What is bone density? Why do we need testing?
Bone mineral density (BMD) refers to the amount of minerals (mainly calcium and phosphorus) contained in a unit of bone mass and is an important indicator of bone strength. As we get older, especially in postmenopausal women, low estrogen levels lead to a gradual decrease in bone density, accelerated bone loss, and a predisposition to osteoporosis. Osteoporosis is a bone disease characterized by a decrease in bone density and the destruction of bone microstructures, which increases the risk of fractures. According to the Hong Kong Health Department, about 30% of women over the age of 50 and about 20% of men over the age of 50 suffer from osteoporosis in Hong Kong.
The main goal of bone densitometry is to detect bone loss at an early stage and take preventive or therapeutic measures in a timely manner. Osteoporosis is known as the "silent killer" because there are usually no obvious symptoms until a fracture occurs. Common fracture sites include hip, spine, and wrist, and hip fractures have a mortality rate of up to 20%, and most patients lose the ability to live independently. Therefore, regular bone density checks are essential for high-risk populations (e.g., the elderly, postmenopausal women, long-term steroid users).
Currently, there are many different methods of bone densitometry, including DXA (dual-energy X-ray absorptiometry), quantitative ultrasonography (QUS), and computed tomography. Among them, DXA is considered the gold standard due to its high accuracy, low radiation dose (about one-tenth of the chest X-ray), and fast and painless procedure. In addition, it is also available in some institutions in Hong KongSpecial attention should be paid to health promotion activities, especially for certain high-risk groups and communities.
DXA Inspection Principles and Processes
DXA (Dual-Energy X-ray Absorptiometry) is a technique that uses X-rays of two different energies to penetrate bone, measure the degree of absorption of X-rays, and calculate bone density. Benefits include:
- High accuracy: It can detect 1% of bone changes, much better than other methods.
- Low radiation: The radiation dose in this test is only 3-5 microsieverts, which is equivalent to a half-day environmental exposure in one day.
- Quick and painless: the whole process takes about 10-15 minutes and does not require special preparation.
Before the examination, the patient should pay attention to:
- Avoid wearing clothing or accessories that contain metal so as not to interfere with the results.
- Calcium supplements should not be taken within 24 hours after the test.
- If you have recently undergone a barium test or a nuclear medicine test, you will have to wait one week.
The procedure is very simple, the patient lies flat on the table, and the device scans the lumbar spine and hip joints (including the forearm if necessary). The technician will ask you to stand still and walk away when the sweep is complete. Available in select regionsX-ray of bone densityPreliminary results are readily available, but detailed reports usually take 1-3 business days.
DXA Test Price Range in Hong Kong
The cost of a DXA inspection in Hong Kong varies depending on the type of organization, department, and region. The general fee range is as follows:
| article | Price Range (HK$) |
|---|---|
| Basic DXA Verification | 800-1,500 |
| Medical consultation fee | 300-800 |
| In-depth analysis of the report | 200-500 |
Recommendations for different populations:
- Women over 65 years old and men over 70 years old: It is recommended to check every two years.
- People with risk factors between the ages of 50 and 64(fracture history, family history, smoking, etc.): screening is recommended every 3-5 years.
- Postmenopausal women: The baseline test can be considered as postmenopausal time.
Some non-profit organisations in Hong Kong, such as the Hong Kong Osteoporosis Foundation, hold regular eventsFree bone density testEspecially for low-income seniors, they need to pay more attention to their activities.免費骨質密度檢查
Comparison of common DXA labs in Hong Kong
There are three main types of organizations that provide DXA control in Hong Kong.
- Public Hospitals: Requires a referral to a doctor, long waiting time (usually 6-12 months), but lowest cost (about HK$300-500).
- Private HospitalsA: State-of-the-art equipment, prompt service (daily to weekly),DXA PricingHigher values (HK$1,200 to HK$2,500).
- Health Examination Center: Prices are mid-range (HKD 800-1,800) and some packages include a doctor's interpretation report.
On the instrumental side, new generations of DXA machines, such as Hologic Discovery and GE Lunar Prodigy, offer higher resolution imagery and 3D analysis capabilities. When choosing an organization, check the model of the device and whether it has an international certification (such as ISCD).
DXA Inspection Report Interpretation and Follow-up Recommendations
Key metrics from the DXA report include:T-valueAndZ-value：
- T-value: In terms of bone density in a healthy adult aged 30 years, the criteria are as follows:
- Greater than -1: Standard
- -1 to -2.5: Osteopenia (osteopenia)
- - Less than 2.5: Osteoporosis
- Z-value: Compared to people of the same age, if it is less than -2.0, you should be aware of secondary osteoporosis.
If you have been diagnosed with osteoporosis, treatment options may include:
- chemotherapy: Bisphosphonates (e.g., alendronate), RANK ligand inhibitors (e.g., denosumab).
- Calcium and vitamin D supplementation: The recommended daily intake is 1,200 mg of calcium and 800 IU of vitamin D.
- physiotherapy: Weight-bearing exercises (walking, tai chi, etc.) stimulate bone production.
Daily health recommendations:
- Diet: eat more dairy products, dark green vegetables and soy products.
- Avoid smoking and excessive alcohol consumption.
- Prevent falls at home: keep the floor dry and install handrails.
In short, understandDXA PricingAnd after the selection of tests, it is necessary to conduct regular examinations according to individual risk factors. Early detection and treatment of bone problems can effectively reduce the risk of fractures and maintain quality of life.