CD8A and delirium: We also analyzed the causal association of T cells and their subsets with delirium at the same time, and the results showed that there was no significant causal association of CD4+ T cells, CD8+ T cells, as well as double-positive (CD4+CD8+) cells and double-negative (CD4−CD8−) cells with the risk of delirium causation, and also that there was no significant causal association of naïve CD4+ T cells, terminal CD4+ T cells, and terminal CD8+ T cells with delirium, as well as NKT cells with delirium (Figure 4).