(EN) 19 BMD MODEL TRAINING METHOD, BMD ABNORMALITY RISK PREDICTION METHOD, BMD ABNORMALITY RISK LEARNING SYSTEM, AND BMD ABNORMALITY RISK PREDICTION SYSTEM ABSTRACT 5 A method of training a bone mineral density (BMD) model, including a training data retrieval step, a positioning step, and a model training step. The training data retrieval step retrieves one or more chest X-ray images with the BMD of a person. The positioning step locates and retrieves specific bone positions in the chest X-ray image. The model training step trains the AI model based on the bone positions in the chest X-10 ray image and the BMD. The specific bone position includes the first segment of the lumbar vertebrae. The BMD is the lumbar BMD value measured by dual-energy X-ray absorptiometry (DXA). FIG. 1