Baseline characteristics of the patient groups
| Magnesium (n=31) | Placebo (n=30) | |
| Age years | 1.7±0.8 | 2.0±1.0 |
| 6–12 months | 6 (19) | 5 (17) |
| 1–2 years | 16 (52) | 9 (30) |
| 2–3 years | 7 (23) | 11 (37) |
| 3–4 years | 2 (7) | 5 (17) |
| Male sex | 17 (55) | 15 (50) |
| Birth weight g | 3346±651 | 3544±469 |
| Duration of respiratory infection days | 3.1±3.7 | 3.0±3.6 |
| Duration of wheezing days | 1.0±0.7 | 1.1±1.4 |
| Number of earlier episodes of wheezing | 5.3±6.7 | 6.1±6.0 |
| Regular use of an inhaled corticosteroid | 7 (23) | 6 (20) |
| Patient history of doctor diagnosed atopy | 11 (36) | 6 (20) |
| Patient history of doctor diagnosed food allergy | 3 (10) | 6 (20) |
| Parental smoking | 14 (45) | 13 (43) |
| Mother with a diagnosis of asthma | 6 (19) | 4 (13) |
| Father with a diagnosis of asthma | 2 (7) | 5 (17) |
| Pets at home | 13 (42) | 13 (43) |
| Number of doses of short-acting beta-agonists before the study treatment | 6.2±3.7 | 6.2±4.5 |
| Supplemental oxygen before the study treatment | 12 (39) | 12 (40) |
| Viral aetiology of wheezing | ||
| Rhinovirus | 22 (71) | 15 (50) |
| Rhinovirus and other virus | 4 (13) | 3 (10) |
| Respiratory syncytial virus | 2 (7) | 3 (10) |
| Adenovirus | 0 (0) | 2 (7) |
| Coronavirus OC43 | 1 (3) | 0 (0) |
| Bocavirus | 0 (0) | 2 (7) |
| Negative | 2 (7) | 5 (17) |
Data are presented as mean±sd or n (%).