Vitamin D supplementation after parathyroidectomy - effect on bone mineral density – a randomized double blind study
Journal of Bone and Mineral Research, 09/27/2013Norenstedt S et al.
Patients with primary hyperparathyroidism (PHPT) have higher bone turnover, lower bone mineral density and an increased risk of fractures. They also have a high incidence of low vitamin D levels (25–OH–vitamin D < 50 nmol/l) that could worsen the negative effect on the bone. Except for a minor improvement of radius BMD, the data show no beneficial effect on BMD or bone turnover markers of vitamin D supplementation after PTX. Preoperative PTH seems to have the strongest association with improvement in BMD.
In this double–blinded clinical trial, 150 patients with PHPT were randomized, after successful parathyroidectomy (PTX), to one–year daily treatment with either cholecalciferol 1600 IU and calcium carbonate 1000 mg (D +) or calcium carbonate alone (D –).
Bone mineral density (BMD) was measured in the lumbar spine, femoral neck, total hip, distal and 33% radius using dual X–ray absorptiometry (DXA) before surgery and after one year of study medication.
Median age was 60 years (30–80 years) and there were 119 (79%) women and 31 (21%) men.
76% had 25–OH–D < 50 nmol/l before PTX.
50% had persistent elevated PTH 6 weeks after PTX.
A similar increase in BMD in the lumbar spine, femoral neck and total hip was observed in both groups (D + : 3.6%, 3.2% and 2.7%, p < 0.001; D–: 3.0%, 2.3% and 2.1%, p < 0.001).
Patients with vitamin D supplementation also increased their BMD in distal radius (2.0% (–1.7 – 5.4), p = 0.013).
The changes in BMD, especially in the hips, were correlated to the baseline concentrations of PTH, ionized calcium and bone markers (p < 0.001).
Except for the increase in distal radius BMD, a benefit from vitamin D substitution was observed among patients with a persistent postoperative PTH elevation, who also improved their BMD at 33% radius and radius UD (p < 0.05).
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