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Study aims to determine safe level of exercise for children with sickle cell anemia
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A multicenter study is underway to determine whether there is a safe level of exercise for children and adolescents with sickle cell anemia.
The 5-year study — funded by a $2.7 million grant from NHLBI — will examine the effect of exercise intensity on inflammation in 140 children, half of whom have sickle cell anemia.
Researchers also will assess for evidence of exercise-induced asthma after exercise and evaluate inflammation pathways on the genetic level to identify whether specific genes are triggered by exercise.
“Most children with sickle cell anemia miss out on the important benefits of exercise because of unsubstantiated fears that it might be harmful in their condition. Our study will be the first step toward developing safe exercise guidelines for these children,” Robert I. Liem, MD, MS, director of the comprehensive sickle cell program at Ann and Robert H. Lurie Children’s Hospital of Chicago and associate professor of pediatrics at Northwestern University Feinberg School of Medicine, said in a press release. “If we can establish the safety of exercise in children with sickle cell anemia, then parents and providers can feel more comfortable allowing them to be more active in gym class or participate in school sports. This can have a substantial impact on their quality of life.”
HemOnc Today spoke with Liem about how the study came about, how it will be conducted, when results may be available and the potential implications of the results.
Question: How did this study come about?
Answer: I have been a pediatric hematologist for some time now and have focused on caring for children with sickle cell disease. I have always been interested in exercise capacity in this patient population, partly because when I finished my fellowship training, I was interested in early cardiopulmonary disease in adolescents and young adults. From there, I became interested in trying to understand the impact of complications — such as heart and lung disease — on physical functioning, and specifically on exercise limitation. After reviewing the literature, I found a huge gap in our knowledge about exercise ability among children and adults with sickle cell disease. There is this unsupported assumption that too much physical exertion may cause these patients to develop sickle cell–related complications, such as pain episodes. Like many patient populations with chronic illness, patients with sickle cell disease often have been told they should not exert themselves physically. That is because sickle cell disease is associated with higher levels of inflammation, which can further increase during exercise and vigorous physical activity. This study will help us clarify if that is, in fact, what happens.
Q: How will you conduct the study?
A: The study is designed to look specifically at the relationship between exercise intensity and inflammation in the body. We will enroll 70 children and adolescents with sickle cell anemia, as well as 70 matched controls without sickle cell anemia or sickle cell trait. Each participant will undergo a series of cycle exercise tests. We will measure biomarkers and perform genomic studies to assess how exercise at different intensities affects inflammation in someone with sickle cell anemia. Because asthma is prevalent in this population, we are interested to see whether someone with sickle cell anemia is more likely to develop signs and symptoms suggestive of exercise-induced asthma and if exercise intensity affects this relationship. We will assess whether these relationships are different between children with and without the disease.
Q: What will the exercise test entail?
A: First, participants will go through a maximal cardiopulmonary exercise test using a stationary cycle so we can determine their maximum fitness level. Half of the study population will be randomly assigned to a follow-up exercise test at moderate or vigorous intensity. During this test, they will do eight 2-minute bouts of exercise at either intensity, with 1-minute rest periods in between. Before and after exercise testing, we will draw blood to look at various biomarkers of inflammation, as well as genetic pathways for inflammation, to identify how they are affected by exercise intensity. We also will conduct lung function tests before and after exercise to determine whether there are changes that indicate exercise-induced asthma.
Q: What is your hypothesis?
A: We hypothesize that vigorous-intensity exercise will not be associated with greater increase in inflammation within the body compared with that seen with moderate-intensity exercise. We are trying to prove it is OK to push these kids to do higher-intensity exercise, and that it does not cause as much inflammation as some think it might. For the asthma part of this study, we hypothesize that children with sickle cell anemia will have a higher incidence of exercise-induced asthma than those without sickle cell disease. We do not know if that is the case, but we need to answer this very important question.
Q: What is the timeline for the study and when will data be available ?
A: We just received funding in April, so now we are developing the infrastructure for the study. There are four recruitment sites: our site, Columbia University, St. Jude Children’s Research Hospital and University of Illinois at Chicago. We hope to enroll starting in late fall. It then will take about 3 years to complete enrollment, after which we hope to have results we can share.
Q: What will future research entail?
A: My primary goal is to figure out how to develop evidence-based exercise prescription guidelines for children and adults with sickle cell disease. This study is looking at proving the safety of moderate- to high-intensity exercise. The next step is to use these data to determine if we can prescribe exercise on a regular basis and in a safe manner. I hope to develop a clinical trial of actual exercise training to see whether there are direct training benefits and disease-modifying effects for people with sickle cell disease.
Q: Is there anything else that you would like to mention?
A: When we look at the literature for other medical conditions, the role of exercise has been studied quite a bit, and people are starting to develop exercise guidelines for these patient populations. However, there are no clinical trials looking at exercise training in sickle cell disease. Before we can tell schools, providers, parents and coaches about the level of physical activity that is safe in this patient population, we really need to do the research to provide the evidence to support these recommendations. – by Jennifer Southall
For more information:
Robert I. Liem, MD, MS, can be reached at Ann and Robert H. Lurie Children’s Hospital of Chicago, 225 East Chicago Ave., Chicago, IL 60611; email: rliem@luriechildrens.org.
Disclosure: Liem reports no relevant financial disclosures.