Lung function in infants with cystic fibrosis diagnosed by newborn screening.
BACKGROUND
Progressive lung damage in cystic fibrosis (CF) starts in infancy, and early detection may aid preventative strategies.


OBJECTIVE
To measure lung function in infants with CF diagnosed by newborn screening and describe its association with pulmonary infection and inflammation.


METHODS
Infants with CF (n = 68, 6 weeks to 30 months of age) and healthy infants without CF (n = 49) were studied. Forced vital capacity, FEV(0.5), and forced expiratory flows at 75% of exhaled vital capacity (FEF(75)) were measured using the raised-volume rapid thoracoabdominal compression technique. Forty-eight hours later, infants with CF had bronchoalveolar lavage (BAL) for assessment of pulmonary infection and inflammation.


RESULTS
In the CF group, the deficit in FEV(0.5) z score increased by -0.77 (95% confidence interval, -1.14 to -0.41; P < 0.001) with each year of age. The mean FEV(0.5) z score did not differ between infants with CF and healthy control subjects less than 6 months of age (-0.06 and 0.02, respectively; P = 0.87). However, the mean FEV(0.5) z score was lower by 1.15 in infants with CF who were older than 6 months of age compared with healthy infants (P < 0.001). FVC and FEF(75) followed a similar pattern. Pulmonary infection and inflammation in BAL samples did not explain the lung function results.


CONCLUSIONS
Lung function, measured by forced expiration, is normal in infants with CF at the time of diagnosis by newborn screening but is diminished in older infants. These findings suggest that in CF the optimal timing of therapeutic interventions aimed at preserving lung function may be within the first 6 months of life.
Linnane
Barry M
BM
Department of Respiratory Medicine, Royal Children's Hospital Melbourne, Parkville, Australia.
Hall
Graham L
GL
Nolan
Gary
G
Brennan
Siobhan
S
Stick
Stephen M
SM
Sly
Peter D
PD
Robertson
Colin F
CF
Robinson
Philip J
PJ
Franklin
Peter J
PJ
Turner
Stephen W
SW
Ranganathan
Sarath C
SC
D001992:Bronchoalveolar Lavage Fluid / Q000166:cytology; D001999:Bronchoscopy; D002452:Cell Count; D002675:Child, Preschool; D003550:Cystic Fibrosis / Q000175:diagnosis / Q000503:physiopathology*; D005260:Female; D005541:Forced Expiratory Volume / Q000502:physiology*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008403:Mass Screening / Q000379:methods*; D011379:Prognosis; D012720:Severity of Illness Index; D014797:Vital Capacity / Q000502:physiology*