Vitamin D supplementation after parathyroidectomy: effect on bone mineral density-a randomized double-blind study

Area of Science:

• Endocrinology
• Bone Metabolism
• Nutritional Science

Background:

• Primary hyperparathyroidism (PHPT) is linked to increased bone turnover, reduced bone mineral density (BMD), and higher fracture risk.
• Many PHPT patients exhibit low vitamin D levels, potentially exacerbating bone health issues.
• Parathyroidectomy (PTX) is a common treatment for PHPT.

Purpose of the Study:

• To investigate the effect of vitamin D supplementation on bone mineral density (BMD) in patients following successful parathyroidectomy (PTX).
• To determine if vitamin D (cholecalciferol) and calcium supplementation offers additional benefits to BMD compared to calcium alone post-PTX.

Main Methods:

• A double-blinded clinical trial randomized 150 PHPT patients post-PTX to receive 1-year of either cholecalciferol 1600 IU + calcium carbonate 1000 mg (D+) or calcium carbonate alone (D-).
• Bone mineral density (BMD) was assessed using dual-energy X-ray absorptiometry (DXA) at baseline and after 1 year.
• Measurements included lumbar spine, femoral neck, total hip, distal radius, and ultradistal radius.

Main Results:

• Both groups showed similar increases in BMD at the lumbar spine, femoral neck, and total hip.
• The vitamin D supplemented group (D+) demonstrated a statistically significant increase in BMD at the distal radius.
• Improvements in BMD, particularly at the hip, correlated with baseline parathyroid hormone (PTH), ionized calcium, and bone markers.

Conclusions:

• Vitamin D supplementation after parathyroidectomy (PTX) provided no significant benefit to overall bone mineral density (BMD) or bone turnover markers.
• A minor improvement in radius BMD was observed with vitamin D supplementation, especially in patients with persistent postoperative hyperparathyroidism.
• Baseline preoperative PTH levels appear to be the strongest predictor of BMD improvement post-surgery.