Relationship between the monocyte-to-HDL-C ratio (MHR) and COPD: a cross-sectional study based on NHANES 2009–2018

The monocyte-to-HDL-C ratio (MHR) is a novel inflammatory marker, yet its association with chronic obstructive pulmonary disease (COPD) remains unclear. This study investigated the relationship between MHR and COPD in the general US population. We analyzed data from 17,058 participants aged 40 years or older from the 2009–2018 National Health and Nutrition Examination Survey (NHANES). Participants were categorized into quartiles based on log10-transformed MHR (logMHR). Weighted multivariable logistic regression models were used to evaluate associations, adjusting for confounders. Restricted cubic splines and subgroup analysis assessed nonlinearity and robustness. The weighted prevalence of COPD was 9.69%. In the fully adjusted model (model 2), for each 1-unit increase in logMHR, the risk of COPD increased by 37% (OR = 1.37, 95% CI: 1.09–1.71, P = 0.005). Compared with Q1, the risk of COPD in Q4 was increased by 39.00% (OR = 1.39, 95% CI: 1.02–1.91, P = 0.039, P for trend = 0.040). The RCS revealed no nonlinear associations between logMHR and COPD. Subgroup analysis revealed that consistent associations across all strata except race, indicating robustness in most population subgroups. The results of the interaction test provide evidence supporting logMHR as an independent risk factor. MHR is positively and independently associated with COPD prevalence, supporting its potential role as a practical inflammatory biomarker for COPD risk assessment. Further validation in diverse populations is needed to establish its clinical utility.