Bone Health in Duchenne Muscular Dystrophy

Bone health in Duchenne muscular dystrophy refers to the surveillance and management of low bone density and fracture risk that develop from reduced weight-bearing and long-term corticosteroid use. It involves periodic DEXA scans, spine imaging, vitamin D and calcium monitoring, and, in selected cases, bisphosphonate therapy.

Bone health is one of the quieter parts of DMD care. It rarely makes headlines, but it carries some of the highest stakes for daily life. A vertebral or long-bone fracture in a patient with DMD can mean weeks of immobilization, accelerated loss of function, and pain that lingers far beyond the radiographic healing.

This post explains why bone fragility is built into DMD, what surveillance looks like, and what families can ask of the care team.

Why bones are vulnerable in DMD

Two forces work against bone density in DMD at the same time.

First, reduced weight-bearing. Bone responds to mechanical load. As DMD progresses and walking becomes more difficult, the daily mechanical signal that maintains bone strength weakens.

Second, glucocorticoid therapy. Corticosteroids slow disease progression and are part of standard care for many patients, but they also reduce bone formation and increase resorption. The net effect over years is reduced bone mineral density and increased fracture risk, especially in the vertebrae.

Together, these mean that vertebral compression fractures and long-bone fractures can occur with minimal trauma, sometimes silently in the case of vertebral fractures.

For background on corticosteroid trade-offs, see corticosteroids in DMD and vamorolone explained.

Surveillance: DEXA, spine imaging, and vitamin D

The 2018 international care considerations recommend regular bone health surveillance for patients with DMD, including those on long-term corticosteroids. (Birnkrant et al., Lancet Neurology 2018, Part 3)

Components of surveillance typically include:

• Dual-energy X-ray absorptiometry (DEXA) of the lumbar spine, often annually after baseline.
• Lateral spine X-rays at intervals to detect vertebral fractures before they cause symptoms.
• Serum 25-hydroxyvitamin D and calcium monitoring.
• Pain history at each visit, with a low threshold for imaging if back pain appears.

The numbers from these tests are interpreted in context. Bone mineral density Z-scores in growing patients on glucocorticoids cannot be compared to general-population norms in the same way as in adults.

Vitamin D and calcium

Many patients with DMD have low vitamin D status, sometimes severely. The 2018 care considerations recommend monitoring 25-hydroxyvitamin D and supplementing when levels are insufficient. (Birnkrant et al., Lancet Neurology 2018, Part 3)

Calcium intake from diet and supplementation is also part of routine care, but doses should be individualized rather than maximized. Excess calcium is not free of risk and provides no extra benefit beyond replete intake.

Bisphosphonates and other interventions

For patients with vertebral fractures or severe declines in bone density, bisphosphonates may be considered. They can be given intravenously and have been studied in pediatric glucocorticoid-treated populations.

Bisphosphonate therapy is initiated and monitored by an endocrinologist or specialist familiar with pediatric bone disease, not by primary care alone. Decisions involve fracture history, density trends, growth status, dental health, and patient preferences.

For families with questions about treatment options, working through the neuromuscular team and a bone-health specialist together is the standard pattern.

Falls, weight, and mobility transitions

Practical risk reduction matters as much as medication.

Falls remain a major fracture mechanism. Home, school, and transport modifications that reduce fall risk are part of DMD care. Weight management is another lever: glucocorticoids contribute to weight gain, and excess body mass amplifies fall impact and respiratory load.

The transition from ambulation to wheelchair use is also a sensitive period for bone health. Loss of weight-bearing accelerates density loss. Continued standing programs, supported transfers, and individualized physiotherapy can help maintain some load on long bones during and after the transition.

Dental care and jawbone

Bone health includes the jaw. Dental decay, infections, and procedures intersect with bisphosphonate therapy in specific ways. Routine dental care, preventive cleaning, and coordination with the bone-health team before invasive dental procedures are important.

This is rarely discussed at neuromuscular visits and is worth raising explicitly.

What is still uncertain

Optimal thresholds for starting bisphosphonates, choice of agent, duration of therapy, and the long-term impact of newer steroid-sparing therapies on bone health are all active questions.

The reasonable framing is that bone health in DMD is monitored, preventable to a significant extent, and modifiable. The decisions belong to the care team working with current information for the individual patient.

For related reading, see DMD standards of care, corticosteroids in DMD, and respiratory care in DMD.

Disclaimer: This post is informational and does not constitute medical advice. Decisions about diagnosis or treatment must be made with a qualified care team.