Tools and Methods Used for the Assessment of Body Composition in Patients With Cystic Fibrosis: A Systematic Review.

BACKGROUND: Cystic fibrosis (CF) is characterized by changes in fat mass and lean body mass that may have important prognostic value. We aim to appraise the type and frequency of application of body composition (BC) methods in child and adult patients with CF. METHODS: We used 4 databases (Embase, PubMed, Scopus, and Web of Science) to perform the literature search. The search was conducted from January 2017 to February 2017. Two independent reviewers selected articles based on titles and abstracts to check eligibility for inclusion. All study designs or types of articles (abstract, full text) were considered. RESULTS: Eighty-four full-text articles and 40 studies presented only as abstracts were selected. Sixty-four studies included children and adolescents (age range of 0.1-18 years), and 41 studies recruited adults (range of 18-57 years); 13 studies included both age groups. Dual-energy X-ray absorptiometry (DXA) was used in 56 studies (33.9%), and bioelectric impedance analysis (BIA) was used in 12 studies (9.7%), whereas 38 studies (30.6%) combined different methods (up to 5 different methods) to assess BC. CONCLUSIONS: The results show a large variability in the application of BC methods in patients with CF that makes the comparison between studies difficult. The only methods with a sufficient body of literature are DXA and BIA.

Association between body composition and pulmonary function in children and young people with cystic fibrosis.

OBJECTIVES: Body mass index (BMI) has significant limitations when assessing nutritional status in pediatric patients with cystic fibrosis (CF). We evaluated whether measurements of lean body mass (LBM) and fat mass (FM) are more sensitive nutritional parameters by testing their association with pulmonary function in adolescent patients with CF. METHODS: Sixty-nine male and female adolescents with CF were studied (age: 14.5 ± 2.3, BMI: 19.5 ± 2.3 kg/m2). Dual-energy x-ray absorptiometry (DXA) was used to measure total and segmental (appendicular, truncal) body composition (FM, LBM bone mineral density, and content) as routine care to monitor bone health. Correlation and multiple regression analyses were performed to assess the association among body composition variables and forced expiratory volume in 1 s (FEV1). We also evaluated the influence of the F508del mutation on body composition. RESULTS: FEV1 was significantly associated with total (r = 0.68, P <0.001), truncal (r = 0.71, P <0.001), and appendicular (r = 0.67, P <0.001) LBM, whereas it was not associated with total (r = 0.02, P = 0.89) and truncal (r = 0.04, P = 0.77) FM. BMI had a significant but weaker correlation with FEV1 (r = 0.52, P <0.001) compared with LBM. LBM was the only significant predictor of FEV1 in fully adjusted regression models. CONCLUSIONS: LBM is a significant predictor of pulmonary function in CF adolescent patients. DXA scanning performed as part of routine bone health monitoring in CF can provide important body composition data relevant to clinical interventions that optimize nutritional status. DXA reference data for LBM in non-adult populations are needed to enhance diagnostic assessment and monitor clinical progression of CF.