Since late 1989, the cycle helmet wearing rate in New Zealand has risen from around 20 percent for adults and teenagers, and 40 percent for younger children, to more than 90 percent in all age groups. Cycle helmet wearing became mandatory under New Zealand law in January 1994. This paper considers the effect of cycle helmet wearing on hospitalised head injuries between 1990 and 1996, using cyclist limb injuries as a measure of exposure to the risk of cycling trauma. Non-motor vehicle crashes were treated separately from those involving a motor vehicle. Non-motor vehicle crashes were further subdivided by age group. A negative correlation between cycle helmet wearing and the cyclist hospitalisations for head injury was found for non-motor vehicle crashes in all age groups, and for motor vehicle crashes. For an increase of 5 percentage points in the helmet wearing rate, the corresponding decreases in head injuries in non-motor vehicle accidents were estimated to be 10.2 percent, 5.3 percent and 3.2 percent for children of primary school age (5-12 years), secondary school age (13-18 years), and adults respectively. The corresponding decrease in hospitalisations for motor vehicle crashes was 3.6 percent. All results were significant at the 95 percent level. The relatively large increase in helmet wearing associated with the passing of a compulsory helmet wearing law in 1994 reduced head injuries by between 24 percent and 32 percent, depending on age group, in non-motor vehicle crashes, and by 20 percent overall in motor vehicle crashes. No increase or decrease in the severity of head injuries for which cyclists were hospitalised over this period could be detected. This may have been due to the small and highly variable number of 'high severity' injuries. (A)
Abstract