The first citation needed under the epidemiology section comes from Luhr OR Antonsen K Karlsson M Incidence and mortality after acute respiratory failure and acute respiratory distress syndrome in Sweden Denmark and Iceland The ARF Study Group Am J Respir Crit Care Med Jun  However the statement above mine is correct and the actual figure is acually around  in  personyears from Rubenfeld GD Caldwell E Peabody E Weaver J Martin DP Neff M Incidence and outcomes of acute lung injury N Engl J Med Oct