METS-IR/HOMA-IR and MAFLD in U.S. adults: dose–response correlation and the effect mediated by physical activity

Abstract Objectives Metabolic dysfunction-associated fatty liver disease (MAFLD), a globally prevalent disease, is closely linked to insulin resistance (IR). Physical activity (PA) is closely linked to both MAFLD and IR. We aim to explore the dose–response relationship between metabolic score for IR (METS-IR)/homeostasis model assessment of IR (HOMA-IR) and MAFLD, and investigate the relationship between PA, IR and MAFLD. Methods Participants from the NHANES study were included in this cross-section study. Logistic regression and the receiver operating characteristic were used to assess the predictive performance of METS-IR/HOMA-IR for MAFLD. Restrictive cubic splines were performed to visualize their dose–response relationship. Decision tree analysis was used to identify high-risk populations of MAFLD. PA’s mediating effect in the association between METS-IR/HOMA-IR and MAFLD was also examined. Results Of all 1,313 participants, 693 had MAFLD (52.78%). There were a positive association between METS-IR (OR = 1.162, 95% CI = 1.126–1.199) and HOMA-IR (OR = 1.630, 95% CI = 1.431–1.856) and MAFLD risk. The AUCs of the METS-IR and HOMA-IR were 0.831 (0.809, 0.853) and 0.767 (0.741, 0.791), respectively, with significantly different predictive performance ( P < 0.001). Adding METS-IR/HOMA-IR to the basic model greatly improved the statistical significance for MAFLD. Five high-risk subgroups were identified for MAFLD. PA mediated about 0.81% and 0.78% (indirect effect/total effect) in the association between METS-IR/HOMA-IR and MAFLD. Conclusions MAFLD risk might be predicted by METS-IR/HOMA-IR, among which METS-IR performed better. And PA mediated the association between them. More attention should be paid to the therapeutic effect of lifestyle changes on MAFLD. Highlights 1. Positive associations were found between METS-IR and HOMA-IR and MAFLD risk. 2. METS-IR has better predictive performance for MAFLD risk than HOMA-IR. 3.Two high-risk subgroups were identified for MAFLD by METS-IR: individuals with METS-IR ≥ 40; Hispanic black individuals with 34 ≤ METS-IR < 40 and aged ≥ 46. 4. In the significant association between METS-IR/HOMA-IR and MAFLD, about 0.81% and 0.78% (indirect effect/total effect), respectively, were mediated by physical activity. Graphical Abstract