Remnant cholesterol and severity of nonalcoholic fatty liver disease

Background Serum remnant cholesterol levels are being increasingly acknowledged as a causal risk factor for atherosclerotic disease, regardless of conventional lipid parameters. The positive association between remnant cholesterol and nonalcoholic fatty liver disease (NAFLD) has been revealed in previous studies. However, whether remnant cholesterol is associated with the severity of NAFLD remains unknown. This study aimed to explore the association between serum remnant cholesterol and the risk of NAFLD severity. Methods This cross-sectional study included a total of 6,053 participants who attended health checkups. The severity of hepatic steatosis was evaluated by liver ultrasound transient elastography. Univariable and multivariable logistic regression analyses were performed to calculate the odds ratio (OR) and 95% confidence interval (95% CI) for the association between remnant cholesterol and the severity of hepatic steatosis. To explore whether the association between remnant cholesterol and NAFLD severity was independent of conventional lipid parameters, we further investigated this association in individuals with normal values of low-density lipoprotein-cholesterol (LDL-C), high-density lipoprotein-cholesterol (HDL-C) and triglycerides. Results In total, 36.9% of individuals had mild steatosis, and 5.9% had moderate-to-severe steatosis. The serum level of remnant cholesterol in nonsteatosis, mild steatosis and moderate-to-severe steatosis gradually increased (0.71 ± 0.33, 0.97 ± 0.52 and 1.07 ± 0.63 mmol/L, respectively). In the multivariable mode, remnant cholesterol was positively associated with mild hepatic steatosis (OR: 1.730, 95% CI: 1.541 − 1.941, P < 0.001) and moderate-to-severe steatosis (OR: 2.342, 95% CI: 1.765 − 3.109, P < 0.001). These associations were not significantly altered in individuals with normal triglycerides, HDL-C and LDL-C (OR: 1.664, 95% CI: 1.448 − 1.911, P < 0.001; OR: 2.269, 95% CI: 1.619 − 3.180, P < 0.001, respectively). Conclusions Higher levels of serum remnant cholesterol were associated with more severe hepatic steatosis, regardless of conventional lipid parameters. Individuals with higher remnant cholesterol may need more attention in regular surveillance of NAFLD.