Mydtskov Nanne Dreier, Lykkedegn Sine, Fruekilde Palle Back Nielsen, Nielsen Jan, Barington Torben, Christesen Henrik Thybo
Clinical Institute, Faculty of Health Sciences, University of Southern Denmark, J. B. Winsløws Vej 19, 5000 Odense C, Denmark.
Clinical Institute, Faculty of Health Sciences, University of Southern Denmark, J. B. Winsløws Vej 19, 5000 Odense C, Denmark; Hans Christian Andersen Children's Hospital, Odense University Hospital, Kløvervænget 25, 5000 Odense C, Denmark.
Clin Biochem. 2017 Dec;50(18):988-996. doi: 10.1016/j.clinbiochem.2017.07.001. Epub 2017 Jul 8.
Analysis of serum 25-hydroxyvitamin D (s-25(OH)D) may be complicated by the less active or in-active vitamin D metabolite C3-epi-25(OH)D (C3-epimer). We aimed to explore the relationship between s-C3-epimer and s-25(OH)D and other determinants and describe the longitudinal course of the C3-epimer fraction in paired mother-child samples.
S-25(OH)D and s-C3-epimer were estimated by liquid chromatography mass spectrometry in 290 mother-infant pairs from the population-based Odense Child Cohort. Longitudinal analyses were feasible in two subcohorts; B) early and late pregnancy, cord, three and 18months (n=132); and C) early and late pregnancy, delivery and cord (n=105).
Mean s-25(OH)D was 50.6-110.4nmol/L at the six time points. The mean C3-epimer fraction was 10.1% at three months, 1.1%-3.0% at the other time points. In multivariate analyses, the s-C3-epimer correlated with s-25(OH)D (all time points, p<0.001), and season, maternal and infant age and maternal vitamin D supplementation at some time points. The C3-epimer fraction fluctuated between adjacent time points. By cosinor analyses, a season-dependent sinusoidal pattern for s-25(OH)D and C3-epimer fraction was found and changes between adjacent time points depended on season (p<0.007 or trend). In early infancy, subtraction of the C3-epi-25(OH)D from total s-25(OH)D resulted in reclassification of 8% of the children by use of the 75nmol/L cut off for s-25(OH)D.
The s-C3-epimer was independently correlated to s-25(OH)D, season, maternal vitamin D supplementation, maternal and infant age. The C3-epimer fraction was only of clinical importance in early infancy, where it could lead to misclassification of the vitamin D status.
血清25-羟基维生素D（s-25(OH)D）的分析可能会因活性较低或无活性的维生素D代谢物C3-表-25(OH)D（C3-表异构体）而变得复杂。我们旨在探讨s-C3-表异构体与s-25(OH)D及其他决定因素之间的关系，并描述配对母婴样本中C3-表异构体比例的纵向变化过程。
通过液相色谱质谱法对来自基于人群的奥登塞儿童队列的290对母婴进行s-25(OH)D和s-C3-表异构体的测定。在两个亚组中进行纵向分析可行；B组：孕早期和晚期、脐带血、3个月和18个月（n = 132）；C组：孕早期和晚期、分娩时和脐带血（n = 105）。
在六个时间点，s-25(OH)D的均值为50.6 - 110.4nmol/L。C3-表异构体的平均比例在3个月时为10.1%，在其他时间点为1.1% - 3.0%。在多变量分析中，s-C3-表异构体与s-25(OH)D（所有时间点，p < 0.001）以及季节、母亲和婴儿年龄以及母亲在某些时间点的维生素D补充情况相关。C3-表异构体比例在相邻时间点之间波动。通过余弦分析，发现s-25(OH)D和C3-表异构体比例存在季节依赖性正弦模式，相邻时间点之间的变化取决于季节（p < 0.007或趋势）。在婴儿早期，从总s-25(OH)D中减去C3-表-25(OH)D后，使用s-25(OH)D的75nmol/L临界值对8%的儿童进行了重新分类。
s-C3-表异构体与s-25(OH)D、季节、母亲维生素D补充情况、母亲和婴儿年龄独立相关。C3-表异构体比例仅在婴儿早期具有临床重要性，在此期间它可能导致维生素D状态的错误分类。
