Association between triglyceride-to-high-density lipoprotein cholesterol ratio and prediabetes: a cross-sectional study in Chinese non-obese people with a normal range of low-density lipoprotein cholesterol

BACKGROUND: Evidence about the relationship between triglyceride-to-high-density lipoprotein cholesterol (TG/HDL-C) ratio and prediabetes (Pre-DM) in Chinese non-obese people with a normal range of low-density lipoprotein cholesterol (LDL-c) is limited. Therefore, the present study was undertaken to explore the link of the TG/HDL-C ratio on Pre-DM among non-obese Chinese population with a normal range of LDL-c. METHODS: This study was a cross-sectional study that enrolled 153163 non-obese individuals with a normal range of low-density lipoprotein cholesterol in a Chinese hospital from January 2010 to December 2014. Logistic regression model, generalized additive model (GAM), smooth curve fitting and a series of sensitivity analyses was used to evaluate the association between TG/HDL-C ratio and Pre-DM. RESULT: The prevalence of Pre-DM was 9.77%.The median TG/HDL-C ratio was 0.671 (interquartile range, 0.468–1.010). After adjusting covariates, the results showed that TG/HDL-C ratio was positively associated with Pre-DM ((OR = 1.185, 95%CI 1.145–1.226). In addition, the TG/HDL-C ratio level has a non-linear relationship with the incidence of Pre-DM, in which the inflection point was 1.617. The effect sizes (OR) on the left and right sides of the inflection point were 1.312 (95%CI 1.242–1.386) and 0.980 (95%CI 0.898–1.070), respectively. And the sensitive analysis demonstrated the robustness of the results. Subgroup analysis showed a stronger association between TG/HDL-C ratio and Pre-DM in females and the population with 30 years < age < 40 years, 18.5 kg/m(2) < body mass index < 24 kg/m(2), and ALT < 40U/L. CONCLUSION: This study demonstrates a positive and non-linear relationship between TG/HDL-C ratio and Pre-DM in Chinese non-obese people with a normal range of low-density lipoprotein cholesterol. TG/HDL-C ratio is strongly related to Pre-DM when TG/HDL-C ratio is less than 1.617. It makes sense to reduce the TG/HDL-C ratio level below the inflection point from a treatment perspective. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12967-022-03684-1.