Free Fraction Vitamin D Measurements to Improve Understanding of Steroid Metabolism in Endocrine Disorders

What this Trial Is About

Researchers are studying how different forms of vitamin D are processed in the body among healthy people, pregnant women, and patients with various hormonal (endocrine) and kidney (renal) disorders. The study aims to understand if measuring "free vitamin D"—the portion available for the body to use—is a better marker of vitamin D status compared to the usual total vitamin D measurement. This research may improve how vitamin D is tested and interpreted in these groups and explore relationships between vitamin D forms and specific endocrine or kidney conditions. Participants include healthy adults, people with obesity, those with chronic kidney disease, pregnant women, individuals with primary hyperparathyroidism, and those with complex calcium and phosphate balance disorders. Each group will provide blood samples at different time points; for example, pregnant women will have blood drawn four times during pregnancy and after delivery, while individuals with primary hyperparathyroidism will have blood drawn before and after surgery. Other groups will have a single blood draw for assessment. During the study, participants will undergo venous blood draws to measure free 25-hydroxyvitamin D3 levels and analyze vitamin D metabolites. Pregnant women and those with primary hyperparathyroidism will have samples collected at multiple time points to track changes. The research team will compare measured and calculated free vitamin D levels across all groups. The entire study involves no treatments but focuses on collecting data to better understand vitamin D metabolism and its role in these conditions.

Free Vitamin D and Steroid Metabolism in Endocrine Disorders