Prevalence of low bone mass and deficiencies of vitamins D and K in pediatric patients with cystic fibrosis from 3 Canadian centers.
OBJECTIVE
In this cross-sectional observational study, we assessed both vitamins D and K status and bone health in pancreatic insufficient pediatric patients with cystic fibrosis from 3 Canadian cystic fibrosis centers.


METHODS
Eighty-one patients who had cystic fibrosis and were clinically stable for at least 3 months were enrolled. At the time of the clinic visit, anthropometric variables, lung function, pubertal status, intake of calcium and vitamins D and K, and physical activity were assessed. Blood was taken for analysis of biochemical biomarkers of bone turnover and status of vitamins D and K, and a urine sample was obtained for calcium, creatinine, sodium, and deoxypyridoline analyses. Whole-body bone mineral content and lumbar spine (L1-L4) bone mineral density were measured.


RESULTS
The children were relatively well nourished and had moderate to mild lung disease. Low bone mineral mass defined as a z score between -1.0 and -2.0, for gender and age was detected in 38% of the children for whole body and in 28% for lumbar spine. z score less than -2.0 was observed in 7 children for both bone measures. Suboptimal vitamin D status occurred in 95% of patients; suboptimal vitamin K status occurred in 82% of patients. Measures of plasma osteocalcin and carboxy-terminal propeptide type 1 procollagen and urinary deoxypyridoline compared with reference values for age, gender, and pubertal status reflected a state of suppressed bone formation and elevated bone resorption in a large proportion of the patients.


CONCLUSIONS
Bone mass of the whole body and spine was lower than expected for chronological age in approximately one third of pediatric patients with cystic fibrosis irrespective of gender or age. This may be explained by the observation of low bone turnover for developmental stage as indicated by bone biomarkers. Suboptimal status of vitamins D and K may be key causative factors of the low bone status for age.
Grey
Vijaylaxmi
V
McMaster Children's Hospital, Hamilton, Ontario, Canada. grey@hhsc.ca
Atkinson
Stephanie
S
Drury
Donna
D
Casey
Linda
L
Ferland
Guylaine
G
Gundberg
Caren
C
Lands
Larry C
LC
D015519:Bone Density; D002170:Canada; D002648:Child; D003430:Cross-Sectional Studies; D003550:Cystic Fibrosis / Q000097:blood / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008297:Male; D011627:Puberty / Q000502:physiology; D014807:Vitamin D / Q000097:blood*; D014812:Vitamin K / Q000097:blood*
D014812:Vitamin K; D014807:Vitamin D