Osteoporosis is diagnosed in a graded manner according to the criteria established by the World Health Organization. Within the standard deviation of bone density to the peak of normal adult bone, it is called normal. When the bone density is within 1-2.5 standard deviations of the peak bone density of normal adults, it is called reduced bone mass. When the bone density is below 2.5 standard deviations of the normal adult peak bone, it is called osteoporosis. After the diagnosis of osteoporosis, if it is accompanied by a fragility fracture, it will be referred to as severe osteoporosis.