A62-17 Association Between Growth Velocity During NICU Hospitalization and Long-Term Pulmonary Function in Children and Adults Following Preterm Birth

Rationale

Preterm infants are at risk for impaired postnatal growth and long-term respiratory morbidity, including bronchopulmonary dysplasia (BPD). Poor weight gain has been linked to adverse pulmonary outcomes, however the impact of early growth velocity on long-term lung function remains underexplored. This study evaluates whether early postnatal growth after preterm birth predicts pulmonary function in later childhood and adulthood among individuals born extremely preterm.

Methods

This nested retrospective cohort study of individuals born <32 weeks’ gestation or with birth weight <1500 g who participated in either the Cardiopulmonary Sequelae in Adolescents and Adults Born Premature Study (ABPS, ages 12-40 years) or the Cardiac Growth and Function Trajectories After Preterm Birth Study (CAPE, ages 8-30 years). Growth parameters (weight, length, head circumference) at birth and hospital discharge were collected from neonatal records and converted to percentiles using Fenton 2025 growth curves. Pulmonary function tests (spirometry and diffusion capacity) were obtained once at ages 8-40 years and converted to Z-scores using Global Lung Initiative reference values. Associations between NICU growth and pulmonary outcomes were assessed using multivariable linear regression and ANCOVA, adjusting for sex, gestational age, race, BMI at PFT.

Results

The cohort included 189 children and adults born preterm (mean PFT age 23 ± 6.9; mean GA 28.2 ± 2.6 weeks; BW 1125 ± 384 g). At NICU discharge, mean weight, length, and head circumference Z-scores declined from birth (Δ weight: -1.03 ± 0.99; Δ length: -1.44 ±1.14; Δ head circumference: -0.70 ± 0.94). At PFT, mean lung function Z-scores were (FVC: 0.47 ± 1.34, FEV₁: -0.16 ± 1.27, FEV₁/FVC: -0.92 ± 1.12). In adjusted models, no significant associations were found between NICU growth parameters and later pulmonary function. The strongest association was between Δ weight Z-score and FVC (β = 0.188, p = 0.103), FEV₁ (β = 0.037, p = 0.737), and FEV₁/FVC (β=-0.189, p = 0.065). ANCOVA showed no significant differences in pulmonary function across weight-gain tertiles (Figure 1).

Conclusions

Early postnatal growth velocity was not significantly predictive of later pulmonary function in this cohort despite notable declines in growth Z-scores during NICU hospitalization. These findings suggest that early somatic growth alone may not be a reliable marker for long-term pulmonary function, though larger studies are likely needed. Further research should explore other early-life factors and possible dysanaptic growth that may influence respiratory outcomes in this population.

This abstract is funded by: NIH