Asthma prevalence at 11.5 years stratified by postnatal ETS exposure
| % (n) with asthma at 11.5 years | ||
| TV viewing | Not exposed | Exposed |
| Not at all | 4.3 (3/70) | 10 (1/10) |
| <1 h per day | 4.5 (30/663) | 3.2 (6/187) |
| 1–2 h per day | 5.5 (52/952) | 5.9 (26/442) |
| 2+ h per day | 9.1 (39/429) | 8.8 (22/249) |
ETS, environmental tobacco smoke.