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 (FEV ₁) 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 FEV ₁ at 6 to <8 years compared to children with NW. The FEV ₁ 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.