Birth order, specific and non-specific infections in childhood and other risk factors for atopic disease
| Risk factors and atopy (expressed as % or events/100 subjects) | Birth order (number of older siblings) | ||||
|---|---|---|---|---|---|
| 1 (0) n=346 | 2 (1) n=906 | 3 (2) n=454 | 4 (3) n=101 | 5 (4) n=62 | |
| Non-specifc infections in first 2 years of life (events/100 subjects) | |||||
| Otitis media | 30 | 28 | 26 | 50 | 27 |
| Tonsillitis | 39 | 36 | 35 | 35 | 21 |
| URTI | 53 | 57 | 62 | 55 | 65 |
| LRTI | 26 | 24 | 30 | 23 | 22 |
| Urinary | 2 | 2 | 3 | 3 | 3 |
| Specifc infections (events/100 subjects) | |||||
| Whooping cough | 6 | 6 | 4 | 5 | 2 |
| Measles | 5 | 5 | 4 | 4 | 3 |
| Mumps | 16 | 20 | 22 | 21 | 16 |
| Croup | 3 | 8 | 9 | 4 | 10 |
| Chickenpox | 29 | 35 | 29 | 33 | 32 |
| Other risk factors (%) | |||||
| Maternal atopy | 13 | 20 | 22 | 23 | 13 |
| Pertussis immunisation | 67 | 74 | 74 | 74 | 67 |
| Antibiotics < 2 years | 68 | 68 | 70 | 69 | 68 |
| Atopic disorders (%) | |||||
| Atopy | 44 | 44 | 46 | 61 | 44 |
| Asthma | 28 | 24 | 26 | 28 | 28 |
| Hay fever | 23 | 25 | 25 | 30 | 23 |
| Eczema | 16 | 18 | 21 | 32 | 16 |
URTI = upper respiratory tract infections; LRTI = lower respiratory tract infections.