When children have diabetes, kidney disease, inflammatory bowel disease or cancer, their doctors and families focus first on keeping the patients alive in the short term. But caregivers also need to consider long-term consequences, including the fact that these chronic diseases, and many others, exact a quiet toll on kids' bones.
Stanford scientist Mary Leonard, MD, who chairs our Department of Pediatrics, has devoted her research career to understanding how chronic diseases weaken children's bones, and what we can do about it. Chronic diseases can hurt the bones in many ways: They may interfere with metabolism of bone-building minerals, require treatments with bone-damaging side effects, cause ongoing inflammation that hurts the bones, or stop children from doing the walking, running and jumping that prompt kids' bones to get stronger.
Leonard's team is gathering detailed measurements to help them uncover exactly what goes awry in several chronic diseases of childhood, as I learned on a recent tour of her lab. One of the highlights of my visit was seeing the team's high-resolution CT scanner for arm and leg bones, the only such machine west of Missouri. A story I wrote explains how it's contributing to their work:
'High-resolution CT scans help us understand why the bones are weak,' Leonard said. 'Is it because the shell of the bone is thin? Is it not dense enough? Does it have pores or holes it shouldn’t have?' These details are telling: Inflammation leaves one type of damage traced on the bone, steroid medications leave another. Vitamin D deficiency looks different, too. 'If we understand the underpinnings of the fragility, it gives us insight into the mechanism of bone damage,' she said.
Once the mechanism of damage is clear, it's easier for doctors to suggest the best bone-preserving approaches for each disease.
The good news is that improved treatments for many chronic childhood diseases have already given patients much longer, healthier lives than they would have had a generation ago. Candice Sheldon, MD, who works with Leonard, told me why, in that context, it makes sense to keep focusing on what's happening with kids' bones:
'Bone fractures are painful, and the young patients we’re studying are already dealing with so many other medical problems,' said Sheldon. 'Ultimately, we want to strengthen their bones so they can be happier and more active in childhood and throughout their adult lives as well.'
Photo of study subject courtesy of the Leonard lab