Cystic fibrosis is a genetic disorder with multiorgan effects. In a subgroup with pancreatic insufficiency malabsorption of the fat soluble vitamins ( A, D, E, K ) may occur. Vitamin D is involved in calcium homeostasis and bone mineralisation and may have extraskeletal effects.
A review has examined the evidence for vitamin-D supplementation in cystic fibrosis.
Three studies are included, although only data from two were available ( 41 adults and children with cystic fibrosis ). One of these studies compared supplemental 800 international units ( IU ) vitamin-D and placebo for 12 months in 30 osteopenic pancreatic insufficient adults; both groups continued 900 IU vitamin D daily.
The other ( abstract only ) compared supplemental 1g calcium alone, 1600 IU vitamin D alone, 1600 IU vitamin D and 1g calcium and placebo in a double-blind randomised cross-over trial; only 11 children ( vitamin D and placebo groups ) after six-months supplementation are included; inclusion criteria, pancreatic sufficiency or disease status of participants are not defined.
There were no significant differences in primary or secondary outcomes in either study. The studies are not directly comparable due to differences in supplementation, outcome reporting and possibly participant characteristics ( eg severity of lung disease, growth and nutrition, pancreatic sufficiency ).
There were no adverse events in either study.
The third study ( abstract only ) compared daily Calcitriol ( 0.25 or 0.5 micrograms ) with placebo in pancreatic insufficient children and young adults, only pre-intervention data were available.
In conclusion, there is no evidence of benefit or harm in the limited number of small-sized published trials. Adherence to relevant cystic fibrosis guidelines on vitamin D should be considered until further evidence is available.
Ferguson JH, Chang AB, Cochrane Database Syst Rev 2009;(4):CD007298
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