The clinical importance of serum γ-glutamyltransferase level as an early predictor of obesity development in Korean men
Serum γ-glutamyl transferase (GGT) levels are known to be positively associated with obesity. We aimed at verifying an association between baseline GGT levels and the development of obesity in Korean men.This prospective cohort study was performed on 18,510 initially non-obese Korean men. The total follow-up period was 66,993.3 person years and the average follow-up period was 3.62 years (standard deviation [SD], 1.44). Cox proportional hazards model was used to determine hazard ratios for the risk of obesity development.We found a strong positive association between serum GGT levels at baseline and obesity development, after adjusting for multiple covariates. The risk of obesity development was found to be significantly and dose-dependently associated with serum GGT level. Moreover, estimated hazard ratios for severe obesity (BMI (body mass index) ≥30 kg/m(2)) attributable to serum GGT levels were much higher than those for obesity (BMI ≥ 25 kg/m(2)). The significant association was also found for WC (waist circumference)-defined obesity (WC > 90 cm).Our findings, which were obtained from a large cohort, indicate that serum GGT is an early predictor of obesity development. Furthermore, this association was remained significant after adjusting for multiple baseline covariates.