Low bone mineral density and fractures are common among people with Duchenne muscular dystrophy (DMD) and need better treatment strategies, according to a systematic review and meta-analysis published in Osteoporosis International.
Across the studies analyzed, 62% of people with DMD had low bone mineral density (BMD), a measure of bone strength, and 38% experienced fractures.
DMD often means long-term treatment with glucocorticoids. These medications can help preserve muscle function but can also weaken bones. Reduced mobility adds to that risk because bones receive less of the mechanical loading that normally helps maintain their strength.
Sign up here to get the latest news, perspectives and information about Duchenne sent directly to your inbox. Registration is free and only takes a minute.
Researchers reviewed 43 studies involving 4,940 people with DMD from 15 countries. Across the studies, the proportion of people with DMD who had low BMD ranged from 16% to 93%, while fracture prevalence ranged from 7% to 87%. Vertebral fractures, which affect the bones of the spine, occurred in an estimated 21% of patients. Fractures outside the spine occurred in about 24%.
Fractures were more common among participants treated with glucocorticoids: 39% had experienced a fracture, compared with 23% of participants who did not receive the medications.
Read more about bone fracture risk in DMD
Fracture prevalence also increased with longer glucocorticoid exposure. Fractures occurred in an estimated 23% of people treated for less than three years, 33% of those treated for three to six years and 59% of those exposed for six years or longer.
The researchers stressed that factors beyond glucocorticoid use contribute to bone fragility in DMD. Studies also linked poorer bone health to older age, reduced muscle function, loss of ambulation and low vitamin D levels. They also linked increased body fat, abnormal calcium metabolism and hormonal imbalances to poorer bone health.
Strategies to protect bone health in DMD include vitamin D and calcium supplementation and weight-bearing exercise. The most appropriate approach depends on a person’s individual needs and bone health.
Regular bone monitoring is also important, as vertebral fractures can occur without noticeable symptoms. Bisphosphonates, medications that help slow bone loss, can improve bone mineral density in people with osteoporosis caused by glucocorticoids. However, whether these medications reduce fracture risk remains unclear.
The review’s authors called for further research into ways to protect bone health in Duchenne. “Given the high burden of bone loss and fractures, clinical trials of bone-protective therapies and strategies to improve bone health in boys with DMD are urgently warranted,” they said.
