Introduction: Bicycling has become increasingly popular in Iceland. Official registration of bicycle accidents is based on police reports. As minor accidents are often not reported to the police, these accidents may be underreported in police records. The aim of this study was to examine the epidemiology of bicycle related accidents in patients seeking medical assistance at the Emergency Department (ED) at Landspitali-University Hospital, Reykjavik (LUH), Iceland.

Materials and methods: This retrospective cohortstudy was conducted at the ED at LUH, Iceland from January 2005 to December 2010. All medical files were reviewed and sex, age, year and month of accident/injury, helmet wearing, ICD-10 diagnosis, severity of injury according to the Abbreviated Injury Scale (AIS) and the Injury Severity Score (ISS) recorded. The rate of hospital admission was examined with length of stay, Intensive Care Unit admission, use of medical imaging and operative treatment.

Results: A total of 3472 patients presented to the ED with bicycle related accidents , 68.3% men and 31.7% female. The average age of patients was 22,6 years (1-95 years). Most are injured during recreational activities (72.4%)  and in residence areas  (45,7%). Most injuries occurred during May-September (71.4%). Data on counterparty was missing in 74.9% of cases. The cause of accident was in 44.0% a low fall or jump. The upper extremity was injured in 47.1% cases. A majority of the patients (65.6%) had a mild injury (ISS≤3points) and 29.3% had a moderate injury (4-8 points). No fatalities were found during the study period. Use of helmets was only recorded in 14.2% of cases. In total 124 patients were admitted during the period where the mean time of admission was 5 days.

Conclusion: The incidence of bicycle injuries increased during the study period but appears to have increased less than the number of bicyclists. Injuries are more frequent among males and the majority are of a young age. The accidents usually occur during the spring and summer. Most injuries are minor but 3.6% required admission.

Picture 1. Age and gender distribution of injured patients in bicycle related accidents at the Emergency Department in Reykjavik, Iceland 2005-2010. 

Picture 2. Location of injury according to the Abbreviated Injury Scale.

Table I. Diagnosis according to ICD-10 in all patients who seek medical attention in the Emergency Department in Reykjavík, Iceland 2005-2010.

Diagnosis - all patients	%
Superficial injury of other parts of head (S00.8)	6.5
Concussion (S06.0)	6.3
Sprain and strain of wrist (S63.5)	5.8
Contusion of knee (S80.0)	5.4
Open wound of cheek and temporomandibular area (S01.4)	4.4
Fracture of lower end of radius (S52.5)	4.4
Fracture of clavicle (S42.0)	3.7

Table II. Diagnosis according to ICD-10 in admitted patients following bicycle related accidents.

Diagnosis - admitted patients	%
Concussion (S06.0)	22.6
Superficial injury of other parts of head (S00.8)	8.9
Fracture of clavicle (S42.0)	7.3
Fracture of lower end of radius (S52.5)	6.5
Fracture of base of skull (S02.1)	6.5
Multiple open wounds of head (S01.7)	5.6
Diffuse brain injury (S06.2)	4.8

Picture 3. Age distribution of admitted patients by gender to Landspítali in 2005-2010.

Picture 4. Injury Severity Score (ISS) in admitted patients due to bicycle related accidents at Landspítali, in 2005-2010.

Picture 5. Annual number of injured cyclist at the Emergency Department in Reykjavík compared to annual number of admitted patient to the local Hospital in Reykjavík, Iceland during 2005-2010.