Abnormal* LF | Normal LF | |||
(n=37) | (n=13) | p Value† | ||
Median (range) age (years) | 3.1 (2.8–3.6) | 3.1 (3.0–3.7) | 0.490 | Mann–Whitney U test |
Parental smoking | 13 (35%) | 5 (38%) | 0.933 | Fisher exact test |
Male | 25 (68%) | 9 (69%) | 0.912 | Fisher exact test |
Airway symptoms | ||||
Ongoing wheeze | 18 (49%) | 3 (23%) | 0.191 | Fisher exact test |
Ongoing cough/dyspnoea | 18 (49%) | 2 (15%) | 0.05 | Fisher exact test |
Ongoing airway symptoms | 36 (97%) | 4 (31%) | <0.001 | Fisher exact test |
Reported use of ICS | 37 (100%) | 6 (46%) | <0.001 | Fisher exact test |
Regular | 27 (73%) | 4 (31%) | 0.018 | Fisher exact test |
Periodic | 10 (27%) | 2 (15%) | 0.480 | Fisher exact test |
Purchase of asthma medication‡ | ||||
Median (IQR) ICS (mg) | 60 (80) | 0 (40) | 0.009 | Mann–Whitney U test |
Median (IQR) inhaled β agonists (mg) | 40 (120) | 0 (40) | 0.002 | Mann–Whitney U test |
Skin prick test positive (n=49) | 10 (27%) | 6 (46%) | 0.304 | Fisher exact test |
Oscillometry (N) | 29 | 10 | ||
Median (IQR) Rrs5 (kPa/l/s) | 1.2 (0.21) | 1.26 (0.32) | 0.357 | Mann–Whitney U test |
Median (IQR) Rrs5 (Z-score) | 0.43 (1.11) | 0.64 (1.32) | 0.217 | Mann–Whitney U test |
Median (IQR) Xrs5 (kPa/l/s) | −0.40 (0.17) | −0.42 (0.17) | 0.384 | Mann–Whitney U test |
Median (IQR) Xrs5 (Z-score) | −0.10 (2.53) | −0.54 (1.90) | 0.335 | Mann–Whitney U test |
Abnormal LF§ at 3 years | 8/29 (28%) | 3/10 (30%) | 1.0 | Fisher exact test |
Bold denotes p<0.05.
↵* Abnormal LF in infancy defined as reduced LF (specific airway conductance sGaw Z-score <−1.65).
↵† Fisher exact test for dichotomous variables and Mann–Whitney U test for continuous variables. The comparisons are between abnormal and normal LF; p values are not corrected for multiple comparison.
↵‡ Purchase of asthma medication during third year of life.
↵§ Abnormal LF at 3 years of age defined as Rrs5 >1.65 SD of predicted or Xrs5 <1.65 SD.
ICS, inhaled corticosteroids; LF, lung function; Rrs5, respiratory resistance; Xrs5, respiratory reactance.