Trends in serious head injuries among English cyclists and pedestrians.

In England the use of bicycle helmets remains low as debate continues about their effectiveness. Time trend studies have previously shown an inverse association between helmet wearing rates and hospital admissions for head injury, but data on helmet wearing are often sparse and admission rates vary for numerous reasons. For the period of this study comprehensive data on helmet wearing are available, and pedestrians are used as a control to monitor trends in admission. Among cyclists admitted to hospital, the percentage with head injury reduced from 27.9% (n = 3070) to 20.4% (n = 2154), as helmet wearing rose from 16.0% to 21.8%. Pedestrian head injury admissions also declined but by a significantly smaller amount. The wearing of a cycle helmet is estimated to prevent 60% of head injuries.