Serum Triglyceride Levels Correlated with the Rate of Change in Insulin Secretion Over Two Years in Prediabetic Subjects

BACKGROUND/AIMS: Increased triglyceride (TG) and decreased high-density lipoprotein cholesterol (HDL-C) levels are considered risk factors for diabetes among prediabetic subjects. In this study, we retrospectively investigated the relationship between lipid profiles and the rate of change in early-phase insulin secretion in prediabetic subjects. METHODS: To evaluate insulin secretion, 50 prediabetic subjects underwent a 75-gram oral glucose tolerance test at the beginning of the study (baseline), and they were reexamined after a 2-year interval. The results were expressed as insulinogenic index (IGI) and disposition index (DI). RESULTS: The lipid profiles and indices of insulin secretion had not significantly changed over 2 years. However, Pearson's correlation analyses indicated that the rate of change in IGI and DI was negatively correlated with log-transformed baseline TG level, but not with baseline HDL-C level. Multiple linear regression analysis confirmed that the rate of change in IGI and DI was negatively correlated with the log-transformed baseline TG level (β = -0.38, p = 0.006, and β = -0.39, p = 0.006, respectively). CONCLUSIONS: Baseline TG level of prediabetic subjects appeared to be associated with rate of change in IGI and DI over a 2-year period, indicating that TG levels among prediabetic subjects should be carefully monitored.