Bone Mineral Density & Genetics: Is There a Link?
Scientists are finding that genetics may be an early way to predict bone density, or how much calcium and other minerals are in your bones, and diseases that follow.
Do you remember seeing commercials that glamorized the power of milk? How about the famous “Got Milk?” campaign plastered across the globe for years?
Although a great marketing tactic that encouraged everyone to consume cow’s milk to keep their bones strong and their body healthy, it may not have been as effective for overall health as they had hoped.
While calcium-rich foods and beverages (milk included!) are a great way to keep our bones strong, some of us may have experienced more fractures or bone-related issues than others.
So why do some people experience more fractures or bone-related issues -- despite consuming more calcium from dairy products? The answer may come from a genetic predisposition to something called bone mineral density (see below). This genetic link alone can make someone more susceptible to breaking bones. And it could even lead to more severe health conditions like osteoporosis.
Either way, no matter what your genetic profile may reveal, we encourage you to stay on top of your bone health and consume ample amounts of calcium, but we won’t ask you whether you’ve “got milk?”
Instead, we recommend speaking to a bone specialist (called an orthopedist) should your profile reveal that you are at higher risk for osteoporosis or other bone-related conditions.
Let’s dive into understanding osteoporosis and genetics's role in overall bone mineral density.
What is bone mineral density?
In simplest terms, bone mineral density (BMD) is the amount of bone mineral found in your bone tissue.
Bone mineral density is one of the most critical measurements for diagnosing osteoporosis and other bone-related conditions—which is common as people age. BMD is so critical, that for most doctors diagnosing osteoporosis, it’s the main measurement they consider.
How is BMD calculated?
A bone mineral density test determines bone mineral density.
The most commonly used BMD test is the central dual-energy x-ray absorptiometry. It is performed the same as a standard x-ray and is entirely painless. The test measures bone density at your hip and lumbar spine.
The calculated results are then compared to a set of standards to determine if you are at risk for or already have decreased bone density.
The score you receive from a BMD test is called a “T-score.”
- A score of zero, +1, or -1 indicates that your BMD is equal to the norm for a healthy adult.
- A score between -1 and -2.5 means you have lower BMD than an average, healthy adult.
- A score of -2.5 or lower indicates you have severe bone density loss and osteoporosis.
What is osteoporosis?
Osteoporosis is a common, chronic aging-related disease characterized by low bone mass and small deterioration of bone tissue.
This disease leads to an increase in bone fragility and susceptibility to fracture (breaking a bone).
Anyone can develop osteoporosis at any time, but increased risk factors include:
- age
- genetics
- gender
- diet
- lifestyle
If left undiagnosed or untreated, severe complications can occur, including death.
Symptoms
Although a BMD test is the best way to detect osteoporosis, some early signs and symptoms could indicate a bone density issue including:
- a loss of height due to changes in the spine
- a slouched posture
- severe back pain
- easy bone breakage, especially in your wrist or hip from what would be categorized as a “normal fall”
- fractures that occur from everyday movements
It has been reported that 15% of white people over 50 years old suffer an osteoporotic fracture in their remaining lifetime.
Therefore, a better understanding of osteoporosis's development and risk factors may help doctors develop medications for prevention and treatment.
Do genetics play a role in my bone mineral density?
Yes, BMD is a highly inheritable trait, with heritability ranging from 50 to 80%.
Previous genome-wide association studies (GWAS) have identified over 500 genomic loci (you can think of loci as a stress address for genes) for BMD, accounting for up to 20% of variations.*
However, compared with the estimated heritability range, there is still a large portion of “missing” heritability to be discovered.
Aiming to identify more genomic loci responsible for BMD variation, researchers conducted a joint association analysis of 2 GWASs.1
The first study is the largest single GWAS of heel BMD (eBMD) in 426,824 UK Biobank (UKB) participants, and the second study is the GWAS of total body BMD (TB-BMD) in 66,628 participants from 30 studies.**
By integrating the information from over 490,000 participants, this largest joint analysis of BMD GWAS identified 12 novel genomic loci at the genome-wide significance level, nine of which were for heel BMD (eBMD) and four for total body BMD (TB-BMD) explaining an additional 0.11 and 0.23% heritability for the two traits.
By conducting a joint analysis of two large-scale genome-wide association studies, they have identified 12 novel loci associated with BMD.
What can I do to assess my risk of bone density issues based on my genetics?
DNA analysis might be the best way to determine your risk of developing bone conditions such as osteoporosis due to your specific bone mineral density.
A DNA testing kit is easy to use, providing countless personalized results. The best part is that your genetic DNA testing results can reveal many answers to questions you may have about your health, bone density included.
Once you’ve taken an at-home DNA test, you can use your raw DNA file to analyze your genetic profile in more detail.
The process is simple: sign in to the Genomelink dashboard to upload your DNA file, and our experts will take care of everything else.
Start your journey to a deeper understanding of how your genetics could influence your health and wellbeing. Unlock your full genetic potential now.
* Phenotypic variations specifically
** Heel BMD was estimated based on quantitative ultrasound speed of sound (SOS) and broadband ultrasound attenuation (BUA). While total body BMD was measured by dual-energy X-ray absorptiometry (DXA). Significant comparisons are not applicable because the two integrated traits are not the same.
1 Liu L, Zhao M, Xie ZG, et al. Twelve New Genomic Loci Associated With Bone Mineral Density. Front Endocrinol (Lausanne). 2020;11:243. Published 2020 Apr 22. doi:10.3389/fendo.2020.00243
