Clinical association between serum γ-glutamyltransferase levels and the development of insulin resistance in Korean men: a 5-year follow-up study

Aims In recent years, gamma-glutamyltransferase has emerged as a predictor of cardiovascular disease, Type2 diabetes mellitus, the metabolic syndrome and hypertension. However, it is not yet certain whether gamma-glutamyltransferase is a predictor for insulin resistance. The aim of this study was to examine the longitudinal association between baseline gamma-glutamyltransferase level and the development of insulin resistance in Korean men. Methods We performed a prospective cohort study, involving 22931 healthy Korean men without baseline insulin resistance (homeostasis model assessment of insulin resistance, HOMA-IR <2.7) for 5years. We checked the HOMA-IR serially to monitor the development of insulin resistance (incidence of HOMA-IR >= 2.7). A Cox proportional hazards model was used to determine hazard ratios for insulin resistance by quartile groups of baseline serum gamma-glutamyltransferase levels. Results During 81208.6 person-years of follow-up, 3856 (16.8%) cases of insulin resistance developed between 2006 and 2010. After adjusting for multiple covariates, including baseline HOMA-IR, the hazard ratios (95%CI) for incident insulin resistance comparing the second to the fourth quartile of baseline serum gamma-glutamyltransferase levels with the first quartile were 1.19 (1.06-1.33), 1.38 (1.23-1.53) and 1.58 (1.41-1.77), respectively (P for trend <0.001). Conclusions Our findings show that serum gamma-glutamyltransferase level could be a predictor of the development of insulin resistance in Korean men.