ARDS is due to diffuse alveolar damage mediated by inflammatory cytokines such as tumour-necrosis factor, interleukin (IL)-1, IL-6 and IL-8 and subsequent neutrophil recruitment and release of oxygen free radicals that damage capillary endothelium and alveolar epithelium.34, 35 Immunomodulatory and proinflammatory associations of vitamin D deficiency are well known. This evidence concerns the gene CXCL8 and vitamin D deficiency.