Early childhood wheezing is associated with lower lung function in cystic fibrosis

OBJECTIVE: To study the association between wheezing in children with cystic fibrosis (CF) and lung function in later life. METHODS: We used data from the Epidemiologic Study of CF, a longitudinal observational study from 1994 to 2005. Wheezing phenotypes were defined as: no wheezing in the first 6 years of life (NW), transient wheezing (TW; wheezing <3 years old, but no wheezing after 3), late wheezing (LW; wheezing only after age 3 years), and persistent wheezing (PW; wheezing both before and after age 3 years). A linear regression model was developed predicting the best forced expiratory volume in 1 sec (FEV1 ) at age 6 or 7 years (6 to <8) for each wheezing phenotype. RESULTS: A total of 1302 children met the cohort inclusion criteria; 61% of the cohort had wheezing in the first 6 years of life. A history of any wheezing in the first 6 years of life was associated with a significantly lower FEV1 at 6 to <8 years compared to children with NW. The FEV1 of children with NW at age 6 to <8 years was 104% predicted, whereas the mean FEV1 in TW, LW, and PW groups was 98%, 100%, and 96% predicted, respectively (P < 0.05 compared to NW). CONCLUSIONS: Childhood wheezing in CF is common and is associated with lower lung function at age 6 to <8 years. Our results identify a clinical feature in early childhood CF associated with lower lung function in later life.