{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,22]],"date-time":"2026-10-22T16:19:00Z","timestamp":1792685940153,"version":"4.5.0"},"reference-count":58,"publisher":"MDPI AG","issue":"16","license":[{"start":{"date-parts":[[2024,8,13]],"date-time":"2024-08-13T00:00:00Z","timestamp":1723507200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Nutrients"],"abstract":"<jats:p>Target values for 25-hydroxy vitamin D and 1,25(OH)2D or 1,25-dihydroxy vitamin D remain a topic of debate among clinicians. We analysed data collected from December 2012 to April 2020 from two cohorts. Cohort A, comprising 455,062 subjects, was used to investigate the relationship between inflammatory indicators (white blood cell [WBC] count and C-reactive protein [CRP]) and 25(OH)D\/1,25(OH)2D. Cohort B, including 47,778 subjects, was used to investigate the connection between 25(OH)D\/1,25(OH)2D and mineral metabolism markers (phosphate, calcium, and intact parathyroid hormone [iPTH]). Quadratic models fit best for all tested correlations, revealing U-shaped relationships between inflammatory indicators and 25(OH)D and 1,25(OH)2D. Minimal CRP and WBC counts were observed at 1,25(OH)2D levels of 60 pg\/mL and at 25(OH)D levels of 32 ng\/mL, as well as of 42 ng\/mL, respectively. iPTH correlated inversely with both 1,25(OH)2D and 25(OH)D, while phosphate as well as calcium levels positively correlated with both vitamin D forms. Calcium-phosphate product increased sharply when 25(OH)D was more than 50 ng\/mL, indicating a possible risk for vascular calcification. Multiple regression analyses confirmed that these correlations were independent of confounders. This study suggests target values for 25(OH)D between 30\u201350 ng\/mL and for 1,25(OH)2D between 50\u201370 pg\/mL, based particularly on their associations with inflammation but also with mineral metabolism markers. These findings contribute to the ongoing discussion around ideal levels of vitamin D but require support from independent studies with data on clinical endpoints.<\/jats:p>","DOI":"10.3390\/nu16162679","type":"journal-article","created":{"date-parts":[[2024,8,13]],"date-time":"2024-08-13T10:54:54Z","timestamp":1723546494000},"page":"2679","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":12,"title":["Target Values for 25-Hydroxy and 1,25-Dihydroxy Vitamin D Based on Their Associations with Inflammation and Calcium-Phosphate Metabolism"],"prefix":"10.3390","volume":"16","author":[{"ORCID":"https:\/\/orcid.org\/0009-0003-3060-282X","authenticated-orcid":false,"given":"Xitong","family":"Li","sequence":"first","affiliation":[{"name":"Fifth Department of Medicine (Nephrology\/Endocrinology\/Rheumatology\/Pneumology), University Medical Center Mannheim, University of Heidelberg, 69120 Mannheim, Germany"},{"name":"Department of Nephrology, Charit\u00e9 Universit\u00e4tsmedizin Berlin, 10117 Berlin, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5688-2108","authenticated-orcid":false,"given":"Yvonne","family":"Liu","sequence":"additional","affiliation":[{"name":"Fifth Department of Medicine (Nephrology\/Endocrinology\/Rheumatology\/Pneumology), University Medical Center Mannheim, University of Heidelberg, 69120 Mannheim, Germany"},{"name":"Department of Nephrology, Charit\u00e9 Universit\u00e4tsmedizin Berlin, 10117 Berlin, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4997-1257","authenticated-orcid":false,"given":"Xin","family":"Chen","sequence":"additional","affiliation":[{"name":"Fifth Department of Medicine (Nephrology\/Endocrinology\/Rheumatology\/Pneumology), University Medical Center Mannheim, University of Heidelberg, 69120 Mannheim, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Christoph","family":"Reichetzeder","sequence":"additional","affiliation":[{"name":"Institute for Clinical Research and Systems Medicine, Health and Medical University, 14467 Potsdam, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Saban","family":"Elitok","sequence":"additional","affiliation":[{"name":"Institute for Clinical Research and Systems Medicine, Health and Medical University, 14467 Potsdam, Germany"},{"name":"Department of Nephrology and Endocrinology, Klinikum Ernst von Bergmann, 14467 Potsdam, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1718-2918","authenticated-orcid":false,"given":"Bernhard K.","family":"Kr\u00e4mer","sequence":"additional","affiliation":[{"name":"Fifth Department of Medicine (Nephrology\/Endocrinology\/Rheumatology\/Pneumology), University Medical Center Mannheim, University of Heidelberg, 69120 Mannheim, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8143-0579","authenticated-orcid":false,"given":"Berthold","family":"Hocher","sequence":"additional","affiliation":[{"name":"Fifth Department of Medicine (Nephrology\/Endocrinology\/Rheumatology\/Pneumology), University Medical Center Mannheim, University of Heidelberg, 69120 Mannheim, Germany"},{"name":"Reproductive and Genetic Hospital of CITIC-Xiangya, Changsha 410008, China"},{"name":"School of Medicine, Central South University, Changsha 410078, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2024,8,13]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1535","DOI":"10.2215\/CJN.01160308","article-title":"Vitamin D in health and disease","volume":"3","author":"Heaney","year":"2008","journal-title":"Clin. J. Am. Soc. Nephrol."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"182","DOI":"10.1007\/s11657-020-00842-0","article-title":"Plain vitamin D or active vitamin D in the treatment of osteoporosis: Where do we stand today?","volume":"15","author":"Ringe","year":"2020","journal-title":"Arch. Osteoporos."},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Christakos, S., Li, S., De La Cruz, J., Shroyer, N.F., Criss, Z.K., Verzi, M.P., and Fleet, J.C. (2020). Vitamin D and the intestine: Review and update. J. Steroid Biochem. Mol. Biol., 196.","DOI":"10.1016\/j.jsbmb.2019.105501"},{"key":"ref_4","doi-asserted-by":"crossref","unstructured":"Zappulo, F., Cappuccilli, M., Cingolani, A., Scrivo, A., Chiocchini, A.L.C., Nunzio, M.D., Donadei, C., Napoli, M., Tondolo, F., and Cianciolo, G. (2022). Vitamin D and the Kidney: Two Players, One Console. Int. J. Mol. Sci., 23.","DOI":"10.3390\/ijms23169135"},{"key":"ref_5","doi-asserted-by":"crossref","unstructured":"Bover, J., Mass\u00f3, E., Gifre, L., Alfieri, C., Soler-Majoral, J., Fusaro, M., Calabia, J., Rodr\u00edguez-Pena, R., Rodr\u00edguez-Chitiva, N., and L\u00f3pez-B\u00e1ez, V. (2023). Vitamin D and Chronic Kidney Disease Association with Mineral and Bone Disorder: An Appraisal of Tangled Guidelines. Nutrients, 15.","DOI":"10.3390\/nu15071576"},{"key":"ref_6","doi-asserted-by":"crossref","unstructured":"Akimbekov, N.S., Digel, I., Sherelkhan, D.K., and Razzaque, M.S. (2022). Vitamin D and phosphate interactions in health and disease. Phosphate Metabolism: From Physiology to Toxicity, Springer.","DOI":"10.1007\/978-3-030-91623-7_5"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"77","DOI":"10.1016\/j.abb.2012.03.003","article-title":"Vitamin D and the kidney","volume":"523","author":"Kumar","year":"2012","journal-title":"Arch. Biochem. Biophys."},{"key":"ref_8","doi-asserted-by":"crossref","unstructured":"S\u00eerbe, C., Rednic, S., Grama, A., and Pop, T.L. (2022). An update on the effects of vitamin D on the immune system and autoimmune diseases. Int. J. Mol. Sci., 23.","DOI":"10.3390\/ijms23179784"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"20503121211014073","DOI":"10.1177\/20503121211014073","article-title":"Vitamin D regulation of the immune system and its implications for COVID-19: A mini review","volume":"9","author":"Bui","year":"2021","journal-title":"SAGE Open Med."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"1146","DOI":"10.1111\/apt.15506","article-title":"Systematic review with meta-analysis: Association of vitamin D status with clinical outcomes in adult patients with inflammatory bowel disease","volume":"50","author":"Gubatan","year":"2019","journal-title":"Aliment. Pharmacol. Ther."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"2142","DOI":"10.1136\/gutjnl-2018-317571","article-title":"Structural weakening of the colonic mucus barrier is an early event in ulcerative colitis pathogenesis","volume":"68","author":"Jabbar","year":"2019","journal-title":"Gut"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"803","DOI":"10.1007\/s00011-014-0755-z","article-title":"Inflammation and vitamin D: The infection connection","volume":"63","author":"Mangin","year":"2014","journal-title":"Inflamm. Res."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"e1","DOI":"10.1017\/jns.2016.37","article-title":"Vitamin D and inflammatory markers: Cross-sectional analyses using data from the English Longitudinal Study of Ageing (ELSA)","volume":"6","author":"Biddulph","year":"2017","journal-title":"J. Nutr. Sci."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"1807","DOI":"10.1210\/jc.2013-3507","article-title":"Vitamin D deficiency is associated with inflammation in older Irish adults","volume":"99","author":"Laird","year":"2014","journal-title":"J. Clin. Endocrinol. Metab."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"313","DOI":"10.1093\/aje\/kwm306","article-title":"Vitamin K and vitamin D status: Associations with inflammatory markers in the Framingham Offspring Study","volume":"167","author":"Shea","year":"2008","journal-title":"Am. J. Epidemiol."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"195","DOI":"10.1007\/s00223-008-9209-3","article-title":"Serum 25-hydroxyvitamin d levels are not associated with subclinical vascular disease or C-reactive protein in the old order amish","volume":"84","author":"Michos","year":"2009","journal-title":"Calcif. Tissue Int."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"2946","DOI":"10.1016\/j.clnu.2020.12.025","article-title":"Vitamin D and cardiovascular health","volume":"40","author":"Vallecillo","year":"2021","journal-title":"Clin. Nutr."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"305","DOI":"10.1016\/j.jsbmb.2014.11.004","article-title":"Vitamin D and the brain: Key questions for future research","volume":"148","author":"Cui","year":"2015","journal-title":"J. Steroid Biochem. Mol. Biol."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"1678S","DOI":"10.1093\/ajcn\/80.6.1678S","article-title":"Sunlight and vitamin D for bone health and prevention of autoimmune diseases, cancers, and cardiovascular disease","volume":"80","author":"Holick","year":"2004","journal-title":"Am. J. Clin. Nutr."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"2739S","DOI":"10.1093\/jn\/135.11.2739S","article-title":"The vitamin D epidemic and its health consequences","volume":"135","author":"Holick","year":"2005","journal-title":"J. Nutr."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"503","DOI":"10.1161\/CIRCULATIONAHA.107.706127","article-title":"Vitamin D deficiency and risk of cardiovascular disease","volume":"117","author":"Wang","year":"2008","journal-title":"Circulation"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"1034","DOI":"10.1258\/ebm.2010.010014","article-title":"Vitamin D nutritional policy needs a vision for the future","volume":"235","author":"Norman","year":"2010","journal-title":"Exp. Biol. Med."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"53","DOI":"10.1210\/jc.2010-2704","article-title":"The 2011 report on dietary reference intakes for calcium and vitamin D from the Institute of Medicine: What clinicians need to know","volume":"96","author":"Ross","year":"2011","journal-title":"J. Clin. Endocrinol. Metab."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"83","DOI":"10.1016\/j.maturitas.2011.11.002","article-title":"EMAS position statement: Vitamin D and postmenopausal health","volume":"71","author":"Brincat","year":"2012","journal-title":"Maturitas"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"305","DOI":"10.1185\/03007995.2013.766162","article-title":"Vitamin D supplementation in elderly or postmenopausal women: A 2013 update of the 2008 recommendations from the European Society for Clinical and Economic Aspects of Osteoporosis and Osteoarthritis (ESCEO)","volume":"29","author":"Rizzoli","year":"2013","journal-title":"Curr. Med. Res. Opin."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"2359","DOI":"10.1007\/s00198-014-2794-2","article-title":"Clinician\u2019s guide to prevention and treatment of osteoporosis","volume":"25","author":"Cosman","year":"2014","journal-title":"Osteoporos. Int."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"394","DOI":"10.1210\/jc.2015-2175","article-title":"Global consensus recommendations on prevention and management of nutritional rickets","volume":"101","author":"Munns","year":"2016","journal-title":"J. Clin. Endocrinol. Metab."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"234","DOI":"10.1210\/jc.2018-01414","article-title":"Controversies in vitamin D: Summary statement from an international conference","volume":"104","author":"Giustina","year":"2019","journal-title":"J. Clin. Endocrinol. Metab."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"2857","DOI":"10.1007\/s00198-010-1484-y","article-title":"Seasonal variation of serum 25-hydroxyvitamin D levels in adult patients with inflammatory bowel disease","volume":"22","author":"Bours","year":"2011","journal-title":"Osteoporos. Int."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"361","DOI":"10.1002\/(SICI)1097-0258(19960229)15:4<361::AID-SIM168>3.0.CO;2-4","article-title":"Multivariable prognostic models: Issues in developing models, evaluating assumptions and adequacy, and measuring and reducing errors","volume":"15","author":"Harrell","year":"1996","journal-title":"Stat. Med."},{"key":"ref_31","doi-asserted-by":"crossref","unstructured":"Mazidi, M., Rezaie, P., and Vatanparast, H. (2018). Impact of vitamin D supplementation on C-reactive protein; a systematic review and meta-analysis of randomized controlled trials. BMC Nutr., 4.","DOI":"10.1186\/s40795-017-0207-6"},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"e010804","DOI":"10.1136\/bmjopen-2015-010804","article-title":"Effect of vitamin D supplementation on inflammation: Protocol for a systematic review","volume":"6","author":"Mousa","year":"2016","journal-title":"BMJ Open"},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"4","DOI":"10.1007\/s11914-011-0094-8","article-title":"Vitamin D in the new millennium","volume":"10","author":"Wimalawansa","year":"2012","journal-title":"Curr. Osteoporos. Rep."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"3661","DOI":"10.1016\/j.clnu.2021.04.029","article-title":"The role of systemic inflammation in the association between serum 25-hydroxyvitamin D and type 2 diabetes mellitus","volume":"40","author":"Wan","year":"2021","journal-title":"Clin. Nutr."},{"key":"ref_35","doi-asserted-by":"crossref","unstructured":"Crescioli, C. (2020). Vitamin d merging into immune system-skeletal muscle network: Effects on human health. Appl. Sci., 10.","DOI":"10.3390\/app10165592"},{"key":"ref_36","doi-asserted-by":"crossref","unstructured":"Lind, L., Zanetti, D., H\u00f6gman, M., Sundman, L., and Ingelsson, E. (2020). Commonly used clinical chemistry tests as mortality predictors: Results from two large cohort studies. PLoS ONE, 15.","DOI":"10.1371\/journal.pone.0241558"},{"key":"ref_37","doi-asserted-by":"crossref","unstructured":"Zhu, Z., and Zhou, S. (2021). Leukocyte count and the risk of adverse outcomes in patients with HFpEF. BMC Cardiovasc. Disord., 21.","DOI":"10.1186\/s12872-021-02142-y"},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"2195","DOI":"10.1056\/NEJMoa0807646","article-title":"Rosuvastatin to prevent vascular events in men and women with elevated C-reactive protein","volume":"359","author":"Ridker","year":"2008","journal-title":"N. Engl. J. Med."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"e12461","DOI":"10.1111\/cpr.12461","article-title":"1,25(OH)2D3 inhibited Th17 cells differentiation via regulating the NF-\u03baB activity and expression of IL-17","volume":"51","author":"Sun","year":"2018","journal-title":"Cell Prolif."},{"key":"ref_40","doi-asserted-by":"crossref","unstructured":"Zhang, X., Wang, G., Li, M., Li, Y., Luo, X., Liu, Y., Zhang, X., Hocher, J.-G., Kr\u00e4mer, B.K., and Hocher, B. (2024). Both partial inactivation as well as activation of NF-\u03baB signaling lead to hypertension and chronic kidney disease. Nephrol. Dial. Transplant., gfae090.","DOI":"10.1093\/ndt\/gfae090"},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"101","DOI":"10.1016\/j.atherosclerosis.2016.06.001","article-title":"Associations between calcium-phosphate metabolism and coronary artery calcification; a cross sectional study of a middle-aged general population","volume":"251","author":"Gerke","year":"2016","journal-title":"Atherosclerosis"},{"key":"ref_42","doi-asserted-by":"crossref","unstructured":"Li, J.-W., Xu, C., Fan, Y., Wang, Y., and Xiao, Y.-B. (2014). Can serum levels of alkaline phosphatase and phosphate predict cardiovascular diseases and total mortality in individuals with preserved renal function? A systemic review and meta-analysis. PLoS ONE, 9.","DOI":"10.1371\/journal.pone.0102276"},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"22","DOI":"10.1111\/nep.13603","article-title":"Calcium-phosphate product and its impact on mortality in hospitalized patients","volume":"25","author":"Thongprayoon","year":"2020","journal-title":"Nephrology"},{"key":"ref_44","doi-asserted-by":"crossref","unstructured":"Chen, X., Chu, C., Doebis, C., Xiong, Y., Cao, Y., Kr\u00e4mer, B.K., Von Baehr, V., and Hocher, B. (2022). Vitamin D status and its association with parathyroid hormone in 23,134 outpatients. J. Steroid Biochem. Mol. Biol., 220.","DOI":"10.1016\/j.jsbmb.2022.106101"},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"2067","DOI":"10.1007\/s40618-023-02057-9","article-title":"Threshold of 25 (OH) D and consequently adjusted parathyroid hormone reference intervals: Data mining for relationship between vitamin D and parathyroid hormone","volume":"46","author":"Gong","year":"2023","journal-title":"J. Endocrinol. Investig."},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"7257913","DOI":"10.1155\/2020\/7257913","article-title":"Older age is associated with decreased levels of VDR, CYP27B1, and CYP24A1 and increased levels of PTH in human parathyroid glands","volume":"2020","author":"Jiang","year":"2020","journal-title":"Int. J. Endocrinol."},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"349","DOI":"10.1111\/j.1600-0684.1987.tb00345.x","article-title":"Serum concentrations of vitamin D metabolites in Cayo Santiago rhesus macaques","volume":"16","author":"Vieth","year":"1987","journal-title":"J. Med. Primatol."},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"1282","DOI":"10.1210\/jcem-69-6-1282","article-title":"Differences in mineral metabolism among nonhuman primates receiving diets with only vitamin D3 or only vitamin D2","volume":"69","author":"Marx","year":"1989","journal-title":"J. Clin. Endocrinol. Metab."},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"219","DOI":"10.1002\/ajp.1350090307","article-title":"Serum concentrations of 1, 25-dihydroxyvitamin D3 in Platyrrhini and Catarrhini: A phylogenetic appraisal","volume":"9","author":"Adams","year":"1985","journal-title":"Am. J. Primatol."},{"key":"ref_50","doi-asserted-by":"crossref","first-page":"1115","DOI":"10.1016\/S0016-5085(99)70014-4","article-title":"Rapid mucosal CD4+ T-cell depletion and enteropathy in simian immunodeficiency virus\u2013infected rhesus macaques","volume":"116","author":"Kewenig","year":"1999","journal-title":"Gastroenterology"},{"key":"ref_51","doi-asserted-by":"crossref","first-page":"26","DOI":"10.1016\/j.pbiomolbio.2006.02.003","article-title":"What is the optimal vitamin D status for health?","volume":"92","author":"Vieth","year":"2006","journal-title":"Prog. Biophys. Mol. Biol."},{"key":"ref_52","doi-asserted-by":"crossref","first-page":"3001","DOI":"10.1210\/jc.2013-1333","article-title":"Is there a reverse J-shaped association between 25-hydroxyvitamin D and all-cause mortality? Results from the U.S. nationally representative NHANES","volume":"98","author":"Sempos","year":"2013","journal-title":"J. Clin. Endocrinol. Metab."},{"key":"ref_53","doi-asserted-by":"crossref","first-page":"720","DOI":"10.1093\/aje\/kww244","article-title":"The Reverse J-Shaped Association Between Serum Total 25-Hydroxyvitamin D Concentration and All-Cause Mortality: The Impact of Assay Standardization","volume":"185","author":"Kramer","year":"2017","journal-title":"Am. J. Epidemiol."},{"key":"ref_54","doi-asserted-by":"crossref","first-page":"1595","DOI":"10.1111\/j.1532-5415.2009.02359.x","article-title":"Prospective study of serum 25-hydroxyvitamin D level, cardiovascular disease mortality, and all-cause mortality in older U.S. adults","volume":"57","author":"Ginde","year":"2009","journal-title":"J. Am. Geriatr. Soc."},{"key":"ref_55","doi-asserted-by":"crossref","first-page":"31","DOI":"10.1093\/ndt\/gfv111","article-title":"Vascular calcification in chronic kidney disease: An update","volume":"31","author":"Schlieper","year":"2016","journal-title":"Nephrol. Dial. Transplant."},{"key":"ref_56","doi-asserted-by":"crossref","first-page":"87","DOI":"10.1016\/j.jsbmb.2017.11.014","article-title":"Why should we measure free 25 (OH) vitamin D?","volume":"180","author":"Tsuprykov","year":"2018","journal-title":"J. Steroid Biochem. Mol. Biol."},{"key":"ref_57","doi-asserted-by":"crossref","first-page":"266","DOI":"10.1056\/NEJMra070553","article-title":"Vitamin D deficiency","volume":"357","author":"Holick","year":"2007","journal-title":"N. Engl. J. Med."},{"key":"ref_58","doi-asserted-by":"crossref","first-page":"319","DOI":"10.1016\/j.chembiol.2013.12.016","article-title":"Vitamin D metabolism, mechanism of action, and clinical applications","volume":"21","author":"Bikle","year":"2014","journal-title":"Chem. Biol."}],"container-title":["Nutrients"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2072-6643\/16\/16\/2679\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T15:35:57Z","timestamp":1760110557000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2072-6643\/16\/16\/2679"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2024,8,13]]},"references-count":58,"journal-issue":{"issue":"16","published-online":{"date-parts":[[2024,8]]}},"alternative-id":["nu16162679"],"URL":"https:\/\/doi.org\/10.3390\/nu16162679","relation":{},"ISSN":["2072-6643"],"issn-type":[{"value":"2072-6643","type":"electronic"}],"subject":[],"published":{"date-parts":[[2024,8,13]]}}}