Association between the neutrophil to lymphocyte ratio and mild cognitive impairment in patients with type 2 diabetes

Aim Evidence indicates that type 2 diabetes (T2D) is associated with mild cognitive impairment (MCI). Inflammation is a recognized sign of many neurodegenerative diseases. The neutrophil-to-lymphocyte ratio (NLR) is a novel and inexpensive marker of inflammation. The purpose of this study was to investigate the relationship between the NLR and MCI in patients with T2D. Methods The sample for this study comprised 787 patients with T2D, including 411 patients with normal cognitive function and 376 patients with MCI. Blood biochemical parameters and routine blood indicators were determined by an automatic analyzer. The NLR was calculated as the neutrophil count divided by the lymphocyte count. Results Compared with the control group, the MCI group was older and had a higher NLR but a lower education level and Montreal Cognitive Assessment (MoCA) score ( p < 0.05). Spearman correlation and multiple linear regression analyses confirmed that the MoCA score was negatively associated with the NLR ( p < 0.001). Multivariate logistic regression analysis demonstrated that the NLR was an independent risk factor for MCI in patients with T2D ( p < 0.001). After adjusting for confounding factors, the risk of MCI for those in the third tertile of the NLR was 2.907 times higher than that of those in the first tertile of the NLR (OR = 2.907, 95%CI = 1.978–4.272, p < 0.001). Conclusion An elevated NLR is associated with MCI in patients with T2D.