Non-Alcoholic Elevated GGT?

I'm a 47 y/o male, 5'9", 195#, with a history of HepB in July 1983 (max billirubin 38.2, SGPT/SGOTs in the 2,000's, no clotting factor anomalies, no necrosis noted, full recovery, post-care viral screenings until no active detected).
I typically consume 1-3 alcholoic beverages weekly, typically red wine or a single beer with a meal.
Ever since, I've had an elevated GGT, typically between 119 & 168.  All other LFTs well within normal ranges, and cholesterol typically 80-85 HDL/90-95 LDL. Two months complete abstention from alcohol only lowered the number by 10-15.
Due to an oversensitive screening test for a cord-blood donation, my wife and I were both screened for the full spectrum of possible additional viral hepatitises in 2002, all with negative results.
Could the elevated GGTs be the result of 27 y/o liver damage?  If so, how can these figures be reduced?