Lifestyle and serum gamma-glutamyltransferase: a study of middle-aged Japanese men.

The association of lifestyle factors with serum gamma-glutamyltransferase (GGT) was examined in 1176 Japanese male office workers aged 40-59 years. Those who had serum aminotransferase levels exceeding the normal range and/or who took prescription medication for, or had a past history of, liver disease were excluded. From the logistic regression analysis, lifestyle factors showing a positive association with high serum GGT (> or = 60 U/l) were body mass index, alcohol intake, cigarette smoking, and snacking between meals. On the other hand, coffee drinking showed an inverse association with high serum GGT. As for the relationships between snacking between meals and other lifestyle factors, snacking between meals was significantly related to alcohol intake (negative) and coffee drinking. Influences of snacking between meals on serum GGT are likely to be indirectly mediated through coping mechanisms of less alcohol drinking and more coffee drinking. Our findings support the conclusions that alcohol drinking, obesity, and cigarette smoking are positively associated with raised serum GGT and that coffee consumption is inversely related to raised serum GGT.