Gamma-glutamyltransferase and risk of chronic kidney disease: A prospective cohort study

Background: Elevated serum gamma-glutamyltransferase (GGT) activity has been linked with an increased risk of chronic kidney disease (CKD) in Asian populations. We aimed to assess the prospective association of serum GGT with risk of CKD in a Caucasian population. Materials and methods: We related GGT activity to the incidence of CKD in 2338 men aged 42-61 years of the Kuopio Ischemic Heart Disease study with normal kidney function at baseline. Repeat measurements of GGT were used to correct for within-person variability. Results: During a median follow-up of 25.6 years, 221 men developed new-onset CKD. The age-adjusted regression dilution ratio of log(e) GGT was 0.70 (95% CI: 0.64-0.75). Gamma-glutamyltransferase was log-linearly associated with risk of CKD in age-adjusted analysis. In Cox regression analysis adjusted for age, the hazard ratio (95% CIs) for CKD per standard deviation increase in loge baseline GGT was 1.25 (1.09-1.43) which was attenuated to 1.01 (0.86-1.19) on further adjustment for several confounders. Conclusion: Contrary to previous evidence of an independent association between elevated GGT and increased risk of CKD in Asian populations, initial evidence of an association between GGT and CKD in Caucasian men was confounded by body mass index, lifestyle factors, and lipids.