• Open Access

Rise in bicycle-related injury hospitalisation rates in middle-aged adults, 2000–09

Authors


Correspondence to: Dr Teresa Ballestas, South Metropolitan Public Health Unit, Level 2/7 Pakenham Street, Fremantle 6160, Western Australia; e-mail: teresa.ballestas@health.wa.gov.au

In the last decade, the importance of cycling as a means of recreation and transport has increased. The health, environmental and social benefits of bicycling are well documented.1–2 It has been demonstrated that as numbers of cyclists increase, the injury rate per kilometre cycled decreases, indicating that there is some safety in numbers.2–3 However, recent reports have shown increasing rates of emergency presentations and hospitalisations due to bicycle injuries in Australia.4

Cycling participation rates vary by sex and age group. In Western Australia, in 2009, cycling for recreation was the fourth most common physical activity for males over 18 years of age and the seventh most common for females.5 Therefore, we analysed trends in hospitalisations due to bicycling injuries by age group and sex.

Linked data from the WA Hospital Morbidity Data System were used. Injuries were coded using the International Classification of Disease tenth revision Australian modification (ICD-10-AM).6 Inclusion criteria were residents of WA hospitalised due to bicycle-related injuries during the period January 2000 to December 2009. To minimise multiple counting of cases, hospitalisations indicating a transfer within the hospital or from one hospital to another within 24 hours of admission were excluded. Age-specific rates were calculated by dividing the number of cases by the population of the same sex and age group for each year. Data were analysed using SAS 9.2.7 Poisson regression was used to model trends.

WA data show 8,586 hospitalisations due to bicycle-related injuries in the period studied. The majority of hospitalisations were for males (80.9%; n=6,947) and for the 0–14 years age group (48.0%; n=4,124).

However, when we examined trends over time by age groups and sex, the rates of hospitalisations have decreased or remained stable for the 0–14, 15–24 and 65 years and over age groups. In contrast, there was a dramatic increase in the rates of hospitalisations due to bicycling injuries in middle-aged males and females.

For males aged 25–44 years, the age-specific rate of hospitalisation due to bicycle-related injuries increased from 33.7 to 55.6 per 100,000 population (p<0.001); while for those aged 45–64 years, it rose from 20.8 to 49.6 per 100,000 population (p<0.001).

For females aged 25–44 years, the age-specific rate of hospitalisation due to bicycling injuries increased from 4.5 to 9.8 per 100,000 population (p<0.001); while for those 45–64 years, it rose from 9.1 to 18.7 per 100,000 population (p=0.001).

Indeed, of all hospitalisations for males due to bicycle-related injuries, the proportion attributed to 25–64 years olds increased from 21.9% (95% CI=18.8–25.1; n=143) in 2000 to 41.1% (95% CI=37.7–44.6; n=327) in 2009. For females, the proportion attributed to 25–64 years olds increased from 19.6% (95% CI=13.5–25.7; n=32) in 2000 to 43.2% (95% CI=36.2–50.2; n=83) in 2009.

For males and females aged 25–64 years, the most common external cause was non-collision transport accident (55.5%; n=1395), followed by collision with car, pick-up truck or van (15.2%; n=382), collision with fixed or stationary object (5.4%; n=35), collision with other pedal cycle (4.5%; n=114) and other specified and unspecified external causes (19.4%; n=487).

Physical activity, including cycling, is important and should be encouraged. The challenge is to achieve a cycling-friendly policy in a regulated environment.2 Cycling organisations need to be involved in the development of safety messages and cycling guidelines. Public health policies should include: use of helmets, clothing and bicycle design, cycling training/education and cycling infrastructure.2,4

The main limitations of these data include the lack of valid age- and gender-specific denominators that reflect the level of exposure to risk, based on both the numbers of cyclists as well as distances travelled by bicycle, over the time period of interest. Although it seems highly plausible, we can not directly link increased participation in cycling to the increase in hospitalisation rates for middle-aged adults with cycling injuries. The increase in cycling injury rates may be related to other factors such as bicycle design, increasing road traffic or a change in cyclist behaviour.

With the national cycling strategy setting a target of doubling the number of people cycling by 2016, strategies to maximise safety are needed to reduce the number of cyclists injured.8 In the light of evidence to suggest that the numbers of cycling injuries resulting in hospital admission are increasing among middle-aged adults, the authors recommend that future policy guidelines and safety messages should include information that specifically targets this group of cyclists with a view to reducing future injuries.

Acknowledgements

We thank Peter Somerford and Jianguo Xiao for providing statistical advice.

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