Trends in Serum AST-to-ALT Ratio Among US Adults: Analysis of the US National Health and Nutrition Examination Survey

Background: Using nationally representative data, we examined the age-, sex-, and ethnic-specific variation in the ratio of serum aspartate aminotransferase and alanine aminotransferase (AST-to-ALT ratio or AAR) of U.S. adults (20+ years). Understanding these subgroup differences in AAR will provide insight into population patterns of these ratios, which provide a basis for normative comparisons for the application of personalized diagnostic information to patients in the clinical setting. Methods: Data for this analysis are based on continuous cycles (1999-2016) of the National Health and Nutrition Examination Survey (NHANES). Results: Within the complete sample (n = 13,731), mean AST and ALT values were similar (similar to 25 U/L), with higher absolute values, but lower AAR, in males compared with females. From 1999-2000 to 2015-2016 there were consistent sex, age, and ethnic differences in the AAR. Specifically, the AAR for individuals 65+ years was markedly higher in all survey years, with subtle ethnic variation [Mexican Americans (0.95-1.04) Other Hispanic (1.0-1.09), Non-Hispanic White (1.05-1.11), Non-Hispanic Black (1.12-1.22), and Other Ethnicity (1.01-1.17)]. Sex-specific analysis reveals that the lower AAR observed among Mexican Americans is almost entirely accounted for by the markedly lower AAR in men. Conclusion: Future work is necessary to understand these subgroup variations in longer term studies with incident disease.