By Robert Preidt

　　Thursday, February 16, 2006

　　THURSDAY, Feb. 16 (HealthDay News) —— Many healthy but premature infants younger than 12 weeks old have reduced lung function, a new Brazilian study finds.

　　"Preemie" boys are more likely to experience impaired lung capacity than girls, the researchers added, as are babies that quickly put on weight.

　　"There was a noticeable reduction in expiratory flows in the preterm groups compared with control infants and reference values," researcher Dr. Marcus H. Jones, of the Hospital Sao Lucas in Porto Alegre, said in a prepared statement.

　　The findings appear in the current issue of the American Journal of Respiratory and Critical Care Medicine.

　　The study involved 62 premature infants with no significant neonatal respiratory disease and 27 full-term infants.

　　Previous studies on full-term infants have noted reduced lung function in boys. After adjusting for gestational age and weight, Jones and his colleagues found that expiratory flows were 30 percent lower in the preterm male infants. The findings could help explain why preemie male babies have a higher risk of death from respiratory illness than girls, the researchers said.

　　Even premature infants who appear to have a healthy lung capacity may have some reduced function, the team noted. "The increased risk of wheezing, chronic cough and hospital readmissions early in life suggests that some degree of airway obstruction is present even in preterm infants without neonatal respiratory distress," Jones said.

　　He said the findings indicate that gestational age does have an independent effect on expiratory flows —— the amount of breath expelled by the lungs.

　　"There is up to a 7 percent increase [in expiratory flow] per week of gestation. It also reinforces the hypothesis that prematurity alone has an important role in the development of persistent airway obstruction," Jones said.