Effect of late preterm birth on longitudinal lung spirometry in children

Introduction: Rates of preterm birth have increased in most industrialised countries (Goldenburgh, R.L. et al. Lancet 2008; 371:75-84) but data on later lung function of late preterm birth is limited. Aims and objectives: To compare lung function at 8-9 and 14-17 years in a population-based cohort of children born at 25-32, 33-34 and 35-36 weeks gestation with similar aged children born at term (≥37 weeks gestation). Methods: From the Avon Longitudinal Study of Parents and Children (ALSPAC, n = 14062), children who had spirometry at 8-9 (n=6712) and/or 14-17 (n=4513) years of age were divided into 4 groups: 25-32, 33-34, 35-36 and ≥37 weeks (term control) of gestation. Results: At 8-9 years of age, all spirometry measures (except FVC, in the 25-32 weeks gestation group) were significantly lower in both 25-32 and 33-34 weeks gestation groups compared to term controls (FEV 1 , mean z-score ± SD -0.461±0.876, -0.498±1.09 and 0.011±1.00 respectively). The 35-36 weeks gestation (FEV 1 0.008±0.908) and term groups had similar values. At 14-17 years of age, most spirometry measures in the 25-32 and 33-34 week gestation groups were not different from term controls except lower FEF 25-75 and FEF 25-75 /FVC in both 25-32 and 33-34 weeks gestation groups and lower FEV 1 /FVC in the latter group. Conclusions: Children born at 33-34 weeks gestation have significantly lower lung function values at 8-9 years of age similar to decrements observed in the 25-32 weeks group although most of these differences were reduced by 14-17 years of age.