Alanine aminotransferase and gamma-glutamyl transferase have different dose-response relationships with risk of mortality by age.

Abstract

It remains unclear whether the respective dose-response relationships between serum alanine aminotransferase (ALT) and gamma-glutamyl transferase (GGT) levels and risk of mortality are consistent by age. We used sampled cohort data from the National Health Insurance Corporation to conduct a retrospective cohort study. A total of 313 252 participants who received medical health check-ups from 2002 to 2008 were assessed for risk of death according to serum ALT and GGT levels over an average of 6 years. The hazard ratios (HRs) for mortality were analysed with Cox proportional hazard model. The crude mortality rate increased linearly with increasing serum ALT and GGT levels in adults aged <60 years. However, the all-cause mortality rate showed a J-shaped relationship with increasing serum ALT levels whereas all-cause mortality rate showed a linear relationship with increasing serum GGT levels in adults aged ≥60 years. The HR of death showed U-shaped relationships with increasing serum ALT levels in adults aged ≥60 years. On the contrary, the HR of death from any cause had a linear association with increasing serum GGT levels among all age groups. In this study, U-shaped relationship patterns were demonstrated between serum ALT levels and risk for all-cause mortality in adults aged ≥60 years while serum GGT levels showed a linear relationship with risk for all-cause death. Very low levels of serum ALT in elderly patients suggest that they are at high risk of mortality.