Effectiveness of helmets in skiers and snowboarders: case-control and case crossover study

The wrong lowest recorded temperature mistakenly slipped through in the electronic version of this paper by Brent E Hagel and colleagues (BMJ 2005;330:281-3, 5 Feb). The value given in the text on data collection and in table 3 should have read < -10°C [not ≤ 10°C]. The version in the printed journal is correct.