Elevated gamma-glutamyl transferase to high-density lipoprotein cholesterol ratio has a non-linear association with incident diabetes mellitus: A second analysis of a cohort study

Objective Evidence regarding the association between the GGT/HDL-c ratio and incident diabetes is still limited. On that account, our research aims to survey the link of the GGT/HDL-c ratio with the risk of diabetes. Methods In this retrospective cohort study, data of 15,171 participants who participated in the medical examination program were collected in Murakami Memorial Hospital in Japan from 2004 to 2015. The independent and dependent variables were the baseline GGT/HDL-c ratio and diabetes during the follow-up, respectively. The Cox proportional-hazards regression model was used to explore the association between the GGT/HDL-c ratio and diabetes risk. A Cox proportional hazards regression with the cubic spline smoothing was used to recognize non-linear relationships between the GGT/HDL-c ratio and incident diabetes. Results After adjusting covariates, the results showed that the GGT/HDL-c ratio was positively associated with incident diabetes (HR = 1.013, 95% CI: 1.002, 1.024). There was also a non-linear relationship between the GGT/HDL-c ratio and the risk of diabetes, and the inflection point of the GGT/HDL-c ratio was 6.477. The HR on the left and right sides of the inflection point was 2.568 (1.157, 5.699) and 1.012 (1.001, 1.023), respectively. The sensitivity analysis demonstrated the robustness of the results. Besides, the performance of the FPG + GGT/HDL-c ratio was better than FPG + GGT, FPG + HDL-c, and FPG in predicting diabetes. Conclusion This study demonstrates a positive and non-linear relationship between the GGT/HDL-c ratio and incident diabetes in the Japanese population. The GGT/HDL-c ratio is strongly related to diabetes risk when it is <6.477.