2.2. Initial data
Demographic variables such as age at accident and gender were
included in the analysis as well as a variable concerning living in
an urban renewal area. Age was divided into 3 categories (less than
6 years, 6 to 11 years and 12 to 15 years)in order to have sufficiently
large samples of the different types of road user. A family sociooccupational
level variable was created by combining five other
variables: single- or two-parent status, occupational status and
occupational category of each parent. The number of persons in the
household was dichotomized as living with one to four persons and
living with at least five persons. Type of road user was divided into
four categories according to mode of transport: four-wheeled vehicle
occupants, motorized two-wheeled vehicle drivers, pedestrians
and other (cyclists, scooter/in-line skate users). Injury severity was
measured by the AIS, which standardizes injury data and scores
lesions from 1 (minor) to 6 (fatal), and by M-AIS, the score of the
most severe injury. Injuries of AIS 2 or more were also classified by
body part involved: head, face, neck, spine, chest, abdomen, upper
limbs, lower limbs and external lesions.