Trends in the incidence of osteoporosis: about 200 million women and 100 million middle-aged men worldwide suffer from primary osteoporosis. about 1/3 of women between 60 and 70 years of age suffer from osteoporosis, about 2/3 of women aged 80 or above suffer from osteoporosis, about 1/5 of men over 50 years of age will suffer from osteoporotic fractures during their lifetime, and 1 person in Europe suffers from osteoporotic hip fracture every 30 seconds. According to the statistics of some provinces and cities in China in 2006, the prevalence of osteoporosis in people over 60 years old was about 59.89%. The T-value used in testing bone mineral density is based on the bone mineral density value of young and healthy white women, and the standard deviation above or below the reference peak is defined as the T-value. The WHO diagnostic criteria for osteoporosis are based on T-values measured by DXA as the only parameter, and this criterion is widely used worldwide, but after more than a decade of use some controversy began to emerge. Vitamin D deficiency is a common risk factor: Chinese people are generally deficient in vitamin D. Serum 25(OH)D in a normal population in Beijing is 16.2±4.6 ng/ml. 12.49±5.43 ng/ml in a random sample of women over 45 years of age in Beijing. Causes of vitamin D deficiency: In winter, most people tend to be less active outdoors, resulting in insufficient sunlight exposure; Heavy clothing reduces the area of skin exposed to sunlight, less intake of dairy products and oil-rich fish; less sunlight radiation reaching the earth’s surface in winter; air pollution further reduces sunlight exposure to the earth’s surface; excessive use of sunscreen; lighter-skinned young people need about 15 to 30 minutes of sunlight exposure per day, while darker-skinned people need longer exposure; older people have a reduced ability to produce vitamin D in their skin decreases; vitamin D deficiency rates of 30 to 80 percent in older adults who are unable to go outside or live in nursing homes. Diseases associated with osteoporosis: endocrine disorders: Cushing’s syndrome, hyperthyroidism, hyperparathyroidism, diabetes mellitus, pituitary prolactinoma, hypogonadism; chronic diseases: gastrointestinal absorption disorders, hepatic impairment, renal malnutrition; renal tubular acidosis, rheumatoid arthritis, fluorosis, anorexia nervosa; malignancies: multiple myeloma, leukemia, lymphoma, mastocytosis; mastocytosis. mast cell hyperplasia; congenital diseases: osteogenesis imperfecta, hyperhemiglobinemia, Fanconi syndrome, Marfan’s syndrome; nutritional disorders: protein deficiency, vitamin C deficiency, hepatomegaly and many other diseases can lead to osteoporosis. Effects of drugs and braking: Drugs: glucocorticoids, antiepileptic drugs, thyroxine, heparin, alcohol, immunosuppressants, GnRH (gonadotropin-releasing hormone) agonists, aromatase inhibitors, diuretics, rosiglitazone, etc. Other: braking, disuse, weight loss. Concept of osteoporotic fracture: It is the result of changes in the normal composition and structure of the bone, so that the bone loses its normal mechanical properties and can be fractured by a very slight external force or by the weight itself. Risk factors for falls: age factor; sensory decompensation: poor vision, poor hearing, reduced tactile pain and joint position sensation, decreased muscle strength, unstable gait, decreased balance function; effects of geriatric diseases: sequelae of cerebrovascular accidents, Parkinson’s disease, cerebellar lesions, postural hypotension, Alzheimer’s disease, cataracts, depression, anemia, prostatic hyperplasia, diabetes, osteoarthrosis, hypoproteinemia Environmental factors (50% of falls are related to this): dark lights, slippery and uneven floors, unfamiliarity with new environments, lack of handles in bathrooms and toilets, changes in the placement of objects, etc.; medication factors: sleep aids and sedatives, antihypertensive drugs, drugs for prostate enlargement, hypoglycemic drugs, painkillers, etc. Psychological factors: frustration, depression, anxiety, poor mood, fear of adding burden to children, etc.; lifestyle habits: alcoholism, shoes do not fit, etc.