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Influence of travel patterns on mortality from injury among teenagers in England and Wales, 1985-95: trend analysis

Carolyn DiGuiseppi, senior research fellow,  Leah Li, medical statistician,  Ian Roberts, director. 

Child Health Monitoring Unit, Department of Epidemiology, Institute of Child Health, University College London Medical School, London WC1N 1EH

Correspondence to: Dr DiGuiseppi

Injuries are the leading cause of death among teenagers.¹ The Health of the Nation strategy aims to reduce mortality from accidents in young people by 25% by 2005.² We previously analysed how changing travel patterns influenced death rates from unintentional injury among children under 14 years of age.³ Here we examine how they affect mortality from unintentional injury among teenagers.

	Subjects, methods, and results

From the Office for National Statistics we obtained anonymised death certificates recording deaths from injury between 1985 and 1995 among people aged 15-19 years in England and Wales. Records included age, sex, external cause of injury (E code), and year of death. We defined deaths of road users by E codes (table) and calculated mortality using census data and the average distance travelled as denominators. Data on the average annual distances travelled were obtained from the national travel surveys, whose methods have been published.⁴ We analysed unpublished data from the 1985-6, 1989-91, and 1992-4 surveys for residents of England or Wales aged 15-19 (Department of Transport, 1996). We estimated the average distance travelled by car, motorcycle, bicycle, and foot each year, from travel survey midpoints using linear regression.³ We estimated trends using Poisson distribution.⁵

Between 1985 and 1995, 10 530 teenagers aged 15-19 died from injury in England and Wales; 7954 deaths were from unintentional injury, of which 6073 (76%) involved road users (table). Mortality from unintentional injury declined by 32% (95% confidence interval 37% to 27%) over this period. There were large declines in death rates for motorcyclists (78%; 81% to 74%), pedestrians (49%; 59% to 36%), and pedal cyclists (38%; 57% to 11%), but not car occupants (2%; 12% to 9%).

Young men accounted for 6279 (79%) deaths from unintentional injury, and young women for 21% (1675). The sex ratio varied by road user (table). Declines in mortality of motorcyclists, pedestrians, and car occupants were similar for men and women. The decline in death rates of cyclists was larger among women, although the point estimates are not very precise.

The average annual distance travelled by motorcycle declined by 78%, from 246 km to 54 km, the average annual distance walked fell by 24%, from 624 km to 472 km, and the average annual distance cycled fell by 31%, from 216 km to 149 km. The average annual distance travelled by car increased by 35%, from 4510 km to 6069 km. Declines in motorcycling (99%), walking (28%), and cycling (60%) were larger and the increase in car travel smaller (28%), in young women than they were in young men (73%, 20%, 24%, and 40%, respectively).

In 1995 mortality was lowest for people travelling by car (1.3 deaths/100 million km travelled). Overall, 2.9 pedestrians, 4.3 cyclists, and 23.9 motorcyclists died per 100 million km travelled. Cumulative declines in deaths per 100 000 population (see above) were larger than declines in deaths per km travelled for motorcyclists (20%; 33% to 5%), pedestrians (33%; 46% to 16%), and cyclists (10%; 37% to 29%). Deaths per km travelled by car declined substantially (27%; 35% to 19%), unlike deaths of car occupants per 100 000 population. Deaths per km declined more for young men than for young women in each road user group (table).

	Comment

The 32% decline in mortality from unintentional injury among people aged 15-19 since 1985 is largely due to falling mortality among motorcyclists, pedestrians, and cyclists. These declines correspond to large decreases in motorcycling, walking and cycling. Mortality among car occupants has not declined, despite a 27% decrease in deaths per km travelled by car, because of the large increases in the distance travelled by car. Transport patterns are an important determinant of adolescent health. Strategies to influence transport patterns could substantially reduce mortality from road crashes.

	Acknowledgments

We gratefully acknowledge the Office for National Statistics and the Department of Transport for providing data for this study.

Contributors: CD participated in study formulation, design and analysis, interpreted the results, and wrote the paper. LL performed the statistical analysis, and edited the paper. IR obtained the data, participated in study formulation and design, and interpretation of results, and edited the paper. Guarantors: CD and IR.

Funding: The Camden and Islington Health Authority funds Dr DiGuiseppi. The Child Health Monitoring Unit is supported by the Sir Siegmund Warburg Voluntary Settlement.

Conflict of interest: None.

	References

Top References

1. Woodroffe C, Glickman M, Barker M, Power C. Children, teenagers and health: the key data. Buckingham: Open University Press , 1993.
2. Department of Health. The health of the nation: strategy for health in England. London: HMSO , 1992.
3. DiGuiseppi C, Roberts I, Li L. Influence of changing travel patterns on child death rates from injury: trend analysis. BMJ 1997; 314: 710-713[Abstract/Free Full Text].
4. Department of Transport. Transport statistics report: National Travel Survey 1992/94. London: HMSO , 1995.
5. Frome EL. The analysis of rates using Poisson regression models. Biometrics 1983; 39: 665-674[Medline].

(Accepted 3 October 1997)