Association between monocyte-lymphocyte ratio and diabetic peripheral neuropathy in the US populations: a population-based study

Background Inflammation has emerged as a significant contributor to the development and progression of diabetic peripheral neuropathy (DPN), and the monocyte-lymphocyte ratio (MLR) is a novel inflammatory marker in peripheral blood. However, research on the association between MLR and DPN is limited. This study aimed to explore the association between MLR and DPN in patients with diabetes. Methods Data from the 1999–2004 National Health and Nutrition Examination Survey on US populations with diabetes were analyzed. Peripheral blood tests and other essential variables were collected. MLR was calculated as the ratio of monocyte to lymphocyte count, both of which were obtained directly from laboratory data files. DPN was defined as participants experiencing numbness, loss of feeling, or painful sensations or tingling in their feet in the previous 3 months or having ≥ 1 insensate area based on monofilament testing. Results A total of 1,345 participants were included, with 56.5% (760 / 1,345) exhibiting DPN. Multivariate regression models revealed that the presence of DPN significantly increased by 10% with a 0.1 unit rise in MLR (adjusted OR: 1.1, 95% CI: 1-1.2, P  = 0.046) after adjusting for all covariates. The restricted cubic spline analysis showed a non-linear curve ( P  = 0.007). There was no significant interaction between MLR and stratification variables in the subgroup analysis ( P  > 0.05). Conclusions Higher MLR levels are associated with DPN in the population of the United States. MLR shows promise as a potential biomarker for early identification of DPN.