Dexa Scan & Osteoporosis

Dec 23, 2019

Dexa Scan & Osteoporosis

Osteoporosis is a condition that affects the bones, weakening them over time. The overall prevalence is over 200 million people worldwide have osteoporosis.

  • Osteoporosis is a condition that affects the bones, weakening them over time
  • 200 million people worldwide have osteoporosis
  • About 54 million Americans have osteoporosis and low bone mass, placing them at increased risk for osteoporosis
  • Osteoporosis causes more than 8.9 million fractures annually
  • A DEXA scan is currently the most widely used test in measuring bone mineral density. It is an important test in assessing the degree of bone thinning in osteoporosis. Bone loss increases the risk of hip and spine fractures

Dexa Scan & Osteoporosis

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Osteoporosis is a condition that affects the bones, weakening them over time. The overall prevalence is over 200 million people worldwide have osteoporosis. About 54 million Americans have osteoporosis and low bone mass, placing them at increased risk for osteoporosis. Studies suggest that approximately one in two women and up to one in four men age 50 and older will break a bone due to osteoporosis. Osteoporosis causes more than 8.9 million fractures annually. Hip fractures projected to increase substantially by 2050: 240% in women 320% in men There is currently no cure for osteoporosis, but there is osteoporosis treatment available to help manage osteoporosis pain, treat fractures and help make bones stronger. You are also likely to be advised to undertake exercises and eat a healthy, balanced diet (read more about diet and exercise for osteoporosis later). Treatment for a fracture will depend upon which bones are affected but will aim to put bones back into place and stop them from moving around, so they can start to heal; this usually involves a sling, cast, splint or brace, to support the bones; The costof Osteoporosis treatment is around 16.9 billion per year. It is caused by the loss of density in the bones and affects women more than men, often soon after they start the menopause. Losing bone mass is part of the natural aging process, but some people lose it much faster than others which can leave them at risk. Fragile bone makes them delicate and easily broken, with sufferers often receiving fractures due to minor falls or a sudden impact, such as a sneeze. The most commonly affected areas are the hip and wrist, but other bones such as the arm, pelvis or spine can also be affected. More than 500,000 people receive hospital treatment for fractures related to osteoporosis. Diagnosis of osteoporosis It can take some time before osteoporosis is diagnosed. This is because there are no easy to spot osteoporosis symptoms. If you attend hospital due to having a fracture, you may be tested for osteoporosis if your doctor thinks you are high risk, you fracture ‘easily’ or through a very minor injury, or if you have had fractures before. If your doctor thinks you may have osteoporosis, they will suggest you undergo some tests that will confirm a diagnosis. You are likely to require a scan to check the density of your bones. For example, a DEXA (dual-energy x-ray absorptiometry) scan. A bone density scan is a quick and painless procedure that involves lying on your back on an X-ray table so an area of your body can be scanned. A DEXA scan is currently the most widely used test in measuring bone mineral density. It is an important test in assessing the degree of bone thinning in osteoporosis. Bone loss increases the risk of hip and spine fractures. No special preparations are needed. You may be able to remain fully clothed, depending on the area of your body being scanned. But you’ll need to remove any clothes that have metal fasteners, such as zips, hooks or buckles. In some cases, you may need to wear a gown. When you have a DEXA scan, you will not need to go into a tunnel or have an injection. Instead, you lie on your back on a flat, open X-ray table. You’ll need to keep very still during the scan so the images are not blurred. The scan will usually be carried out by a radiographer, a specialist in taking X-ray images. During the scan, a large scanning arm will be passed over your body to measure bone density in the center of the skeleton. As the scanning arm is moved slowly over your body, a narrow beam of low-dose X-rays will be passed through the part of your body being examined. This will usually be your hip and lower spine to check for weak bones in Osteoporosis But as bone density varies in different parts of the skeleton, more than one part of your body may be scanned. Some of the X-rays that are passed through your body will be absorbed by tissue, such as fat and bone. An X-ray detector inside the scanning arm measures the amount of X-rays that have passed through your body. This information will be used to produce an image of the scanned area. The scan usually takes 10 to 20 minutes. You’ll be able to go home after you have had it done. Your results A bone density scan compares your bone density with the bone density expected for a young healthy adult or a healthy adult of your own age, gender and ethnicity. The difference is calculated as a standard deviation (SD) score. This measures the difference between your bone density and the expected value. The difference between your measurement and that of a young healthy adult is known as a T score, The difference between your measurement and that of someone of the same age is known as a Z score. The World Health Organization (WHO) classifies T scores as follows:

  • above -1 SD is normal
  • between -1 and -2.5 SD is defined as mildly reduced bone mineral density (BMD) compared with peak bone mass (PBM)
  • at or below -2.5 SD is defined as osteoporosis

If your Z score is below -2, your bone density is lower than it should be for someone of your age. Although BMD results provide a good indication of bone strength, the results of a bone density scan will not necessarily predict whether you’ll get a fracture. For example, someone with low bone density may never break a bone, whereas someone with average bone density may have several fractures. This is because other factors, such as age, sex or whether you have previously had a fall, also determine if you’re likely to sustain a fracture. Your doctor will consider all of your individual risk factors before deciding if treatment is necessary. If you have a lower than normal bone density, you are likely to have osteoporosis or be at risk of it developing, which is called osteopenia. The tests conducted will compare your bone density level with data on what is considered a healthy bone density, of someone similar to you. If you undergo such a test, you will be given a score. If this is below -2.5, you are likely to be diagnosed with osteoporosis. You may also undergo a FRAX or Q-Fracture risk assessment to predict your risk of having a fracture in the future. You may also need to undergo blood tests to explore whether other conditions are causing your low bone density or fractures. If you think you may have or be at risk of developing osteoporosis, speak to your GP. For more information on how a diagnosis of osteoporosis is made, visit the https://advancedimagingnj.com/women/ Prevalence data by decade from the Rochester project. This uses T -2.5 or below to define osteoporosis, in white women. Melton determined mean and SD for his population, which are different from those determined in NHANES III. Thus, prevalence figures from Rochester are different from those in NHANES. Note that prevalence increases with age at all there sites. However, the number of people diagnosed with osteoporosis varies according to which skeletal site is measured. This concept of discordance will be addressed in greater detail later in the course. Even if one uses the spine, hip, and wrist, the prevalence is about 70% over age 80. Thus, not all women develop osteoporosis, not all have to be treated, and the measurement of BMD is important. Note spine has a higher prevalence than other sites in younger people because it has more cancellous bone and is thus more sensitive to bone loss. However, in elderly people prevalence based on the spine is lower than that of other sites because degenerative changes are more common at the spine and because more bone loss has occurred in the hip. All women 50 and older T-score –2.5 or below **”Hip” was either femoral neck or intertrochanteric region, whichever was lower 4 Data from Melton LJ III et al. J Bone Miner Res. 1995;10:175.

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How do you prevent it?

Certain factors can increase the risk of developing osteoporosis. These include having a low Body Mass Index (BMI), heavy drinking or smoking, a family history of osteoporosis or long-term use of certain medications that affect hormone level or bone density. Stopping smoking, cutting down on drinking and ensuring you have a healthy BMI are all lifestyle changes you can make. Taking regular exercise and eating healthier are all preventative measures you can take. Try focusing on foods rich in calcium and vitamin D, as well as taking a daily supplement of vitamin D. What are the symptoms? Often osteoporosis will go unnoticed until an initial fall or impact causes a fracture, leading to its diagnosis. The condition is not painful until the fractures begin, but spinal fractures can often leave people in chronic long-term pain. A stooped back is often a characteristic of someone with osteoporosis due to the fractures in the spine. How is it treated? Treatment for osteoporosis is based around preventing fractures, and scans are taken assessing bone density. Treatment plans will also factor in your age, sex, risk of fracture and previous injury history. Medication is used to help strengthen bones, and extra calcium may also be prescribed by your GP. There is currently no cure for osteoporosis, but there is osteoporosis treatment available to help manage osteoporosis pain, treat fractures and help make bones stronger. You are also likely to be advised to undertake exercises and eat a healthy, balanced diet (read more about diet and exercise for osteoporosis later). Treatment for a fracture will depend upon which bones are affected but will aim to put bones back into place and stop them from moving around, so they can start to heal; this usually involves a sling, cast, splint or brace, to support the bones Preventing a fall is also key, including reducing clutter, removing rugs, poor lighting, putting down non-slip mats and going up and downstairs. Poor eyesight can also be a factor, so ensure you have your eyes tested to spot any potential hazards. Certain exercises can also improve your strength and balance, decreasing the likelihood of a fall. Other measures include hot and cold treatments, such as baths or ice packs and relaxation techniques. A transcutaneous electrical nerve stimulation (TENS) device can also be used, which is a small battery-operated device that stimulates the nerves to reduce pain. There are many types of medication for osteoporosis you may be prescribed, which are designed to help slow down the degeneration of the old bone, stimulate the building of new bone or a combination of these. Here are the most common ones: • Bisphosphonates • Teriparatide and parathyroid hormone • Raloxifene • Calcitonin • Denosumab You are also likely to be recommended to take calcium and vitamin D supplements, which support bone development and strength. Can osteoporosis be reversed? In a word, yes. It may take a little time to find a medication for osteoporosis that is suitable for you, as some do have side effects. After a lengthy period of taking medication, your doctor may ask that you have a break because the drugs you are taking have a long-lasting effect and your bone density has improved. Some people find that by changing their lifestyle through implementing exercises for osteoporosis and eating an osteoporosis diet, they are able to improve their bone strength to such a level that they are no longer considered to have the condition. Traditionally, women going through the menopause were prescribed hormone replacement therapy (HRT) to help prevent or treat osteoporosis. Whilst still widely used, there are many alternative medications available now which have fewer potential risk factors compared to HRT, which is thought to increase a woman’s risk of developing breast cancer and other conditions. The information in this document does not replace a medical consultation. It is for personal guidance use only. We recommend that patients ask their doctors about what tests or types of treatments are needed for their condition.