S-25-hydroxyvitamin D and C3-epimers in pregnancy and infancy: An Odense Child Cohort study

Mydtskov, Nanne; Lykkedegn, Sine; Fruekilde, Palle Bach Nielsen; Nielsen, Jan; Barington, Torben; Christesen, Henrik Thybo

doi:10.1016/j.clinbiochem.2017.07.001

Cited by 20 publications

(14 citation statements)

References 36 publications

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“…The epimer concentration is relatively constant throughout life, but constitutes a larger fraction of total 25(OH)D in infancy (mean of 10.1%, up to 61%) than in adulthood (mean of 2.3%-3.2%). [15][16][17][18] While LC-MS/MS has made significant inroads as a measurement technique, traditional immunoassays are still the mainstay in most clinical laboratories. There is a lack of consensus among the various professional societies on how to diagnose and treat vitamin D deficiency.…”

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confidence: 99%

Accuracy-Based Vitamin D Survey: Six Years of Quality Improvement Guided by Proficiency Testing

Erdman

Palmer-Toy

Horowitz

et al. 2019

Archives of Pathology &Amp; Laboratory Medicine

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Context.— The goal of the College of American Pathologists Accuracy-Based Proficiency Testing Program is to promote the quality, standardization, and harmonization of clinical laboratory results through proficiency testing specimens that are free from matrix effects, have target values that are traceable to reference methods, and that probe the limitations of current methods. Objective.— To summarize the first 6 years of the Accuracy-Based Vitamin D Survey and highlight key insights from the data generated as it relates to assay performance. Design.— Accuracy-based challenges were created by using pooled human serum samples. Certain samples were derived from participants in an institutional review board–approved protocol in which vitamin D–deficient participants were treated with ergocalciferol (vitamin D2). Reference targets for the survey were set by the Centers for Disease Control and Prevention using isotope-dilution liquid chromatography–tandem mass spectrometry. Each method was compared with the reference method procedure over the course of the program (n = 43 proficiency testing samples). Results.— Linear regression versus the reference method procedure revealed proportional biases across the methods, ranging from 0.0% to 16.7%. Pearson correlation coefficients ( r2) ranged from 0.902 to 0.996. Results were influenced by the concentration of 25-hydroxyvitamin D2 as well as the C-3 epimer of 25-hydroxyvitamin D3. During the 6 years, 2 manufacturers altered their assays to match the reference method procedure more closely. Conclusions.— There is considerable bias, both proportional bias and sample-specific matrix effects, affecting many assays. This ongoing accuracy-based proficiency testing program for vitamin D will provide the data needed for laboratories and manufacturers to improve their assays and thereby patient care.

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confidence: 99%

Accuracy-Based Vitamin D Survey: Six Years of Quality Improvement Guided by Proficiency Testing

Erdman

Palmer-Toy

Horowitz

et al. 2019

Archives of Pathology &Amp; Laboratory Medicine

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“…C3-epimers were included in the s-25(OH)D measurements. In a tested subsample, C3-epimer concentrations in pregnancy and cord blood were between 1•1 and 3•0 nmol/l, that is, 0•5-2•3 % of total s-25(OH)D concentration (33) .…”

Section: Assessment Of Vitamin D Statusmentioning

confidence: 89%

Bone mineral density at age 7 years does not associate with adherence to vitamin D supplementation guidelines in infancy or vitamin D status in pregnancy and childhood: an Odense Child Cohort study

et al. 2021

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Vitamin D supplementation in infancy is recommended to prevent rickets. At the population level, its effects on bone mineralisation are largely unknown. We aimed to explore whether adherence to national vitamin D supplementation guidelines (10 µg/day up to age 2 years), supplementation at ages 5 and 7 years, and serum 25-hydroxyvitamin D (s-25(OH)D) at various time points associated with bone mineral density (BMD) at age 7 years in the Odense Child Cohort, Denmark (n=1,194). High adherence was defined as supplementation with 10 µg vitamin D 6-7 times per week during ≥ 80 % of the observation time. S-25(OH)D was analysed using liquid chromatography-tandem mass spectrometry. Total-body-less-head (TBLH) BMD was measured by dual-energy X-ray absorptiometry. At median age 18.1 months, 53.9 % (n=475/881) reported high adherence. The median s-25(OH)D was 64.7, 78.8, 46.0, and 71.8 nmol/l in early pregnancy, late pregnancy, cord blood, and at 5 years, respectively. The mean (SD) TBLH BMD at median age 7.1 years was 0.613 (0.049) g/cm2 (z-score +0.363 (0.824)). In adjusted analyses, vitamin D supplementation up to 18 months, and at 5 and 7 years, was not associated with TBLH BMD. Similarly, no robust associations were found between TBLH BMD and s-25(OH)D at any time point. No associations were found for TBLH bone mineral concentration or bone area. In this population with relatively high s-25(OH)D concentrations, no consistent associations were found between adherence to vitamin D supplementation recommendations or vitamin D status in pregnancy or childhood, and bone mineralisation at age 7 years.

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“…For optimal calibration of the PTAD LC-MS/MS method, we used a NIST 972-calibrated LC-MS/MS method performed on a Thermo Scientific TLX1 system connected to a Thermo Scientific Discovery Ultra TSQ as previously described. 17 Serum samples were added triple deuterium-marked 25-OH-Vitamin D3 as internal standard and deproteinized with ZnSO 4 in methanol and then centrifuged at 3200 g for 10 min. The supernatant was transferred and injected (100 µ L) on the TurboFlow LC-MS/MS.…”

Section: Methodsmentioning

confidence: 99%

Measurement of vitamin D in dried blood spots stored under different temperature conditions

2021

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Background: As part of the Survey of Health, Ageing and Retirement in Europe (SHARE) study, dried blood spot (DBS) samples were obtained for measurement of potential biological biomarkers, among those vitamin D. Unfortunately, no studies describe the impact of high temperatures on DBS samples and vitamin D measurements. Materials and methods: Capillary samples were collected on DBS cards from 40 outpatients (median age 78 years) along with venous blood samples. To mimic the different environmental and temporal challenges during collection and shipment until final storage in the SHARE study, DBS cards were stored at different temperatures, at time span and with/without freeze-thaw. Vitamin D concentrations in venous plasma samples was measured by conventional immunoassay (on Architect i2000SR), while vitamin D concentrations in DBS samples were measured using LC-MS/MS with a well-described extraction method and with relevant calibration and comparison with a reference method. Results: Vitamin D measured in DBS samples did not differ significantly from venous plasma measurements under the different storage conditions tested. The optimal vitamin D correlation between the two matrices were by storage at either 21 Â°C or 35 Â°C for four days (r = 0.9060 and 0.9026, resp.). Freeze-thaw of the DBS samples did not have any significant effect. Conclusion: We find that vitamin D measured in DBS samples do not differ significantly from venous plasma measurements despite storage at different temperatures and freeze-thaw, which enables the use of DBS in multicenter studies taking place under alternating temperature conditions.

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S-25-hydroxyvitamin D and C3-epimers in pregnancy and infancy: An Odense Child Cohort study

Cited by 20 publications

References 36 publications

Accuracy-Based Vitamin D Survey: Six Years of Quality Improvement Guided by Proficiency Testing

Accuracy-Based Vitamin D Survey: Six Years of Quality Improvement Guided by Proficiency Testing

Bone mineral density at age 7 years does not associate with adherence to vitamin D supplementation guidelines in infancy or vitamin D status in pregnancy and childhood: an Odense Child Cohort study

Measurement of vitamin D in dried blood spots stored under different temperature conditions

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