Table 1. Characteristics and asthma risk factors of the children at two years of age.
All data are given as n and %, unless otherwise stated. The control group is the group from the reference population.
| Bronchiolitis group N = 203 |
Control group N = 155 |
|
|---|---|---|
| Boys n (%) | 117 (57.6%) | 89 (57.4%) |
| Age months, mean (SD) | 24.2 (3.2) | 24.3 (3.7) |
| Weight kg, mean (SD) | 13.2 (1.6) | 12.9 (1.5) |
| Length cm, mean (SD) | 87.0 *** (4.1) | 88.7(4.2) |
| Breastfeeding at enrolment n (%) | 149 (73.4%) | 122 (78.7%) |
| Second-hand smoke exposure in infancy n (%) | 25 (14.4%)** | 5 (3.3%) |
| Second-hand smoke exposure at 2 years | 5 (2.5%) | 1 (0.7%) |
| Atopic manifestations defined at 2 years | ||
| At least one n (%) | 103 (50.7%) | 37 (23.9%) |
| Two or more n (%) | 19 (9.4%) | 25 (7.3%) |
| rBO (at least 3 wheeze episodes) n (%) | 98 (48.3%)*** | 22 (14.2%) |
| Atopic dermatitis at 2 years n (%) | 30 (14.8%) | 25 (16.1%) |
| Allergic sensitisation1 n (%) | 17 (8.4%) | 11 (7.4%) |
| At least one parent asthma n (%) | 35 (22.2%) | 46 (29.7%) |
| At least one parent AD n (%) | 33 (18.2%)* | 46 (29.7%) |
| At least one parent allergic rhinoconjunctivitis n (%) | 62 (34.4%)*** | 84 (54.2%) |
| Higher education mothers2 n (%) | 122 (70.1%)*** | 142 (91.6%) |
| Higher education fathers2 n (%) | 100 (57.8%)*** | 129 (83.8%) |
| Income mothers3, mean (SD) | 1.92 ** | 2.13 |
| Income fathers3, mean (SD) | 2.32 *** | 2.59 |
| Caucasian mother n (%) | 189 (93.6%) | 147 (94.8%) |
| Caucasian father n (%) | 191 (95.0%) | 143 (92.3%) |
1Allergic sensitisation was defined by at least one positive skin prick test to common inhalant and food allergens
2Higher education at least three years after secondary school
3Annual income before tax. 1: <300.000 NOK. 2: 300.000–500.000 NOK. 3: >500.000 NOK.
* p<0.05
** p<0.01
***<0.001