History and Symptoms
Neonatal and maternal health data was obtained from medical records and
the KEMH neonatal database. Respiratory symptoms history was obtained
using validated general and respiratory questionnaires adapted from the
International Study of Asthma and Allergies in Childhood (ISAAC)
questionnaires.27 Respiratory symptoms such as wheeze,
shortness of breath, cough and rattly chest in the 3 months prior to the
participant’s study visit were parentally or self-reported, as
appropriate.