Nutritional status and pulmonary and respiratory muscle function in children and young people with cystic fibrosis

Abstract

Background: Nutritional status in cystic fibrosis (CF) is routinely assessed using the body mass index (BMI). Measurements of lean body muscle, e.g. fat free mass (FFM), may better correlate to lung and respiratory muscle function in CF (Sheikh S et al. Front Pediatr 2014;2:33). Portable bioelectrical impedance analysis (BIA) devices give body composition analysis avoiding exposure to ionising radiation. Aims: To evaluate whether FFM by BIA, rather than BMI, better correlate with pulmonary function, respiratory muscle strength and exercise capacity. Methods: BMI was calculated and body composition analysis obtained with the Inbody S10. Lung function was assessed by spirometry and respiratory muscle function data using the Micro RPM. Exercise tolerance was assessed with the modified shuttle walk test. Results: Twenty-seven children and young adults were assessed. Their (median, (range)) age was 15.3 (12.2-19.0) years, BMI z-score -0.09 (-2.20-1.19), FFM 37.00 (25.20-67.50) kg, fat mass 11.50 (4.20-21.50) kg, FEV 1 z-score -1.72 (-5.57-0.82), FVC z-score -0.94 (-5.84-1.08), maximum inspiratory pressure 78 (32-107) mmH 2 0, maximum expiratory pressure 104 (59-160) mmH 2 0, number of shuttles 88 (32-150). FFM, but not BMI correlated with lung function, respiratory muscle strength and exercise tolerance: Conclusion : Portable bioelectrical impedance analysis may provide important body composition analysis results in CF patients.