title: 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.
abstract: 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.
authors.affiliation: Manchester Adult Cystic Fibrosis Unit, South Manchester University Hospitals NHS Trust, Wythenshawe Hospital, Southmoor Road, Manchester, M23 9LT, UK. charles.haworth@papworth.nhs.uk
authors.forename: Charles S
authors.initials: CS
authors.lastname: Haworth
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Jones
authors.forename: Judith E
authors.initials: JE
authors.lastname: Adams
authors.forename: Peter L
authors.initials: PL
authors.lastname: Selby
authors.forename: A Kevin
authors.initials: AK
authors.lastname: Webb
mesh_terms: 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*
chemical_list: D014807:Vitamin D; D002118:Calcium