The weight-adjusted-waist index is positively associated with metabolic dysfunction-associated fatty liver disease in US adults: A cross-sectional NHANES Study

Objectives Metabolic dysfunction-associated fatty liver disease (MAFLD) poses a major global health burden due to risks of cirrhosis and liver cancer; however, the relationship between MAFLD and weight-adjusted-waist index (WWI) remains unclear. Our study aims to clarify this relationship and identify potential clinical predictors for MAFLD. Methods A population-based cross-sectional study was conducted using data from the National Health and Nutrition Examination Survey (NHANES) 1999–2010 and 2015–2018. Multivariable logistic regression and Restricted Cubic Splines (RCS) was employed to examine the nonlinear association between WWI and MAFLD. Following this, a subgroup analysis was performed to detect any variations and ensure the robustness of the findings. Results The study included 17,930 participants aged ≥ 18 years, with a mean age of 45.54 years and 48.43% males. The sample was comprised of 44.36% Non-Hispanic White, 20.69% Mexican American, 19.55% Non-Hispanic Black, 8.00% Other Hispanic, and 7.41% Other/Multi-Racial individuals. Among them, 5850 individuals were diagnosed with MAFLD. The study found a statistically significant association between WWI and MAFLD (odds ratio (OR) = 4.35, 95% confidence interval [95% CI]: 4.08–4.63), which remained significant even after adjusting for all relevant factors (OR = 2.73, 95% CI: 2.48–3.01). The RCS analysis revealed a significant nonlinear relationship between WWI and MAFLD ( p < 0.05). Subgroup analysis indicated that WWI remained positively correlated with MAFLD, but no significant interaction was observed ( p -interaction > 0.05) Conclusions WWI is a significant predictor of MAFLD, suggesting its potential as a simple, non-invasive screening tool for the occurrence of MAFLD.