Changes in Alanine Aminotransferase/Aspartate Aminotransferase Ratio Are Associated with Changes in Insulin Resistance in Japanese Community-Dwelling Middle-Aged and Elderly Women

Abstract

Liver marker {e.g., alanine aminotransferase (ALT) and aspartate aminotransferase (AST)} levels independently predict insulin resistance. The aim of the present study is to examine how changes in liver markers are associated with changes in insulin resistance after exercise in Japanese community-dwelling adults. The participants were 76 women aged 67 ± 6 years from a rural village. Nordic walk (NW) exercise of 120 min per week was performed for 12 weeks. Before and at the end of the 12-week intervention, various confounding factors and insulin resistance {e.g., Homeostatic Model Assessment of Insulin Resistance (HOMA-IR)} were measured. The baseline, follow-up, and changes in ALT/AST ratio (β = 0.390, P < 0.001; β = 0.393, P < 0.001; and β = 0.321, P = 0.004, respectively) were each significantly and independently associated with HOMA-IR. When the data were further stratified by baseline and change in ASL/AST ratio, changes in HOMA-IR decreased more significantly in participants with baseline ASL/AST ratio ≥ 0.762 and change in ALT/AST ratio of < 0 than those with change in ALT/AST ratio of ≥ 0 (baseline ASL/AST ratio < 0.762, P = 0.002 and ASL/AST ratio ≥ 0.762, P = 0.047). This study is of interest because liver transaminase markers, which are inexpensive and routinely collected in clinical settings, may provide a simple and accurate enhancement to models currently used to identify subjects with changes in insulin resistance. These results suggest that a higher baseline and decreased change in ALT/AST ratio may be a predictor for decreased insulin resistance after a 12-week walking exercise in community-dwelling middle-aged and elderly women.