Characteristics of children
| Boys/girls | 116/110 |
| Age (years) | 10.0 ± 0.9 (8–12) |
| BMI (kg/m2) | 18.2 (10.7–33.8) |
| Urban/rural | 79/147 |
| White/non-white | 168/58 |
| Sporting practice (other than swimming) | 129 (57%) |
| Swimming pool attendance | |
| n | 204 (90.2%) |
| hours/week × years | 1.88 (0.55–6.42) |
| Home environment | |
| Housing density (persons/room) | 0.53 (0.19–5) |
| Parental smoking | 109 (48.2%) |
| Pets | 116 (51.3%) |
| Mould on bedroom walls | 16 (7.1%) |
| House with double-glazed windows | 162 (71.7%) |