The Effect of Bronchopulmonary Dysplasia on Growth at School Age

Abstract

Objective. To determine the effect of bronchopulmonary dysplasia (BPD) on growth at school age. Design. A prospective cohort study. Methods. The sample included 406 children selected from a reconstructed cohort of infants of very low birth weight previously enrolled in a multisite, randomized, controlled clinical trial. The children were contacted at 8 to 10 years of age. Height, weight, and head circumference (HC) were measured. Possible confounders including sociodemographic data, and neonatal factors were also recorded. Results. The children in the BPD group were significantly smaller in weight (z score, -0.50 ± 1.19 SD vs -0.06 ± 1.30 SD) and HC (z score, -1.41 ± 1.32 SD vs -0.63 ± 1.62 SD) than those without BPD. However, after controlling for cofounders (using analysis of covariance), no significant differences were demonstrated between the two groups. Power analyses showed that a difference of at least 0.43 z score units could have been detected. The previously documented associations between BPD and suspected confounders were reconfirmed. Conclusions. Significant differences were noted between children with and without BPD for weight and HC but not height. When possible confounders were taken into account, the differences were no longer appreciated. Thus, the previously reported poor growth in children with BPD may have been related to other factors and not necessarily to BPD.