Characteristics at birth, study enrolment and 2 years of age are reported stratified by the presence or absence of recurrent wheeze at 2 years of age
| Recurrent wheeze | No recurrent wheeze | p-value | |
| Participants | 143 (48.6%) | 151 (51.4%) | |
| At birth | |||
| Male sex | 96/143 (67.1%) | 85/151 (56.3%) | 0.06 |
| GA weeks | 38.6±2.4 | 38.5±4.0 | 0.95 |
| Born at GA <37 weeks | 14/110 (12.7%) | 15/116 (12.9%) | 0.96 |
| Birth weight g | 3347±632 | 3497±642 | 0.05 |
| At enrolment | |||
| Age days mean (range) | 134 (14–348) | 115 (7–363) | 0.05 |
| Weight g | 6650±1886 | 6245±1794 | 0.06 |
| Eczema | 15/131 (11.5%) | 14/140 (10.0%) | 0.70 |
| One previous episode of wheeze | 34/127 (26.8%) | 35/133 (26.3%) | 0.93 |
| Length of hospital stay h | 85±72 | 76±59 | 0.16 |
| Need of supportive treatment | 73/142 (51.4%) | 79/150 (52.7%) | 0.83 |
| Virus detected during acute bronchiolitis | |||
| RSV | 107/129 (82.9%) | 112/137 (81.8%) | 0.80 |
| HRV | 45/129 (34.9%) | 48/137 (35.0%) | 0.98 |
| HRV A or B | 12/129 (9.3%) | 16/137 (11.7%) | 0.53 |
| HRV C | 33/129 (25.6%) | 32/137 (23.4%) | 0.67 |
| RSV high genomic load | 68/129 (52.7%) | 77/137 (56.2%) | 0.57 |
| HRV high genomic load | 8/129 (6.2%) | 8/137 (5.8%) | 0.90 |
| More than one virus | 80/129 (62.0%) | 90/137 (65.7%) | 0.53 |
| Allergic sensitisation# | |||
| Any sensitisation | 9/130 (6.9%) | 13/141 (9.2%) | 0.49 |
| Any food sensitisation | 8/130 (6.2%) | 12/141 (8.5%) | 0.46 |
| Any inhalant sensitisation | 3/130 (2.3%) | 2/141 (1.4%) | 0.59 |
| Egg sensitisation | 5/130 (3.8%) | 3/141 (2.1%) | 0.40 |
| Cow's milk sensitisation | 4/130 (3.1%) | 9/141 (6.4%) | 0.20 |
| Peanut sensitisation | 1/141 (0.7%) | 2/130 (1.5%) | 0.52 |
| Polysensitisation | 4/130 (3.1%) | 3/141 (2.1%) | 0.62 |
| Monosensitisation | 4/130 (3.1%) | 9/141 (6.4%) | 0.20 |
| Cortisol mmol·L−1 geometric mean (95% CI) | 37.0 (30.2–45.4) | 33.7 (28.5–39.8) | |
| At the 2-year follow-up | |||
| Age days mean (range) | 747 (291–1055) | 725 (368–979) | 0.07 |
| Asthma diagnosed by physician | 51/143 (35.7%) | 5/151 (3.3%) | <0.001 |
| Asthma medication used | 108/134 (80.6%) | 28/142 (19.7%) | <0.001 |
| Parental education | |||
| Maternal education¶ | 3.93±0.94 | 4.05±1.03 | 0.31 |
| Paternal education¶ | 3.76±0.97 | 3.92±1.02 | 0.21 |
| Parental allergic diseases | |||
| Any+ | 70/128 (54.7%) | 60/136 (44.1%) | 0.09 |
| Maternal asthma | 22/112 (19.6%) | 14/123 (11.4%) | 0.08 |
| Paternal asthma | 16/112 (14.3%) | 15/123 (12.2%) | 0.64 |
| Maternal rhinoconjunctivitis | 21/124 (16.9%) | 21/134 (15.7%) | 0.78 |
| Paternal rhinoconjunctivitis | 31/124 (25.0%) | 25/134 (18.7%) | 0.22 |
| Maternal eczema | 20/128 (15.6%) | 11/135 (8.1%) | 0.06 |
| Paternal eczema | 15/128 (11.7%) | 10/135 (7.4%) | 0.23 |
| Environment | |||
| Smoking at home | 19/124 (15.3%) | 19/129 (14.7%) | 0.90 |
Data are presented as n/N (%) or mean±sd, unless otherwise stated. GA: gestational age; RSV: respiratory syncytial virus; HRV: human rhinovirus. #: specific immunoglobulin E ≥0.35 kU·L−1; ¶: categorised from 1 (no school completed) to 5 (higher education, >3 years); +: reported asthma, eczema and/or rhinoconjunctivitis.