Bicyclists, helmets and head injuries: a rider-based study of helmet use and effectiveness

Wasserman RC, Waller JA, Monty MJ, Emery AB, Robinson DR.
American Journal of Public Health, 1988 Sep;78(9):1220-1.

BRIEF NOTES
This is not a complete Commentary but a summary of observations and criticisms that have been made relating to this paper

Summary of paper (from authors' abstract)

516 bicyclists over the age of 10 were interviewed regarding helmet use and head injuries. Although 19% owned helmets, only 8% were wearing them when interviewed. Riders wearing helmets were more highly educated and reported higher car seat belt use. Nearly 4% of the bicyclists reported striking their heads in a cycling mishap during the previous 18 months; those wearing helmets at the time were less likely to have sustained head injuries.

Peer criticism

By Towner et al, 2002 :

The actual number of cyclists hitting their heads was only 21, of whom just 7 suffered head injuries. These are very small numbers for comparison.
The fact that helmeted cyclists were better educated and more likely to use seat belts was a source of bias between cases and controls.
Self-report data, subject to bias.
No data on injury severity.
The number of cyclists using helmets was small.
There was a very large proportion of students in the sample.
Due to the small numbers involved, little weight can be put on this study.

Helmet wearers more likely to hit their heads

At the time of questioning by the researchers, 40 (7.8%) of the cyclists were wearing helmets and 476 were not. Of the 21 cyclists who reported striking their heads in the previous 18 months, eight had been wearing helmets at the time of the mishap. This is 20% of the 40 helmeted cyclists questioned. The 13 other, unhelmeted, cyclists who had struck their heads represented 2.7% of the 476 unhelmeted cyclists who were questioned in the study. Thus helmet wearers were 7 times more likely to hit their heads than those who cycled bare-headed.

References

Towner et al, 2002

Towner E, Dowswell T, Burkes M, Dickinson H, Towner J, Hayes M, 2002. Bicycle helmets - a review of their effectiveness: a critical review of the literature. Department for Transport Road Safety Research Report 30.