Randomised double blind placebo controlled trial investigating the effect of calcium and vitamin D supplementation on bone mineral density and bone metabolism in adult patients with cystic fibrosis.
BACKGROUND
Low bone mineral density (BMD) is prevalent in adults with cystic fibrosis and might be related to calcium and vitamin D malabsorption from the gastrointestinal tract. The aim of this study was to investigate the effect of calcium and vitamin D supplementation on BMD and bone metabolism in these subjects.


METHODS
Patients were invited to participate if they had a BMD Z score of -1 or less in the lumbar spine, proximal femur or distal forearm. Patients were randomised to receive calcium 1 g+vitamin D 800 IU or placebo daily, in addition to their regular vitamin D supplements (900 IU/day). BMD and bone biochemical markers were measured before and after 1 year of treatment.


RESULTS
After 12 months, the treatment group (n=15) showed a reduced rate of bone loss compared with the control group (n=15) in the lumbar spine (mean difference 1.9% [CI -0.9% to 4.6%]), total hip (mean difference 0.7% [CI -2.2% to 3.5%]) and distal forearm (mean difference 1.7% [CI -2.2% to 5.5%]), but these changes did not reach statistical significance. There was also a trend towards a reduction in bone turnover in the treatment group.


CONCLUSIONS
Calcium and vitamin D supplementation reduced the rate of bone turnover and bone loss in adult patients with cystic fibrosis, but these changes did not reach statistical significance. These data suggest that a longer term trial of this simple intervention would be justified.
Haworth
Charles S
CS
Manchester Adult Cystic Fibrosis Unit, South Manchester University Hospitals NHS Trust, Wythenshawe Hospital, Southmoor Road, Manchester, M23 9LT, UK. charles.haworth@papworth.nhs.uk
Jones
Andrew M
AM
Adams
Judith E
JE
Selby
Peter L
PL
Webb
A Kevin
AK
D015502:Absorptiometry, Photon; D000284:Administration, Oral; D000293:Adolescent; D000328:Adult; D015519:Bone Density / Q000187:drug effects*; D001842:Bone and Bones / Q000378:metabolism*; D002118:Calcium / Q000008:administration & dosage*; D003550:Cystic Fibrosis / Q000188:drug therapy* / Q000378:metabolism; D019587:Dietary Supplements; D004311:Double-Blind Method; D005269:Femur / Q000378:metabolism; D005500:Follow-Up Studies; D006801:Humans; D008159:Lumbar Vertebrae / Q000378:metabolism; D012189:Retrospective Studies; D014807:Vitamin D / Q000008:administration & dosage*
D014807:Vitamin D; D002118:Calcium