Body composition and lung function in cystic fibrosis and their association with adiposity and normal-weight obesity

• Type of Material: Article
• Authors: Jessica Alvarez, Emory University; Thomas Ziegler, Emory University; Erin C. Millson, Emory University; Arlene Stecenko, Emory University
• Language: English
• Date: 2015-10-29
• Publisher: SAGE Publications (UK and US)
• Publication Version: Author Accepted Manuscript (After Peer Review)
• Copyright Statement: © 2016 Elsevier Inc.
• License: Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International
• Final Published Version (URL): http://dx.doi.org/10.1016/j.nut.2015.10.012
• Title of Journal or Parent Work: Nutrition in Clinical Practice
• ISSN: 0884-5336
• Volume: 32
• Issue: 4
• Start Page: 447
• End Page: 452
• Grant/Funding Information: This work was supported, in part, by the Cystic Fibrosis Foundation grant CFF STECEN07A0 (AAS) and National Institutes of Health grants T32 DK007298 and K01 DK102851 (JAA), K24 DK096574 (TRZ), and UL1 TR000454 (Atlanta Clinical and Translational Science Institute).
• Keywords: FAT-FREE MASS; CHILDREN; ADULTS; Lung function; Cystic fibrosis; DEPLETION; MODEL; INDEX; Diet; POPULATION; NUTRITIONAL-STATUS; Nutrition & Dietetics; Obesity; Life Sciences & Biomedicine; Normal-weight obesity; Body composition; Science & Technology; GLUCOSE-TOLERANCE; AIR-DISPLACEMENT PLETHYSMOGRAPHY
• Research Categories: Health Sciences, Nutrition

Abstract

Objectives: This study aimed to evaluate the relationship between lung function and body composition in cystic fibrosis (CF) and examine the presence of normal-weight obesity (NWO), a high body fat percentage with a normal body mass index (BMI), in this population. Methods: In a pilot, cross-sectional study, 32 subjects with CF and a reference group of 20 adults without CF underwent body composition analysis with air displacement plethysmography. NWO was defined as a BMI <25 kg/m2 and body fat >30% (for women) or >23% (for men). Lung function in subjects with CF was determined by the percentage of predicted forced expiratory volume in 1 s (FEV1% predicted). Results: Despite lower BMI and fat-free mass index (P < 0.01), fat mass index and percent body fat did not differ between subjects with CF and the reference group. Among subjects with CF, FEV1% predicted was positively associated with fat-free mass index (β = 6.31 ± 2.93, P = 0.04) and inversely associated with fat mass index (β = -6.44 ± 2.93, P = 0.04), after adjusting for age, sex, and BMI. Ten subjects with CF (31%) had NWO, which corresponded with lower fat-free mass index and FEV1% predicted compared with overweight subjects (P = 0.006 and 0.004, respectively). Conclusions: Excess adiposity, particularly in the form of NWO, was inversely associated with lung function in CF. Larger prospective studies should be undertaken to confirm these findings and determine the long-term metabolic and clinical consequences of excess adiposity in CF. As the lifespan of individuals with CF increases, nutrition screening protocols, which primarily rely on BMI, may require reassessment.