The Importance of Body Composition in Cystic Fibrosis

The Importance of Body Composition in Cystic Fibrosis 150 150 Mary Bates, PhD

Lean mass deficits are common in pediatric patients with cystic fibrosis and associated with impaired lung and bone health. Now, experts are calling for increased use of body composition measurements in clinical care. 

In cystic fibrosis — a multisystem disorder characterized by progressive lung disease, pancreatic insufficiency, malabsorption and malnutrition — nutrition status is correlated with clinical outcomes and survival. While body mass index (BMI) is commonly used as a tool to reflect nutrition status, this measure has limitations, as it does not accurately reflect body composition.

“Increasingly, body composition, in addition to weight and BMI, has become more important in clinical medicine,” says Ala Shaikhkhalil, MD, an attending pediatric gastroenterologist and physician nutrition specialist at Nationwide Children’s. “Body composition has been tied to clinical outcomes in many disease processes, particularly cystic fibrosis.”

Although assessing body composition is now recommended in the 2020 U.S. Dietary Guidelines, there is a paucity of research on body composition in cystic fibrosis, especially in children.

To address this gap, Dr. Shaikhkhalil and colleagues conducted a retrospective review of over 100 pediatric patients with cystic fibrosis seen at Nationwide Children’s between 2015 and 2020. The researchers took advantage of data gathered from these patients’ dual-energy X-ray absorptiometry (DXA) scans. DXA scans are primarily used to monitor patients’ bone mineral density, but also provide information on their body composition. The research team extracted body composition parameters from the DXA scan reports and explored their relationship to clinical parameters including lung function, bone mineral density and hospital admissions.

Although this cohort of children with cystic fibrosis was relatively healthy (as defined by pulmonary function and BMIs), the researchers found a high prevalence of lean mass (sometimes referred to as fat-free mass) deficits. What’s more, the patients with fat-free mass deficits had lower lung and bone mineral density and tended to have more hospital admissions.

“We found that close to 40% of this cohort had fat-free mass deficits, and their lung function was approximately 10% lower than their counterparts without those deficits,” says Dr. Shaikhkhalil, who is also an associate professor of clinical pediatrics at The Ohio State University College of Medicine. “This size change in someone’s lung function in cystic fibrosis is extremely significant. If two people have ten points difference on their lung function, their clinical course can be very different.”

The results suggest that using BMI as the primary marker of nutrition status in patients with cystic fibrosis has limitations, says Susan Gemma, MS, RD, LD, a clinical dietitian in the Cystic Fibrosis Center at Nationwide Children’s and one of the study’s co-authors.

“Currently, if bone density is within the normal range, the standard of care for obtaining DXA scans is every five years after the age of 8 years,” she says. “If we incorporate assessing body composition into standard practice, we may be able to identify patients who may benefit from interventions earlier. These patients could receive recommendations to increase physical activity to minimize the fat-free mass deficits.”

The researchers conclude that it is time to view body composition as a marker of nutritional status in cystic fibrosis. They say that implementing measures of body composition into routine clinical practice is needed, whether that is with more regular DXA scans, biomarkers or some other tool. Once cystic fibrosis patients with fat-free mass deficits are identified, interventions based on nutrition or physical exercise can be initiated to help optimize health outcomes.



Ritchie H, Nahikian-Nelms M, Roberts K, Gemma S, Shaikhkhalil A. The prevalence of aberrations in body composition in pediatric cystic fibrosis patients and relationships with pulmonary function, bone mineral density, and hospitalizations. Journal of Cystic Fibrosis. 2021 Sep;20(5):837-842.







About the author

Mary a freelance science writer and blogger based in Boston. Her favorite topics include biology, psychology, neuroscience, ecology, and animal behavior. She has a BA in Biology-Psychology with a minor in English from Skidmore College in Saratoga Springs, NY, and a PhD from Brown University, where she researched bat echolocation and bullfrog chorusing.