Early growth characteristics and the risk of reduced lung function and asthma: A meta-analysis of 25,000 children.

Background: Children born preterm or with a small size for gestational age are at increased risk for childhood asthma.

Objective: We sought to assess the hypothesis that these associations are explained by reduced airway patency.

Methods: We used individual participant data of 24,938 children from 24 birth cohorts to examine and meta-analyze the associations of gestational age, size for gestational age, and infant weight gain with childhood lung function and asthma (age range, 3.