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The variation in free 25-hydroxy vitamin D and vitamin D-binding protein with season and vitamin D status

PURPOSE: Serum 25-hydroxy vitamin D [25(OH)D] varies greatly with season at northern latitudes. The purpose of this study was to determine if the seasonal variations in serum total 25(OH)D are followed by a concomitant variation in free 25(OH)D or if the variation is damped by alterations in the bin...

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Autores principales: Oleröd, Göran, Hultén, Lillemor Mattsson, Hammarsten, Ola, Klingberg, Eva
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Bioscientifica Ltd 2017
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5428908/
https://www.ncbi.nlm.nih.gov/pubmed/28179376
http://dx.doi.org/10.1530/EC-16-0078
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author Oleröd, Göran
Hultén, Lillemor Mattsson
Hammarsten, Ola
Klingberg, Eva
author_facet Oleröd, Göran
Hultén, Lillemor Mattsson
Hammarsten, Ola
Klingberg, Eva
author_sort Oleröd, Göran
collection PubMed
description PURPOSE: Serum 25-hydroxy vitamin D [25(OH)D] varies greatly with season at northern latitudes. The purpose of this study was to determine if the seasonal variations in serum total 25(OH)D are followed by a concomitant variation in free 25(OH)D or if the variation is damped by alterations in the binding capacity of DBP. METHODS: Serum was collected from 540 healthy blood donors (60% men; mean age 41 ± 13 years) during 12 months and analyzed for total 25(OH)D, directly measured free 25(OH)D, vitamin D-binding protein (DBP) and albumin. Calculated free 25(OH)D was estimated. RESULTS: The UV-B radiation during the sampling month was positively correlated with the serum levels of total 25(OH)D (r = 0.355, P < 0.001), directly measured free (r = 0.336, P < 0.001) and calculated free 25(OH)D (r = 0.275, P < 0.001), but not with DBP and albumin. The percentage of free 25(OH)D was higher during the winter months than that during the summer months (0.020 ± 0.005% vs 0.019 ± 0.004%; P = 0.007) and higher in participants with a serum 25(OH)D below 25 nmol/L than that in participants with a serum 25(OH)D above 75 nmol/L (0.031 ± 0.007% vs 0.017 ± 0.003%; P < 0.001). iPTH was correlated with directly measured free 25(OH)D (r = −0.226; P < 0.001), but only weakly with calculated free 25(OH)D (r = −0.095; P = 0.027). CONCLUSIONS: Directly measured free serum 25(OH)D was highly correlated with total serum 25(OH)D and followed the same seasonal variation, whereas the serum concentrations of DBP and albumin were stable. The fluctuation in free 25(OH)D was only marginally damped with an increase in the percentage of free 25(OH)D during the winter months and in participants with vitamin D deficiency.
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spelling pubmed-54289082017-05-16 The variation in free 25-hydroxy vitamin D and vitamin D-binding protein with season and vitamin D status Oleröd, Göran Hultén, Lillemor Mattsson Hammarsten, Ola Klingberg, Eva Endocr Connect Research PURPOSE: Serum 25-hydroxy vitamin D [25(OH)D] varies greatly with season at northern latitudes. The purpose of this study was to determine if the seasonal variations in serum total 25(OH)D are followed by a concomitant variation in free 25(OH)D or if the variation is damped by alterations in the binding capacity of DBP. METHODS: Serum was collected from 540 healthy blood donors (60% men; mean age 41 ± 13 years) during 12 months and analyzed for total 25(OH)D, directly measured free 25(OH)D, vitamin D-binding protein (DBP) and albumin. Calculated free 25(OH)D was estimated. RESULTS: The UV-B radiation during the sampling month was positively correlated with the serum levels of total 25(OH)D (r = 0.355, P < 0.001), directly measured free (r = 0.336, P < 0.001) and calculated free 25(OH)D (r = 0.275, P < 0.001), but not with DBP and albumin. The percentage of free 25(OH)D was higher during the winter months than that during the summer months (0.020 ± 0.005% vs 0.019 ± 0.004%; P = 0.007) and higher in participants with a serum 25(OH)D below 25 nmol/L than that in participants with a serum 25(OH)D above 75 nmol/L (0.031 ± 0.007% vs 0.017 ± 0.003%; P < 0.001). iPTH was correlated with directly measured free 25(OH)D (r = −0.226; P < 0.001), but only weakly with calculated free 25(OH)D (r = −0.095; P = 0.027). CONCLUSIONS: Directly measured free serum 25(OH)D was highly correlated with total serum 25(OH)D and followed the same seasonal variation, whereas the serum concentrations of DBP and albumin were stable. The fluctuation in free 25(OH)D was only marginally damped with an increase in the percentage of free 25(OH)D during the winter months and in participants with vitamin D deficiency. Bioscientifica Ltd 2017-02-08 /pmc/articles/PMC5428908/ /pubmed/28179376 http://dx.doi.org/10.1530/EC-16-0078 Text en © 2017 The authors http://creativecommons.org/licenses/by-nc-nd/4.0/ This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (http://creativecommons.org/licenses/by-nc-nd/4.0/) .
spellingShingle Research
Oleröd, Göran
Hultén, Lillemor Mattsson
Hammarsten, Ola
Klingberg, Eva
The variation in free 25-hydroxy vitamin D and vitamin D-binding protein with season and vitamin D status
title The variation in free 25-hydroxy vitamin D and vitamin D-binding protein with season and vitamin D status
title_full The variation in free 25-hydroxy vitamin D and vitamin D-binding protein with season and vitamin D status
title_fullStr The variation in free 25-hydroxy vitamin D and vitamin D-binding protein with season and vitamin D status
title_full_unstemmed The variation in free 25-hydroxy vitamin D and vitamin D-binding protein with season and vitamin D status
title_short The variation in free 25-hydroxy vitamin D and vitamin D-binding protein with season and vitamin D status
title_sort variation in free 25-hydroxy vitamin d and vitamin d-binding protein with season and vitamin d status
topic Research
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5428908/
https://www.ncbi.nlm.nih.gov/pubmed/28179376
http://dx.doi.org/10.1530/EC-16-0078
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