Endocrine Abstracts

Introduction: Primary hyperparathyroidism (PHPT) associated with multiple endocrine neoplasia type 1 (MEN1) impairs bone mineral density and causes ostoporosis already in young patients. We aimed to investigate BMD in a contemporary cohort of patients with MEN1-related PHPT after long term follow-up and compare these results to that of healthy controls.

Methods: Thirty-five patients with genetically confirmed MEN1 were diagnosed with MEN1 at mean age 28.7 +/- 13.6 yrs. Thirty-two (91.4%) underwent primary parathyroidectomy at mean age 33.3 +/- 13.7 yrs, twelve had undergone at least two surgeries with on average 7.3 +/- 5.9 yrs between the operations. BMD was assessed by DXA at the end of mean follow-up, 13.2 yrs after the primary parathyroidectomy and compared to that of 35 age- and gender-matched controls. At the time of DXA, 22 patients (62.9%) had mild persistent hyperparathyroidism (mean serum ionized calcium 1.38 +/- 0.06 mmol/l), seven (20.0%) received medication for postoperative hypoparathyroidism.

Results: At mean age of 42.8 +/- 15.7 yrs, T- and Z-scores in lumbar spine, femoral neck and total hip were all within reference ranges. Absolute BMD values in MEN1 patients compared to controls in the lumbar spine, femoral neck and total hip were 0.986 +/- 0.123 vs 1.172 +/- 0.139 g/cm² (P < 0.001), 0.782 +/- 0.119 vs 0.967 +/- 0.129 g/cm² (P < 0.001) and 0.931 +/- 0.130 vs 1.022 +/- 0.128 g/cm² (P = 0.004), respectively.

Conclusion: More than 10 yrs after the first parathyroidectomy, mean BMD in patients with MEN1 is in the normal range. However, it is still significantly lower compared to healthy controls.