Purpose

To evaluate total and free vitamin D metabolites and hormone-to-prohormone [1,25(OH)₂D/25(OH)D] “activation ratio” in PHPT patients with low or insufficient vitamin D status.

Methods

Thirty female patients with primary hyperparathyroidism (PHPT) and 30 age and body mass index (BMI) matched healthy controls were enrolled. Serum levels of calcium, intact parathyroid hormone (iPTH), vitamin D binding protein (DBP), albumin, total 25(OH)D and 1,25(OH)₂D were measured. The activation ratio of vitamin D was calculated as total 1,25(OH)₂D/25(OH)D. Calculated serum-free 25(OH)D and 1,25(OH)₂D levels were also reported.

Results

Compared to the control subject, patients with PHPT had a lower total 25(OH)D and DBP levels (p < 0.001). The serum concentration of free 25(OH)D and total 1,25(OH)₂D were similar between the two groups; but free 1,25(OH)₂D levels were about 26% higher in the PHPT patients compared to controls (p < 0.001). PHPT patients had a significantly higher activation ratio (p < 0.01), although their total 25(OH)D were lower than controls. The free (but not total) 1,25(OH)₂D level was inversely correlated with DBP (p < 0.01). Both free 1,25(OH)₂D levels and activation ratio were positively correlated with iPTH and calcium levels (p < 0.01). The activation ratio was highly correlated with levels of total vitamin D stores and free vitamin D metabolites (p < 0.001).

Conclusion

Patients with PHPT had significantly higher free 1,25(OH)₂D levels and activation ratio compared to control subjects. We suggest that levels of free vitamin D metabolites and vitamin D activation ratio may provide additional values for the diagnosis and therapeutic choices in these patient populations with compromised vitamin D status.

中文翻译：

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原发性甲状旁腺功能亢进症患者的总和游离维生素 D 代谢物

目的

评估维生素 D 状态低或不足的 PHPT 患者的总维生素 D 代谢物和游离维生素 D 代谢物以及激素与激素原 [1,25(OH) _{2 D/25(OH)D]“激活比”。}

方法

招募了 30 名患有原发性甲状旁腺功能亢进 (PHPT) 以及 30 岁和体重指数 (BMI) 匹配的健康对照的女性患者。测定血清钙、完整甲状旁腺激素 (iPTH)、维生素 D 结合蛋白 (DBP)、白蛋白、总 25(OH)D 和 1,25(OH) ₂ D 水平。维生素 D 的活化率计算为总 1,25(OH) ₂ D/25(OH)D。还报告了计算的无血清 25(OH)D 和 1,25(OH) ₂ D 水平。

结果

与对照组相比，PHPT 患者的总 25(OH)D 和 DBP 水平较低（p  < 0.001）。两组血清游离25(OH)D浓度和总1,25(OH)2D浓度_相近；但与对照组相比，PHPT 患者的游离 1,25(OH) ₂ D 水平高出约 26%（p  < 0.001）。PHPT 患者的激活率显着升高 ( p  < 0.01)，尽管他们的总 25(OH)D 低于对照组。游离（但不是全部）1,25(OH) ₂ D 水平与 DBP 呈负相关（p  < 0.01）。游离 1,25(OH) ₂ D 水平和活化率均与 iPTH 和钙水平呈正相关（p  < 0.01)。活化率与总维生素 D 储存量和游离维生素 D 代谢物水平高度相关（p  < 0.001）。

结论

与对照组相比，PHPT 患者的游离 1,25(OH) ₂ D 水平和活化率显着升高。我们建议游离维生素 D 代谢物的水平和维生素 D 活化率可能为这些维生素 D 状态受损的患者群体的诊断和治疗选择提供额外的价值。