Causes of death according to Flu exposure. Stacked cumulative incidence plots of overall mortality subdivided by cause for the full cohort (A), patients exposed above optimum (B), patients exposed below optimum (C), and patients with an exposure within the optimal range (D). For each cause, the cumulative incidence was computed throughout the follow-up period. At every time point, the incidence of all causes was summed up to get the overall mortality incidence. MOF, multiorgan failure.