The AST/ALT level demonstrated relatively high strength in predicting osteopenia/osteoporosis with AUC = 0.807 (95% CI 0.77–0.84); the optimal cut-off value was 0.968, suggesting that an AST/ALT ratio higher than 0.968 are accompanied by a higher risk of osteopenia/osteoporosis in patients with T2DM (Fig. 4). This evidence concerns the gene GPT and osteoporosis.