Bone health is an important part of human health, and its evaluation indicators include not only calcium content, but also bone strength and other factors, and bone density can reflect bone health to a certain extent. To be clear, not everyone needs a bone density test. Moreover, the current popular body fat scale and ultrasound bone density test commonly used in physical examination cannot be used as the basis for diagnosing osteoporosis. Correctly understanding the applicable population of bone density testing can not only avoid the waste of medical resources, but also reduce unnecessary health anxiety.

Who doesn't need a routine bone density test

1 Children and adolescents

Some parents will take their children for bone density checks regularly because they are worried about their children's height or nutritional problems. This behavior lacks medical basis. At present, there is no reference database for bone density for children and adolescents at home and abroad, and the examination results of children can only be compared with the standards of adults over 20 years old. Due to the characteristics of growth and development, children's bone density is lower than that of adults, and if it is determined that bone density is low, it is easy to mislead parents. This test is only necessary if the child has repeated fractures, bone deformities, or if long-term monitoring of bone density is required for treatment. It is worth noting that some parents directly link bone density to the rate of growth and development, and even blindly give calcium to their children. This can lead to excessive calcium intake, increase the burden on the kidneys, or lead to premature closure of the epiphysis, which affects the normal growth and development of children.

2 Healthy young and middle-aged people

Young people with balanced nutrition, regular work and rest, and love to exercise do not need to include bone density testing in their annual physical examination. Human bone mass peaks around the age of 30, and then gradually loses with age, and the rate of loss accelerates in women after menopause. Therefore, healthy young and middle-aged people do not have to worry about osteoporosis in the short term, and excessive examination may cause psychological burden.

Who needs to have regular bone density checks?

1 Elderly group

Women over 65 years old and men over 70 years old should use bone density testing as the basic assessment, and if there is a problem, review it according to the doctor's advice. This is because women's estrogen levels drop sharply after menopause, and the annual bone loss rate can reach 2%~3%, while men have hypogonadism after the age of 70, and the risk of bone metabolism imbalance increases significantly.

2 People with risk factors for fracture

Postmenopausal women to 65 years old and men aged 50~70 need to undergo bone density testing if there are risk factors for fractures, such as low back pain, height loss of more than 3 cm, hunchback, decreased mobility, etc.

3 People who have had fractures

Patients over 50 years of age who have fractures from any cause need to be assessed by bone density testing. Clinical data show that the risk of re-fracture within one year in patients with osteoporotic fractures is 5 times that of normal people, and timely intervention can significantly reduce the probability of secondary fractures.

4 People with related diseases or taking specific medications

People with rheumatoid arthritis, digestive disorders, kidney disease, or people who have been taking medication for a long time and may cause bone loss should monitor bone density regularly, regardless of age. Taking glucocorticoids as an example, the annual bone loss rate of long-term users can reach 3%~5%, and such people need to undergo bone density tests every 6~12 months before and during medication.

These methods of measuring bone density are not reliable

The "bone salt amount" index of the body fat scale

The "bone salt content" of the body fat scale refers to the weight of calcium, phosphorus and bone matrix in the bones, which can theoretically reflect bone health, but the actual detection principle is questionable. Body fat scales estimate the amount of bone salt through resistance measurement, combined with height, weight and other data, and subtle errors in water intake, usage, ambient temperature and even height data will affect the accuracy of the results. For example, the results of morning fasting and post-meal measurements may differ by 1~2 kg; In winter, when the temperature difference between indoor and outdoor is large, the data fluctuations are more obvious. Therefore, body fat scales cannot be used as a screening or diagnostic tool for osteoporosis.

Ultrasound bone densitometry

Ultrasound bone density examination is used by physical examination centers and community hospitals to measure bone density in the heel, finger or wrist because it is simple to operate and does not have radiation. It should be noted that this examination is only a screening method, and even if the results show abnormalities, further examination must be done in a regular hospital. People with osteoporosis who undergo this test may also have normal results. This is because ultrasound examination mainly reflects the hardness of the bone, and the bone mineral content cannot be accurately measured, and the missed diagnosis rate is high for early osteoporosis or areas dominated by cancellous bone, such as the lumbar spine.

Dual-energy X-ray absorptiometry (DXA) is the "gold standard" for diagnosing osteoporosis, which is to measure bone density in the waist and hips with low-dose X-rays, as well as to assess the body's fat and muscle mass. It is important to note that only a single site is examined, which may lead to missed diagnosis. After getting the examination report, even if the values are within the normal range, they should be comprehensively judged by specialists based on the patient's symptoms, disease history, family history, etc., and the patient should not interpret it by himself.