Does a Geographical Context of Deprivation Affect Differences in Injury Mortality? A Multilevel Analysis in South Korean Adults Residing in Metropolitan Cities

Background: This study aimed to examine whether the socioeconomic context of urban areas affects differences in adult mortality from injuries in the districts of all seven South Korean metropolitan cities, after adjusting for individual demographic and socioeconomic indicators.

Methods: Two different sets of data were used in this study: (1) the National Death Registration data from 2003 to 2008; and (2) the National Census in 2005. Variables for individual characteristics were gender, age, residential area and educational level. A geographic deprivation index was calculated based on the Carstairs Index. Multilevel Poisson regression models were used to analyse the relationship between area deprivation levels and injury mortality.

Results: Greater mortality risks of traffic accidents, falls, suicide and all injuries were found in the elderly, the less educated and men, compared with their counterparts. The most deprived districts were at greater risks of death due to traffic accidents (risk ratio (RR)=1.34; 95% CI 1.05 to 1.73), falls (RR=1.63; 95% CI 1.20 to 2.20), suicide (RR=1.09; 95% CI 1.01 to 1.17) and all injuries (RR=1.14; 95% CI 1.07 to 1.22) compared with the least deprived districts, even after individual level socioeconomic variables were controlled for. However, area level deprivation did not show cross level interactions with the individual level education in estimating fatal injury risks.

Conclusions: Both contextual and compositional effects of socioeconomic status on injury mortality among urban areas in South Korea should be considered in allocating resources for injury prevention.