Airway function in infants newly diagnosed with cystic fibrosis

The lung function of infants with cystic fibrosis is often reduced shortly after diagnosis. We measured the airway function of newly diagnosed infants to test whether this reduction is independent of clinically recognised low er respiratory illness. We compared the airway function of 33 infants with cystic fibrosis and 87 healthy controls after adjustment for sex, age, body weight and length, and exposure to maternal smoking. Airway function was si gnificantly reduced in children with cystic fibrosis, even in those without clinically recognised previous lower respiratory illness. Our findings rai se important questions about the onset and natural history of impaired airw ay function in infants with cystic fibrosis.