Een prospectieve cohort studie van lichte fietsongevallen in het woon-werkverkeer in België Bas de Geus* G. Vandenbulcke**, L. Int Panis***, I. Thomas**, B. Degraeuwe***, E. Cumps* J. Aertsens***, R. Torfs***, R. Meeusen* *VUB, Dept. Human Physiology & Sports Medicine, Belgium ** UCL, C.O.R.E. & Département de Géographie, Belgium *** VITO, Integrated Environmental Studies, Belgium
Preface
Preface So??? Commuter Cycling positive for health?? SHAPES-project
INTRODUCTION
Introduction Cyclists incur higher crash risks than motorists (in particular car drivers) in terms of accidents per distance covered (van Boggelen, 2005; BRSI, 2009; Elvik, 2009; Tin Tin, 2010) e.g. risk of injury (=fatalities/kilometer): cycling > car drivers: Norway: ± 7.5 x (Pucher & Dijkstra, 2000; Elvik, 2009) the Netherlands: ± 5.5 x (CBS, 2008)
Introduction shortcoming 1 Most statistics/literature on bicycle accidents: hospital & police data retrospective surveys (Jacobson, 2003) weakness: selection and recall bias serious injuries strongly underestimate total number cycling accidents tip of the iceberg (Dhillon, 2001; De Mol & Lammar, 2006; Hoffman, 2010) e.g.: Belgium only 15% cycling accidents are officially reported (Doom & Derweduwen, 2005; De Mol & Lammar, 2006; BRSI, 2006)
Introduction shortcoming 2 Most epidemiological data: count absolute number of accidents ± recording of exposure data (bicycle usage) (Aultman-Hall & Hall, 1998) incidence rate (IR) implementation of safety measures (Jacobsen, 2003; Christie, 2007)
Purpose Purpose: report on Incidence Rate of (minor) bicycle accidents using a prospective study design
MATERIALS & METHODS
Materials & Methods Studied area: Belgium: highly urbanised bicycle share of 2.4% (traveller-km/person/yr) (Vandenbulcke, 2011) 3 institutional regions: large bicycle usage & bicycle culture Brussels: 1-4% Flanders: 12% Wallonia: 2%
Materials & Methods Online registration system After leaving e-mail: www.shapes-ssd.be Inclusion criteria online registration: between 18-65 years; paid job outside home; cycle to work > 2 times/wk;
Materials & Methods general questionnaire + 1 st Travel diary (TD) TD automatically send every week (1 year) cycling past 7 days last question: injury in past week? if INJURY: prospective injury questionnaire (PQ) Inclusion criteria injury: past week; route to work (not recreational cycling); acute + corporal damage
Materials & Methods Incidence: number (N) of injuries during 1-year follow-up period Incidence rate (IR): number (N) of injuries / unit of exposure IR (95% CI): (i) 1000 trips; (ii) 1000 hours; (iii) 1000 kilometers
RESULTS & DISCUSSION
Results: General After 1-year: N=1,187 participants included in data analysis 20,107 weeks 78,099 hours cycled 1.5 million kilometers cycled Study population: 68% men middle aged: 40 10 years
Results: General Incidence (number of trips): 70 bicycle accidents 62 participants: 44 men; 18 women Severity of the injury: minor bicycle accidents 2 participants hospitalized > 24 hours
Results: General Reported in official statistics All injured participants Police with official record 7.1 without official record 4.3 no police intervention 88.6 Hospital self-care 47.1 ambulant 25.7 emergencies 10.0 no medical intervention 17.1 Insurance yes 30.0 no 70.0 More severe injuries 40.0 33.3 6.5 0.0 16.7 57.1 0.0 28.6 2.0
Results: General Cause of the injury Cause of the injury Slipping Direct contact car Direct contact pedestrian Direct contact cyclist Hindrance on the road (constructions) Direct contact road sign Fall Other
Results: General Paying attention On the question could you have avoided the accident : 37.1% said that they could have avoided the accident Imprudence from the cyclist itself was a cause of the accident in 25.7% of the cases. Distraction was responsible for 11.4% of the accidents.
Results: Overall IR 1 accident occurred every 1,116 hours or 21,071 kilometers cycled Overall incidence rate (IR) 0.896 acc /1,000 hours (95% CI 0.686-1.106) 0.047 acc /1,000 kilometers (95% CI 0.036-0.059) Vandenbulcke (2009): mostly major accidents (hospital > 24h), fatal injuries seriously injured or killed is 0.069 per 100,000 minutes cycled in this study: 1.493 minor accidents per 100,000 minutes
Results: Overall IR IR weeks with snow or icy roads 0.099 (95% CI 0.053-0.145) IR weeks without snow or icy roads 0.048 (95% CI 0.036-0.060) * snow, icy roads
Results: per region Incidence, exposure and incidence rate per region INCIDENCE BRUSSELS FLANDERS WALLONIA Number of injuries (N) 28 34 8 EXPOSURE Time (h) 20,153 45,190 8,540 Distance (km) 325,210 909,033 160,873 INCIDENCE RATE (95% CI) /1,000 h 1.389 (0.875-1.904) 0.752 (0.499-1.005) 0.937 (0.288-1.586) /1,000 km 0.086 (0.054-0.118) 0.037 (0.025-0.050) 0.050 (0.015-0.084) Values in Bold indicate a significant difference (P<0.05)
Discussion: per region SAFETY IN NUMBERS principle is based on official statistics, including mostly major and fatal injuries (Jacobsen, 2003; Robinson, 2005; Elvik, 2009) Vandenbulcke (2009): major injuries and fatal accidents Flanders incidence + exposure Flanders incidence rate safety in numbers principle is also applicable for minor bicycle accidents
Results: per gender Incidence, exposure and incidence rate per gender MEN WOMEN INCIDENCE Number of injuries (N) 44 18 EXPOSURE Time (h) 57,633 18,891 Distance (km) 1,143,299 304,164 INCIDENCE RATE (95% CI) /1,000 h 0.885 (0.642-1.128) 1.006 (0.554-1.458) /1,000 km 0.045 (0.032-0.057) 0.062 (0.034-0.091)
Discussion: per gender IR per gender: Tin Tin (2010): men > women ( injuries/million hours cycling) (not sign) Statistical sign should be interpreted with caution: small # injuries Cycling exposure (travelled time & distance): in cities/countries with low cycling exposure: men > women e.g. this study, Canada, USA in cities/countries with high cycling exposure: women > men e.g. the Netherlands, Denmark, Portland (US) metropolitan area Women are considered an indicator species for bike-friendly cities/countries Women should be stimulated to cycle more
CONCLUSION
Conclusion 97% minor bicycle accidents; Underreporting of minor bicycle accidents in Belgium is confirmed Reported: if severity IR: 0.896 (95% CI 0.686-1.106) per 1,000 hours of exposure; Exposure must be taken into account when statements about safety measures are made; safety in numbers principle: applicable for minor and major bicycle accidents
FUTURE RESEARCH
Adolescents FWO Levenslijn 2012 "Meer en veiliger mobiliteit voor kinderen en jongeren". Naam project: Online registratie van exposure, lichte en zware fietsongevallen bij adolescenten. Een retrospectieve en prospectieve studie. Objectives: 1) monitor and get insight in minor and major bicycle accidents, using a retrospective and a prospective study design. 2) record exposure data in order to calculate the incidence rate of bicycle accidents in adolescents. Exposure : cycling frequency, time and distance, different aspects of the built environment (e.g. roundabout, junction,...).
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