Table 1

Details of the datasets and study populations in the USA and UK, respectively

US dataUK data
Sample size94633055
No of FEV1 measures per person
(median (IQR), (full range))
24 (11–40), (1–199)4 (2–7), (1–17)
No of individuals with one FEV1 measure (%)251 (2.7)398 (13.0)
No of FEV1 measures per person per year (median (IQR))4 (3–6)1 (1–1)
Time in years between first and last FEV1 measurement included in the study per person (median (IQR))*5.5 (2.7–8.4)4.9 (2.2–7.5)
Informative drop-out during study period (%)
Lung transplants142 (1.5)27 (0.9)
Deaths263 (2.8)70 (2.3)
Sex (%)
Female4625 (48.9)1457 (47.7)
Male4838 (51.1)1598 (52.3)
Year of birth (median) (IQR)1996 (1991–2002)1996 (1991–2002)
Race (%)
Non-Caucasian384 (4.1)71 (2.3)
Caucasian9083 (95.9)2984 (97.7)
Age at diagnosis in years (median (IQR))0.3 (0.0–1.2)0.2 (0.0–1.0)
Diagnosis by newborn screening (%)1079 (11.4)501 (16.3)
%FEV1 at age 6 (mean (SD))92.96 (17.7)88.17 (16.9)
  • *Excluding individuals with only one FEV1 measurement.

  • FEV1, forced expiratory volume in 1 s.