The association between non–high-density lipoprotein cholesterol to high-density lipoprotein cholesterol ratio and nonalcoholic fatty liver disease in non-obese individuals: A cross-sectional study

ObjectiveThis study aimed to investigate the association between the non-high-density lipoprotein cholesterol to high-density lipoprotein cholesterol ratio and nonalcoholic fatty liver disease in non-obese individuals, using data from the National Health and Nutrition Examination Survey.MethodsThis cross-sectional study analyzed data from the National Health and Nutrition Examination Survey (2017-2023), including 6265 eligible participants. The ratio of non-high-density lipoprotein cholesterol to high-density lipoprotein cholesterol was calculated, and nonalcoholic fatty liver disease was diagnosed using liver ultrasound transient elastography. The association between the ratio and nonalcoholic fatty liver disease was assessed using multivariable logistic regression and restricted cubic spline models. Threshold effect analysis was conducted to evaluate potential nonlinear relationships, while subgroup analyses and interaction tests were performed to assess consistency across demographic groups. Sensitivity analyses were also conducted using alternative controlled attenuation parameter thresholds to ensure the robustness of the findings.ResultsAmong the 6265 participants (mean age, 44.32 years), 1355 (21.62%) had nonalcoholic fatty liver disease. Restricted cubic spline analysis revealed a nonlinear dose-response relationship between the ratio and nonalcoholic fatty liver disease risk (P for nonlinearity <0.0001). When the ratio was below 3.4, the odds ratio was 2.17 (95% confidence interval, 1.51-3.12, P < 0.0001), indicating a strong positive association. However, when the ratio exceeded 3.4, the relationship plateaued (odds ratio, 1.40; 95% confidence interval, 1.11-1.75; P = 0.003). Subgroup analyses showed that the association was more pronounced among non-Hispanic White females aged over 60 years, although further validation is needed. Sensitivity analyses using controlled attenuation parameter thresholds of 248 and 288 dB/m showed similar patterns, supporting the stability of the observed associations.ConclusionsIn non-obese adults, higher levels of non-high-density lipoprotein cholesterol to high-density lipoprotein cholesterol ratio are associated with a greater prevalence of nonalcoholic fatty liver disease, with the strongest association observed when the ratio was below 3.4. As this study is cross-sectional, causal relationships cannot be inferred. This ratio may serve as a simple indicator for identifying individuals at higher risk of nonalcoholic fatty liver disease, but further longitudinal studies are needed to confirm these findings.