Elevated Serum Netrin-1, Platelet-to-Lymphocyte Ratio, and Monocyte-to-Lymphocyte Ratio are Associated with Impaired Fasting Glucose in Adults with Central Obesity

Abstract

BACKGROUND: Adults with central obesity may develop impaired fasting glucose (IFG) due to chronic low-grade inflammation. Although C-reactive protein (CRP) is a common marker of systemic inflammation, it is nonspecific and cannot fully capture obesity-related inflammatory pathways. Netrin-1 promotes macrophage retention in visceral adipose tissue, thereby sustaining inflammation and insulin resistance, while platelet-to-lymphocyte ratio (PLR) and monocyte-to-lymphocyte ratio (MLR) reflect complementary inflammatory pathways; however, their discriminatory performance and associations with IFG remain uncertain. Therefore, this study was conducted to evaluate these markers in adults with central obesity.

METHODS: Blood samples from 88 adults with central obesity were obtained, and fasting glucose concentration was measured using hexokinase method to determine IFG status. Serum Netrin-1 was measured using an enzyme-linked immunosorbent assay (ELISA), serum CRP was measured using fluorescence immunoassay (FIA); PLR and MLR were calculated from complete blood counts. Receiver operating characteristic (ROC) analysis assessed discriminatory performance, while exploratory logistic regression adjusted for age, sex, and BMI to examine biomarker associations with IFG.

RESULTS: Among 88 participants, 54.5% had IFG. The AUCs were 0.694, 0.627, 0.689, and 0.532 for Netrin-1, PLR, MLR, and CRP, respectively. In crude prevalence-ratio (PR) analysis, Netrin-1 ≥315.35 pg/mL (PR=1.742; p=0.006), PLR ≥132.43 (PR=1.593; p=0.019), and MLR ≥0.20 (PR=2.119; p<0.001) were associated with IFG, whereas CRP was not. In separate ROC analysis, MLR had an AUC of 0.689 (p=0.002). After adjustment for age, sex, and BMI; MLR ≥0.20 remained associated with IFG (adjusted OR=7.516; p<0.001).

CONCLUSION: Elevated serum Netrin-1, PLR, and MLR were associated with IFG in adults with central obesity. MLR showed the strongest crude association and was the only evaluated inflammatory biomarker retained in the exploratory adjusted logistic regression model. As an inexpensive index derived from a routine complete blood count, MLR may complement fasting-glucose assessment by helping characterize the inflammatory phenotype of adults with central obesity.

KEYWORDS: central obesity, C-reactive protein, impaired fasting glucose, netrin-1, monocyte-to-lymphocyte ratio, platelet-to-lymphocyte ratio