Association of Fasting Glucose Level with Neutrophil-Lymphocyte Ratio Compared to Leukocyte Count and Serum C-Reactive Protein

Background The neutrophil-lymphocyte ratio (NLR) is often used as an inflammatory marker in chronic diseases such as cancer or cardiovascular diseases. However, there are few studies about the association between the NLR and diabetes mellitus (DM) or impaired fasting glucose (IFG) patients in Korea. This study investigated the association between the fasting plasma glucose (FPG) level and NLR in Koreans. Methods This cross-sectional retrospective study included 3,219 healthy subjects who visited Konyang University Hospital in South Korea for regular health examinations. Participants with a history of insulin administration, anti-diabetic drugs, anti-inflammatory drugs, or underlying diseases related to inflammation were excluded. Results All statistical evaluation was performed by dividing participants into males and females. Based on FPG levels, the subjects were classified into three groups, with normal fasting glucose (n=1,969), IFG (n=1,138), and DM (n=122). The NLR had no significant mean differences among these groups for both sexes. Multiple linear regression analysis between FPG level and NLR showed an independent and significantly negative association (β±standard error, -0.67±0.24; P=0.006) in normal subjects after adjustment. Log(serum C-reactive protein [S-CRP]) showed an independently and significantly positive association with FPG in male IFG/DM patients. Total leukocyte (white blood cell [WBC]) showed an independently and significantly positive association with FPG in female IFG/DM patients. Conclusion In normal subjects, NLR shows an independently and significantly negative association with FPG. In IFG/DM patients, NLR was not significantly related to FPG. WBC count in female patients and S-CRP level in male patients were significantly positively associated with FPG only in IFG/DM.