Determination of Free 25(OH)D Concentrations and Their Relationships to Total 25(OH)D in Multiple Clinical Populations.

ABSTRACT:

Context

The optimal measure of vitamin D status is unknown.

Objective

To directly measure circulating free 25-hydroxyvitamin D [25(OH)D] concentrations and relationships to total 25(OH)D in a clinically diverse sample of humans.

Design

Cross-sectional analysis.

Setting

Seven academic sites.

Patients

A total of 1661 adults: healthy (n = 279), prediabetic (n = 479), outpatients (n = 714), cirrhotic (n = 90), pregnant (n = 20), nursing home resident (n = 79).

Interventions

Merge research data on circulating free 25(OH)D (directly-measured immunoassay), total 25(OH)D (liquid chromatography/tandem mass spectrometry), D-binding protein [DBP; by radial (polyclonal) immunodiffusion assay], albumin, creatinine, intact parathyroid hormone, and DBP haplotype

SUBMITTER: Schwartz JB 

PROVIDER: S-EPMC6126881 | biostudies-literature | 2018 Sep

REPOSITORIES: biostudies-literature