Reduced Lung Function at Birth and the Risk of Asthma at 10 Years of Age
Geir Håland,*† Karin C. Lødrup Carlsen,*‡ Leiv Sandvik,§ Chandra Sekhar Devulapalli,*†‡ Monica Cheng Munthe-Kaas,*‡ Morten Pettersen,† Kai-Håkon Carlsen,†‡ and For Oraacle
(N Engl J Med, 355:1682-1689, 2006)
*Department of Pediatrics, Division of Woman and Child, Ulleval University Hospital, Voksentoppen, †Department of Pediatrics, Rikshospitalet-Radiumhospitalet Medical Center, Oslo, ‡Faculty of Medicine, University of Oslo, and §Center for Clinical Research, Ulleval University Hospital, Voksentoppen, Norway.
Reduced lung function in early infancy has been linked to obstructive airway diseases in later life. Whether reduced lung function shortly after birth predicts asthma 10 years later was assessed in a prospective birth cohort study of healthy infants in which lung function was measured shortly after birth using tidal breathing flow-volume loops (the fraction of expiratory time to peak tidal expiratory flow to total expiratory time [tPTEF/tE]) in 802 infants and passive respiratory mechanics, including respiratory-system compliance, in 664 infants. At age 10 years, 616 children (77%) were reassessed by measuring lung function, exercise-induced bronchoconstriction, and bronchial hyperresponsiveness (by methacholine challenge) and by conducting a structured interview to ascertain whether there was a history of asthma or current asthma. Compared with children whose tPTEF/tE shortly after birth was above the median, children whose tPTEF/tE was at or below the median were more likely at age 10 years to have a history of asthma (24.3% vs. 16.2%), to have current asthma (14.6% vs. 7.5%), and to have severe bronchial hyperresponsiveness, defined as a methacholine dose of less than 1.0 µmoL causing a 20% drop in the forced expiratory volume in 1 second (FEV1) (9.1% vs. 4.9%). Compared with children whose respiratory-system compliance was above the median, children with respiratory compliance at or below the median more often had a history of asthma (27.4% vs. 14.8%) and current asthma (15.0% vs. 7.7%), although this measure was not associated with later measurements of lung function. At 10 years of age, tPTEF/tE at birth correlated weakly with the maximal midexpiratory flow rate (r = 0.10) but not with FEV1 or forced vital capacity. Reduced lung function at birth is associated with an increased risk of asthma by 10 years of age.