Socioeconomic diVerences in road traYc injuries during childhood and youth: a closer look at diVerent kinds of road user

Study objective—To investigate if there are socioeconomic diVerences in road traYc injuries among Swedish children and adolescents, and if this applies to the same extent to all categories of road users. To assess the modification eVect of gender of child. Design—A closed population-based cohort study based on the Swedish Population and Housing Census of 1985. Individual census records are linked to Sweden’s National Hospital Discharge Register (1987–1994). Setting and subjects—All children aged 0–15 years in 1985 (approximately 1.5 million subjects) were monitored for five categories of road traYc injuries over eight years, and divided into seven socioeconomic groups on the basis of parental socioeconomic status. Odds ratios and population attributable risks were computed using the children of intermediate and high level salaried employees as reference group. Main results—The injury risks of pedestrians and bicyclists are 20% to 30% higher among the children of manual workers than those of intermediate and high level salaried employees. Socioeconomic diVerences are greatest for injuries involving motorised vehicles—that is, moped, motorcycle and car. If all children had the same rate as children in the reference group, the rate for all groups would be 25% lower for moped riders and 37% lower for car drivers. Conclusions—Socioeconomic diVerences in road traYc injuries are substantial for both boys and girls. Socioeconomic injury-risk diVerentials increase when young people use motorised vehicles. (J Epidemiol Community Health 2001;55:858–862) Injury is a major cause of death, serious morbidity, and permanent disability among children and adolescents. This period of life involves encounters and confrontations with a series of new situations and environments that entail an increased range of risks. An example of central concern is the road traYc environment, where young people make their debuts—as pedestrian, bicyclist, moped rider, motorcyclist, and car driver, in turn. In industrialised countries road traYc injuries (RTIs) account for a large proportion of socioeconomic disparities in health, in particular in childhood and youth. The bulk of evidence, gathered above all from ecological studies (see examples in references) suggest that young persons living in deprived areas have higher injury rates than those living in more privileged areas. 6 But whether these area-based diVerences also apply to individual socioeconomic status (SES) has not been much investigated. And it is also unclear if socioeconomic disparities are found in all modes of transportation. Moreover, little is known about the extent to which socioeconomic diVerences are modified by gender of child. Sweden lacks knowledge about the socioeconomic distribution of RTIs. Nevertheless, scattered evidence, mainly from mortality statistics, reveal that socioeconomic diVerences with regard to all injuries, and to traYc injuries in particular, are considerable. The study was embarked upon in order to investigate the following questions: (1) Are there socioeconomic diVerences in RTIs among Swedish children and adolescents? (2) Is the magnitude of the socioeconomic difference the same for all categories of road users? (3) Are socioeconomic diVerences, for any given type of traYc injury, modified by gender? Methods The study population is based on the Swedish Population and Housing Census of 1985, and consists of all children aged 0–15 years living in households with one or two adults (parents or guardians) at that time (approximately 1.5 million subjects). For the census, a household was defined as a person or group of persons, registered in the same municipality, living in the same dwelling. Record linkage, by Swedish personal identification number (which uniquely identifies each permanent resident in Sweden), to Sweden’s National Hospital Discharge Register was eVected for the years 1987–1994. The census also contains information on ages of children and parents, parental socioeconomic characteristics, country of birth of mother, and area of living. Socioeconomic groups were defined according to a classification used by Statistics Sweden, which is primarily based on occupation but also takes educational level, type of productive activity, and position at work into account. The SES of the household was used: the statuses of the two parents/guardians were compared, and if these diverged, the SES of the higher of the two was attributed to the household. On this basis, each child was allocated to one of the following socioeconomic groups: intermediate and high level salaried employees; assistant non-manual J Epidemiol Community Health 2001;55:858–862 858 Karolinska Institutet, Department of Public Health Sciences, Division of Social Medicine, SE-171 76 Stockholm, Sweden