title: Incidence, risk, and protective factors of bicycle crashes: findings from a prospective cohort study in New Zealand.
abstract: OBJECTIVE
  To estimate the incidence and risk of medically or police attended bicycle crashes in a prospective cohort study in New Zealand.
  
  
  METHODS
  The Taupo Bicycle Study involved 2590 adult cyclists recruited from the country's largest cycling event in 2006 and followed over a median period of 4.6 years through linkage to four administrative databases. Incidence rates with Poisson distribution confidence intervals were computed and Cox regression modelling for repeated events was performed.
  
  
  RESULTS
  The 66 on-road crashes and 10 collisions per 1000 person-years corresponded to 240 crashes and 38 collisions per million hours spent road cycling. The risk increased by 6% and 8% respectively for an extra cycling hour each week. There were 50 off-road crashes per 1000 person-years. Residing in urban areas and in Auckland (region with the lowest level of cycling), riding in a bunch, using a road bike and experiencing a previous crash predicted a higher risk. Habitual use of conspicuity aids appeared to lower the risk.
  
  
  CONCLUSIONS
  The risk is higher in urban areas and where cycling is less common, and increased by bunch riding and previous crashes. These findings alongside the possible protective effect of conspicuity aids suggest promising approaches to improving cycle safety.
authors.affiliation: Section of Epidemiology Biostatistics, School of Population Health, University of Auckland, Auckland, New Zealand. s.tintin@auckland.ac.nz
authors.forename: Sandar
authors.initials: S
authors.lastname: Tin Tin
authors.forename: Alistair
authors.initials: A
authors.lastname: Woodward
authors.forename: Shanthi
authors.initials: S
authors.lastname: Ameratunga
mesh_terms: D000059:Accidents / Q000401:mortality / Q000706:statistics & numerical data*; D000293:Adolescent; D000328:Adult; D001642:Bicycling / Q000293:injuries* / Q000523:psychology; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009520:New Zealand; D011446:Prospective Studies; D011482:Protective Devices; D012307:Risk Factors; D040242:Risk Reduction Behavior; D055815:Young Adult
keywords: Bicycling; Cohort studies; Epidemiology; Incidence; Medical record linkage; Risk; Wounds and injuries