Effects of coffee consumption against the development of liver dysfunction: A 4-year follow-up study of middle-aged Japanese male office workers

The association of coffee consumption with the development of increased serum aspartate aminotransferase (AST) and/or alanine aminotransferase (ALT) activities over 4 years was studied in 1221 liver dysfunction-free (serum AST and ALT less than or equal to 39 IU/I and no medical care for or no past history of liver disease) Japanese male office workers aged 35 to 56 years. From the analysis using the Kaplan-Meier method, the estimated incidence of serum AST and/or ALT greater than or equal to 40 IU/I, greater than or equal to 50 IU/I, and greater than or equal to 60 IU/I decreased with an increase in coffee consumption. From the Cox proportional hazards model, coffee drinking was independently inversely associated with the development of serum AST and/or ALT greater than or equal to 40 IU/I (p = 0,019 by test for tendency), greater than or equal to 50 IU/I (p = 0,002), and greater than or equal to 60 IU/I (p = 0,007), controlling for age, body mass index, alcohol intake, and cigarette smoking, These results suggest that coffee may be protectively against the liver dysfunction in middle-aged Japanese men.