Objective  To investigate the effect of serum 25-hydroxyvitamin D₃25(OH)D₃ on cognitive function after stroke in elderly patients with with first-episode ischemic stroke.

  Methods  A total of 270 elderly patients with first-episode cerebral infarction were selected as study subjects. The National Institutes of Health Stroke Scale (NIHSS) scores and Montreal Cognition Scale (MoCA) scores were assessed at admission. The follow-up period lasted 6 months, and the MoCA score was re-measured at 3 months, and the modified Rankin Scale (mRS) score was assessed at 6 months. According to the MoCA score at 3 months, the patients were divided into early post-stroke cognitive impairment (PSCI) group and early post-stroke cognitive normal (non-PSCI) group, and the clinical data of the two groups was compared. Logistic regression analysis was used to determine the independent influencing factors of early PSCI in elderly patients with first-episode cerebral infarction. Receiver operating characteristic (ROC) curve was drawn to evaluate the predictive value of serum 25(OH)D₃ level on early PSCI in elderly patients with first-episode cerebral infarction. Patients were further divided into low VD group and normal VD group according to the serum 25(OH)D₃ cut-off value, and the early PSCI incidence and MoCA scores between the two groups were compared.

  Results  Among 270 patients, the incidence rate of early PSCI was as high as 60.37% (163/270). Serum 25(OH)D₃ level was an independent influencing factor for early PSCI in elderly patients with first-episode acute cerebral infarction(OR=0.834, 95%CI, 0.766 to 0.907, P < 0.001). The correlation between serum 25(OH)D₃ level and early cognitive function after cerebral infarction was stronger in female patients than in males. The area under ROC curve of serum 25(OH)D₃ in predicting early PSCI of elderly patients with first-episode cerebral infarction was 0.751 (P < 0.05), and the best cutoff value was 23.17 ng/mL. The incidence of early PSCI in low VD group was higher than that in normal VD group, and the MoCA score was lower than that in normal VD group, the difference was statistically significant (P < 0.05).

  Conclusion  Normal serum 25(OH)D₃ is an independent protective factor for early PSCI in elderly patients with first-episode cerebral infarction. Serum 25(OH)D₃ level can affect the cognitive function after stroke in elderly patients with first-episode cerebral infarction, and its effect on the cognitive function after stroke is greater in elderly women than elderly men.