Background and Purpose--Serum aminotransferase levels are known to be associated with cardiovascular risk factors, but the relation with stroke incidence is not well known. We investigated the relation between serum aminotransferase levels and the incidence of stroke.

Methods--We measured serum aspartate and alanine aminotransferase levels and traditional cardiovascular risk factors in 108 464 Korean men, aged 35 to 59 years, in 1990 and 1992. Serum aminotransferase levels were classified into 3 categories (<35, 35 to 69, and 70 IU/L). The outcomes were hospital admissions and deaths from stroke subtypes (ischemic stroke, intracerebral hemorrhage [ICH], and subarachnoid hemorrhage [SAH]) from 1993 to 2002.

Results--During the 10 years, 1728 ischemic, 1051 hemorrhagic (718 ICH and 222 SAH), and 243 unspecified stroke events occurred. After adjustment for age and other traditional risk factors and according to Cox proportional-hazards models, serum aminotransferase level had an independent positive associations with ICH. However, ischemic stroke and SAH were not associated with aminotransferase levels. Compared with the level <35 IU/L, the adjusted relative risks (95% confidence interval) of ICH for an aspartate aminotransferase level of 35 to 69 and 70 IU/L were 1.49 (1.21 to 1.83) and 4.21 (3.06 to 5.77), respectively. The corresponding risks for alanine aminotransferase were 1.34 (1.09 to 1.65) and 2.89 (2.09 to 4.01), respectively. These associations were consistent regardless of the level of obesity, blood pressure, fasting glucose, alcohol intake, and follow-up length.

Conclusions--These findings suggest that an elevated aminotransferase level is a predictor of ICH. The biologic significance of aminotransferase level for the development of ICH merits further study.