Vitamin D insufficiency is a risk for both skeletal and nonskeletal health. However, some ambiguity remains about threshold serum 25(OH)D for vitamin D insufficiency. To determine the threshold serum 25(OH)D to maintain normal calcium availability without elevation in serum parathyroid hormone (PTH) among Japanese subjects with various calcium intakes, we conducted a multicenter prospective open-labeled study. We recruited 107 ambulatory subjects without disorders affecting vitamin D metabolism to whom oral vitamin D₃ 800 IU/day for 4 weeks or 1,200 IU/day for 8 weeks was given. Serum 25(OH)D, PTH, calcium, phosphate, and magnesium were measured before and after vitamin D₃ supplementation. Calcium intake was assessed by questionnaires. When all the data were combined, serum 25(OH)D was negatively correlated with PTH. The cubic spline curve between serum 25(OH)D and PTH indicated PTH reached its plateau between 35 and 40 pg/ml at 25(OH)D between 25 and 30 ng/ml. Vitamin D₃ supplementation increased serum 25(OH)D and decreased PTH. Change in PTH correlated positively with baseline serum 25(OH)D. From the regression analyses, baseline serum 25(OH)D above 28 ng/ml corresponded to the threshold level without reduction in PTH after vitamin D₃ supplementation. In multivariate regression analyses, age but not calcium intake was a significant determinant of PTH. We concluded that a serum 25(OH)D level of 28 ng/ml was identified as a threshold for vitamin D insufficiency necessary to stabilize PTH to optimal levels.
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http://dx.doi.org/10.1007/s00774-010-0200-5 | DOI Listing |
Nutr Metab (Lond)
January 2025
Shenzhen Center for Chronic Disease Control, No. 2021 Buxin Road, Luohu District, Shenzhen, 518020, China.
Background: Serum vitamin D deficiency is intricately linked to metabolic disorders, however, evidence on its association with continuous metabolic risk in children and adolescents remains insufficient. This study aims to elucidate the relationship between serum vitamin D levels and continuous metabolic risk.
Methods: The cross-sectional analysis involved 4490 participants aged 6 ~ 18, and the longitudinal investigation included 1398 individuals aged 6 ~ 12 years.
J Steroid Biochem Mol Biol
January 2025
Department of Pharmaceutical Engineering, Faculty of Engineering, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama 939-0398, Japan. Electronic address:
It is well known that vitamin D is essential for human health; however, many people suffer from vitamin D deficiency or insufficiency worldwide, including in Japan. Serum 25-hydroxyvitamin D (25(OH)D) concentrations are typically measured to evaluate vitamin D status. In a previous study, we demonstrated that the concentrations of vitamin D metabolites in urine, measured using the NLucVDR assay system composed of a split-type nanoluciferase and the ligand-binding domain (LBD) of the human vitamin D receptor, correlated with serum 25(OH)D concentrations measured using liquid chromatography-mass spectrometry (LC-MS) or electrochemiluminescence immunoassays (ECLIAs).
View Article and Find Full Text PDFEpilepsy Behav
January 2025
Department of Pharmacy, the Fifth Affiliated Hospital of Zhengzhou University, Zhengzhou 450015, China. Electronic address:
Objective: The study aimed to investigate the causal relationship between serum 25-hydroxyvitamin D (25(OH)D) levels and epilepsy using Mendelian randomization (MR), thereby addressing confounding and reverse causality issues in observational studies.
Methods: We employed a two-sample bidirectional MR design utilizing summary-level data from the IEU OpenGWAS project. Serum 25(OH)D levels were analyzed using the publicly available dataset ebi-a-GCST90000618, which included 496,946 European samples and 68,960,93 SNPs.
J Steroid Biochem Mol Biol
January 2025
Department of Medicine, Washington University School of Medicine, St. Louis, MO, USA; Department of Medicine, VA Medical Center, St. Louis, MO, USA; Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO, USA. Electronic address:
Targeting optimal glycemic control based on hemoglobin A1c (A1c) values reduces but does not abolish the onset of diabetic kidney disease and its progression to chronic kidney disease (CKD). This suggests that factors other than the average glucose contribute to the residual risk. Vitamin D deficiency and frequent episodes of acute hyperglycemia (AH) are associated with the onset of albuminuria and CKD progression in diabetes.
View Article and Find Full Text PDFPrz Gastroenterol
December 2024
Department of Gastroenterology, Dietetics and Internal Diseases, Poznan University of Medical Sciences, Poznan, Poland.
Introduction: Decreased bone mineral density (BMD) is one of the most frequent extraintestinal symptoms of celiac disease (CD).
Aim: The study aimed to investigate BMD, body composition, 25(OH)D, and ionised calcium blood parameters, and to compare them between women with CD and healthy individuals.
Material And Methods: The study covered 30 adult women with CD and 28 healthy controls.
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