Trajectories of airflow limitation from childhood to early adulthood: an analysis of six population-based birth cohorts.

Summary

Across six birth cohorts (n=8114 discovery; n=1337 replication), four airflow-limitation trajectories from school age to early adulthood were identified: normal, persistent, worsening, and improved. Improvement tended to occur between middle childhood and adolescence, while worsening was more frequent from adolescence to early adulthood; BMI and wheeze status modified the probability of improvement.

Key Findings

• Four trajectories identified: normal (80.8%), persistent obstruction (15.8%), worsening (2.0%), and improved (1.5%).
• Improvement was more common from middle childhood to adolescence (57.8%), whereas worsening was more common from adolescence to early adulthood (61.5%).
• Higher BMI reduced improvement among current wheezers (RRR 0.69) but increased improvement among non-wheezers (RRR 1.38); low birthweight modified BMI effects depending on asthma status.

Clinical Implications

Integrate weight optimization and wheeze control in pediatric respiratory care, especially during middle childhood and adolescence, to shift individuals toward favorable lung-function trajectories and reduce future chronic airway disease risk.

Limitations

• Observational design limits causal inference; potential residual confounding.
• Spirometry protocols and population characteristics may vary across cohorts.

Future Directions

Intervention trials targeting weight and wheeze in specified developmental windows to test trajectory modification; validation in diverse ancestries and settings.