A study by Stapleton et al. on 1409 patients with acute respiratory distress syndrome demonstrated that those patients with obesity and ARDS have lower biomarkers of inflammation (IL-6 and IL-8 cytokines) and surfactant protein D (a marker of alveolar epithelial injury) than those with normal weight. This evidence concerns the gene CXCL8 and obesity due to melanocortin 4 receptor deficiency.