Diagnostic criteria for primary osteoporosis: It is recommended to refer to the diagnostic criteria recommended by the World Health Organization (WHO). Based on DXA measurement: Bone density values less than 1 standard deviation below the peak bone mass of healthy adults of the same sex and race are considered normal; a decrease between 1 and 2.5 standard deviations is considered low bone mass (bone loss); a decrease equal to and greater than 2.5 standard deviations is considered osteoporosis; a decrease in bone density that meets the diagnostic criteria for osteoporosis and is accompanied by one or more fractures is considered severe osteoporosis. Nowadays, it is also usually expressed by T-Score (T-value), i.e. T-value ≥ -1.0 is normal and -2.5 value.