Bicycle injury events among older adults in Northern Sweden: a 10-year population based study.

Bicycles are a common mode of transportation and injured bicyclists cause a substantial burden on the medical sector. In Sweden, about half of fatally injured bicyclists are 65 years or older. This study analyzes the injury mechanisms, injuries, and consequences among bicyclists 65 years or older and compare with younger bicyclists (< or =64) and older adults as passenger car drivers, to give a basis for an injury preventive discussion for this age group. Umeå University Hospital's primary catchments area had 142,000 inhabitants in 2006. Nearly all injured road users in the well-defined geographic area are treated at this hospital and a 10-year data set (N=456) of injured bicyclists aged 65+ from the hospital's continuous injury registration (1997-2006) was analyzed. The results show that the annual injury incidence was 2.4 and 2.2 per 1000 men and women, respectively, aged 65 or older. For men the incidence rate was constant in the three age groups 65-74, 75-84 and 85+, while it decreased strongly for women. The incidence rate for old adults as passenger car drivers and younger bicyclists was 1.0 and 4.6, respectively. Most frequent injury mechanisms were falls when getting on or off a bicycle (20%) and by potholes or irregularities on the ground, edge of a sidewalk, or similar (13%). Only 6% were hit by cars, trucks, or buses. Half of the injured suffered fractures or dislocations, and 10% suffered concussion or more serious intracranial injuries. Getting on or off the bicycle caused most fractures (especially a high fraction of the hip and femur fractures) and resulted in 27% of all inpatient days in hospital. Three individuals died. One-third of the injured were treated as inpatients for a total of 1413 days (on average 9 days), with 69% of the days being caused by fractures. The cost for out- and inpatient acute treatment was approximately USD 4700 (SEK 33,000) per injured. The results merit an interest for this target group; bicycle injuries among older adults are costly both for the individual and the medical sector. Injury mitigation strategies focused on the needs of this group are probably as well motivated as those focused on older car drivers.