Background and aims Current recommendation in managing CF patients regarding Vitamin D status ( 2005 European Consensus) are annually Vitamin D, Calcium and electrolytes identifications with prompt therapeutic intervention.

Methods 1 year retrospective Study with 68 children included (29 girls and 39 boys ) in which annual determination of Vitamin D was conducted. All children between 1 year and 18 years were included, with a medium age of 7.9 years. In patients with significant vitamin D deficiency identified treatment with high Vitamin D daily dose was established (btw. 2000-4000UI/d) and 6 Months close monitoring was conducted.

results: In 15% severe Vitamin D deficiency was identified (<20 nmol/L), moderate vitamin D deficiency ( values btw. 20–75 nmol/L) was found in 47% and normal Vitamin D levels were determined in 38% of included children. Recommended treatment with 6 months monitoring highlighted that 35% of the Vitamin D deficiency group did not recover the normal levels of Vitamin D despite correct initiated treatment.

Conclusions Vitamin D deficiency is frequent among cystic fibrosis patients, 15% of them having severe deficiency. Recovering the deficit should include, besides Vitamin D supplementing, interventions on all the other factors involved in absorption of Vitamin D in cystic fibrosis children.