Is there equalisation in socioeconomic differences in the risk of traffic injuries in childhood? A study of three cohorts of Swedish school children.

Equalisation of socioeconomic differences in injury risks at school ages is investigated, considering changes in risk inequalities over time for various categories of road users. Three national cohorts of children were followed up after their entry in different compulsory school levels (about 190,000 subjects by cohort). Subjects were attributed a household socioeconomic status in 1990 and their traffic injuries were sought over a five-year period (1990--94) in the national hospital discharge and causes of death registers. Socioeconomic inequality was measured by year and cohort for various RTI (Road Traffic Injury) diagnoses using the Relative Index of Inequality (RII). Whether equalisation arose or not was assessed considering changes in RII scores within the five-year period, measured by Chi-squared test. RII scores were generally high except for bicycle-related injuries among boys from the oldest cohort throughout the follow up. This relative equality in bicycle-injury risk benefited boys from all socioeconomic groups. Also, there was some, though short lasting, equalisation in bicycle-related injury risk for the younger cohort at the end of the first grade of compulsory school. Hence, some but limited support to the concept of equalisation was found, especially among young male bicycle riders. Population-based intervention aimed at improving safety behaviours among bicycle or motor-vehicle users should target not only suspected class-related influences, but even influences from the school, peer group and youth culture. Transitional periods in modes of transportation are a major concern.