Diasorin, 1951 Northwestern Avenue, Stillwater, Minnesota 55082, USA.
J Clin Endocrinol Metab. 2012 Nov;97(11):3989-95. doi: 10.1210/jc.2012-2276. Epub 2012 Aug 29.
Several studies define optimal serum 25-hydroxyvitamin D (25-OHD) levels based on serum PTH level reaching an asymptote. However, results differ widely, ranging from 25-OHD levels of 12-44 ng/ml: many studies are constrained by small sample size.
The objective of the study was to determine the relationship between serum PTH and 25-OHD levels and age in a very large reference laboratory database.
This was a detailed cross-sectional analysis of 312,962 paired serum PTH and 25-OHD levels measured from July 2010 to June 2011.
Median PTH levels and the proportion of patients (PTH > 65 pg/ml), from 63 successive 25-OHD frequency classes of 5000 patients, provide smooth, exceptionally well-fitted curves (R(2) = 0.994 and R(2) = 0.995, respectively) without discernible inflection points or asymptotes but with striking age dependencies. Serum 25-OHD was below the recent Institute of Medicine sufficiency guidance of 20 ng/ml in 27% (85,000) of the subjects. More importantly, 40 and 51% of subjects (serum 25-OHD <20 and 10 ng/ml, respectively) had biochemical hyperparathyroidism (PTH > 65 pg/ml).
This analysis, despite inevitable inherent limitations, introduces several clinical implications. First, median 25-OHD-dependent PTH levels revealed no threshold above which increasing 25-OHD fails to further suppress PTH. Second, the large number of subjects with 25-OHD deficiency and hyperparathyroidism reinforces the Third International Workshop on Asymptomatic Primary Hyper parathyroidism's recommendations to test for, and replete, vitamin D depletion before considering parathyroidectomy. Third, strong age dependency of the PTH-25-OHD relationship likely reflects the composite effects of age-related decline in calcium absorption and renal function. Finally, this unselected large population database study could guide clinical management of patients based on an age-dependent, PTH-25-OHD continuum.
一些研究根据血清 PTH 水平达到渐近线来定义最佳血清 25-羟维生素 D（25-OHD）水平。然而，结果差异很大，范围从 25-OHD 水平 12-44ng/ml：许多研究受到样本量小的限制。
本研究旨在确定一个非常大的参考实验室数据库中血清 PTH 与 25-OHD 水平和年龄之间的关系。
这是对 2010 年 7 月至 2011 年 6 月期间测量的 312962 对血清 PTH 和 25-OHD 水平进行详细的横断面分析。
中位数 PTH 水平和患者比例（PTH>65pg/ml），来自 63 个连续的 25-OHD 频率为 5000 例的频率类，提供了光滑、拟合极好的曲线（R²=0.994 和 R²=0.995，分别），没有明显的拐点或渐近线，但具有明显的年龄依赖性。血清 25-OHD 在 27%（85000 名）的受试者中低于最近的医学研究所充足指导值 20ng/ml。更重要的是，40%和 51%的受试者（血清 25-OHD<20 和 10ng/ml，分别）存在生化甲状旁腺功能亢进（PTH>65pg/ml）。
尽管存在不可避免的固有局限性，但这项分析提出了一些临床意义。首先，中位数 25-OHD 依赖性 PTH 水平揭示了没有一个阈值，超过这个阈值，增加 25-OHD 不能进一步抑制 PTH。其次，大量的 25-OHD 缺乏和甲状旁腺功能亢进患者强化了第三届无症状原发性甲状旁腺功能亢进症国际研讨会的建议，即在考虑甲状旁腺切除术之前，检测并补充维生素 D 缺乏症。第三，PTH-25-OHD 关系的强年龄依赖性可能反映了与年龄相关的钙吸收和肾功能下降的综合影响。最后，这项未选择的大型人群数据库研究可以根据年龄依赖的 PTH-25-OHD 连续体来指导患者的临床管理。
