CD4 and Cognitive impairment: Higher Th17 cells (/CD4+) (OR = 1.924, P < 0.001), higher IL-17A levels (OR = 1.039, P = 0.022), history of hyperlipidemia (yes vs. no) (OR = 2.870, P = 0.023), and postoperative complications (yes vs. no) (OR = 2.577, P = 0.044) were all independently related to increased cognitive impairment risk in elderly gastric cancer patients (Table 6).