To define the therapeutic effect of Vitamin D in the treatment of non-Cystic Fibrosis bronchiectasis by means of a prospective randomized placebo-controlled double blind study with a follow-up of at least one year. To explore whether correction of Vitamin D deficiency by the oral supplementation of Vitamin D triggers the vitamin D receptors-mediated cathelicidin pathway and increases local or systemic concentrations of the natural antimicrobial polypeptide cathelicidin with enhanced eradication of bacteria.