Body composition and pulmonary function in Cystic Fibrosis

• Main Authors: Saba eSheikh, Babette S Zemel, Virginia A Stallings, Ronald C Rubenstein, Andrea eKelly
• Format: Article
• Language: English
• Published: Frontiers Media S.A. 2014-04-01
• Series: Frontiers in Pediatrics
• Subjects: Body Mass Index; Lean Body Mass; Fat Mass Index; Lean Body Mass Index; Pancreatic Insufficient
• Online Access: http://journal.frontiersin.org/Journal/10.3389/fped.2014.00033/full

Background: Lower body mass index (BMI) is associated with worse pulmonary function in cystic fibrosis (CF). <br/>Hypothesis: Lean body mass (LBM) is more strongly associated with pulmonary function than BMI is.<br/>Methods: Anthropometrics, body composition by dual x-ray absorptiometry, and pulmonary function were determined in pancreatic insufficient CF (PI-CF) youth. Sex and age-adjusted Z-scores (BMI-Z, LBMI-Z, FMI-Z) were generated for CF and controls. 1) Associations of BMI-Z with LBMI-Z and FMI-Z and 2) age-adjusted associations of BMI-Z, LBMI-Z, and FMI-Z with FEV1%-predicted were tested. <br/>Results: 208 PI-CF subjects had lower BMI-Z, LBMI-Z, FMI-Z compared to 390 controls. BMI-Z was associated with lower LBMI-Z (p< 0.0001) in PI-CF. In females, LBMI-Z and BMI-Z were positively associated with FEV1%-predicted; this relationship did not persist for FMI-Z after adjustment for LBMI-Z. In males, only LBMI-Z and BMI-Z were associated with FEV1%-predicted. <br/>Conclusions: In PI-CF youth, deficits in LBM were apparent. At lower BMI percentiles, BMI may not accurately depict LBM in PI-CF. In under-nourished PI-CF youth this preservation of FM in preference to LBM is relevant since LBMI-Z, but not FMI-Z, is positively associated with FEV1%-predicted. LBMI is more strongly associated with lung function compared to BMI, especially in the undernourished child and adolescent with PI-CF. <br/>