Can You Have Too High Bone Mass? A Guide to Elevated Bone Density

While many focus on the dangers of low bone mineral density (BMD), some research has documented cases of unusually high BMD, or elevated bone mass. While seemingly beneficial, this condition can paradoxically indicate underlying disorders that may increase fracture risk or present other health challenges.

Quick Summary

An unusually high bone mass, or elevated bone mineral density, can be a sign of underlying medical issues, including rare genetic disorders, specific acquired conditions, or spinal degeneration. The quality and structure of the bone are as important as its density.

Key Points

• High Bone Density Doesn't Always Mean Stronger Bones: Conditions like osteopetrosis and Paget's disease cause high bone mass, but result in brittle, fragile bones that are more susceptible to fracture.

• High Bone Mass Can Mask Health Issues: Degenerative conditions like DISH can cause artificially high BMD readings on DXA scans, potentially masking underlying osteoporosis or other problems.

• Genetic Factors Can Cause High Bone Mass: Rare inherited disorders, such as mutations in the LRP5 or SOST genes, can lead to excessively high bone density and other skeletal issues.

• High BMD Has Been Linked to Other Diseases: Some studies show an association between high bone mass and increased risk for conditions like breast cancer in postmenopausal women and osteoarthritis.

• Diagnosis Requires Further Investigation: If a DXA scan reveals high BMD, a doctor will perform further tests, including detailed imaging and blood work, to identify the root cause and ensure it's not a serious underlying pathology.

• Management Depends on the Cause: The treatment plan for high bone mass is determined by the specific underlying condition, ranging from monitoring to specialized medical or surgical intervention.

Understanding High Bone Mass

High bone mass, also known as osteosclerosis, occurs when your bones have a mineral density significantly above the average for your age and sex. While a high bone mass seems like a sign of strength and durability, it can sometimes be a marker for underlying pathology. It's crucial to understand that bone density doesn't always correlate directly with bone quality or strength; some conditions that cause high bone mass can result in brittle or disorganized bone tissue, making it more prone to fractures.

What Defines High Bone Mass?

High BMD is typically identified through a dual-energy X-ray absorptiometry (DXA) scan, the standard test for measuring bone density. While low BMD is defined by specific T-scores to diagnose osteopenia or osteoporosis, a standard definition for high BMD has not been as universally established. However, clinicians may be alerted to potential underlying issues when a patient's Z-score (a measure comparing BMD to age-matched peers) is significantly high, often defined as a Z-score greater than +2.5.

Causes of Elevated Bone Mass

The causes of high bone mass are varied and can be categorized into several groups, ranging from common age-related changes to rare genetic disorders.

Degenerative and Acquired Causes

In older adults, the most common reason for an elevated BMD reading is a degenerative disease, particularly of the spine. Conditions that can cause an artificially high reading include:

• Diffuse idiopathic skeletal hyperostosis (DISH): A form of arthritis that causes ligaments and tendons to harden and calcify, particularly in the spine.
• Ankylosing Spondylitis: This inflammatory disease can lead to spinal fusion and ossification, increasing the calcium content measured by a DXA scan.
• Vertebral fractures: A compression fracture can reduce the vertebra's size, but the bone mineral content remains, causing an increase in the calculated BMD.
• Vascular calcifications: Calcified plaque in the abdominal aorta, especially in older individuals, can interfere with lumbar spine DXA measurements.

Other acquired conditions associated with generalized high BMD include:

• Renal osteodystrophy: Can lead to osteosclerosis in the ribs, pelvis, and spine.
• Hepatitis C-associated osteosclerosis: A rare condition linked to HCV infection.
• Myelofibrosis: A chronic disorder of the bone marrow.
• Mastocytosis: A disease of widespread mast cell tissue infiltration.

Genetic Disorders

Some rare genetic conditions can lead to pathologically high bone mass. These include:

• Osteopetrosis: A group of genetic disorders where the bones harden and become denser due to defective osteoclasts, the cells that break down old bone. This can cause bones to be brittle despite their high density.
• LRP5 and SOST mutations: Mutations in these genes can disrupt the normal regulation of bone growth, leading to excessively high bone mass.
• Pyknodysostosis: A rare inherited disorder that results in bones that are abnormally dense but fragile, with other physical abnormalities.

Risks and Health Implications of High Bone Mass

While good bone density is generally protective, the risks associated with high bone mass vary significantly depending on the underlying cause. Some individuals with unexplained high BMD from higher body mass may have a lower fracture risk. However, for others, the picture is more complex.

Fracture Risk Paradox

Paradoxically, conditions like osteopetrosis and Paget's disease, which are characterized by high BMD, are also associated with an increased risk of fracture due to poor bone quality and abnormal bone structure. The bone may be dense but structurally unsound, much like concrete with an inadequate rebar structure.

Other Comorbidities

High bone mass can also be linked to other health issues. Research has suggested an association between higher bone density and an increased risk of certain conditions, such as breast cancer in postmenopausal women and osteoarthritis. While the bone density itself doesn't cause these conditions, it can be a marker for underlying hormonal factors or other systemic issues.

Neurological Symptoms

In some genetic disorders, such as sclerosteosis and van Buchem's disease, overgrowth of cranial bone can lead to compression of cranial nerves. This can cause hearing loss, facial nerve palsy, and persistent headaches.

Diagnosis and Management

If a DXA scan indicates a significantly high BMD, further investigation is necessary to determine the underlying cause and rule out any serious conditions. A thorough evaluation may involve:

• A review of clinical history: Your doctor will consider your medical history, family history, and other symptoms.
• Additional imaging studies: Radiographs can provide better visualization of bone structure than a DXA scan, revealing abnormalities characteristic of certain disorders.
• Blood and urine tests: These can check for elevated markers that point to specific conditions like Paget's disease or certain malignancies.
• Genetic testing: This may be required to diagnose rare inherited disorders.

Management of high bone mass is dependent on the diagnosis. For degenerative causes, addressing the underlying arthritis is key. For more serious conditions, specialized treatment may be needed. However, in cases where high BMD is simply a result of higher body mass and no other pathology is found, no specific treatment may be necessary. A collaborative approach with a healthcare provider is essential.

Comparison of Bone Mass Categories

Feature	Low Bone Mass (Osteopenia)	Optimal Bone Mass (Normal)	High Bone Mass (Osteosclerosis)
Definition	BMD lower than average, but not low enough to be osteoporosis.	BMD within the expected range for age and sex.	BMD significantly higher than average.
T-Score Range	-1.0 to -2.5	-1.0 and above	Not officially defined, but often considered at high Z-scores (e.g., >+2.5).
Fracture Risk	Increased risk of fracture.	Lowest risk of fracture.	Varies greatly; can be increased, decreased, or unaffected depending on the cause.
Quality of Bone	Structurally weaker, more porous.	Structurally sound and healthy.	Can be structurally sound or pathologically disorganized and brittle.
Associated Factors	Age, menopause, low body weight, medication side effects.	Good diet, regular weight-bearing exercise, healthy lifestyle.	Genetic conditions, chronic diseases, degenerative changes, obesity.

Conclusion

While most of the focus in senior care is rightly on combating low bone mass and osteoporosis, the question of "Can you have too high bone mass?" reveals a more nuanced aspect of skeletal health. An elevated BMD reading is not always a sign of exceptional strength but rather a signal for further investigation. It's a reminder that bone health involves more than just density; it encompasses the underlying quality and structure of the skeleton. For anyone concerned about their bone density readings, a detailed discussion with a healthcare provider is the best course of action. They can help determine whether a high BMD reading is a benign finding or a sign of an issue requiring attention.

For more detailed information on high bone mass from a clinical perspective, you can read articles published by the National Institutes of Health(https://pmc.ncbi.nlm.nih.gov/articles/PMC3651616/).

Frequently Asked Questions

Can you have too high bone mass naturally?

Yes, some individuals may have naturally higher bone mass, particularly those with a higher body mass index (BMI) or with a specific genetic predisposition that isn't a disorder. However, a doctor will need to rule out underlying medical conditions first.

What is the clinical term for having too high bone mass?

The clinical term for having excessively high bone mass is osteosclerosis. It can be caused by a variety of conditions, ranging from benign to more serious medical disorders.

Is having a high BMD always a bad thing?

Not necessarily. For many, a high BMD is simply an indicator of a robust skeleton and a lower risk for osteoporosis. However, a very high reading can signal the presence of a medical condition that needs further investigation.

Can high bone mass increase fracture risk?

Yes, paradoxically, in conditions like osteopetrosis and Paget's disease, the bone tissue is dense but disorganized and structurally weak, making it more susceptible to fractures.

How is high bone mass diagnosed?

High bone mass is first identified via a DXA scan, which measures bone mineral density. A doctor will then order additional tests, such as X-rays, blood tests, or genetic screenings, to determine the specific cause.

Can lifestyle factors cause too high bone mass?

While lifestyle influences peak bone mass, most cases of pathologically high bone mass are caused by genetic factors or acquired conditions, not simply diet or exercise. However, obesity is linked to higher BMD.

What is the treatment for high bone mass?

The treatment for high bone mass depends entirely on the underlying cause. There is no single treatment. For serious medical conditions, management is focused on treating that specific disorder. If no underlying pathology is found, no treatment may be needed.