Osteoporosis (OP) is a systemic bone disease characterized by low bone mass and destruction of bone microarchitecture, leading to increased bone fragility and susceptibility to fracture (World Health Organization, WHO). 2001, the National Institutes of Health (NlH) proposed that osteoporosis is a disease of the osteoiliac system characterized by decreased bone strength and increased risk of fracture. Bone strength reflects two major aspects of the skeleton, namely bone mineral density and bone mass. The disease can occur in different genders and at any age, but is more common in postmenopausal women and older men. Osteoporosis is divided into two major categories: primary and secondary. Primary osteoporosis is divided into postmenopausal osteoporosis (type I), senile osteoporosis (type II), and idiopathic osteoporosis (including adolescent type). Postmenopausal osteoporosis generally occurs within 5 to 10 years after menopause in women; senile osteoporosis generally refers to osteoporosis occurring after the age of 70 years in the elderly: and idiopathic osteoporosis mainly occurs in adolescents, the cause of which is still unknown. Osteoporosis is a health problem with well-defined pathophysiological, psychosocial and economic consequences. A serious consequence of osteoporosis is the occurrence of osteoporotic fractures (fragility fractures), which are fractures that can occur with minor trauma or during daily activities due to decreased bone strength. Osteoporotic fractures greatly increase the disability and mortality rate in the elderly. I. Risk factors 1. Uncontrollable factors: ethnicity (Caucasians and yellow people have a higher risk of osteoporosis than blacks), old age, female menopause, maternal family history. 2, controllable factors: low body weight, low sex hormones, smoking, excessive alcohol consumption, coffee and carbonated beverages, etc., lack of physical activity, dietary calcium and/or vitamin D deficiency (low light or intake), diseases affecting bone metabolism and the application of drugs affecting bone metabolism (see the section on secondary osteoporosis). II. Clinical manifestations Pain, spinal deformation and the occurrence of fragility fractures are the most typical clinical manifestations of osteoporosis. However, many patients with osteoporosis often do not have obvious conscious symptoms in the early stage, and are often found to have osteoporotic changes only after the fracture occurs by X-ray or bone density examination. Pain: Patients may have low back pain or peripheral pain, and the pain may increase when the load increases or the activity is limited, and in severe cases, there are difficulties in turning, sitting and walking. 2. Spinal deformation: Those with severe osteoporosis may have height shortening and hunchback. Vertebral compression fracture can lead to thoracic deformation, abdominal compression, affecting cardiopulmonary function, etc. 3. Fracture: A fracture occurs after mild trauma or daily activities as a fragility fracture. The common sites where fragility fractures occur are the thoracic and lumbar spine, hip, radius, distal ulna and proximal humerus. Fractures can also occur at other sites. After a fragility fracture, the risk of a second fracture increases significantly. The common clinical indicators used to diagnose osteoporosis are: the occurrence of fragility fracture and/or low bone density, and the lack of clinical means to directly measure bone strength. 1, fragility fracture: is the ultimate manifestation of bone strength decline, there has been a fragility fracture clinically can be diagnosed osteoporosis. Bone mineral density (BMD) is the best quantitative indicator for diagnosing osteoporosis, predicting the risk of osteoporotic fracture, monitoring the natural course of the disease, and evaluating the efficacy of drug interventions. BMD reflects only about 70% of bone strength. The risk of fracture is associated with low BMD, and the risk of fracture is increased when accompanied by other risk factors. (1) Bone density measurement methods: Dual-energy X-ray absorptiometry (DXA) is currently the internationally accepted method of bone density examination, and its measured value is used as the gold standard for the diagnosis of osteoporosis. Other bone density examination methods such as various single photon (SPA), single energy X-ray (SXA), quantitative computed tomography (QCT,) etc. can also be used for reference in the diagnosis of osteoporosis according to specific conditions. (2) Diagnostic criteria: It is recommended to refer to the diagnostic criteria recommended by the World Health Organization (WHO). Based on DXA measurement: Bone density value less than 1 standard deviation below the peak bone value of healthy adults of the same sex and race is normal; a decrease of 1 to 2.5 standard deviations is low bone mass (bone loss); a decrease equal to and greater than 2.5 standard deviations is osteoporosis; a decrease in bone density in accordance with the diagnostic criteria for osteoporosis accompanied by one or more fractures is severe osteoporosis.