Age-specific education and income gradients in morbidity and mortality in a Canadian province

Abstract

While important age-related trends in the use of health care services over the past two decades in Canada have been well described, a comprehensive description of socioeconomic gradients in morbidity and mortality across age cohorts for a representative population has not been accomplished to date in Canada. The objective of this study was to describe age-specific socioeconomic differentials in mortality and morbidity for a representative sample of a single Canadian province. The study sample was formed from the linkage of individual respondent records in the 1986 census to vital statistics records and comprehensive records of health care utilization for a 5% sample of residents of the province of Manitoba. Using two measures of socioeconomic status derived from census responses, attained education and household income, individuals were stratified into age-specific quartile ranks. Based on diagnostic information contained on health care utilization records, the proportion of the sample in treatment during a 12-month observation period was calculated for 15 broadly defined categories of morbidity and tested for differences across socioeconomic quartiles. Mortality was inversely associated with both income and education quartile rank. In the analysis of morbidity, no association between socioeconomic status and treatment prevalence was observed in the majority, no association between socioeconomic status and treatment prevalence was observed in the majority of the 122 age- and disorder-specific strata tested. Of the observed associations, however, negative relationships were dominant, indicating a higher treatment prevalence among individuals of lower attained education or lower household income. Across the age course, negative relationships were most frequently present among young and middle aged adults, those aged 30-64, and were more consistently found for income than for education. The general findings of this study of a representative Canadian population support observations from other developed country settings that socioeconomic differences in relative rates of mortality and morbidity over the life course are greatest in the adult years.