Factors in childhood associated with lung function decline to adolescence in cystic fibrosis

Abstract

BackgroundDespite improvements in general health and life expectancy in people with cystic fibrosis (CF), lung function decline continues unabated during adolescence and early adult life. MethodsWe examined factors present at age 5-years that predicted lung function decline from childhood to adolescence in a longitudinal study of Australasian children with CF followed from 1999 to 2017. ResultsLung function trajectories were calculated for 119 children with CF from childhood (median 5.0 [25%-75%=5.0–5.1]) years) to early adolescence (median 12.5 [25%-75%=11.4–13.8] years). Lung function fell progressively, with mean (standard deviation) annual change -0.105 (0.049) for forced vital capacity (FVC) Z-score (p<0.001), -0.135 (0.048) for forced expiratory volume in 1-second (FEV1) Z-score (p<0.001), -1.277 (0.221) for FEV1/FVC% (p<0.001), and -0.136 (0.052) for forced expiratory flow between 25% and 75% of FVC Z-score (p<0.001). Factors present in childhood predicting lung function decline to adolescence, in multivariable analyses, were hospitalisation for respiratory exacerbations in the first 5-years of life (FEV1/FVC p = 0.001, FEF25–75p = 0.01) and bronchoalveolar lavage neutrophil elastase activity (FEV1/FVC% p = 0.001, FEV1p = 0.05, FEF25–75p = 0.02). No examined factor predicted a decline in the FVC Z-score. ConclusionsAction in the first 5-years of life to prevent and/or treat respiratory exacerbations and counteract neutrophilic inflammation in the lower airways may reduce lung function decline in children with CF, and these should be targets of future research.