Weight-adjusted waist circumference index with hepatic steatosis and fibrosis in adult females: a cross-sectional, nationally representative study (NHANES 2017-2020)

Background Obesity is detrimental to liver health. Weight-adjusted waist circumference (WWI) is a new indicator of obesity that is superior to body mass index (BMI) and waist circumference (WC) in predicting obesity. There are limited studies on the relationship between Metabolic Associated Fatty Liver Disease (MASLD) and WWI. Therefore, this study aimed to investigate the association between WWI, Controlled Attenuation Parameters (CAP), and Liver Stiffness Measurement (LSM), with special attention to gender differences. Methods This cross-sectional study included participants from the 2017 to 2020 National Health and Nutrition Examination Survey (NHANES). The study used multiple linear regression models, smoothed curves, and threshold effects analyses to describe the relationships between variables. Multiple regression analyses were used to examine the associations between the four obesity indicators and CAP and LSM. Subject work characteristics (ROC) curves were used to assess the predictive value of WWI and other traditional obesity indicators for hepatic steatosis and liver fibrosis, and predictive power was assessed by area under the curve (AUC). Results The study involved 6713 participants, including 3072 men (46%) and 3641 women (54%). The results showed that among female participants, higher WWI was associated with hepatic steatosis (OR = 1.71, 95% CI: 1.43, 2.04; P < 0.0001) and hepatic fibrosis (OR = 2.11, 95% CI: 1.58, 2.84; P < 0.0001). Smoothed curve fitting of WWI versus CAP showed a statistically significant positive correlation between WWI in male and female participants There was a statistically significant positive correlation with CAP for both male and female participants. The same significant non-linear relationship was found between WWI and LSM, with no significant difference between males and females. WWI was also a good predictor of hepatic steatosis compared to other obesity indicators and was more pronounced in male participants (AUC = 0.8224). Whereas in the comparison of WWI with LSM, wBMI was a better predictor in female participants (AUC = 0.7751). Conclusions Based on this study, WWI was significantly associated with the risk of hepatic steatosis and hepatic fibrosis in women, suggesting the potential of WWI as a screening tool. Due to the cross-sectional design, causality cannot be inferred. Longitudinal studies are needed to validate our findings.