Socioeconomic disadvantage and disease-specific mortality in Asia: systematic review with meta-analysis of population-based cohort studies

Background That socioeconomic deprivation has shown a correlation with disease-specific mortality in Western societies is well documented. However, it is unclear whether these findings are also apparent in Asian societies. Accordingly, we conducted the first systematic review and meta-analysis of studies from Asia that have reported on the association between socioeconomic position and adult mortality risk. Methods Relevant studies were identified through an electronic search of databases. Studies were included if they had published quantitative estimates of the association between socioeconomic status (SES) and mortality in a general population-based sample. The pooled multiple-adjusted relative risks for mortality in the lowest SES group relative to the highest SES group were studied. Random effects meta-analyses were computed. Results A total of 29 cohort studies from 10 Asian countries were identified, comprising 1 370 023 individuals and 71 818 total deaths. The three markers of SES most widely used (education, income, occupation) were inversely related to mortality outcomes under consideration (all-causes, cardiovascular disease, cancer). For instance, the pooled relative risks of low education compared with high education were: 1.40 (95% CI 1.29 to 1.52) for all-cause mortality, 1.66 (1.23 to 2.25) for cardiovascular mortality and 1.16 (1.07 to 1.27) for cancer mortality. There was some evidence that the age of cohort members at study induction, the gross national product of the country from which the cohort was drawn and geographical region modified the association between SES and mortality. Conclusions Concordant with findings from Western societies, socioeconomic disadvantage is associated with total and cause-specific mortality in Asia.