Vitamin D Supplementation After Parathyroidectomy: Effect on Bone Mineral Density—A Randomized Double‐Blind Study

Patients with primary hyperparathyroidism (PHPT) have higher bone turnover, lower bone mineral density (BMD), 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. In this double‐blinded clinical trial, 150 patients with PHPT were randomized, after successful parathyroidectomy (PTX), to 1‐year daily treatment with either cholecalciferol 1600 IU and calcium carbonate 1000 mg (D +) or calcium carbonate alone (D–). BMD was measured in the lumbar spine, femoral neck, total hip, distal and 33% radius using dual‐energy X‐ray absorptiometry (DXA) before surgery and after 1 year of study medication. Median age was 60 (range 30–80) years and there were 119 (79%) women and 31 (21%) men; 76% had 25‐OH‐D <50 nmol/L before PTX and 50% had persistent elevated parathyroid hormone (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, respectively; and D–: 3.0%, 2.3%, and 2.1%, respectively, p < 0.001). Patients with vitamin D supplementation also increased their BMD in distal radius (median 2.0%; interquartile range, ?1.7% to 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). 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 ultradistal (p < 0.05). In conclusion, except for a minor improvement of radius BMD, our 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. © 2014 American Society for Bone and Mineral Research.