Respiratory function at age 8-9 after extremely low birthweight or preterm birth in Victoria in 1997

Abstract

To determine if respiratory function at 8 years of age in extremely low birth weight (ELBW; birth weight <1,000 g) or extremely preterm (EPT, <28 weeks' gestation) children born in 1997 remains worse than normal birth weight (NBW; birth weight, >2,499 g) and term (37-42 weeks) controls, particularly in those ELBW/EPT children who had bronchopulmonary dysplasia (BPD). This was a cohort study of 201 consecutive ELBW/EPT survivors born in the state of Victoria during 1997, and 199 contemporaneous randomly selected NBW/term controls. Respiratory function was measured at 8 years of age according to standard guidelines, and compared with previous cohorts born in 1991-1992. Respiratory function data were available for almost 75% of both cohorts. ELBW/EPT subjects had substantial reductions in airflow compared with controls (e.g., mean difference in forced expiratory volume in 1 sec [FEV1 ] -0.91 SD, 95% confidence interval [CI] -1.19 to -0.63 SD, and in maximum expiratory flow between 25% and 75% of vital capacity [FEF25-75% ] -0.96 SD, 95% CI -1.22 to -0.71). These differences were similar to those observed between ELBW/EPT and controls subjects born in 1991-1992. Within the ELBW/EPT cohort, children who had BPD in the newborn period had significant reductions in both the FEV1 (-0.76 SD) and FEF25-75% (-0.58 SD) compared with those who did not have BPD, which were not statistically significant from those in the 1991-92 cohort. ELBW/EPT children born in 1997 still have significantly abnormal lung function compared with NBW/term controls, but results were similar to an earlier era when survival rates were lower. Pediatr Pulmonol. 2013; 48:449-455. © 2012 Wiley Periodicals, Inc.