# Nonlinear Relationship Between Triglyceride‐to‐High‐Density Lipoprotein Cholesterol Ratio and Non‐Alcoholic Fatty Liver Disease: A Secondary Retrospective Analysis Based on a Japanese Longitudinal Study

## TL;DR

This study finds a nonlinear link between the triglyceride-to-HDL cholesterol ratio and non-alcoholic fatty liver disease risk, especially when the ratio is below 1.42.

## Contribution

The study reveals a nonlinear relationship between TG/HDL-C ratio and NAFLD risk, identifying a turning point at 1.42.

## Key findings

- The TG/HDL-C ratio shows a stronger association with NAFLD risk below a threshold of 1.42.
- Younger individuals, females, and those with lower BMI show a stronger correlation with NAFLD risk.
- The nonlinear relationship was confirmed using Cox regression and smooth curve fitting.

## Abstract

The purpose of this research is to investigate the particular connection between the triglyceride to high‐density lipoprotein cholesterol (TG/HDL‐C) ratio and non‐alcoholic fatty liver disease (NAFLD) to offer a more precise foundation for evaluating NAFLD risk.

This study involves a secondary analysis of a retrospective cohort study conducted from 2004 to 2015 in a Japanese population, which included 14,106 participants. The TG/HDL‐C ratio was determined by the levels of triglycerides (TG) and high‐density lipoprotein cholesterol (HDL‐C). Participants were grouped according to the quartiles of TG/HDL‐C. We analyzed the relationship between TG/HDL‐C and NAFLD using Cox proportional hazards regression, smooth curve fitting, and sensitivity analysis.

The average age of the study participants was 43.51 ± 8.89 years, with 7275 (51.57%) being male. After considering potential confounding factors, the study found a positive correlation between TG/HDL‐C and NAFLD (OR: 1.37, 95% CI: 1.31–1.43, p < 0.001). Moreover, a nonlinear relationship between TG/HDL‐C and NAFLD was found, with a turning point at 1.42. The odds ratio (OR) on either side of this inflection point were 3.71 (95% CI: 2.87–4.79) on the left and 1.23 (95% CI: 1.17–1.29) on the right, indicating a stronger correlation when TG/HDL‐C is below 1.42, particularly in younger individuals, females, and those with a BMI under 25 kg/m2.

The TG/HDL‐C index shows a nonlinear positive correlation with NAFLD risk, particularly when the TG/HDL‐C ratio is below 1.42, with a stronger association observed in younger individuals, females, and lower‐BMI populations.

This study reveals a nonlinear positive correlation between the TG/HDL‐C ratio and the risk of NAFLD. The association is particularly pronounced when the ratio is below 1.42.