Serum 25(OH)-vitamin D levels and bone metabolism in patients on maintenance hemodialysis

Aims: An increasing amount of evidence suggests that 25-hydroxy vitamin D-3 (25(OH)D-3) may contribute to the bone health of patients with chronic kidney disease (CKD). The underlying vitamin D status of these patients, however, has often been neglected. In a cross-sectional study we assessed the association between vitamin D status and parathyroid function, bone turnover, bone mass and structure in patients on maintenance hemodialysis. Methods: 69 patients on maintenance hemodialysis were assessed by bone densitometry (DEXA) and quantitative bone ultrasound (QUS). Serum 25-hydroxy vitamin D3 levels, serum markers of bone turnover and clinical data were tabulated. Results: A high prevalence of potentially significant vitamin D3 deficiency was found in this patient group: 59% of the patients had a 25(OH)D-3 level below 20 nmol/l. There was a significant negative correlation between serum25(OH)D-3 levels and serum intact parathyroid hormone (iPTH) (r = -0.231, p < 0.05), and this association remained significant after controlling for potential covariables. Furthermore, we show here that serum 25(OH)D-3 concentration is positively correlated with bone mineral density (BMD) measured at the radius (r = 0.424, p < 0.01). Finally, we show for the first time that 25(OH)D-3 levels are significantly and independently correlated with broadband ultrasound attenuation (P = 0.262, p < 0.05) measured with calcaneal quantitative bone ultrasound (QUS) in patients with chronic renal failure. Conclusion: Vitamin D-3 deficiency may contribute to the impaired bone health of patients on maintenance dialysis.