1. Introduction

Cycling is a popular form of transport and recreation in Western Australia, especially among young people. Although several publications report general statistics on road injuries in this State, few focus specifically on the injuries incurred by cyclists.

In Australia, a number of documents on bicycle-related injuries have been published in recent years, many of which concentrate on the impact of helmet legislation. National trends indicate that overall numbers of bicycle-related fatalities and hospitalisations have decreased since 1990, the year in which helmet legislation was first introduced in Victoria (FORS, 1997). Similar trends, especially for bicycle-related head injuries, have been shown in at least some Australian States (Finch et al, 1993a; Marshall & White, 1994; Henderson, 1995). An association between helmet-wearing and the frequency and severity of head injuries (which account for a large proportion of serious bicycle crash injuries) has also been demonstrated (FORS, 1997; Henderson, 1995; Marshall & White, 1994).

Although helmet legislation has undoubtedly increased helmet-wearing rates in Australian cyclists, it has also been associated with decreased bicycle usage in some cyclist sub-groups (Finch et al, 1993b; Marshall & White, 1994). Furthermore, some hospital admission practices have changed since the introduction of the helmet legislation. For example, patients presenting to emergency departments with short episodes of concussion are no longer routinely admitted to hospital for observation. The introduction of case-mix funding may also have affected admission rates. Thus, it is difficult to conclude from preliminary studies that reduced bicycle injury numbers (more precisely head injuries) are a direct result of the helmet legislation.

This report examines bicycle injury hospitalisations and deaths in Western Australia over the period 1981 to 1995. It compares trends in bicycle injuries over this period with those of injuries involving all vehicle types and with corresponding patterns for all injury causes. It examines changes over time in the frequencies and rates of bicycle injury hospitalisations and deaths, based on the demographic details of injured cyclists and on the type of crash. For hospitalisations, it also investigates changes over time in the nature of injuries and in the length of hospital stays associated with bicycle injuries.

The statistics presented in this report are derived from available hospital morbidity and mortality data. As these data sources do not provide extensive information about the exact circumstances of bicycle crashes, it has not been possible to explore risk factors (other than demographic characteristics) in much detail. Nor has it been possible to examine less severe bicycle injuries such as those presenting to emergency departments and general practitioners’ surgeries.

Assessment of the effect of helmet legislation on bicycle injury morbidity and mortality was considered for this study. Unfortunately, it was felt that such an assessment was severely restricted by data limitations. Firstly, as helmet use details were not available for individual cases, it was not possible to compare the injuries incurred by cyclists who wore a helmet with those sustained by cyclists who did not.

Secondly, the effect of the helmet legislation on bicycle injuries requires an examination of injury rate patterns among cyclists. Unfortunately, bicycle usage data in Western Australia has been collected quite sporadically and inconsistently over the study period. Thus, adequate bicycle exposure data are not available to generate the required injury rates for the WA cyclist population. Overall population size has been used as a proxy measure to estimate trends in bicycle injury rates in Western Australia. Should changes in the cyclist population not parallel those of the overall WA population, the population-based rates would be inappropriate in assessing the effect of helmet use on bicycle injuries.

Thirdly, bicycle injury rates may have been affected by preventive measures other than the helmet legislation. Bicycle education programs, media campaigns and other interventions have taken place in Western Australia in recent years. As the timing and effect of these interventions is not well documented, it would be difficult to isolate the impact of helmet legislation from the effect of other interventions. Similarly, the effect of changes in hospital admission practices and of other potential confounding factors should also be accounted for in evaluating the effect of helmet legislation. Limitations in resources have not permitted any further investigation of these factors.

Nonetheless, this document provides a useful overview of bicycle injury trends in Western Australia over the 15-year study period. The Health Department of Western Australia has published two previous documents on bicycle injury hospitalisations, entitled:

This report is similar in nature to its predecessors, but is somewhat more comprehensive.

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Last Updated: Wednesday, 21 October 1998 14:25