Study identifies how prednisone impairs bone health in children with muscular dystrophy

Prednisone has long been a cornerstone of treatment for Duchenne muscular dystrophy in children, slowing muscle decline and extending mobility during critical years. But the drug carries a steep hidden cost: it damages bone health precisely when children's skeletons are still forming. A new study published in Scientific Reports has now identified the biological mechanism behind this trade-off, offering clarity on why some children treated with prednisone develop weakened bones even as their muscles stabilize.

The research emerged from a double-blind clinical trial involving boys aged 4 to 7 with Duchenne muscular dystrophy. Over 48 weeks, participants received one of three treatments: placebo, prednisone at 0.75 milligrams per kilogram of body weight daily, or vamorolone, a newer drug designed specifically to treat the disease. After the first 24 weeks, those on placebo or prednisone switched to vamorolone, while the vamorolone group continued unchanged. The trial was led by an international team that included researchers from Binghamton University.

The findings were stark. Prednisone significantly suppressed four established markers of bone formation and turnover: alkaline phosphatase, osteocalcin, procollagen type I N-terminal propeptide, and collagen type I C-terminal telopeptide. These proteins are the body's way of signaling that bone is being built and remodeled. Neither vamorolone nor placebo produced this effect. When boys switched away from prednisone to vamorolone, the suppressed markers rebounded toward their baseline levels, suggesting the damage was reversible rather than permanent.

The researchers then cast a wider net, screening blood samples for additional proteins involved in bone and cartilage formation. They identified ten more proteins reduced by prednisone alone. Many of these are associated with osteoblasts, the cells that build bone, or with specialized cells in the growth plate—the cartilage region at the ends of children's long bones that drives their lengthening. Mutations in these same proteins can cause inherited skeletal disorders, hinting at how fundamental they are to normal development.

The pattern was consistent and reversible. As Utkarsh Dang, the study's lead statistician, noted, the prednisone-associated changes appeared in both standard clinical tests and the broader protein analysis, and the markers moved back toward baseline after the drug was discontinued. This pattern pointed to a direct drug effect rather than disease progression. Prednisone appears to promote the loss of growth-plate cells and interfere with osteoblast function—mechanisms that vamorolone does not trigger.

Yet the study carries important limitations. It involved a smaller subset of the overall trial population, focused exclusively on young boys, and was not designed to measure whether these biomarker changes translate into actual fractures or loss of skeletal strength over years or decades. The researchers cannot yet say whether the proteins reliably predict future bone problems or whether they behave the same way in girls or in children with other diseases that require corticosteroids.

Eric P. Hoffman, the senior author and associate dean for research at Binghamton University, emphasized that prednisone remains an important therapy for Duchenne muscular dystrophy—both prednisone and vamorolone improved motor outcomes in the trial. The difference is that only prednisone produced the adverse biomarker signature. Hoffman suggested these proteins could eventually become a practical tool for monitoring the biological health of the growth plate during treatment, and potentially in other pediatric conditions where corticosteroids or chronic disease interfere with normal growth.

The next step is clear: larger, longer studies will be needed to determine whether these biomarkers actually predict subsequent changes in bone health later in life, and whether they perform similarly across different populations. For now, the research has illuminated a mechanism that clinicians and families have long observed but not fully understood—the painful paradox that a drug that helps children move can simultaneously weaken the skeleton that carries them.