 and +0.64 ± 0.94, respectively). Bone reabsorption rate and other histomorphometric variables of bone remodeling in patients with hypoparathyroidism were lower than in the control group. Patients with hypoparathyroidism also had significantly greater cancellous bone volume (P = 0.02), trabecular width (P = 0.03) and cortical width (P = 0.05), regardless of whether their hypoparathyroidism was idiopathic or the result of thyroid surgery. Duration of hypoparathyroidism correlated positively with both trabecular width and cortical width.

The authors conclude that patients with hypoparathyroidism have reduced bone turnover and increased bone volume. The atypical bone quality observed in these patients is most probably a result of parathyroid hormone deficiency.