Characteristics of symptom dynamic phenotypes and reference phenotypes
| Phenotype 1 | Phenotype 2 | Phenotype 3 | p-value | |||||
| Dynamic (n=145) | Reference (n=147) | Dynamic (n=135) | Reference (n=128) | Dynamic (n=42) | Reference (n=47) | Dynamic | Reference | |
| Respiratory symptoms | ||||||||
| Weeks with severe symptoms | 0.22±0.43 | 0.14±0.37 | 0.82±1.03 | 0.87±0.98 | 2.11±1.64 | 2.14±1.53 | <0.001 | <0.001 |
| Weeks with any symptoms | 1.84±1.58 | 1.57±1.09 | 7.03±3.64 | 6.61±1.96 | 12.19±3.56 | 13.87±3.03 | <0.001 | <0.001 |
| Respiratory symptoms transition states | ||||||||
| Entropy of transition states | 0.08±0.05 | 0.13±0.16 | 0.56±0.14 | 0.54±0.25 | 1.03±0.12 | 0.91±0.23 | <0.001 | <0.001 |
| Risk factors | ||||||||
| Male sex | 50.3 | 43.5 | 49.6 | 56.3 | 64.3 | 65.9 | 0.223 | 0.012 |
| Siblings | 37.2 | 38.1 | 57.1 | 53.9 | 66.7 | 72.4 | <0.001 | <0.001 |
| Caesarean section | 24.8 | 23.8 | 10.4 | 10.2 | 9.5 | 12.7 | 0.002 | 0.008 |
| Maternal asthma | 9.6 | 8.8 | 9.6 | 10.2 | 16.7 | 17.1 | 0.385 | 0.278 |
| Maternal atopy | 37.2 | 33.3 | 34.8 | 35.9 | 35.7 | 44.7 | 0.914 | 0.370 |
| Childcare | 13.7 | 11.5 | 19.3 | 20.3 | 38.1 | 40.4 | 0.006 | <0.001 |
| Maternal smoking during pregnancy | 7.6 | 6.8 | 8.2 | 10.2 | 11.9 | 8.5 | 0.668 | 0.606 |
| Parental smoking during infancy | 24.8 | 23.1 | 15.5 | 20.3 | 30.9 | 21.3 | 0.051 | 0.805 |
| Breastfeeding ≤26 weeks | 21.4 | 20.4 | 21.5 | 23.4 | 23.8 | 21.3 | 0.941 | 0.829 |
| Low maternal education | 64.1 | 61.9 | 62.2 | 64.1 | 59.5 | 61.7 | 0.851 | 0.983 |
| Season of birth | ||||||||
| Spring | 25.5 | 26.5 | 31.1 | 27.3 | 19.1 | 27.7 | 0.264 | 0.983 |
| Summer | 22.1 | 18.4 | 27.4 | 35.9 | 33.3 | 21.3 | 0.289 | 0.003 |
| Autumn | 35.8 | 35.4 | 16.3 | 15.6 | 14.3 | 17.1 | <0.001 | <0.001 |
| Winter | 16.5 | 19.7 | 25.2 | 21.1 | 33.3 | 34.1 | 0.042 | 0.111 |
| Outcomes at 6 year follow-up | ||||||||
| Any wheezing# | 27.6 | 22.4 | 28.9 | 38.3 | 64.3 | 51.1 | <0.001 | <0.001 |
| Current wheezing¶ | 9.6 | 8.8 | 9.6 | 11.7 | 26.2 | 21.3 | 0.008 | 0.071 |
| Atopic disease+ | 35.4 | 36.3 | 37.1 | 39.4 | 46.3 | 36.2 | 0.449 | 0.855 |
| SPT positive§ | 13.3 | 14.5 | 12.3 | 13.1 | 19.4 | 13.2 | 0.545 | 0.942 |
Data are presented as % or mean±sd. Symptom dynamic phenotypes were defined by the average entropy of transition states and reference phenotypes by weeks with any respiratory symptom. Differences in the distribution of characteristics across phenotypes were assessed using Chi-squared tests for categorical variables and Kruskal–Wallis tests for continuous variables. Significant p-values at the Bonferroni-corrected α-level of 0.017 are shown in bold. SPT: skin-prick test. #: defined as any wheezing episode between one and 6 years of age; ¶: defined as wheezing over the past 12 months before follow-up; +: defined as allergic rhinitis, allergic asthma, or atopic dermatitis before follow-up; §: a SPT was completed in a subset of 270 children.