Association between metabolic score for visceral fat and chronic pain: a cross-sectional analysis of NHANES 1999-2004.

Background: The Metabolic Score for Visceral Fat (METS-VF) offers a refined measure of visceral adiposity, potentially surpassing traditional metrics. This study examines the association between METS-VF and chronic pain in U.S. adults. Methods: We analyzed data from 5,905 adults aged 18 years and older from the National Health and Nutrition Examination Survey (NHANES) 1999-2004. Weighted multivariate linear regression and restricted cubic spline analyses were conducted to investigate the linear associations between METS-VF and chronic pain. Threshold effects were determined using a two-part linear regression model. Subgroup analyses were conducted across three age groups (18-39, 40-64, and ≥65 years). The predictive accuracy of METS-VF, body mass index (BMI), and waist circumference (WC) was evaluated using ROC curve analysis. Influential predictors of chronic pain were identified via XGBoost, and mediation analysis assessed the role of C-reactive protein (CRP). Results: Among participants (mean age, 46.8 years; 50.8% female), chronic pain prevalence was 14.6%. Higher METS-VF was associated with increased odds of chronic pain (adjusted OR per unit increase, 1.46; 95% CI, 1.13-1.87), with a threshold effect at METS-VF 5.714. The highest METS-VF quartile showed greater odds of chronic pain (OR, 1.87; 95% CI, 1.28-2.72; Conclusion: METS-VF independently associated with higher odds of chronic pain, especially in older adults.