Vitamin D binding protein and the need for vitamin D in hemodialysis patients.
OBJECTIVE
Vitamin D binding protein (DBP) is a polymorphic serum protein with a predominant role in a spectrum of biological activities. Chronic renal failure is characterized by deficient vitamin D metabolism. The present study investigates the impact of DBP polymorphism on the need for vitamin D in hemodialysis patients.


METHODS
This was a retrospective study.


METHODS
This study included hemodialysis patients from the Renal Unit of Ghent University Hospital (Ghent, Belgium) and the Algemeen Stedelijk Ziekenhuis Geraardsbergen Hospital (Geraardsbergen, Belgium).


METHODS
One hundred and ninety-one hemodialysis patients and 211 healthy subjects were recruited from the hemodialysis database. The DBP phenotypes were determined by polyacrylamide gel electrophoresis. Serum DBP, parathyroid hormone, 25-hydroxyvitamin D(3), 1,25-dihydroxyvitamin D(3), calcium, albumin, and phosphate were measured. Information regarding the intake of vitamin D analogues was collected.


RESULTS
The phenotypic distributions of DBP were in agreement with Hardy-Weinberg equilibrium. Comparing allele frequencies of the two groups, there was an increased proportion of the DBP 2 allele in hemodialysis patients (P < .05). The median serum DBP concentration was lowest in the DBP 2-2 group. The need for oral vitamin D differed significantly (P < .01) between DBP phenotypes, and was greatest in DBP 2-2.


CONCLUSIONS
The present study demonstrates an altered DBP allele frequency in hemodialysis patients, compared with the general population. More importantly, vitamin D intake differs depending on the DBP polymorphism, and is greatest for end-stage renal disease patients with a DBP 2-2 phenotype. Therefore, vitamin D treatment deserves more careful monitoring among DBP 2-2 patients with end-stage renal disease.
Speeckaert
Marijn M
MM
Department of Clinical Chemistry, University of Ghent, Ghent University Hospital, Ghent, Belgium.
Glorieux
Griet L
GL
Vanholder
Raymond
R
Van Biesen
Wim
W
Taes
Youri E
YE
Clement
Frédéric
F
Wehlou
Charline
C
Delanghe
Joris R
JR
D000368:Aged; D016022:Case-Control Studies; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D005787:Gene Frequency; D006801:Humans; D007676:Kidney Failure, Chronic / Q000628:therapy; D008297:Male; D008875:Middle Aged; D009751:Nutritional Requirements; D010281:Parathyroid Hormone / Q000097:blood; D010641:Phenotype; D011110:Polymorphism, Genetic; D006435:Renal Dialysis; D012189:Retrospective Studies; D014807:Vitamin D / Q000008:administration & dosage*; D014809:Vitamin D-Binding Protein / Q000235:genetics*
D010281:Parathyroid Hormone; D014809:Vitamin D-Binding Protein; D014807:Vitamin D