Aspartate aminotransferase/alanine aminotransferase ratio is a predictor of all-cause mortality rate among Japanese community-dwelling individuals

Background: An elevated ratio of aspartate aminotransferase (AST) to alanine aminotransferase (ALT) not only independently affects aging-related health, but also plays a critical role in mortality. However, there are limited predictive data on all-cause mortality, particularly in the context of community-dwelling individuals in Japan. This study examined the association between the AST/ALT ratio and survival prognosis using two follow-up studies based on 19-year and 7-year intervals. Methods: The study included 1,573 male (63 years old ± 14 years; range, 20–90 years old) and 1,980 female participants (65 years old ± 12 years; range, 19–89 years old). The participants were those involved in a Nomura cohort study conducted in 2002 (first cohort) and 2014 (second cohort) that continued to participate throughout the follow-up periods (follow-up rates were 90.3% and 97.4% for each cohort). A Cox proportional hazards model was adopted to calculate the multivariate-adjusted hazard ratios (HRs) of death from the baseline health check-up to the follow-up periods while controlling for potential confounding factors. Results: The follow-up survey revealed that there were 473 male deaths (30.1% of total male participants) and 432 female deaths (21.8% of total female participants). The univariate Cox regression analysis showed that HRs for all-cause mortality were greater for participants in higher AST/ALT ratio quartiles ( p < 0.001). The multivariate Cox regression analysis with adjusted variables showed a significant association between those in the fourth AST/ALT ratio quartile (HR: 1.83, 95% confidence interval, 1.46–2.29) and risk of all-cause mortality. This association holds irrespective of gender and age, and was particularly the case for participants with body mass index (BMI) < 25 kg/m 2 , without a history of cardiovascular disease (CVD) and diabetes, and with elevated gamma-glutamyl transpeptidase. Conclusions: Our results reveal that an elevated AST/ALT ratio is an independent factor that can predict risk of all-cause mortality among community-dwelling individuals.