Serum gamma-glutamyltransferase within its normal range predicts a chronic elevation of alanine aminotransferase: a four year follow-up study.

Background: Previous epidemiological and experimental studies support the concept that serum gamma-glutamyltransferase (GGT) activity within its normal range is related to oxidative stress. Since oxidative stress plays a crucial role in the pathogenesis of various liver diseases, serum GGT may predict development of liver damage.

Methods: A total of 6,523 healthy male workers with normal alanine aminotransferase (ALT, <35 U/l) in a steel manufacturing company were followed for four years.