What is Increased Bone Mass? Understanding High Bone Density and Its Implications

While maximizing bone density is a common health goal to prevent conditions like osteoporosis, a naturally or pathologically increased bone mass can sometimes indicate underlying medical issues. In some rare cases, what seems like strong bones can actually lead to increased fracture risk.

Quick Summary

Increased bone mass, or high bone density, refers to a condition where bone mineral density is higher than average, which can be a protective genetic trait or a sign of an underlying illness. It requires medical investigation to differentiate between harmless high peak bone mass and a more serious condition like osteopetrosis or another metabolic disorder.

Key Points

• High vs. Low Density: Increased bone mass is the opposite of osteoporosis, but is not always a sign of stronger, healthier bones.

• Pathological Causes: Underlying health conditions like osteopetrosis, myelofibrosis, or certain genetic mutations can cause high bone density.

• Symptom Awareness: While some with high peak bone mass are asymptomatic, others with underlying diseases may experience pain, fractures, or nerve problems.

• Diagnosis is Key: A DEXA scan, X-rays, and blood tests help determine the cause of high bone mass, separating a benign trait from a medical issue.

• Tailored Treatment: Treatment is not standard; it depends entirely on the specific cause of the increased bone mass, addressing the underlying condition.

• Fracture Risk: Paradoxically, some pathological conditions that cause high density can lead to weaker, more brittle bones and an increased risk of fractures.

What Exactly is Increased Bone Mass?

Increased bone mass describes a state where an individual has a higher than average bone mineral density (BMD). The interpretation of this finding depends heavily on its cause. For many, a high peak bone mass, achieved in young adulthood, offers lifelong protection against osteoporosis. However, in other cases, elevated BMD can be a symptom of a disease, leading to brittle rather than stronger bones.

The Role of Bone Remodeling

Our bones are constantly undergoing a process called remodeling, where old bone tissue is broken down by cells called osteoclasts and new bone tissue is formed by osteoblasts. Increased bone mass results from an imbalance in this process—either too much new bone is formed, or too little old bone is removed. The critical distinction is whether this process creates structurally sound bone or if the bone becomes abnormally dense and fragile.

High Bone Mass vs. Osteosclerosis

When discussing increased bone mass, it is important to distinguish between high bone mass (HBM) and conditions that cause osteosclerosis. While HBM can be a protective genetic trait, osteosclerosis is a pathological condition characterized by bone hardening. Conditions causing osteosclerosis often impair the normal bone remodeling cycle, which can compromise the bone's structural integrity despite its high density.

Causes Behind High Bone Density

Increased bone mass is not a single diagnosis but a finding that can result from various factors. Understanding the cause is critical for determining health risks and appropriate management.

Genetic and Inherited Conditions

Some individuals are genetically predisposed to having higher bone density. In these cases, it is often a benign trait that provides protection against osteoporosis later in life. However, rare genetic disorders can also cause increased bone mass, including:

• Osteopetrosis: A group of rare, inherited disorders known as "marble bone disease." It is caused by the impaired function of osteoclasts, leading to abnormally dense but structurally flawed bones that are prone to fracture.
• LRP5 Mutations: Certain mutations in the LRP5 gene can lead to high bone mass, often without the negative health consequences seen in osteopetrosis.

Acquired and Metabolic Causes

Various acquired health problems can also cause generalized or localized increases in bone density. These are often discovered during routine imaging for other health concerns.

• Myelofibrosis: A bone marrow disorder where normal bone marrow is replaced by fibrous tissue, which can cause increased bone density.
• Mastocytosis: A disorder caused by an excess of mast cells, which can trigger abnormal bone formation.
• Fluorosis: Chronic exposure to excessive fluoride can result in osteosclerosis, with thickening of bones, especially in the spine and pelvis.
• Renal Osteodystrophy: Advanced kidney disease can cause imbalances in bone metabolism, leading to a range of bone abnormalities, including increased density.

Non-Pathological Factors

Sometimes, high bone density on a scan is an artifact rather than a systemic issue. These causes include:

1. Degenerative Joint Disease: Osteoarthritis in the spine can lead to localized increases in measured bone density.
2. Vertebral Fractures: Healed fractures in the spine can cause a localized increase in density, skewing overall DEXA results.
3. Obesity: Higher body weight can put more stress on bones, stimulating increased density.

Symptoms and Implications

Many people with genuinely high bone mass experience no symptoms, and for them, it can be a health advantage. However, when the increased density is a result of a pathological condition, symptoms can emerge:

• Bone Pain and Fractures: In conditions like osteopetrosis, despite high density, bones can be structurally weak and prone to breaks.
• Nerve Impingement: Excess bone growth, especially in the skull, can compress nerves, leading to vision, hearing, or other neurological problems, as seen in some types of osteopetrosis.
• Hematological Issues: In conditions affecting bone marrow, like myelofibrosis, the marrow space is reduced, which can lead to problems with blood cell production.
• Osteophytosis: In cases of high bone mass associated with osteoarthritis, bone-forming features called osteophytes can appear in the joints.

Diagnosis of Increased Bone Mass

Determining the cause of increased bone mass requires a thorough diagnostic process involving several types of tests.

Medical Tests Used for Evaluation

• Dual-energy X-ray Absorptiometry (DEXA) Scan: While primarily used to diagnose osteoporosis, a DEXA scan can also reveal an unusually high T-score, prompting further investigation.
• X-rays and CT Scans: Conventional radiography can show generalized or localized areas of increased bone density, with CT providing more detailed images.
• Blood Tests: Blood work can check for conditions like kidney disease, hormonal imbalances (PTH, thyroid), or high calcium levels (hypercalcemia) that could be related to the bone changes.
• Bone Biopsy: In some cases, a small sample of bone tissue is removed and examined to determine the specific cause of the increased density.

High Peak Bone Mass vs. Pathological Osteosclerosis

Feature	High Peak Bone Mass	Pathological Osteosclerosis (e.g., Osteopetrosis)
Cause	Primarily genetic predisposition and lifestyle factors in youth	Genetic mutations, metabolic disorders, or acquired illnesses
Symptom Profile	Generally asymptomatic, often considered a protective factor against osteoporosis	Can cause pain, nerve impingement, fractures, and blood cell production issues
Bone Quality	Dense and structurally strong	Dense but often brittle or structurally compromised due to flawed remodeling
Diagnosis	Identified via DEXA scan showing high BMD; often no further investigation needed	Requires further testing (imaging, blood tests, biopsy) to identify the specific underlying condition
Treatment	No treatment needed; focus is on maintaining bone health	Management of the underlying condition; therapies to address specific symptoms or complications

Treatment and Management

Treatment for increased bone mass is entirely dependent on its cause. If a diagnostic workup reveals that the high bone density is simply a reflection of a healthy, robust skeleton and not a pathological process, then no specific treatment is required.

However, if an underlying condition is identified, management focuses on treating that disorder. For example, some rare genetic conditions like osteopetrosis may involve symptom-based supportive therapy to manage complications such as cranial nerve issues or fractures. In cases where increased bone mass is secondary to other diseases, such as myelofibrosis, treatment is directed at managing the primary illness. For those who are simply trying to maintain bone health and have a high peak bone mass, proper nutrition and exercise are always beneficial.

For more information on general bone health and prevention of osteoporosis, you can consult authoritative health sources like the National Institute of Health, which provides guidance on maintaining healthy bones throughout your life. For specific concerns about high bone mass, a consultation with a healthcare professional is always recommended to determine the underlying cause and the most appropriate course of action.

Conclusion

While a higher than average bone mass may sound like a universally positive attribute, it is a medical finding that warrants careful attention. Increased bone mass can range from a beneficial genetic trait offering protection against osteoporosis to a sign of a serious, underlying disease that can paradoxically weaken bones. Through comprehensive diagnostic testing, medical professionals can differentiate between these causes and recommend the appropriate management, ensuring that what appears to be a strong skeleton truly is.

Visit the NIH website for more information on bone health and diseases.

Frequently Asked Questions

Is increased bone mass a good or bad thing?

It depends. For some, increased bone mass is a positive sign of having reached a high peak bone mass in youth, which helps prevent osteoporosis. For others, it's a symptom of an underlying disease that can cause bones to be abnormally dense but fragile.

What is osteosclerosis?

Osteosclerosis is a pathological condition characterized by abnormal bone hardening and density. Unlike high peak bone mass, which typically results in strong bones, osteosclerotic bone can be structurally flawed and more prone to fractures.

How is high bone density diagnosed?

Diagnosis starts with a DEXA scan, which measures bone mineral density. If the results are unusually high, a doctor will likely order additional tests, including X-rays, blood work, or even a bone biopsy, to find the underlying cause.

Can diet and exercise cause high bone density?

Yes, a healthy diet rich in calcium and vitamin D combined with weight-bearing exercise can help you build and maintain a high peak bone mass in your younger years. However, lifestyle changes are not the cause of pathologically high density from a disease.

What is the difference between high bone mass and osteopetrosis?

High bone mass is a general term for high bone mineral density, which can be benign. Osteopetrosis is a rare genetic disease that causes high density due to faulty bone resorption by osteoclasts, leading to brittle and fragile bones.

Do I need treatment for increased bone mass?

Treatment is only necessary if the high bone mass is a symptom of an underlying medical condition. If it is determined to be a benign, healthy trait, no treatment is needed, but monitoring and good bone health practices are still important.

What are the health risks associated with pathological increased bone mass?

Depending on the cause, risks can include a higher propensity for fractures despite dense bones, complications from bone marrow dysfunction, and nerve compression. A medical professional will explain specific risks based on the diagnosis.