Physical activity level in children born extremely preterm: a comparison
between children with and without bronchopulmonary dysplasia
Introduction: Children with a history of bronchopulmonary
dysplasia (BPD) may have lower physical activity levels, but evidence to
date is based on self-report. This study compared physical activity
levels between children born extremely preterm with and without history
of BPD, and examined their associations with pulmonary magnetic
resonance imaging (MRI) and pulmonary function test (PFT) indices.
Methods: This multi-centre cross-sectional study included
children aged 7-9 years born extremely preterm, with and without BPD.
Children wore a pedometer for one week, then completed the Physical
Activity Questionnaire (PAQ), pulmonary MRI, and PFT. Spearman
correlations and multivariable linear regression modelling were
performed. Results: Of 45 children, 28 had a history of
moderate-severe BPD. There were no differences in any physical activity
outcomes by BPD status. Higher average daily step count and higher
average daily moderate-vigorous physical activity (MVPA) were each
correlated with greater forced vital capacity (r=0.41 and 0.58), greater
MRI lung proton density at full expiration (r=0.42 and 0.49), and lower
lung clearance index (r=-0.50 and -0.41). After adjusting for MRI total
proton density and BPD status, a 5% increase in forced expiratory
volume at one second was associated with 738 (95%CI: 208, 1268) more
steps per day and 0.1 (0.0, 0.2) more hours of MVPA, respectively.
Conclusion: School-aged children born extremely preterm have
similar physical activity levels to their peers, regardless of history
of BPD. MRI and PFT measures suggestive of gas trapping and/or airflow
obstruction are associated with lower physical activity levels.