Lung function after extremely preterm birth-A population-based cohort study (EXPRESS)

Pediatr Pulmonol. 2018 Jan;53(1):64-72. doi: 10.1002/ppul.23919. Epub 2017 Nov 20.


Background and objectives: Follow-up studies of children and young adults born very-to-moderately preterm show persistent and significant lung function deficits. The aim of the study was to determine lung function and airway mechanics in school-aged children born in 2004 to 2007 and extremely preterm (after 22-26 weeks of gestation).

Methods: In a population-based cohort of children born extremely preterm and controls born at term (n = 350), follow-up at 6½-years-of-age was performed using spirometry and impulse oscillometry. Associations to gestational age, smallness for gestational age (SGA), and bronchopulmonary dysplasia (BPD) were assessed.

Results: Children born extremely preterm had lower forced vital capacity (FVC, z-score: -0.7, 95%CI: -1.0;-0.4), forced expiratory volume (FEV1 , z-score: -1.1, 95%CI: -1.4; -0.8), higher frequency-dependence of resistance (R5-20 , 0.09, 95%CI: 0.05; 0.12 kPa · L-1 · s-1 ) and larger area under the reactance curve (AX, 0.78, 95%CI: 0.49; 1.07 kPa · L-1 ) than controls. In children born at 22-24 weeks of gestation, 24% had FVC and 44% had FEV1 below the lower limit of normal. SGA and severe BPD only marginally contributed to pulmonary outcomes. Asthma-like disease was reported in 40% of extremely preterm children and 15% of controls.

Conclusion: Many children born extremely preterm have altered airway mechanics and significant obstructive reduction in lung function. This warrants consideration for treatment and continued follow-up.

Keywords: lung function tests; preterm birth; respiratory mechanics.

MeSH terms

  • Asthma / physiopathology
  • Bronchopulmonary Dysplasia / physiopathology
  • Child
  • Cohort Studies
  • Female
  • Follow-Up Studies
  • Forced Expiratory Volume
  • Humans
  • Infant, Extremely Premature / physiology*
  • Infant, Newborn
  • Lung / physiopathology*
  • Male
  • Premature Birth / physiopathology*
  • Respiratory Function Tests
  • Spirometry
  • Vital Capacity