Abstract: FR-PO0267
Association Between Serum 25-Hydroxyvitamin D and Bone Metabolism in Patients on Hemodialysis: Tokai Dialysis Cohort Study
Session Information
- Bone and Mineral Metabolism: Clinical Epidemiology and Outcomes
November 07, 2025 | Location: Exhibit Hall, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Bone and Mineral Metabolism
- 502 Bone and Mineral Metabolism: Clinical
Authors
- Shimamura, Norisuke, Division of Nephrology, Endocrinology and Metabolism, Tokai University School of Medicine, Isehara, Kanagawa, Japan
- Nakagawa, Yosuke, Division of Nephrology, Endocrinology and Metabolism, Tokai University School of Medicine, Isehara, Kanagawa, Japan
- Takahashi, Hiroo, Jinken Clinic, Ebina, Kanagawa, Japan
- Kakuta, Takatoshi, Division of Nephrology, Endocrinology and Metabolism, Tokai University Hachioji Hospital, Hachioji, Tokyo, Japan
- Komaba, Hirotaka, Division of Nephrology, Endocrinology and Metabolism, Tokai University School of Medicine, Isehara, Kanagawa, Japan
Background
Vitamin D deficiency, defined by low serum 25-hydroxyvitamin D (25(OH)D) concentrations , can impair bone mineralization and lead to rickets and osteomalacia. Vitamin D deficiency is known to be common in patients with chronic kidney disease, particularly in those on maintenance dialysis. However, little is known about the association between 25(OH)D and bone metabolism in patients with kidney failure.
Methods
We examined the association between serum 25(OH)D levels and bone metabolism in the Tokai Dialysis Prospective Cohort Study, which included 654 hemodialysis patients. We used multivariate linear regression analysis to explore the associations of serum 25(OH)D levels with alkaline phosphatase (ALP), bone-specific alkaline phosphatase (BAP), and metacarpal bone mineral density (BMD). Serum 25(OH)D levels were measured using an electrochemiluminescence immunoassay (Elecsys Vitamin D total II; Roche Diagnostics). Vitamin D deficiency was defined as a serum 25(OH)D concentration of less than 20 ng/mL.
Results
The median serum 25(OH)D level was 12.4 ng/mL (interquartile range 8.3-18.5 ng/mL), and 78.6% of patients were vitamin D deficient. Patients with higher serum 25(OH)D levels were more likely to be female; were less likely to have diabetes, a history of cerebral infarction, or peripheral arterial disease; had higher serum albumin and creatinine levels; and were more frequently prescribed lanthanum carbonate and active vitamin D. There was no association between 25(OH)D levels and serum calcium, phosphorus, or intact parathyroid hormone (PTH) levels. Higher serum 25(OH)D levels were associated with lower ALP and BAP levels and higher metacarpal BMD. However, this association disappeared after adjustment for nutritional indicators, mineral metabolism parameters, and use of related medications. Serum 25(OH)D levels were also not associated with previous or incident fractures.
Conclusion
Vitamin D deficiency is common in patients undergoing hemodialysis, but was not associated with signs of osteomalacia, such as elevated ALP, low calcium, or low phosphorus. These findings suggest that vitamin D deficiency has at most a limited impact on bone metabolism in patients undergoing hemodialysis. Further studies are needed to clarify the role of 25(OH)D in bone metabolism in kidney failure.