Bone Density Myths: Why DEXA Scores Aren’t Everything

Osteoporosis is one of the most widely misunderstood diagnoses in modern medicine. For decades, we’ve been told to fear low bone mineral density (BMD) as the harbinger of fractures, immobility, and frailty. And yet, as is often the case in health and fitness, the story is far more nuanced.

Here’s the truth: a low BMD score does not automatically equal fragility, nor is it the sole predictor of future fracture risk. Even more critically, there’s growing evidence that functional strength—especially relative to body weight—is far more important in determining real-world risk than a Dual-energy X-ray Absorptiometry (DEXA) scan suggests. And this isn’t just a theory, it’s backed by research.

Let’s dismantle some of the most pervasive myths around osteoporosis and build a clearer, stronger picture of what bone health really means.

Myth 1: A low bone density score automatically means a high risk of fracture

The World Health Organization defines osteoporosis based on a T-score of -2.5 or lower on a DEXA scan. But this threshold, while statistically derived, isn’t destiny.

In a 2014 study published in Osteoporosis International (1), researchers found that more than 80% of all fractures in older women occurred in those without an osteoporosis diagnosis—that is, with T-scores above -2.5. This data highlights a critical flaw in how we interpret bone density: it’s only one piece of the puzzle.

Fracture risk is multifactorial. Factors such as fall risk, neuromuscular coordination, body mass, and muscle strength all play major roles. According to The Journal of Bone and Mineral Research, frailty, low grip strength, and slow gait speed are all better predictors of fracture than T-score alone (2).

In short: it’s not about the patient’s bone density score in isolation—it’s about how their body actually functions.

Myth 2: Bone density is the primary goal in osteoporosis management

We’ve been conditioned to think the path to better bone health lies in improving BMD scores, often through pharmaceuticals like bisphosphonates. While these medications may reduce fracture risk in some populations, they do not address what truly matters: the patient’s capacity to tolerate load and prevent falls.

A stronger determinant of fracture risk is body mass. Numerous studies have shown that low body weight is one of the strongest predictors of osteoporosis and related fractures (3). But again, this correlation doesn’t mean causation in all cases. Why? Because low body mass may simply reflect low muscle mass—which in turn limits the ability to generate force, stabilize joints, and recover from stumbles.

Instead of fixating on bone density numbers, a better goal is to increase muscle mass, improve relative strength, and—if appropriate—increase total body weight. These adaptations can have a more profound impact on long-term function and fracture resistance than small improvements in bone mineral scores.

Myth 3: If the patient can’t gain weight, they’re doomed to fragile bones

Some people—due to genetics, medical conditions, or lifestyle—may struggle to gain significant body mass. This often triggers fear when associated with a low BMD result. But again, context matters.

A low BMD in a light individual with high relative strength, excellent balance, and no history of fractures is not the same as a low BMD in a frail, sarcopenic adult with poor motor control and a history of falls.

In a 2022 study in The Journal of Clinical Densitometry (4), researchers argued that BMD must be interpreted in the context of functional capacity, not just population norms. In fact, they suggest that for individuals with high strength-to-weight ratios and minimal fall risk, a low T-score may be clinically irrelevant.

In other words: bone density should not be assessed in a vacuum.

Instead, we should focus on:

Strength-to-bodyweight ratio
Muscle cross-sectional area
Reaction time and dynamic balance
Neuromuscular control during gait and load-bearing tasks

These are the factors that truly determine whether the patient is at risk.

Myth 4: Strong bones are built by pills and milk alone

Calcium and vitamin D have long been marketed as the magic duo for bone health. While they are important, they are far from sufficient.

Bone responds to mechanical loading. Wolff’s Law tells us that bone adapts to the stress placed upon it. Resistance training, especially when progressively loaded, is one of the most effective ways to increase—or maintain—bone mass.

A landmark study known as the LIFTMOR trial demonstrated that heavy resistance training in postmenopausal women with low bone mass led to significant improvements in BMD, functional strength, and posture—with no reported fractures or serious adverse events (5).

Even more impressively, this study showed that high-intensity training was safe and more effective than low-load programs often recommended in osteoporosis guidelines.

So yes—calcium and vitamin D matter. But they’re only tools in the toolbox. The real builder of bone resilience is strength training.

So what should we focus on instead?

Let’s shift the goalposts. Instead of obsessing over DEXA scores, let’s aim for:

Increased lean muscle mass: More muscle means more metabolic reserve, better insulin sensitivity, and stronger bones, especially at critical sites like the hip and spine.
Improved strength-to-bodyweight ratio: This metric has real-world implications for lifting, climbing stairs, and recovering balance during a fall.
Most fractures happen during falls, not from bones crumbling under their own weight. The best fracture prevention strategy? Don’t fall—and learn to fall well. Fall prevention is about more than avoiding slips; it’s about improving proprioception, reaction time, and strength in the muscles that stabilize the joints during unexpected perturbations. And when falls do happen, having the mobility, body awareness, and reflexes to fall in a controlled way can make the difference between a bruise and a break.
Robust movement patterns: Can the patient squat, hinge, push, pull, and carry without compensation? These are the patterns that build resilient bones and joints.
Individualized assessment: A 115-pound athlete with low BMD but excellent strength and balance may be at lower risk than a 160-pound sedentary person with borderline scores and poor mobility.

A patient is not their scan

This is especially evident when we look at osteoporosis alongside another misunderstood condition: osteoarthritis (OA). Osteoporosis is often feared due to its association with fracture risk, while OA is viewed as painful and disabling due to joint degeneration. Yet both conditions challenge the reliability of imaging in predicting outcomes.

Many people with osteoporosis live long, active lives without ever sustaining a fracture. Conversely, many individuals with advanced osteoarthritic changes on imaging have little or no pain. A 2012 systematic review found that over 40% of people with significant knee OA on radiographs reported no knee pain whatsoever (6).

What’s the common thread? Function doesn’t always correlate with imaging.

In OA, excess body mass is one of the strongest predictors of both symptom onset and pain severity. In osteoporosis, higher body mass—particularly lean mass—is often protective, offering the mechanical stimulus necessary to support bone health.

This highlights an important clinical divergence:

In osteoporosis: Increasing body weight (especially through lean muscle) and building strength tends to lower risk.
In osteoarthritis: Reducing excessive body weight and improving strength-to-weight ratio often reduces pain and improves function.

Despite their differences, both conditions point to the same core truth: how the patient’s body performs in the real world matters far more than what the scan says.

Wrapping up

Osteoporosis, like so many other “silent” conditions, is easy to fear—especially when medical advice is reduced to numbers on a DEXA scan. But strength, function, and muscle mass tell a far more complete story.

Yes, bone density matters. But not nearly as much as how the patient moves, trains, and how much functional capacity they carry—particularly in the form of lean muscle. In fact, a stronger, more muscular, and more capable version of the patient, regardless of their bone density score, is the best insurance policy against the outcomes we truly fear: falls, fractures, and loss of independence.

Patients should train smart, move often, and build muscle. Don’t let their diagnosis define their destiny.

If you want to learn more about bone density and osteoporosis, be sure to check out expert physio Lora Giangregorio’s Strategies for Osteoporosis Management and Fracture Prevention Masterclass HERE.