Serum γ-glutamyltransferase as an independent predictor for incident type 2 diabetes in middle-aged and older adults: Findings from the KoGES over 12 years of follow-up

Backgrounds and aims: Limited evidence is available on whether serum γ-glutamyltransferase (GGT) has value as a predictor of type 2 diabetes in East Asian populations. We investigated the causal relationship between serum GGT level and incident type 2 diabetes in Korean adults. Methods and results: A total of 7739 nondiabetic adults aged 40–69 years from the Korean Genome and Epidemiology Study were studied. We divided the population into four groups according to sex-specific quartiles by serum GGT levels. Hazard ratios (HRs) with 95% Confidence intervals (CIs) for incident type 2 diabetes were prospectively analyzed using multivariate Cox proportional hazards regression models. A total of 1432 (18.5%) participants developed type 2 diabetes over 12 years of follow-up. The higher the serum GGT group quartile, the higher the cumulative type 2 diabetes incidence over 12 years with significance in both sexes (log-rank test P < 0.001). HRs (95% CIs) for incident type 2 diabetes for the highest quartile versus referent lowest quartile for serum GGT levels were 2.55 (1.86–3.51) for men and 1.90 (1.40–2.58) for women after adjusting for confounding variables. Conclusions: Higher serum GGT levels preceded and positively associated with incident type 2 diabetes among community-dwelling middle-aged and older Korean adults.