The effect of vitamin K supplementation on biochemical markers of bone formation in children and adolescents with cystic fibrosis.
BACKGROUND
Impaired vitamin K status in cystic fibrosis (CF) has been considered as a newly emerged pathogenetic factor for reduced bone mineral density (BMD).


OBJECTIVE
Our aim was to evaluate the effectiveness of vitamin K supplementation in managing bone formation abnormalities in children and adolescents with CF.


METHODS
The statuses of vitamins K and D in relation to biochemical markers of bone metabolism and BMD were examined in 20 CF children receiving vitamin D supplements but not vitamin K supplements. Laboratory tests were carried out at the beginning of the study period and after 1 year of vitamin K supplementation (10 mg single oral dose/week) and the results were compared; the results were also compared with those of 25 healthy controls.


CONCLUSIONS
Ten of the CF patients had BMD z-score<or=2.5 (n=5) or between -1 and -2.5 (n=5). Biochemical tests on patients before vitamin K supplementation revealed that the levels of osteoblastic activity markers, namely, bone alkaline phosphatase (BAP), serum osteocalcin (Gla-OC), serum carboxy-terminal propeptide of type I procollagen (PICP) and serum amino-terminal propeptide of type I procollagen (PINP), were significantly reduced compared with those of the controls. These patients had also lower 25-hydroxy-vitamin D (25(OH)D) and vitamin K serum levels, higher undercaboxylated osteocalcin (Glu-OC) and parathormone (PTH) levels and a higher calcium to creatinine ratio (Ca/Cr) than the controls. Vitamin K intake was associated with an increase in Gla-OC, PINP, PICP levels and a decrease in Glu-OC levels. PTH levels were lower after vitamin K supplementation without any difference in BMD z-scores.


CONCLUSIONS
Our data indicate that vitamin K supplementation may have a beneficial role in bone health in CF children.
Nicolaidou
Polyxeni
P
Third Department of Pediatrics, Athens University Medical School, University General Hospital Attikon, Athens, Greece. pedatt@med.uoa.gr
Stavrinadis
Ilias
I
Loukou
Ioanna
I
Papadopoulou
Anna
A
Georgouli
Helen
H
Douros
Konstantinos
K
Priftis
Kostas N
KN
Gourgiotis
Dimitrios
D
Matsinos
Yiannis G
YG
Doudounakis
Stavros
S
D000293:Adolescent; D000469:Alkaline Phosphatase / Q000097:blood; D015415:Biomarkers / Q000032:analysis; D015519:Bone Density; D001851:Bone Diseases, Metabolic / Q000209:etiology / Q000517:prevention & control; D002118:Calcium / Q000032:analysis; D016022:Case-Control Studies; D002648:Child; D003404:Creatinine / Q000032:analysis; D003550:Cystic Fibrosis / Q000150:complications / Q000188:drug therapy*; D005260:Female; D006801:Humans; D008297:Male; D015675:Osteocalcin / Q000097:blood; D010012:Osteogenesis; D010281:Parathyroid Hormone / Q000097:blood; D010446:Peptide Fragments / Q000097:blood; D011347:Procollagen / Q000097:blood; D014807:Vitamin D / Q000031:analogs & derivatives / Q000097:blood; D014812:Vitamin K / Q000097:blood / Q000627:therapeutic use*; D014815:Vitamins / Q000627:therapeutic use*
D015415:Biomarkers; D010281:Parathyroid Hormone; D010446:Peptide Fragments; D011347:Procollagen; D014815:Vitamins; C047202:procollagen Type I N-terminal peptide; D015675:Osteocalcin; D014812:Vitamin K; D014807:Vitamin D; C104450:25-hydroxyvitamin D; D003404:Creatinine; D000469:Alkaline Phosphatase; D002118:Calcium