Serum 25-Hydroxyvitamin D Insufficiency in Search of a Bone Disease.

Serum 25-Hydroxyvitamin D Insufficiency in Search of a Bone Disease.

J Clin Endocrinol Metab. 2017 Mar 30;:

Authors: Shah S, Chiang C, Sikaris K, Lu Z, Bui M, Zebaze R, Seeman E

Abstract
Introduction: Vitamin D 'insufficiency' and 'deficiency' are defined as a serum 25-hydroxyvitamin D (25(OH)D) below 75 and 30 nmol/L respectively. We aimed to determine whether these values signal hypocalcaemia and hypophosphatemia, secondary hyperparathyroidism, high bone remodeling, low areal bone mineral density (aBMD), microstructural deterioration, or reduced matric mineralization density (MMD), and so suggest whether bone fragility is present.
Method: Concentrations of 25(OH)D, calcium, phosphate, creatinine and parathyroid hormone (PTH) were measured in 11,855 subjects. Serum C-terminal telopeptide of type 1 collagen (CTX), Procollagen type 1 N-terminal propeptide (P1NP), aBMD and distal radius microstructure and MMD were measured in a second subset of 150 subjects.
Results: A breakpoint for calcium, PTH and ALP was identified at a threshold 25(OH)D < 30 nmol/L. There was no plateau beyond 75 nmol/L. In the subgroup with measurements of bone morphology, no associations were detectable between serum 25(OH)D concentration, aBMD, trabecular density, cortical porosity or MMD. Among 1439 subjects with serum 25(OH)D under 30 nmol/L, 6.1% had low serum calcium, 3.4% had a low serum phosphate, 6.1% had a high alkaline phosphatase, and 34.2% had an elevated PTH. The majority of subjects did not have any abnormalities.
Conclusion: At a threshold of 25(OH)D of 30 nmol/L or below, abnormalities in biochemical features are supportive of the notion of a 'deficiency' state predisposing to bone disease. However, no deleterious effects are found in subjects within an 'insufficient' threshold of 25(OH)D of 30 to 75 nmol/L which challenges the rationale in using supplementation of these individuals.

PMID: 28379394 [PubMed - as supplied by publisher]

http://ift.tt/2oH3dci