Hospital Clínic de Barcelona, IDIBAPS. CIBERehd, Barcelona, Spain.
Servicio de Bioquímica Clínica, Hospital Clinic, Barcelona, Spain.
Osteoporos Int. 2017 Aug;28(8):2457-2464. doi: 10.1007/s00198-017-4062-8. Epub 2017 May 2.
Determination of different forms of 25-OHD (total, free and bioavailable) in healthy young women does not offer additional advantages over standard 25-OHD for evaluating vitamin D deficiency. In these subjects 25-OHD values <15 ng/ml would be more appropriate for defining this deficiency.
Determination of 25-OH vitamin D serum levels (25-OHD) constitutes the method of choice for evaluating vitamin D deficiency. However, vitamin D-binding protein (DBP) may modulate its bioavailability thereby affecting correct evaluation of 25-OHD status. We analysed the impact of the determination of 25-OHD (total, free and bioavailable) on the evaluation its biologic activity (estimated by serum PTH determination) in healthy young women.
173 premenopausal women (aged 35-45 yrs.) were included. We analysed serum values of total 25-OHD (25-OHD), DBP, albumin, PTH and bone formation (PINP,OC) and resorption (NTx,CTx) markers. Free(25-OHD) and bioavailable (25-OHD) serum 25-OHD levels were estimated by DBP and albumin determinations and also directly by ELISA (25-OHD). We analysed threshold PTH values for the different forms of 25-OHD and the correlations and differences according to 25-OHD levels <20 ng/ml.
62% of subjects had 25-OHD values <20 ng/ml and also had significantly lower 25-OHD and 25-OHD values, with no significant differences in bone markers and PTH values. The PTH threshold value was similar for all forms of 25-OHD (∼70 pg/ml). Women with PTH values >70 had lower 25-OHD (15.4 ± 1.4 vs. 18.3 ± 2.7, p < 0.05) and 25OHD values (1.7 ± 0.2 vs. 2.2 ± 0.09, p < 0.05). The different forms of 25OHD were significantly intercorrelated, with marginal correlations between PTH and 25-OHD (r = -0.136, p = 0.082).
Determination of different forms of 25-OHD in healthy young women does not offer additional advantages over standard 25-OHD for evaluating vitamin D deficiency. In these subjects 25-OHD values <15 ng/ml would be more appropriate for defining this deficiency.
评估维生素 D 缺乏症时，测定健康年轻女性的 25-OHD（总、游离和生物可利用）的不同形式是否比标准 25-OHD 更有优势。在这些受试者中，25-OHD 值＜15ng/ml 可能更适合定义这种缺乏。
纳入 173 名绝经前妇女（年龄 35-45 岁）。我们分析了总 25-OHD（25-OHD）、维生素 D 结合蛋白（DBP）、白蛋白、甲状旁腺激素（PTH）和骨形成（PINP、OC）及骨吸收（NTx、CTX）标志物的血清值。游离（25-OHD）和生物可利用（25-OHD）血清 25-OHD 水平通过 DBP 和白蛋白测定以及 ELISA（25-OHD）直接估计。我们分析了不同形式 25-OHD 的 PTH 阈值，并根据 25-OHD 值＜20ng/ml 分析了它们的相关性和差异。
62%的受试者 25-OHD 值＜20ng/ml，且 25-OHD 和 25-OHD 值明显更低，骨标志物和 PTH 值无显著差异。所有形式的 25-OHD 的 PTH 阈值均相似（～70pg/ml）。PTH 值＞70 的女性 25-OHD 水平较低（15.4±1.4 vs. 18.3±2.7，p＜0.05）和 25-OHD 值较低（1.7±0.2 vs. 2.2±0.09，p＜0.05）。不同形式的 25-OHD 之间呈显著的相关性，PTH 与 25-OHD 之间存在边缘相关性（r=-0.136，p=0.082）。
评估健康年轻女性的 25-OHD 不同形式并不比标准 25-OHD 更有优势。在这些受试者中，25-OHD 值＜15ng/ml 可能更适合定义这种缺乏。
