Does the vitamin D receptor genotype predict bone mineral loss in haemodialysed patients?

BACKGROUND It has been suggested that the vitamin D receptor (VDR) gene BsmI-polymorphism is a genetic determinant of bone metabolism. DESIGN To test this hypothesis, the relationship between VDR genotypes, bone mineral density (baseline and after 18 months) and parameters of calcium metabolism and bone turnover were investigated prospectively in 88 haemodialysed patients not receiving active vitamin D metabolites. METHODS Whole body, lumbar spine and femoral neck bone mineral density (BMD) were assessed by dual energy X-ray absorptiometry (DEXA). In addition calcium, phosphorus, 25(OH)D3, 1,25(OH)2D3, osteocalcin serum concentrations, alkaline phosphatase activity and intact 1,84 PTH levels were measured. RESULTS VDR genotype BB, Bb and bb were found in 27, 49 and 24% of patients. Initial BMD (g/cm2) of whole body, lumbar spine and femoral neck did not differ between genotypes (whole body: BB 1.055 +/- 0.120, Bb 1.082 +/- 0.102, bb 1.128 +/- 0.120; lumbar spine: BB 1.075 +/- 0.199, Bb 1.079 +/- 0.185, bb 1.099 +/- 0.170; femoral neck: BB 0.808 +/- 0.160, Bb 0.862 +/- 0.127, bb 0.842 +/- 0.125; mean +/- SD), but the decrease of whole body and femoral neck BMD during 18 months was significantly (P < 0.02) different between the genotype groups (whole body: BB -0.048 +/- 0.028, Bb -0.031 +/- 0.029, bb -0.024 +/- 0.023; femoral neck BB -0.044 +/- 0.069, Bb -0.032 +/- 0.081, bb -0.012 +/- 0.029 g/cm2). CONCLUSION This preliminary study suggests faster mineral loss in BB genotype of VDR in haemodialysed patients.

[1]  J. Montoliu,et al.  Association between vitamin D receptor gene polymorphism and relative hypoparathyroidism in patients with chronic renal failure. , 1997, Journal of the American Society of Nephrology : JASN.

[2]  E. Salido,et al.  Influence of vitamin D receptor genotype on bone mass changes after renal transplantation. , 1996, Kidney international.

[3]  M. Peacock.  Vitamin D receptor gene alleles and osteoporosis: A contrasting view , 1995, Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research.

[4]  B. Dawson-Hughes,et al.  Vitamin D receptor alleles and rates of bone loss: Influences of years since menopause and calcium intake , 1995, Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research.

[5]  A. Więcek,et al.  Function of endocrine organs in hemodialyzed patients of long-term erythropoietin therapy. , 1995, Artificial organs.

[6]  N. Lyhne,et al.  Changes in bone mineral content during long-term CAPD. Indication of a sex-dependent bone mineral loss. , 1995, Nephrology, dialysis, transplantation : official publication of the European Dialysis and Transplant Association - European Renal Association.

[7]  J. Eisman,et al.  Prediction of bone density from vitamin D receptor alleles , 1994, Nature.

[8]  S. Scharla,et al.  A sensitive and simplified radioimmunoassay for 1,25-dihydroxyvitamin D3. , 1984, Clinica chimica acta; international journal of clinical chemistry.