Social inequalities in road traffic deaths at age 16-20 years among all 611 654 Norwegians born between 1967 and 1976: a multilevel analysis

Background: Road traffic injury is a major cause of death among youths. Aims: To estimate mortality differences in family socioeconomic position (SEP) and municipal disadvantage level. Methods: Data on all Norwegians born in 1967–76, gathered from national registries, were linked by a unique national identification number. The 611 654 participants were followed-up for 5 years from age 16 years. Parental education level, father's income level, and proportion of high-income earners in the municipality served as SEP indicators. Associations between SEP and road traffic deaths were analysed by multilevel Poisson regression. Results: Road traffic deaths (n=676, rate 22.2 per 100 000 person-years) constituted a major cause of death, of which 91.9% were motor vehicle occupants. SEP distributions differed according to gender and type of motor vehicle crash (collision, non-collision). There was an inverse relationship between municipal proportions of high-income earners and mortality (population attributable fraction (PAF) 0.43, 95% CI 0.30 to 0.53) in all categories of gender-specific crash types. Family SEP gradients were not found except for male non-collision deaths, where increasing mortality was found in association with decreasing parental education level (PAF 0.94, 95% CI 0.59 to 0.99) and increasing paternal income (PAF 0.25, 95% CI 0.06 to 0.40). Conclusion: The different SEP patterns...