Pilling LC, Jones LC, Masoli JAH, et al. - To determine if there is a link between low vitamin D levels and raised risk of delirium, researchers performed this prospective cohort study to understand the prognostic ability of blood vitamin D concentrations with regard to delirium. This analysis involved 351,320 adults aged 60 and older by the end of follow‐up, 3,634 (1.03%) of whom had at least one incident hospital‐diagnosed delirium episode. Findings revealed that elevated risks of incident hospital‐diagnosed delirium were predicted by progressively lower vitamin D concentrations, and a shared causal pathway was supported by the genetic evidence. Since the detection of low vitamin D levels is simple and low levels can be corrected safely and economically, an intervention trial to verify these findings is urgently required.