Abstract
BACKGROUND: This study aimed to investigate the densitometric characteristics and qualitative bone status in patients with normocalcemic primary hyperparathyroidism (PHPT) compared with those in controls who were younger adults under 50 years. METHODS: This retrospective study included 60 controls and 31 patients with PHPT who underwent dual energy X-ray absorptiometry (DXA) of the lumbar spine (LS), femoral neck (FN), and total hip (TH). Trabecular bone score (TBS) was derived from LS DXA images. Bone mineral density (BMD) values were assessed using Z-scores, and correlations between TBS, BMD, and laboratory parameters were examined. RESULTS: The median ages of the control and PHPT groups were 41 and 42 years, respectively. The proportion of individuals classified as "below the expected range for age" based on Z-scores differed significantly between groups only when considering any site collectively. Median TBS was significantly lower in PHPT patients than in controls, even when BMD values at LS, FN, and TH fell within similar diagnostic categories. In controls, TBS and BMD demonstrated very low correlation coefficients. In contrast, PHPT patients showed a stronger correlation between TBS and femoral BMD, whereas the association between TBS and LS BMD was largely absent. Among laboratory markers, only serum intact parathyroid hormone was significantly negatively correlated with TBS. CONCLUSIONS: Young adults with PHPT exhibit impaired bone quality despite relatively preserved BMD, suggesting early microarchitectural deterioration. These findings support the combined use of LS and femoral BMD with TBS for more accurate assessment of skeletal health in PHPT.