Design of the cohort study
The original cohort consisted of 100 children aged younger than 24
months who were hospitalized in 1992–1993 because of a first wheezing
episode associated with LRTI.14 The study was
performed in Kuopio University Children’s Hospital, Finland. After the
index episode, the cohort was prospectively followed-up at four control
visits: one year after the index episode14 and again
at median ages of 4.0 years,15 7.2
years12 and 12.3 years.16 In 2010,
49 cohort subjects aged 17–20 years attended the last follow-up
visit.17 Supplementary E-figure 1 provides information
on the asthma status of the participants from 1992 to 2010. All the
analyses in the current study include the data on the 49 participants
who attended the clinical follow-up visit in 2010 at a mean age of 18.8
years.