Table I.
Baseline characteristics of the cohort of 183 children, assessed at 11 months of age at the start of the diary data collection period. Listed are (for interval-scale data) medians with inter-quartile range (IQR) and full range of the data, or (for categorical data) numbers in each category with percentages.
| Characteristic | Missing | ||
| Sex (%) | Boys | 102 (55.7) | 0 |
| Girls | 81 (44.3) | ||
| Mother's age (year) | Median (IQR) | 32 (29–34) | 0 |
| Range | 21–41 | ||
| Father's age (year) | Median (IQR) | 34 (30–37) | 0 |
| Range | 23–51 | ||
| Episodes of illness since birth (no.) | Median (IQR) | 2 (1–4) | 2 |
| Range | 0–15 | ||
| Medication regularly (%) | No | 160 (88.4) | 2 |
| Yes | 21 (11.6) | ||
| Visits to the GP since birth (no.) | Median (IQR) | 1 (0–2) | 0 |
| Range | 0–9 | ||
| No. of siblings (%) | 0 | 52 (30.2) | 11 |
| 1 | 85 (49.4) | ||
| 2 | 28 (16.3) | ||
| 3 | 5 (2.9) | ||
| ≥4 | 2 (1.2) | ||
| Siblings that are often ill (%) | No | 146 (80.7) | 2 |
| Yes | 35 (19.3) | ||
| Parent-rated health of the child (%) | Extremely good | 72 (39.3) | 0 |
| Good | 95 (51.9) | ||
| Fairly good | 15 (8.2) | ||
| Poor | 1 (0.6) | ||
| Very poor | 0 (0.0) | ||
| (Selected) symptoms since birth (%) | Fever | 150 (82.0) | 0 |
| Cough | 140 (76.5) | 0 | |
| Vomiting | 61 (33.3) | 0 | |
| Diarrhoea | 88 (48.1) | 0 | |
| Rash | 47 (25.7) | 0 | |
| Wheezing | 58 (31.7) | 0 | |
| Earache | 44 (24.0) | 0 | |
| A cold, a runny nose | 172 (94.0) | 0 | |
| Eye infection | 67 (36.6) | 0 | |
| Restless sleep | 123 (67.2) | 0 | |
| Allergic reaction | 11 (6.0) | 0 | |
| (Selected) illness since birth (%) | Cold | 169 (96.6) | 8 |
| Pneumonia | 19 (10.9) | 8 | |
| Infection of the middle ear | 33 (18.9) | 8 | |
| Bronchitis | 14 (8.0) | 8 | |
| Fever cramps | 1 (0.6) | 8 | |
| Eczema | 26 (14.9) | 8 | |
| Diarrhoea and/or vomiting | 57 (32.6) | 8 |