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

•Lean body mass is a significant predictor of pulmonary function in adolescent with cystic fibrosis.•Pulmonary function was weakly correlated with body mass index in preadolescent and adolescent patients with cystic fibrosis.•Fat mass was not associated with pulmonary function in non-adult patients with cystic fibrosis. 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. 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. FEV1 was significantly associated with total (r = 0.68, P