What is a DEXA scan?
DEXA stands for Dual-Energy Xray Absoptiometry, meaning it uses a very small amount of Xray to evaluate your body tissues. We use it as an imaging tool to perform two different types of tests: 1) a body composition analysis and 2) a bone density analysis. I will talk about the two types of DEXA scans we perform and what the benefits are for each one.
Above image shows two body composition images from the same individual, performed five years apart. This individual gained muscle mass (seen in pink) and lost body fat (seen in yellow).
DEXA Body Composition
This is a study that scans your body head to toe and evaluates your muscle mass, your fat mass, your abdominal (visceral) fat levels, calculates how many calories you burn at rest (your resting metabolic rate), and does a screening evaluation of your bones for your risk of bone loss.
As low muscle mass is associated with an increased risk of death in the elderly, this DEXA test is ideal for individuals who want to improve their health by increasing their muscle mass. Additionally, it is considered to be the gold standard of measuring your visceral abdominal fat, which is highly correlated with your risk of developing heart disease or diabetes in your lifetime.
Above image demonstrates a Bone Density survey performed on a body composition analysis. This test screens your overall skeleton for signs of loss of bone density.
DEXA Bone Density
This is a study that is typically done on women over 65 or men over 70 to look for weak bones, a condition called osteoporosis. This scan evaluates your low back (lumbar spine) and both of your hips. This scan helps you determine your risk of having a broken bone (a fracture) if you fall down. Hip fractures are highly associated with death in older individuals, and therefore it is very important to identify who is at higher risk and would benefit from bone-strengthening treatment.
The above image is an example of a bilateral hip DEXA scan to screen for osteoporosis.
The only downside is that a DEXA bone scan is only covered by insurance for women over 65 and is only covered for men or younger women if they have a condition that puts them at high risk for bone loss. Since it is much easier for young people to build bone, it my opinion that it is better for individuals to understand their risk of developing osteoporosis when they are younger and can take action to keep their bones strong, rather than reversing bone loss when they are older.
Why should I care about loss of bone density?
Loss of bone density, called Osteoporosis, significantly increases your risk of hip fractures as you get older. Studies have shown that there is about a 30% mortality rate in individuals one year after having a hip fracture over the age of 65. By reducing your risk of osteoporosis, we can reduce your risk of hip fracture and therefore reduce your risk of death. Postmenopausal women lose bone mass at a much higher rate than men.
The above image shows the typical amount of bone density in women (red) and men (blue) over time. Note that bone density rapidly declines for women after menopause.
Is there radiation in a DEXA scan?
We measure radiation from imaging like Xray and CT scans in a unit called microsieverts. According to the CDC, a DEXA scan delivers about 1-4 microsieverts. A Chest X-ray gives you about 60 microsieverts. Walking on the Earth at sea level gives you 7 microsieverts per day. Therefore the amount of radiation from a DEXA scan is very low.
How often do I need a DEXA scan?
Depending on your goals, a follow up DEXA can be helpful to measure your progress. A bone density DEXA can be performed every 1-2 years if you are making changes like doing weight-resistance exercises on a consistent basis.
A body composition DEXA will show measureable changes as soon as every 3 months, but we typically recommend you repeat the scan 6-12 months after your initial scan if you have changed your diet and exercise routine in a consistent manner.
The bottom line:
DEXA scans have many benefits to help you understand your muscle mass, visceral fat mass, and bone density and allows you to track those measurements over time in a highly accurate way.
To schedule your DEXA scan today, visit our Book Now section to schedule your appointment!
Comments