The association between weight-adjusted waist index (WWI) and nonalcoholic fatty liver disease (NAFLD) in non-diabetic individuals: A study based on the NHANES database(2017–2023)

The focus of this study was to explore the association between the weight-adjusted waist index (WWI) and nonalcoholic fatty liver disease (NAFLD) in non-diabetic individuals. A cross-sectional study was conducted utilizing data from the National Health and Nutrition Examination Survey spanning the years 2017 to 2023. The study encompassed a cohort of 8939 participants who were non-diabetic. WWI was computed as the waist circumference (in centimeters) divided by the square root of body weight (in kilograms). NAFLD was evaluated using liver ultrasound transient elastography (LUTE). To investigate the association between WWI and NAFLD, multiple linear regression analysis and smoothed curve fitting were employed. Additionally, threshold effect analysis was conducted to identify potential non-linear relationships. Subgroup analyses were performed to assess the robustness of the relationship between the independent and dependent variables across different population subsets. Among the 8939 participants, the mean age was 42.97 years (SD = 22.33), and 2842 (31.79%) were diagnosed with NAFLD. The relationship between WWI and NAFLD was non-linear. When WWI was <11.5, the odds ratio (OR) was 2.11 (95% confidence interval [CI]: 1.84-2.43, P < .0001), indicating a strong positive association. However, when WWI exceeded 11.5, the association weakened, with OR = 0.96 (95% CI: 0.78-1.17, P = .666). The results suggest that the risk of NAFLD increases with WWI but plateaus when WWI reaches 11.5.Upon conducting subgroup analyses based on indicators such as age and gender, it was observed that the positive association between WWI and NAFLD was more pronounced among male participants under the age of 60. In non-diabetic individuals, the association between WWI and NAFLD is non-linear, particularly when WWI is below 11.5. a higher WWI was associated with an increased risk of NAFLD.