Gender differences in the ratio of eicosapentaenoic acid to arachidonic acid in an inland prefecture, Tochigi: Tochigi Ryomo EPA/AA Trial in Coronary Artery Disease (TREAT-CAD).

OBJECTIVE: The plasma eicosapentaenoic acid to arachidonic acid ratio (EPA/AA), which is determined only by dietary intake, has been attracting attention as a new risk marker for coronary artery disease (CAD). A Japanese inland prefecture, Tochigi, ranks higher mortality rate from CAD and lower seafood consumption, compared to other prefectures. The aim of this study was to investigate the EPA/AA ratio in residents of Tochigi prefecture. METHODS: We measured the EPA/AA ratio in patients undergoing diagnostic coronary angiography, because of suspicion for having CAD, all of whom were residents of Tochigi prefecture or its bordering area. Patients A total of 428 patients were enrolled in 5 centers. RESULTS: The median value of the EPA/AA ratio in the study patients was 0.37, which seems to be lower than the value of the whole Japan. The EPA/AA ratio was similar in patients with and without CAD. Female patients had lower EPA/AA ratios than male patients. When subjects were divided into 10-year age groups, 30- to 39-year-old male and female patients displayed similar EPA/AA ratios. However, the ratios of 50- to 59-year old female patients (p=0.001) and 60- to 69-year old female patients (p=0.034) were significantly lower than those of age-matched male patients. CONCLUSION: In female residents of Tochigi prefecture, and particularly in menopausal female patients suspected of CAD, the EPA/AA ratio might be lower than male patients. EPA intake can help prevent cardiovascular events, especially in menopausal female residents of an area where the fish intake is low.